GENERAL PRACTITIONER EXAM
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Which of the following haematological disorders is inherited as an Autosomal recessive condition?
Thalassemia is an inherited autosomal recessive blood disease. In thalassemia the genetic defect, which could be either mutation or deletion, results in reduced rate of synthesis or no synthesis of one of the globin chains that make up hemoglobin. This can cause the formation of abnormal hemoglobin molecules, thus causing anemia, the characteristic presenting symptom of the thalassemias.
Anti-thrombin 3 (AT3) is a plasma inhibitor protein that blocks the enzymatic activity of some serrin proteases coagulation factors. The activity is synthesised by the liver, is not vitamin K dependent, and can be consumed during disseminated intravascular coagulation (DIC).
Normal newborns have reduced activity. Congenital AT3 deficiency is an autosomal dominant. Treatment of thrombotic in these events in these patients may be difficult. Protein C is an inhibitor that once activated inhibits clot formation and enhances fibrinolysis. It is liver synthesised and vitamin K dependent. Protein C is converted to an active enzyme by a thrombin-thrombomodulin complex on the endothelial cell surface. Activated protein C inhibits a plasminogen activator inhibitor, which results in enhanced fibrinlysis and, with protein S as a co-factor, inhibits the clotting of the activated factors 5 and 8 by limited proteolosis.
Activated protein thus controls the conversion of factor 10 to 10a and Prothrombin to thrombin.
Congenital deficiency is an autosomal dominant trait. Acquired Glucose-6-phosphate dehydrogenase deficiency is the most important disease of the pentose phosphate pathway, and is responsible for two clinical syndromes:
The level of cellular telomerase activity will affect:
The telomere is a DNA sequence at the end of each chromosome which becomes progressively shorter with each division the cell undergoes. When it is reduced to a critical length the cell is not capable of dividing, the enzyme telomerase is able to lengthen the telomere thus preventing this occurring.
A 17-year-old female patient is referred with primary amenorrhoea. Investigations reveal a 46 XY karyotype. Which of the following concerning the condition is true?
which of the following disorders is characterised by an Autosomal dominant mode of inheritance?
All the others are autosomal recessive of course
A 19-year-old attending the A+E department is noted to have central cyanosis. She is perfectly well but was told to go to A+E by her friends who said she looked blue. What is the most likely cause?
A 77 year old man lives alone. He is a smoker and has a typical tea and toast diet. He presents with bleeding gums and loose teeth. The most likely reason is which of the following?
Vitamin C (ascorbic acid) is essential for the formation, growth, and repair of bone, skin, and connective tissue (which binds other tissues and organs together and includes tendons, ligaments, and blood vessels). Vitamin C helps maintain healthy teeth and gums. It helps the body absorb iron, which is needed to make red blood cells. Vitamin C also helps burns and wounds heal. In adults, vitamin C deficiency usually results from a diet low in vitamin C. For example, vitamin C deficiency may result from diet deficient in fresh fruits and vegetables. Also, cooking can destroy some of the vitamin C in food. Pregnancy, breastfeeding, disorders that cause a high fever or inflammation, surgery, and burns can significantly increase the body´s requirements for vitamin C and the risk of vitamin C deficiency. Smoking increases the vitamin C requirement by 30%. Incidence also peaks in elderly populations, who sometimes have “tea and toast” diets deficient in vitamin C.
Which of the following is false regarding fibroadenoma of the breast?
The most effective means of preventing viral hepatitis in a physician is
The greatest advance in prevention of hepatitis B has been the development of an effective vaccine which imparts immunity to close to 100% of those vaccinated. Following universal precautions and treatment with immune serum globulin enriched with anti-hepatitis B globulins can decrease the risk of hepatitis B transmission. Bleach is recommended as an irrigant following needle sticks. Unenriched immune serum globulin is only effective against hepatitis A.
A 28 year old woman with a long history of type 1 diabetes becomes pregnant. She has difficulty controlling her blood glucose during pregnancy and she gives birth to a baby who dies in the first week of life. Autopsy of the baby reveals a severe cardiac malformation. The most likely pathogenesis of the diagnosis is
Maternal diabetes is best known for causing large but immature-age babies. There is also a specific association between maternal diabetes and transposition of the great vessels which is caused by failure of the AP septum to twist. In transposition of the great vessels, the aorta takes off from the anterior part of the right ventricle and the pulmonary trunk takes of from the posterior part of the left ventricle. This produces a complete separation of the systemic and pulmonary circulations. Without surgical correction most affected infants die within the first months of life, although a patent ductus arteriosus, patent foramen ovale, or ventricular septal defect may allow enough mixing of blood to temporarily sustain life. Associate atrial septal defect (choice D) with Down syndrome. There is an incomplete septum between the ventricles and the atria due to the endocardial cushion defect. It is a major prognostic factor for survival in children with Down syndrome. Associate Ectopic ductal tissue (choice A) with coarctation of the aorta. Tetralogy of Fallot consists of a ventricular septal defect, an overriding aorta, pulmonic stenosis, and right ventricular hypertrophy. Itis the most common cause of early cyanosis and is caused by failure of the AP septum to align (choice B). Failure of neural crest cells to migrate (choice E) is endocardial cushion defect, common in Down syndrome.
Which of the following is NOT included in the HACEK group?
Eikenella corrodens is the other member of the HACEK group (the “E” in HACEK), which comprises a group of fastidious Gram- negative bacteria. Enterococcus is not part of the group. HACEK organisms can cause a subacute bacterial endocarditis. IV drug abusers and individuals with prosthetic valves are more at risk for HACEK infection.
Ovarian carcinoma is associated with an elevated CA-125 level is
CA-125 may be elevated in ovarian epithelial tumors, such as a cystadenocarcinoma. AFP can be elevated with either an endodermal sinus tumor or embryonal carcinoma. An elevated hCG can be seen with choriocarcinomas. Sertoli-Leydig and granulosa-theca cell tumors do not usually produce an elevated CA- 125, AFP, or hCG level.
A male aged 55 years was hospitalized for pneumonia. He was started on broad spectrum antibiotics for 14 days. He developed diarrhea, fever, and crampy abdominal pain after treatment. The most likely diagnosis is
Pseudomembranous colitis shows up as yellow and yellow white adherent plaques on colonoscopy, and it is caused by the Clostridium difficile cytotoxin. It is almost always associated with antibiotic use, and it can be treated with oral vancomycin or metronidazole. Diverticulitis is an inflammation of the colon and is treated with antibiotics, not caused by antibiotics. Colon cancer is indolent in nature and would usually present with bleeding, not diarrhea. Laxative abuse is associated with a syndrome called melanosis coli, and the colon is hyperpigmented in appearance. Familial polyposis is an autosomal dominant disease associated with multiple colon polyps and a high risk of colon cancer.
A 44 year old man who usually drinks a fifth of Scotch a day develops paresthesias in a stocking glove distribution. What is the most likely cause of this neuropathy?
Alcoholics often develop folate deficiency, and this is most commonly manifested by a stocking glove peripheral neuropathy Mononeuritis multiplex is an inflammatory condition of nerves, often associated with an autoimmune process. Vasculitis can produce inflammation of the vasa nervorum, resulting in isolated areas of neuritis. Iron deficiency is not responsible for paresthesias. Diabetes can cause a similar peripheral neuropathy, but would not be the most likely etiology for this patient´s symptoms.
A 45 years old man presents with skin lesions. On examination a bullous eruption of the skin on the face and extremities of the patient is revealed. Which of the following condition may NOT contribute to this clinical presentation?
By which one of the following chronic manifestations of Lyme disease may NOT be accounted for?
The initial manifestation of Lyme borreliosis is the characteristic skin lesion, erythema migrans. Several days to weeks later, the organism disseminates hematogenously. Immediately following infection, there is only a minimal mononuclear response to Borrelia burgdorferi antigens. Several weeks later, there is a heightened mononuclear cell response to these same antigens. Specific IgM antibody titers peak three to six weeks following infection, but IgG specific antibodies peak only after many months or even years. Maternal fetal transmission is very uncommon. Three genomic subgroups of Borrelia burgdorferi have been identified. The differences in these subgroups probably account for clinical variations in disease presentations
Which one of the following is the only form of the malaria parasite capable of infecting erythrocytes?
Which one of the following describes a hydatidiform mole?
A 35 year old man develops pulmonary hemorrhage and glomerulonephritis. Lung biopsy with immunofluorescence shows IgG deposition along the basement membrane. These antibodies are directed against a type of collagen that is also characteristically found in which structure of the body?
The disease described is Goodpasture syndrome, in which autoantibodies to basement membrane proteins cause damage to the lungs and kidneys. Pulmonary hemorrhage (especially in smokers) and rapidly progressive glomerulonephritis are common. The characteristic autoantibody present is directed against type IV collagen, a component of the basement membrane, also found in the lens of the eye. Type X collagen is found in epiphyseal plates. Type I collagen is found in bone skin tendon dentin fascia and late wound repair. Type Ill collagen is found in skin blood vessels uterus, fetal tissue and granulation tissue. Type II collagen is found in cartilage (including hyaline cartilage), the vitreous body of the eye, and the nucleus pulposus of the intervertebral disks.
A 6 months girl who was normal at birth begins to show signs of motor retardation. Although she could sit up at 5 months she can no longer do so. She continues to deteriorate and eventually becomes unresponsive to visual or auditory stimuli. Funduscopic examination reveals a cherry red spot. The genetic abnormality that is most often related to the development of this disease is
Most cases of Tay Sachs produces a frameshift mutation, resulting in the creation of a premature stop codon downstream from the inserted nucleotides. The disease presents as described in the question and is more common in Ashkenazi Jews. The carrier rate in this population is 1 in 25. There is currently no effective treatment, and survival beyond 4 years of age is rare. Confined placental mosaicism is caused by a genetic aberration (e.g., a trisomy), occurring in the trophoblast or extraembryonic progenitor cells in the inner cell mass of the embryo. This leads to abnormal placental development and intrauterine growth retardation. However, no embryologic mutation or abnormality is present. Expansion of tandem nucleotide repeats is thought to be etiologically involved in fragile X syndrome and Huntington disease. The latter is a devastating neurologic disease that typically affects individuals in the 4th and 5th decades of life, prior to which they are completely normal. The former is an X-linked disorder and is thus much more common in males. The neurologic deterioration is not as dramatic as in Tay Sachs. Fragile X patients reach early developmental milestones, after which they experience declining 10 with increasing age, autistic like behavior, and aggressive tendencies. Motor deficits are not prominent in this disease. Non-disjunction during meiosis is a common cause of trisomy, e.g., trisomy 21, or Down syndrome. Down syndrome children have very characteristic features, including up-slanting palpebral fissures, bilateral epicanthal folds, a hypoplastic nasal bone, and a flat nasal bridge. They are generally cheerful in affect. There is no progressive decline in these children; the mental retardation is consistent from birth. Translocations are frequently involved in leukemias, lymphomas, and solid tumors. A minority of cases of Down syndrome are actually due to a translocation rather than to trisomy.
A 32 year old male with a history of intravenous drug abuse presents with a large abscess on his arm. On histologic section of the abscess, many of the observed neutrophils show nuclear fragmentation. The phenomenon most likely occurring is
Karyorrhexis refers to a pattern of nuclear degradation in which a pyknotic or partially pyknotic nucleus undergoes fragmentation followed by complete lysis. This pattern is common in the neutrophils present in acute inflammation. The type of necrosis seen in an abscess is liquefactive necrosis. Liquefactive necrosis can be seen in some bacterial infections, especially those caused by pyogenic Staphylococci, Streptococci, or certain coliform bacteria; these bacteria are associated with the formation of abscess. Caseous necrosis is seen in tuberculosis and some other granulomatous diseases; coagulative necrosis is seen following infarctions of many organs (other than the brain). Karyolysis is also a degenerative change affecting nuclei. In this case, however, it is seen as a decrease in nuclear basophilial which is presumably the result of DNAse activity. Mitosis does not occur in neutrophils at a site of inflammation. Mitosis, or somatic cell division, follows a well characterized sequence of events resulting in two daughter cells.
An AIDS patient has had severe diarrhea with fluid losses of over 5 liters per day for several months. Acid fast oocysts are present on sugar flotation stool concentration. By which mechanism the most likely causative agent causes diarrhea?
The figure shows the genome of a strain of bacterium with resistance to multiple antibiotics. The loci encoding these resistances are shown. “IS” is the attachment site for a temperate phage. Which of the following resistance genes is most likely to be transferred by specialized transduction?
Specialized transduction is a mechanism of transfer of DNA that involves an accident in the life cycle of a temperate (lysogenic) phage. In cases in which lysogeny is terminated by the destruction of the viral repressor gene, errors of excision of the phage DNA out of the chromosome can cause transfer of bacterial DNA to another cell. The genes that are most likely to be transferred in this way are those that are closest to the insertion site of the phage. In this diagram, the drug resistance gene to “iS” is the sulfonamide resistance gene. Ciprofloxacin resistance is the gene located closest to oriT on this genetic map, so it is the gene that is most likely to be transferred during conjugation of this cell (an Hfr cell) with an F- cell.
Clindamycin resistance is the gene located downstream from the ciprofloxacin resistance gene, so it could be transferred in the Hfr to F- conjugation but it is drawn as being a long way away from oriT, so it is not as likely to be transferred in this way. Gentamicin resistance is the gene found on the other side of the insertion sequence for the phage, so it could be transferred by specialized transduction, but because it is shown as being farther away from “iS” than the sulfonamide resistance gene, it is not as likely to be transferred in this way. Vancomycin resistance is the gene located between oriT and tra. It is unlikely to be transferred during conjugation (that transfer could occur with ciprofloxacin resistance or clindamycin resistance, in that order). It is also unlikely that it would be transferred by, specialized transduction because it is at such a great genetic distance from the viral insertion sequence.
Testicle lump removed from a 20 year old man shows a non-encapsulated, yellow mucinous mass with endodermal sinuses apparent microscopically. He is advised a routine follow up examination to assess for recurrence or metastasis. The tumor marker most appropriate for this purpose is
An elderly critically ill male patient undergoes abdominal CT scan. Bilateral adrenal enlargement due to hemorrhage is found. Adrenocortical assessment reveals primary adrenal insufficiency. What would further lab testing reveal?
Primary adrenal insufficiency occurs when the adrenal glands fail to produce adequate cortisol. Cortisol secretion is normally stimulated by ACTH release from the anterior pituitary. Once cortisol is released, it feeds back to the pituitary to inhibit further ACTH secretion. Therefore, if cortisol secretion was impaired, ACTH levels would be elevated rather than reduced.
Elevated cortisol does not occur in adrenal insufficiency. Instead, cortisol secretion would be decreased. Epinephrine is released by the adrenal medulla and could be reduced by adrenal insufficiency rather than increased by it. CRH is released by the hypothalamus and acts on the anterior pituitary to stimulate the secretion of ACTH from the anterior pituitary. It is inhibited when cortisol feeds back to turn off its production in the hypothalamus. Therefore CRH levels would be elevated in the absence of cortisol rather than decreased.
A 46 year old female with a 10 lb weight gain over the past six months has been tired lately. Exam reveals BP of 90/60 mmHg, heart rate of 55/min, and temperature of 35°C (95.0°F). Her reflexes are sluggish. Thyroid is enlarged but non-tender. Serum T4 is 5.5µg/dL and serum TSH is 8µU/mL. Antimicrosomal antibodies are present. What is the likely diagnosis?
Hashimoto thyroiditis is an autoimmune disorder in which antibodies directed against various thyroid components (e.g. thyroid peroxidase) are inappropriately produced. These antibodies are commonly called “microsomal” antibodies because thyroid peroxidase appears in the microsomal fraction of follicular cells. Other potential antibodies include anti-thyroglobulin antibodies and thyroid receptor inhibiting antibodies. The autoimmune reaction results in lymphocytic infiltration of the thyroid gland potentially destroying the normal thyroid architecture. Early in the disease serum T4 may remain within the low-normal range because the increased TSH can cause thyroid enlargement, helping to maintain adequate hormone secretion. However, as the disease progresses thyroid gland failure results in frank hypothyroidism. Graves disease is also an autoimmune disorder. However, in this case, the antibodies (thyroid stimulating immunoglobulins) are TSH receptor-stimulating antibodies. This results in excessive thyroid hormone secretion and hyperthyroid (not hypothyroid) symptoms. Serum levels of TSH are usually undetectable because of feedback suppression by the elevated T4. Secondary hypothyroidism occurs because of decreased TSH secretion by the anterior pituitary. The increased serum TSH in this patient rules out secondary hypothyroidism. Tertiary hypothyroidism which is due to decreased TPH secretion by the hypothalamus also results in decreased (not increased) serum TSH. Toxic adenoma can produce a nodular goiter but is associated with excessive T4 secretion and hyperthyroidism. Serum TSH levels are suppressed due to the negative feedback effects of the T4 at the pituitary and hypothalamus.
An African male aged 40 years presents with severe abdominal pain. He has sickle cell anemia and has had many episodes of this type of pain in his abdomen as well as his extremities. He is hydrated and given analgesics. Which organ is likely functionally and structurally atrophic in this patient?
In patients with chronic sickle cell disease, serial infarctions cause the spleen to become an atrophic vestige after a few years. The spleen receives its blood supply from a single source, and this lack of collateral circulation makes it prone to infarction from sickle cell disease. Patients become functionally asplenic, and are rendered susceptible to infection by encapsulated organisms. Pneumococcal vaccination is indicated. Colon is not involved in sickle cell disease. The liver is incorrect. Patients with sickle cell disease tend to have hepatomegaly, and gallstones are common. Portal vein is uninvolved in sickle cell disease. The stomach is not involved in sickle-cell disease.
A tall man with gynecomastia and testicular atrophy has a testicular biopsy that shows sparse, completely hyalinized seminiferous tubules with a complete absence of germ cells and only rare Sertoli cells. Leydig cells are present in large clumps between the hyalinized tubules. Which genetic disorder should be suspected?
The testicular changes described are those observed in Klinefelter syndrome, most often due to 47, XXY genetics. Testicular feminization syndrome is due to a genetically determined unresponsiveness to testosterone that produces a phenotypic female in an individual with 46, XY chromosomes. Trisomy 18 is Edwards syndrome, characterized by facial features that are small and delicate. Trisomy 21 is Down syndrome, the most common trisomy. Characteristics include oblique palpebral fissures, epicanthal folds, endocardial cushion defects, simian creases, and a high-arched palate, among other anomalies. Turner syndrome, 45, XO, produces a sterile but phenotypic female of short stature with webbing of the neck.
A previously healthy 48 year old male presents with lower back pain from a vertebral collapse due to osteoporosis. Which investigation would be the most appropriate for him?
Osteoporosis in a young male would be unusual. Any symptoms or features of hypogonadism or hypercalcaemia should be elicited. Hyperprolactinaemia cause hypogonadism would need to be present for a considerable amount of time before producing osteoporosis. Prostate malignancy does not cause osteoporosis.
Out of the following, which one is associated with congenital adrenal hyperplasia (CAH)
A male aged 68 years presents with tiredness and dyspnoea and is diagnosed with acute myeloid leukaemia. The most important prognostic factor is which one of the following?
Options A, C, and D have no prognostic value. White cell count at diagnosis is however important, but most important is the karyotype of bone marrow, as this result stratifies patients into lower risk, standard risk and poor risk, which has prognostic significance.
Two months ago,a 62-year-old female received a prosthetic valve replacement for mitral regurgitation. She presents with low grade fever, dyspnoea and fatigue. Echocardiography shows vegetations. Which of the following is responsible?
S. epidermidis causes biofilms to grow on plastic devices placed within the body. This occurs most commonly on intravenous catheters and on medical prostheses. Generally there are two identifiable modes of prosthetic valve endocarditis. The first occurs within the first year after surgery affecting 0.7-3% of cases and is often due to staphylococci.
Late endocarditis observed after two years post surgery is found in 0.5 – 1% of cases and is typically due to streptococci -typically alpha haemolytic otherwise known as Streptococcus viridans.
Lipoprotein lipase deficiency is associated with:
Lipoprotein lipase deficiency is autosomal recessive and associated with increased chylomicrons and marked hypertriglyceridaemia.
A 34-year-old smoker is diagnosed with a vasculitis. Serum p-ANCA is raised along fibrinoid necrosis of small arteries. Which one of the following represents the most likely diagnosis?
Classic polyarteritis nodosa is a vasculitis associated with involvement of small arteries and p-ANCA antibodies. While smoking is associated with thromboangiitis obliterans (Buerger´s Disease), it is not associated with an increase in autoantibodies. Wegener´s granulomatosis is known to be associated with c-ANCA autoantibodies. The presence of c-ANCA antibodies is highly suggestive of a diagnosis of Wegener´s granulomatosis. Temporal and Takayasu´s arteritis are not associated with autoantibodies.
Which one of the following forms of transmission is NOT commonly associated with the spread of hepatitis B?
| A tall male with gynecomastia and testicular atrophy has a testicular biopsy that shows sparse, completely hyalinized seminiferous tubules with a complete absence of germ cells and only rare sertoli cells. Leydig cells are present in large clumps between the hyalinized tubules. The genetic disorder suspected in this patient is | ||
The testicular changes described are those observed in Klinefelter syndrome, most often due to 47,XXY (genetics. One in 11000 male births have this abnormality, and there is an increased incidence with increased maternal age; in 60% of cases, the extra X is of maternal origin. The males are typically infertile with small testes, a small penis, and low testosterone levels. Affected individuals have a eunuchoid body shape with long extremities. Almost 50% of these patients have eunuchoid. Other, less common findings include diabetes mellitus, scoliosis, and mild mental retardation.
Testicular feminization syndrome (choice A) is due to a genetically determined unresponsiveness to testosterone caused by abnormalities in androgen receptors, producing a phenotypic female in an individual with 46, XY chromosomes.
Trisomy 18 (choice B) is Edwards syndrome, characterized by mental retardation, micrognathia, delicate facial features low-set ears, cardiac defects, renal defects, and rocker- bottom feet. Survival is rare beyond 1 year.
Trisomy 21 (choice C) or Down syndrome is the most common trisomy. Characteristics include oblique palpebral fissures, epicanthal folds endocardial cushion defects, simian creases, and high-arched palate, among other anomalies. Most patients have mental retardation.
Turner syndrome, 45.XO (choice D) produces a sterile but phenotypic female individual of short stature with webbing of the neck.
A 59 year old woman has a 30 years, 2pack/day history of cigarette smoking. She undergoes bronchoscopy. Bronchial tissue biopsy shows replacement of the normal pseudostratified ciliated columnar epithelium with stratified squamous epithelium. The above mentioned histological change is also seen in which of the following?
Squamous metaplasia is a frequent airway response to chronic irritation from cigarette smoking. It represents the replacement of one differentiated tissue with another mature differentiated tissue; this is to protect itself, to prevent the continuous harmful exposure, and to try to minimize or avoid further damage. It is believed that the squamous epithelium is more resistant to injurious agents, and so represents an adaptive response. Similarly, Barrett esophagus is the metaplasia of distal esophageal squamous epithelium to either gastric or intestinal epithelium in response to chronic reflux disease. Atypical ductal hyperplasia of the breast is a form of dysplasia characterized by pleomorphism (the individual cells may vary widely in appearance) rather than by replacement with another mature epithelium (squamous). Benign prostatic hyperplasia is under the category of hyperplasia, referring to growth of a tissue or organ by cellular proliferation. Hyperplasia is considered to be a physiologic response to a specific stimulus, and the cells of a hyperplastic growth remain subject to normal regulatory control mechanisms. This stands in contrast to neoplasia, in which abnormal cells proliferate in a nonphysiologic manner and do not respond to the normal stimuli. Colonic adenocarcinoma represents malignant transformation, the multistep process by which normal cells progress to the “cancer” phenotype. Metaplasia is not malignant transformation, although the stimuli producing metaplasia may also be associated with the development of malignancy. Post-myocardial infarction fibrosis represents the category of necrosis and repair resulting in re-epithelialization and / or fibrosis, not metaplasia.
FALSE statement regarding infection resulting from B. anthracis is
Bacillus anthracis causes cutaneous, inhalation, and gastrointestinal anthrax. The cutaneous form accounts for more than 95% of cases. Humans are infected when spores of the organism are introduced into the body by contact with infected animals or by contaminated animal products. Virulence of the organism is determined by both a plasmid mediated group of exotoxins, known as plasmid pX01, and another plasmid mediated antiphagocytic polydiglutamic acid capsule, known as plasmid pX02. Both plasmids appear to be necessary for virulence. Anthrax toxin consists of three proteins, known as protective antigen (PA), edema factor (EF), and lethal factor (LF). The larger PA fragment on the cell surface serves as a specific receptor that mediates entry of EF or LF into target cells. The combination of PA and EF decreases polymorphonuclear neutrophil function and causes local edema. The combination of PA and LF may produce death in an hour.
A 33 year old HIV positive male presents with sudden onset of right sided hemiplegia. Brain CT scan with contrast reveals a ring enhancing lesion in the left parietal lobe. CMV antibody is positive. The most likely diagnosis is
CNS toxoplasmosis infection is the most common cause of a ring-enhancing lesion in the brain of an AIDS patient. Five percent of patients will not have a positive toxoplasmosis anti- body titer in the serum. A focal neurologic deficit is the most common initial presentation. Cryptococcal meningitis presents with nuchal rigidity, fever, and photophobia. It would not present as a ring enhancing lesion. Tuberculoma would be rare unless other signs of tuberculosis are present. Cerebral infarct would not be common in someone this young. Hodgkin´s lymphoma usually spreads to the hilar and retro peritoneal lymph nodes. CNS non Hodgkin´s lymphoma occurs in 25% of AIDS patients with a ring enhancing lesion in the brain.
A diabetic male aged 56 years presents with symptoms of intermittent claudication of the buttocks and thighs. He also complained of impotence. On examination this patient had signs of peripheral vascular disease. His femoral pulses were not palpable. The most likely diagnosis is
All of the following are considered as risk factors for coronary artery disease, EXCEPT
Some studies have suggested that minimal consumption of alcohol might actually be beneficial in reducing atherosclerosis. Cigarette smoking, hypertension, elevated serum cholesterol levels, and a family history of coronary artery disease are all well described risk factors
A male aged 58 years is diagnosed with Wegener´s granulomatosis. LEAST likely finding in this patient is which one of the following?
Wegener´s granulomatosis is an immune disorder associated with abnormal production of c-ANCA autoantibodies. The vasculitis typically affects small and medium sized vessels. However, there is often an accompanying necrotizing glomerulonephritis and necrotizing granuloma formation in the upper respiratory tract. The therapy for Wegener´s granulomatosis is immunosuppression. “Palpable purpura” is associated with hypersensitivity angiitis.
A 32 year old female searches a new boyfriend. Several weeks later, a week after her menstrual period the woman develops a painful, swollen right knee. Organism responsible for this has which of the following characteristics?
The causative organism is Neisseria gonorrhoeae, which is a sexually transmitted gram negative coccus. It is estimated that N. gonorrhoeae may express over one million variants of pili, resulting in the virtual absence of immunity to re-infection with this agent. The pili of this organism also are protective against phagocytosis and mediate attachment to the mucosal surfaces. The organism is the most common cause of septic arthritis in otherwise healthy, sexually active adults. The treatment is usually with ceftriaxone. The chlamydiae are intracellular organisms that cannot make ATP and do not usually cause septic arthritis. Having both hyphae and spores would be true of Candida, which usually causes arthritis as a rare complication of systemic candidiasis in immunocompromised patients.
Mycoplasma do not have true cell walls and do not usually cause septic arthritis.
Syphilis is caused by a spirochete that is visible only with dark field microscopy or direct fluorescent antibody. Secondary syphilis can (uncommonly) cause an acute arthritis, but the interval between acquiring the infection and developing the arthritis is usually months to years.
What tumor marker is most likely to be elevated in pheochromocytoma
Urine metanephrine testing is primarily used to help detect and rule out pheochromocytomas in symptomatic patients. It may also be ordered to help monitor the effectiveness of treatment when a pheochromocytoma is discovered and removed and to monitor for recurrence. The alpha-fetoprotein (AFP) tumor marker may be elevated in HCC. Prostate specific antigen (PSA) may rise in prostate carcinoma. CA- 125 can be elevated in ovarian carcinoma. Carcinoembryonic antigen (CEA) may be elevated in colon carcinoma.
A 28 years old female presents with complaints of vaginal bleeding and severe nausea and vomiting. During the pelvic examination, she is found to have an enlarged uterus. She has been trying to get pregnant for the past 15 months, with no success. She is now excited however, because a home pregnancy test was positive. An ultrasound demonstrates a multi-loculated cystic structure within the uterine cavity, but there is no clearly defined embryo. Serum hCG levels are markedly elevated (>100,000 mlU/ml). The mass is removed with dilation and curettage of the uterus after establishing the diagnosis and although placenta like tissue is observed during pathologic examination, fetal tissue is not present. Which of the following karyotypes are revealed on chromosomal examination?
The lesion described is a hydatidiform mole, of which two forms exist, complete and partial. In a complete mole, the karyotype is 46, XX (or, in a few cases, 46, XY). In this form, fetal tissue is not identified. The most common presenting symptom is vaginal bleeding. Serum hCG levels are dramatically increased and the uterus is enlarged. Hyperemesis can occur in patients with complete moles, probably due to the extremely high hCG levels, but is rare in patients with partial moles. The chorionic villi have a characteristic grapelike, multicystic appearance. It is important to note that unlike the partial mole, which very rarely develops into choriocarcinoma, complete moles carry a 2% increased risk for the development of choriocarcinomas.
This represents a postfertilization event with either a diploid or triploid genotype rather than, haploid (choice A). The disease is unrelated to Turner syndrome, XO (choice B)
A complete mole contains the normal number of chromosomes, and does not contain an additional single Y chromosome (choice D)
In a partial hydatidiform mole, fetal tissue is often evident. The conceptus is triploid, with a 69, XXX or 69, XXY karyotype (choice E). Both enlarged and normal villi are present.
A patient with uncontrolled diabetes mellitus and acidosis probably has which one of the following?
A patient with uncontrolled diabetes mellitus and acidosis probably has ketoacidosis. Lactic acidosis is most common in individuals with severe circulatory abnormalities in the absence of other forms of acidosis. Mixed metabolic acidosis and respiratory alkalosis do not present in the setting of uncontrolled diabetes and acidosis. Uncontrolled diabetes causes an anion gap due to ketone bodies, thus making normal anion gap acidosis an incorrect answer. Mixed metabolic acidosis and respiratory acidosis are not associated with uncontrolled diabetes.
By which one of the following chronic manifestations of Lyme disease may NOT be accounted for?
The initial manifestation of Lyme borreliosis is the characteristic skin lesion, erythema migrans. Several days to weeks later, the organism disseminates hematogenously. Immediately following infection, there is only a minimal mononuclear response to Borrelia burgdorferi antigens. Several weeks later, there is a heightened mononuclear cell response to these same antigens. Specific IgM antibody titers peak three to six weeks following infection, but IgG specific antibodies peak only after many months or even years. Maternal fetal transmission is very uncommon. Three genomic subgroups of Borrelia burgdorferi have been identified. The differences in these subgroups probably account for clinical variations in disease presentations.
A 37 year old man presents with severe unilateral flank pain that radiates to the groin. He has a normal serum calcium level and hematuria. Urine pH is below 7.0. The patient is afebrile. No visible opaque stones are present on the IV pyelogram. The most likely diagnosis is
Uric acid stones in the kidneys are the only ones which are radiolucent. They account for 5% of all stones and are secondary to excessive purine intake. The urine pH is usually very low in urate nephrolithasis. Calcium oxalate/carbonate nephrolithiasis is the most common form of kidney stones and accounts for 75% of all kidney stones. These stones are secondary to hypercalcemia and are usually radio opaque. Cystine stones contain sulfur. They are caused by a hereditary defect of amino acid transport in the renal proximal tubules. Struvite stones are secondary to chronic urinary tract infections with urea splitting organisms such as proteus. These stones are composed of ammonium, magnesium, phosphate, and calcium. They sometimes form staghorn calculi which have to be removed surgically. Oxalate stones are rare less than 5% of all kidney stones. They are secondary to ileal resection or bypass.
Kernicterus is developed by deposition which compoung in the basal ganglia?
Accumulation of unconjugated bilirubin in the basal ganglia is responsible for this syndrome of bilirubin encephalopathy. Iron, conjugated bilirubin, biliverdin, and galactosamine are not involved in kernicterus.
Multiple malformation syndromes does NOT include
SLE is not associated with multiple malformation syndromes, while all of the other conditions are.
A patient has intermittent, severe pain in the right upper quadrant of the abdomen, especially after fatty meals. Ultrasound shows multiple small opacities in the gallbladder. A risk factor this patient´s condition is
The patient has gallstones (cholelithiasis). A useful mnemonic to remember the risk factors for gallstones is the 5 F´s: female, fat, fertile, forty, and flatulent. Gallstones are usually composed predominantly of cholesterol with lesser amounts of other components such as calcium salts, bile acids, and bile pigments. Exceptions to this rule are nearly pure cholesterol stones and pigment (calcium bilirubinate) stones. The incidence of mixed stones and cholesterol stones is also increased in association with Crohn disease, cystic fibrosis, clofibrate therapy, estrogen therapy, rapid weight loss, and Native American origin. Risk factors for pigment stones include chronic hemolysis, alcoholic cirrhosis, and biliary infection. The typical age for gallstones is 40 years or older, not 20 years. Female, not male sex predisposes the individual for gallstones. Many patients with gallstones are multiparous (fertile), not nulliparous. Gallstones are associated with obesity (fat), not a thin build
A colony of Neisseria gonorrhoeae is isolated on Thayer Martin medium. Over the course often generations in culture, this strain produces a homogeneous antigenic type of pili. Lysates from a culture of N. gonorrhoeae with a different pilus type are added to the stable colonies. The bacteria are cloned after overnight incubation and their pilus expression is analyzed. A new antigenic form of pilus is new expressed in 50% of the new colonies. These cultures have gone through which one of the following
Biopsy of an ulcerated gastric lesion of a 62 year old smoker shows glands containing cells with enlarged, hyperchromatic nuclei below the muscularis mucosa. Two tripolar mitotic figures are noted. The feature most strongly associated with oncogenesis caused by the most likely organism in this case is
A 29 year old primigravid female in her second trimester of pregnancy presents with urinary frequency and burning. A clean catch specimen of urine is obtained analysis. Ureases positive gram negative bacilli with swarming motility are detected. The proton motive force that generates energy for flagella located in this organism is which one of the following?
Routine examination of a 54 year old male shows fusiform enlargement of the distal fingers, with upward doming of the nail beds. He has long standing emphysema for which he requires oxygen and bronchodilatory therapy. Hand radiograph shows new bone formation beneath the periosteum of the distal phalanges. This is most strongly associated with which disorder?
Enlargement of the distal segments of the fingers and toes due to proliferation of connective tissue is known as clubbing. Clubbing maybe associated with lung cancer, mesothelioma, bronchiectasis, and hepatic cirrhosis. In these conditions, the clubbing is accompanied by formation of new subperiosteal bone (hypertrophic osteoarthropathy or hypertrophic pulmonary osteoarthropathy-HPO). Additionally, this patient has emphysema likely due to smoking, which also causes lung cancer. It is now the subject of vigorous debate whether it is the cancer that actually causes HPO or the emphysema, which is often associated with lung cancer. Either way, when HPO is identified, it is incumbent upon the clinician to look for a potential lung cancer. Chronic renal failure causes renal osteodystrophy, which may manifest s combination of osteitis fibrosa cystica and osteomalacia. This is due to elevated parathyroid hormone, which causes the leaching of bones. Multiple exostoses are sometimes associated with multiple colonic polyps and colon cancer in Gardner syndrome. A variety of endocrine adenomas can be seen in polyostotic fibrous dysplasia. The most well known of these is McCune-Albright syndrome: precocious puberty and polyostotic fibrous dysplasia. Profound anemia can be seen in diseases that destroy the marrow, such as ac osteopetrosis, mastocytosis, myelofibrosis, lymphoma, or leukemia.
The peritoneal mesentery of a patient with cancer shows carcinomatosis from cancer spread within the abdominal cavity. The innumerable nodules are composed of metastatic neoplasm. Which tumor is most likely to give rise to this condition?
Peritoneal carcinomatosis develops from transcoelomic spread of cancers located within the abdominal cavity. Ovarian carcinoma is the most common source of this neoplastic spread, but other cancers such as carcinoma of the colon, may produce a similar picture. Bronchogenic carcinoma may metastasize anywhere in the body but it usually produces metastatic nodules within solid organs. Carcinoid tumor may develop at any site along the gastrointestinal tract, most frequently in the appendix or ileum. It metastasizes to the liver and not to the peritoneum. Glioblastoma multiforme (GBM) is the most frequent malignant primary brain tumor. It is composed of highly anaplastic astrocytes. It does not metastasize outside the central nervous system, although rare cases have been reported of GBM spreading to the peritoneal cavity through ventriculoperitoneal shunts. Hepatocellular carcinoma usually arises in cirrhotic livers or livers harboring hepatitis B virus. It invades the hepatic vein system and spreads first to the lungs.
A child aged 7 months has a 4-day history of fever, deepening cough, and dyspnea. CXR shows multiple interstitial infiltrates and hyperinflation of the lungs. Multinucleated giant cells with cytoplasmic inclusion bodies are seen when a nasal wash is inoculated into tissue culture. The most appropriate therapy is
Ribavirin is an antiviral drug approved for the treatment of severe respiratory syncytial virus infection, the most common cause of pneumonia and bronchiolitis in children younger than 1 year. It should be given by aerosol. Acyclovir is a guanosine analog that is useful for the treatment of primary and recurrent herpes infections and herpes simplex virus encephalitis. Ganciclovir is a guanosine analog used in the treatment of cytomegalovirus retinitis and cytomegalovirus infections in AIDS patients. Trifluorothymidine is a thymidine analog used topically for the treatment of recurrent epithelial keratitis and primary keratoconjunctivitis due to herpes simplex viruses. Zidovudine is a thymidine analog that inhibits reverse transcriptase. It is active against human retroviruses, including HIV-1, HIV-2, and HTLV-I.
| An African boy develops massive unilateral enlargement of his lower face in the vicinity of the mandible. Biopsy reveals sheets of medium sized blast cells with admixed larger macrophages. This type of tumor has been associated with which one of the following? | ||
The patient has Burkitt lymphoma. This high grade B cell lymphoma occurs endemically in Africa (it is the most common neoplasm in children in an equatorial belt that includes Africa and New Guinea) and sporadically in the U.S. and Europe. The sporadic form is often in an abdominal site and occurs in young adults. The African form of Burkitt lymphoma has been strongly associated with antibodies directed against Epstein Barr virus; the association is weaker in sporadic cases. A characteristic translocation,
t(8;14) (q24.13;q32.33) has been described. Malaria infection is a cofactor.
Hepatitis B is associated with hepatocellular carcinoma. t(9;22) is the Philadelphia chromosome, which is seen in some cases of chronic myelogenous leukemia (CML) and acute myelogenous leukemia (AML). Herpesvirus type 8 is associated with Kaposi sarcoma. CD5 is a marker seen in small lymphocytic and mantle cell lymphomas. HIV is linked to AIDS. Some patients also develop primary lymphomas (not usually Burkitt). CD4 is a marker for helper T cells and some T cell lymphomas. Human papillomavirus is linked with common warts, genital condylomata, and genital cancers. t(2;5) is linked to anaplastic large cell lymphoma.
A 54 year old nonsmoker and non-alcoholic woman presents with fatigue. She has been weak and tired for the past few months and has lately been feeling palpitations. CBC shows a normochromic anemia with no reticulocytes. RBC morphology is normal. Platelets and myeloid cells are unaffected. Bone marrow biopsy is normocellular and is significant for a lack of erythroid precursors, but all other elements are normal. She should be further evaluated for which condition?
In the rare pure red cell aplasia, the erythroid marrow elements are absent or nearly absent, while granulopoiesis and thrombopoiesis remain unaltered. This condition occurs in both primary and secondary forms, both of which are thought to be related to autoimmune destruction of erythroid precursors. There is a relatively weak general association between cancers and red cell aphasia, which is probably due to triggering of autoimmune disease by the cancers. In addition, be aware that there is a specific association between thymic tumors (thymoma) and autoimmune hematologic diseases, specifically pure red cell aplasia. This association is strong enough that a patient with pure red cell aplasia should be specifically evaluated for thymoma. The other answer choices are distracters with no specific association with red cell aplasia, although cancer in general can be a predisposing factor.
An 18 year old girl presents for examination. She admits that she is afraid that she will get cancer, as her mother suffered from cervical cancer. According to her physician there are certain risk factors over which she has some control. Which is a risk factor for carcinoma of the cervix?
The risk for cervical carcinoma include: young age at first coitus, human papillomavirus infection, multiple sexual partners, smoking, and multiparity. Aromatic amine exposure is a risk factor for transitional cell carcinoma of the bladder. Other risk factors for this carcinoma include: smoking, schistosomiasis, and employment in the trucking or petroleum industries. A high fat diet is a risk factor for colorectal adenocarcinoma. Other risk factors include: low fiber diet, family history of colon carcinoma, inflammatory bowel disease, and obesity. A high-fiber diet is not a risk factor for cervical cancer. Nulliparity is protective for cervical carcinoma. Nulliparity, however, is a risk factor for breast cancer.
A 3 day old full term male child born by cesarean section has not passed meconium since birth. He weighed 3.2 kg at birth and had normal Apgar scores. Formula feeding was started, which was tolerated without vomiting. He passed urine shortly after birth. On exam, he is not distressed, there are no dysmorphic features, and abdomen exam is normal. Perineum exam reveals normal genitalia and a normally placed anal atresia. The most likely cause for his constipation is
An infant who has not passed meconium for over 48 hours should be investigated for intestinal obstruction. Normal full-term infants will pass meconium by 36 hours, and most will do so within the first 24 hours. Hirschsprung disease is caused by absence of ganglion cells in the bowel wall, starting from the internal anal sphincter and extending proximally for a variable length of the bowel. It is the most common cause of lower intestinal obstruction in the newborn period and more commonly affects males. Diagnosis is based upon radiographic evidence and rectal suction biopsy, which demonstrates absence of ganglion cells. Anal atresia can also present similar to Hirschsprung disease in the newborn period but can be detected during the newborn examination when an ectopic or absence of anal opening can be detected. Newborns with duodenal atresia or pyloric stenosis typically present with vomiting as the predominant symptom. Vomiting starts soon after birth in duodenal atresia, whereas patients with pyloric stenosis often present in the second or third week of life. Meckel diverticulum, which occurs in 2 to 3% of all infants, can present with lower gastrointestinal tract bleeding or bowel obstruction due to intussusception. The symptoms, however, typically start in the first decade of life, and the disorder does not present at birth.
A 66 year old smoker and alcoholic male has poor appetite and difficulty swallowing both solid and liquid foods over the course of the past 4 months. He has lost 20 lb and occasionally vomits blood. A mass is detected in esophagus and is biopsied. The most likely histologic appearance of the biopsy would be
The most common esophageal cancer is squamous cell in origin (although the incidence of adenocarcinoma is rising). Recall that the esophageal mucosa consists of stratified, nonkeratinized, squamous epithelium. Smoking and alcohol increase the risk for the development of esophageal squamous cell carcinoma. Suspect cancer when there are signs like rapid weight loss in a short period of time and symptoms such as dysphagia, hematemesis, and anorexia. Glandular epithelium is associated with adenocarcinoma, which is often associated with Barrett´s esophagus. This is not as common as squamous cell carcinoma, especially in smokers. A mesenchymal tumor is a sarcoma. A teratoma can be derived from all three germ layers, e.g., a dermoid cyst in the ovary. Transitional cell morphology is found in the urinary system and not in the esophagus, unless a urinary tract tumor was metastatic to that location.
Labs of a 41 year old woman with hematuria show proteinuria, bacteria, and white cell in the urine. Blood urea nitrogen and creatinine are elevated. Ultrasound reveals enlarged kidneys. A provisional diagnosis of polycystic renal disease is made. What would be decreased in her?
Polycystic kidney disease leads to progressive decrements in renal function, eventually resulting in renal failure (evidenced by the increased BUN and creatinine). These abnormalities are caused by a reduction in glomerular filtration rate (GFR), which produces a decrease in creatinine clearance. The production of creatinine, a waste product of metabolism, bears a direct relation to the muscle mass of an individual and is independent of renal function. Because creatinine is freely filtered by the glomerulus, but not secreted or reabsorbed to a significant extent, the renal clearance of creatinine is approximately equal to the GFR. Therefore, creatinine clearance is commonly used to assess renal function in the clinical setting. The extracellular sodium concentration is not expected to change significantly in this patient. Glucose is not normally excreted, so glucose clearance is normally zero. Thus, it is not possible for glucose clearance to be decreased. Plasma creatinine concentration increases when GFR decreases. Insulin clearance is used to estimate GFR. However, insulin is foreign to the body, and insulin plasma levels are normally zero.
A 33 year old woman with insomnia undergoes an electroencephalogram (EEG) in a sleep disorder clinic. At 3:00 AM, the EEG technician notes that the woman is exhibiting vertex waves, sleep spindles, and K complexes. At this time she is in which stage of sleep?
Stage 2 sleep is characterized by low amplitude, mixed frequency EEG activity with more theta waves than Stage 1. In addition, vertex waves (sharply contoured potentials at the vertex), sleep spin-dies (short bursts of 12-16 Hz activity), and K complexes (high-amplitude waves with superimposed sleep spindles) occur intermittently. Muscle tone is slightly reduced, and eye movements are absent. REM sleep is characterized by low-amplitude, mixed frequency activity. Ponto-geniculo-occipital (PGO) spikes, which are transient, larger amplitude potentials, occur over the occipital arras There are also episodic bursts of rapid eye movements (BEMs), and skeletal muscle tone is decreased Stage 1 sleep, or drowsiness, is characterized by a transition from alpha rhythms (relaxed wakefulness) to theta rhythms. Electromyographic (EMG) activity is decreased, compared with relaxed wakefulness, and there are slow, roving eye movements. Stages 3 and 4 are also known as slow-wave sleep. They are characterized by high amplitude slow waves, especially delta waves. Eye movements are absent, and EMG activity is decreased compared with relaxed wakefulness.
A 17 year old girl has 1 year history of secondary amenorrhoea. On exam she had galactorrhoea to expression. Her prolactin concentration was 6100 mU/L (50-450). Pregnancy test was negative. What is the most likely diagnosis?
A characteristic feature of primary hyperaldosteronism is which one of the following?
Primary hyperaldosteronism or Conn´s syndrome is characterised by hypokalaemic hypertension. Patients can present with tetany (alkalosis) and muscle weakness (hypokalaemia). Oedema and oliguria are more features of secondary hyperaldosteronism (cirrhosis); and vitiligo (suggesting auto-immunity) is not a feature.
The correct pairing of cell type and substance synthesized by them is which one of the following?
Islet beta cells produce insulin and Amylin, as well as C-peptide, pro-insulin and GABA. Islet D cells produce somatostatin, F cells produce pancreatic polypeptide and alpha cells produce glucagon. Gastric chief cells produce pepsinogen whilst gastric parietal cells produce acid and intrinsic factor.
A 41 year old man is referred with gastro esophageal reflux disease. Which statement concerning gastro esophageal reflux disease is correct?
Symptoms of GERD do not correlate with the mucosal appearances at endoscopy. Although endoscopy should be performed in cases that are not clear cut or do not respond to PPI, it is not mandatory. The risk with Barrett´s and hence the diagnosis of Barrett´s can only be clarified with biopsy. Monitoring of pH is not a good guide to therapy but symptomatic improvement is a good guide to the efficacy of therapy. PPIs can be given continuously where the diagnosis has been satisfactorily proven and relapse of symptoms persist after withdrawal.
The gut hormone that stimulates acid secretion in the stomach is which one of the following?
Gastrin is secreted from the antrum of the stomach when stimulated by parasympathetic nerves and the presence of amino acids in the stomach.
It stimulates:
-gastric motility
-growth and acid secretion and
-intestinal motility.
The secretion of gastrin is inhibited by acid in stomach and somatostatin.
The most correct statement regarding disseminated intravascular coagulation (DIC) is which one of the following?
DIC is caused by the enhanced and abnormally sustained generation of thrombin, and is associated with elevated products of fibrin breakdown one of these being D-dimer. Treatment of the underlying cause, for example, sepsis, does not always lead to resolution of the condition, and recombinant human activated protein C has been shown to be effective in reducing mortality from DIC in patients with sepsis.
DIC is associated with a falling platelet count and decreased fibrinogen, but the clotting factors may be normal, especially when or considers that the acute phase response may shorten the activated partial thromboplastin time (APTT) and increase fibrinogen.
| A 16 year old boy has fever, headache and neck stiffness for 24 hours. He had an identical illness requiring admission to hospital for one year previously. CSF analysis shows white cells of 400/ml with a 90% neutrophilia and gram stain revealed scanty gram-negative diplococci. The component of immune system that is likely to be defective is which one of the following? | ||
This young man has recurrent meningococcal meningitis, and deficiencies of complement C5-9 predispose to Neisseria infections (complement deficiencies). One must recognise that the diplococci seen on microscopy are those of Neisseria meningitides.
A 66 year old man presents with renal colic. The following day he passes a stone in his urine with analysis revealing that it is composed of uric acid. The most likely cause of this type of renal stone is which one of the following?
A characteristic of myasthenia gravis is which one of the following?
Myasthenia gravis is more common in females (it is an autoimmune disease).
The most common features include ptosis, diplopia and ophthalmoplegia. It is a neuromuscular disorder and therefore does not cause any lower motor neuron signs such as fasciculations, wasting, and loss of reflexes. Pupils are always normal. Lid lag is a feature of thyroid eye disease.
Regarding the epidemiology of infections, which of the following statements is true?
Falciparum is the major resistance problem in sub-Saharan Africa. Most vivax is chloroquine sensitive, though resistant strains are appearing in New Guinea and Indonesia.
Diphtheria is still prevalent in many parts of the world. An upsurge in polio is now nearing eradication. Tetanus is still common.
AIDS is increasing inexorably.
Although United States is a low prevalence area, Hepatitis B transmission predominantly occurs through homosexual and heterosexual contacts. Transmission by vertical route occurs in High prevalence areas like south East Asia.
Link bcr-able fusion protein with its function:
Which one of the following diseases is associated with an increased risk of colon cancer?
People with inflammatory bowel disease (ulcerative colitis and Crohn´s disease) are at increased risk of colon cancer. The risk is greater the longer a person has had the disease. The other conditions are not associated with a predisposition to colon cancer.
Which one of the following does NOT characterize gastroesophageal reflux?
Unless very low, LES pressure is not very useful in predicting if reflux is present in an individual patient. Gastroesophageal reflux disease (GERD) refers to the clinical presentations associated with reflux of stomach and duodenal contents into the esophagus. The mean LES pressure is significantly lower in persons with GERD than in normal persons. The inappropriate relaxation of the LES is the most common event associated with reflux. If acid is placed within the esophagus, it is cleared poorly when compared to normal. The composition of refluxed materials also plays a role in reflux disease. The combination of gastric acid and bile salts is more injurious to the esophagus than either agent alone.
A 47 year old female complains of severe pruritis over several months. Examination shows hepatomegaly, and investigations reveal elevated serum alkaline phosphatase, serum cholesterol, and anti mitochondrial antibody titers. The most likely diagnosis is
Primary biliary cirrhosis is common in middle aged women. It is associated with jaundice, hepatosplenomegaly, and xanthomata. Portal hypertension is present in late stage disease. Alkaline phosphatase levels are usually elevated. Sclerosing cholangitis is more common in males and is associated with ulcerative colitis. Hepatitis B is associated with an elevation in serum transaminase levels initially. Hepatoma would be associated with weight loss and an elevation in serum alpha fetoprotein. Autoimmune chronic active hepatitis is usually associated with an elevation in anti smooth muscle antibody titers.
A 17 year old girl presents with steatorrheaand weight loss without any fever. She is anemic and when she eats wheat bread and oatmeal, her diarrhea gets worse. Her mother also has similar symptoms. A jejunal biopsy would most likely show
This patient has celiac sprue disease, which is inherited, and malabsorption with steatorrhea occurs when eating wheat, oats, and barley. Stool fat analysis reveals fat greater than 6 gms/day. Bacterial overgrowth syndrome would also cause malabsorption and biopsy would reveal bacteria. Whipple´s disease is rare and caused by a bacterium; biopsy would show mucosa with macrophages that stain positive for periodic acid schiff. Fibrosis of the small intestine would cause malabsorption. Fibrosis could be secondary to post radiation therapy and progressive systemic sclerosis. Mastocytosis would result in malabsorption secondary to infiltration of mast cells. Options B, C, D, and E would all be unrelated to gluten levels in the diet.
What is the most common solid renal tumor in adults?
Wilms´ tumor is the most common solid renal tumor in children. Renal cell carcinoma is the most common solid tumor in adults. The other tumors are far less common.
Which one of the following is NOT a cause of female infertility?
Which one of the following does NOT produce aspiration related injuries?
The most likely mode of transmission of the infectious agent Coxiella burnetti is which one of the following?
Coxiella burnetti, the causative agent of Q fever, is unique amongst rickettsia in that it does not require an arthropod vector for transmission. Instead, inhalation of sheep or goat dust containing the infectious agent may cause infection.
There has been an increase in the resistance of pneumococcal species against the penicillins and first generation cephalosporins. In cases of childhood meningitis, the empiric treatment is to first assume that the causative organism is S. pneumoniae and that it is resistant. Therefore, initial antibiotic therapy is with vancomycin and a third generation cephalosporin. Genes for this type of drug resistance are most likely present in which one of the following?
Transposons are mobile segments of DNA that can move themselves or a copy of themselves from one molecule of DNA to another. They are found in eukaryotic cells, bacteria, and viruses. They need at least one gene coding for a transposase, which are the enzymes involved in this movement. The transposase recognizes a specific nucleotide sequence; and the DNA inserts into this position. This insertion creates direct repeats on each side of the transposon. Transposons include some genes for drug resistance and play an important role in building multiple drug resistance plasmids. Bacteriophages are viruses affecting the bacterial cell. Temperate phage DNA maybe inserted into the bacterial chromosome.
Imported bacterial DNA, i.e. DNA that has been transferred into a cell by conjugation, transformation or transduction, is on short linear pieces of DNA called exogenotes. Most linear DNA is not stable in cells, because it is broken down by exonucleases. A prophage is a repressed temperate phage DNA inserted into a bacterial chromosome. The prophage DNA may encode the synthesis of products that make bacteria more pathogenic. This enhanced virulence is called lysogenic conversion. Restriction endonucleases are site specific endonucleases that recognize specific base sequences and cleave the nucleic acid backbone in the interior of the nucleic acid strand.
Gram stain of the sputum of a child with recurrent upper respiratory tract infections, who has chronic progressive cough, reveals gram negative aerobic rods. The infectious agent for this child´s pneumonia is also causes of which disease?
Gram stain that reveals slightly curved, motile, gram negative aerobic rods is most likely Pseudomonas aeruginosa. Now the question is: which of the diseases listed is also caused by Pseudomonas? The answer is otitis externa. P. aeruginosa is often found in the external ear, especially if the conditions are moist (“swimmer´s ear”) and there is any sort of inflammation. External otitis is usually a benign process, with the only symptom being an itchy, painful ear. If, however, the organism penetrates the epithelium and invades the soft tissue, cartilage, and cortical bone, the process becomes malignant otitis externa, which can progress to osteomyelitis leading to cranial nerve palsies. This condition is most common in diabetics. The treatment is antipseudomonal penicillin and aminoglycosides. Croup, also called laryngotracheobronchitis, is a respiratory disease of children that presents with a characteristic “barking” cough. Croup is caused by parainfluenza virus. Epiglottitis is a potentially fatal infection in children, caused by H. influenzae, which presents with drooling, difficulty breathing, and stridor. The incidence of this disease has dropped dramatically with the introduction of the H. influenzae type B(HiB) vaccine. Meningitis is caused by numerous different bacteria, depending on the age of the patient. The most common causes include S. pneumoniae (elderly people), H. influenzae (unvaccinated children), group B Strep and E. coli (neonates), and N. meningitidis (age 1 month to adult). While P. aeruginosa can cause meningitis, it is nota common cause. The most common causes of otitis media include S. pneumoniae and H. influenzae. Even in cases of external ear infections with P. aeruginosa, the middle ear is typically spared.
A 37 year old female sustains a closed head injury in accident. She does not immediately seek medical attention, but is brought to the ER two hours later. On exam there is mydriasis and loss of the papillary light reflex. Several hours later, she is unable to follow a flashlight with her eyes. Which type of herniation most likely occurring in her?
S. aureus culture is selected over many months for its ability to grow in increasing concentrations of penicillin. When capable of growth on blood agar containing 400,000 IU penicillin, the colonies are picked from the agar, placed in a nutrient broth, and a lytic phage is added. The bacteria and phage are co-cultured until viral maturation is complete. After centrifugation of culture the supernatant liquid is added to culture tubes containing clones of penicillin-sensitive S. aureus. 4 hours later at 37°C, these broth cultures are dumped onto blood agar Petri dishes containing 400,000 IU penicillin and incubated for 24 hours. Out of 100 Petri dishes, 4 grow colonies. In this experiment which one of the following process has taken place?
Generalized transduction is the process by which a phage (bacterial virus) with a lyric life cycle can mistakenly incorporate pieces of the genomic DNA of a bacterium into its capsid and transfer that trait to a new bacterium it infects. The virus “delivers” the bacterial DNA from one bacterium to another, and the newly transferred DNA must be stabilized by the process of homologous recombination. In this way, DNA that had encoded a mutant penicillin binding protein from the chromosome of the penicillin resistant strain was accidentally picked up by the lyric phage and delivered to the penicillin sensitive bacteria. Those that successfully incorporated the mutant DNA were transduced to become penicillin-resistant. Mobilization of transposons is a process of movement of segments of mobile DNA within a bacterial cell. Transposons require no presence of virus and do not mediate the transfer of traits from one bacterium to another. Transposons can only be moved from cell to cell if the DNA they inhabit is transferred by conjugation, transformation, or transduction. Site specific recombination is the process by which circular, foreign DNA molecules can be joined into the chromosome of the bacterial cell. It is a requirement of the process of specialized transduction, but does not occur in generalized transduction, as described in this question stem. Specialized transduction is the process by which a phage with a temperate life cycle accidentally carries a portion of the bacterial genome with it as it excises its DNA from the chromosome prior to leaving the cell. This accidentally excised bacterial DNA can then be delivered to another bacterium that the specialized transducing phage infects. In this case, the experiment stipulates that a lytic, not a temperate phage is added; so specialized transduction is not a possibility. Transformation is the process by which free DNA can be taken up and incorporated by bacteria competent to do so. In this experiment, free DNA is not mentioned, and addition of a phage is mentioned, so the process has to be either specialized or generalized transduction.
A 13 year old girl has temperature of 102.5°F and a sore throat. 2 days later, she develops a diffuse erythematous rash. Exam reveals circumoral pallor, and an erythematous rash with areas of desquamation. The myocardial damage that can follow this infection is produced in a manner similar to the damage associated with
This is a case of rheumatic fever, which is an immunologically mediated sequela to Streptococcus pyogenes pharyngitis. It is a type II cytotoxic hypersensitivity, involving antibodies that bind to cardiac tissue, activate complement, and thereby cause cell destruction. It is therefore most similar to idiopathic thrombocytopenic purpura, which is also a form of type II cytotoxic hypersensitivity, in this case mediated by antibodies against platelets producing complement fixation and causing the clotting dyscrasia. Atopic allergy is a form of type I hypersensitivity, mediated by IgE antibodies, basophils, and mast cells. Contact dermatitis is a form of type IV hypersensitivity mediated by T cells and macrophages. Graft versus host disease is a form of type IV hypersensitivity mediated by T cells and macrophages. Graves disease is a form of type II hypersensitivity, but it is NOT cytotoxic in its action. Instead, antibodies to the TSH receptors on thyroid cells cause over-stimulation of the gland and its eventual exhaustion.
A 28 year old female feels a lump in her breast. Tissue biopsy is taken and examined, with multiple areas showing only benign features. Which finding implies an increased risk of subsequently developing invasive carcinoma?
Sclerosing adenosis is a type of proliferative fibrocystic disease that is often seen with other variants of fibrocystic disease. It is a proliferation of small ducts and myoepithelial cells near the terminal duct lobular unit. It also is characterized by fibrosis that distorts the glands and lobules into a whorled pattern. When the sclerosing adenosis shows hyperplastic changes, atypical lobular hyperplasia, or a typical ductal hyperplasia, there is an increased risk for subsequent invasive breast cancer. Apocrine metaplasia is the term used to describe a transformation of ductal epithelial cells to eosinophilic cells resembling apocrine sweat gland epithelium. This is a benign, common, nonproliferative change that is not associated with increased cancer risk. A blue domed cyst of blood good is a fluid-filled cyst, sometimes up to 5 cm in size that appears blue grossly before it is incised. When incised, the fluid is serous and dark colored. These cysts are part of benign nonproliferative fibrocystic disease and do not carry increased cancer risk. Duct ectasia is characterized by a large dilated duct with inspissated material. It is associated with periductal inflammation and fibrosis of the large collecting ducts under the areola. It is common in elderly women, although the cause is not clear. There is no increased risk of cancer. Intraductal papilloma is a benign tumor that occurs in the large subareolar ducts. It is usually solitary and found in females who are middle aged to elderly. Clinically, it mimics cancer and may be associated with nipple discharge. It is covered with benign epithelium and attached to the duct by a fibrovascular stalk. A solitary lesion is not precancerous nor is it a risk for subsequent cancer.
An 81 year old hypertensive female is admitted for hip fracture treatment. Her right hip is pinned and she is confined to bed rest. On the third day, she develops chest pain, dyspnea, and cyanosis and dies. What is the most important etiologic factor in her death?
90% of deep vein thrombi are formed in the lower extremities; these thrombi may dislodge and travel to distant sites, most importantly, the lungs. The most frequent cause of pulmonary thromboembolism is deep venous thrombosis of the legs. In this case, the patient´s prolonged bed rest predisposed her to deep venous thrombosis. Other factors that predispose to clot formation include pregnancy, cancer, or other hypercoagulable states. Some emboli are clinically silent others affect only those with preexisting cardiac compromise. However, if the clot is large enough, it will cause nearly instantaneous death. A postoperative patient is at risk of a myocardial infarction; however, in this case, this is not the most likely scenario. A pulmonary embolus can cause heart failure, but this is not the primary etiologic event. Fat emboli can occur after a fracture of long bones; this is also much less likely than a thromboembolus. The fat particles cause a systemic inflammatory response. Veins in the upper limbs rarely develop thrombosis. This occurs only in disorders leading to a marked thrombotic propensity, such as carcinoma associated migratory thrombophlebitis (Trousseau sign), antiphospholipid antibody syndrome, protein C deficiency, and inherited mutations of the factor gene.
An embolus to the pulmonary artery is the typical sequela of deep venous thrombosis, rather than clot formation in the pulmonary vein.
A 55 year old woman´s skin of armpits and groin “keeps getting darker and darker.” On exam velvety brown and warty skin in the axilla and groin is seen. Beside cosmetic considerations, which is the medical significance of these lesions?
A driver sustains a blunt chest in an automobile accident and is brought to the emergency room. The physician wants to determine if the heart was bruised when he collided with the steering wheel. The levels of which creatine kinase isoenzymes or combinations of creatine kinase isoenzymes would be most useful for this determination?
The MB isoenzyme of creatine kinase is associated with heart damage; the MM isoenzyme is associated with muscle damage; and the BB isoenzyme is associated with brain damage. Actually, most tissues contain a mix of creatine kinase isoenzymes, but one species often predominates. In the case of myocardial infarction not occurring in the setting of trauma, either total creatine kinase, or, preferentially, the MB isoenzyme can be used for monitoring. However, in a complex setting such as in this case, where there is known skeletal muscle damage secondary to trauma the ratio of the MB isoenzyme to total creatine kinase is most informative.
Autopsy on a 71 year old man with a history of peripheral vascular disease reveal an atherosclerotic plaque in left anterior descending coronary artery, which results in 80% luminal stenosis. It is covered by a smooth endothelial lining without evidence of thrombosis, ulceration, or hemorrhage. Remaining coronary vessels are spared. Which condition would have resulted from this lesion?
The atherosclerotic lesion described here is referred to as fixed coronary obstruction, which becomes clinically manifest with chest pain when increased myocardial demand cannot be compensated by vasodilatation. This usually occurs when the obstruction is more than 75% the cross sectional area of the lumen, unless there are additional predisposing factors. Fixed coronary artery obstruction manifests with stable angina, i.e., chest pain triggered by exercise or emotional strain and promptly relieved by rest. Chest pain that awakens a patient in the early morning is characteristic of Prinzmetal angina, which is due to coronary artery vasospasm and is not often associated with atherosclerotic lesions. Chest pain occurring with progressive frequency and severity refers to unstable angina, in which chest pain manifests with relatively unpredictable patterns. Pain becomes increasingly frequent and less responsive to rest or medication. This form is related to plaque rupture, hemorrhage, ulceration, and superimposed thrombosis. Progressive development of congestive heart failure without chest pain defines chronic ischemic heart disease, which is usually due to involvement of all three coronary branches and associated with diffuse loss of myofibers and fibrosis throughout the ventricles. Prolonged (more than 30 minutes) chest pain accompanied by shock is most likely due to myocardial infarction. This is usually caused by occlusive thrombosis complicating acute plaque changes, such as ulceration or rupture.
A 33 year old woman with insomnia undergoes an electroencephalogram (EEG) in a sleep disorder clinic. At 3:00 AM, the EEG technician notes that the woman is exhibiting vertex waves, sleep spindles, and K complexes. At this time she is in which stage of sleep?
Stage 2 sleep is characterized by low amplitude, mixed frequency EEG activity with more theta waves than Stage 1. In addition, vertex waves (sharply contoured potentials at the vertex), sleep spin-dies (short bursts of 12-16 Hz activity), and K complexes (high-amplitude waves with superimposed sleep spindles) occur intermittently. Muscle tone is slightly reduced, and eye movements are absent. REM sleep is characterized by low-amplitude, mixed frequency activity. Ponto-geniculo-occipital (PGO) spikes, which are transient, larger amplitude potentials, occur over the occipital arras There are also episodic bursts of rapid eye movements (BEMs), and skeletal muscle tone is decreased Stage 1 sleep, or drowsiness, is characterized by a transition from alpha rhythms (relaxed wakefulness) to theta rhythms. Electromyographic (EMG) activity is decreased, compared with relaxed wakefulness, and there are slow, roving eye movements. Stages 3 and 4 are also known as slow-wave sleep. They are characterized by high amplitude slow waves, especially delta waves. Eye movements are absent, and EMG activity is decreased compared with relaxed wakefulness.
A 65 year old male has a 4 mm rough, tan, and slightly raised skin lesion on the face. Biopsy shows atypical basal cells with eosinophilic cytoplasm but persistent intercellular bridges. The stratum corneum is thickened, and parakeratosis is present; the remainder of the epidermis is thinned. Which feature would also be seen in the dermis?
The lesion described is an actinic keratosis. This common premalignant lesion is caused by solar damage, which also characteristically damages the elastic fibers (changing their color in stained tissue to blue gray) of the superficial dermis. Benign nevocellular nevus cells are found in common moles (nevocellular nevi). Large numbers of spindle shaped fibroblasts are found in dermatofibromas. Malignant nevus cells are found in melanoma. Touton giant cells are found in xanthomas.
A 71 year old woman presents to the doctor prior to beginning chemotherapy for newly diagnosed small cell lung carcinoma. Exam is notable for obesity, BP of 180/110 mm Hg, facial hair, abdominal striae, and an acneiform rash on her chest and back. Serum glucose is 250 mg/dL. CXR shows a right perihilar mass and severe diffuse osteoporosis. This clinical picture is likely due to
This woman has all the classic findings of Cushing syndrome: obesity, hypertension, hirsutism, acne, striae, glucose intolerance, and osteoporosis. Cushing syndrome may be caused by excess production of cortisol due to bilateral adrenal hyperplasia or an adrenal neoplasm; by excess production of corticotropin (ACTH) by a pituitary adenoma; or by ectopic production of ACTH by a tumor, most commonly a small cell lung carcinoma (major clue in the question stem!). Destruction of the adrenal glands bilaterally or of the anterior pituitary by metastases would cause a deficiency of cortisol and ACTH, respectively, and would lead to a syndrome of cortisol deficiency with orthostatic hypotension, malaise, nausea, and weight loss. Ectopic production of gastrin, as seen in Zollinger-Ellison syndrome, causes severe refractory peptic ulcer disease.
Ectopic production of parathyroid hormone (PTH), which can be seen in squamous cell lung carcinoma, would result in hypercalcemia.
A child aged 5 years has a 1 month history of fevers and lassitude. He is found to have severe anemia, moderate thrombocytopenia, and a white blood count of 12,000 cells per mm3. What would be likely seen on the bone marrow biopsy?
Acute lymphoblastic leukemia (ALL) is primarily a disease of children, with peak incidence at 4 years of age. Approximately 80% of child-hood leukemias are of the ALL type. Other features in this scenario that further support an acute leukemia are fevers and anemia without marked elevations of the white blood cell count. Acute myeloblastic leukemia (AML) would present in a similar fashion acute symptoms and anemia with thrombocytopenia. Bone marrow biopsy is needed to definitively differentiate ALL and AML, but AML represents only 20% of childhood leukemias. AML is primarily a disease of adolescents and young adults. The chronic leukemias are diseases of adulthood that present with nonspecific symptoms and are typically diagnosed when white counts are markedly elevated. Chronic myeloid leukemia, a neoplasm of a pluripotent stem cell, also may present with thrombocytosis, rather than thromborytopenia.
Hairy cell leukemia is a relatively rare leukemia of older men. It infiltrates the spleen early in its course and tends to present with pancytopenia due to bone marrow failure and splenic sequestration.
A 45 year old female presents with feature suggestive of Cushing´s syndrome. Initial investigations reveals a 24 hr Urine free cortisol concentration of 350 nmol/day (<250). The appropriate investigation of her suspected Cushing´s syndrome is
This patient is clinically suspected to have Cushing´s syndrome with the diagnosis being supported by elevated urine free cortisol concentrations. However, the diagnosis of hypercortisolism needs to be` established and the best way of doing this is with a low dose dexamethasone suppression test (DXM 0.5 mg qds for 2 days). The high dose test (2 mg qds for 2 days) adds little diagnostic value over and above the low dose test. 9am and Midnight cortisol concentrations would not add much to the suspicion of hypercortisolism which is provided by the urine free cortisol. Short synacthen tests are used to assess for hypoadrenalism. A CRF test is used occassionally to distinguish between ectopic and pituitary dependent Cushing´s. ACTH concentrations would also be valuable after the diagnosis is confirmed to assess for ACTH dependency.
A male aged 68 years presents with tiredness and dyspnoea and is diagnosed with acute myeloid leukaemia. The most important prognostic factor is which one of the following?
Options A, C, and D have no prognostic value. White cell count at diagnosis is however important, but most important is the karyotype of bone marrow, as this result stratifies patients into lower risk, standard risk and poor risk, which has prognostic significance.
Heinz bodies in red blood cells in haemolytic anaemia are present in which one of the following condition?
Heinz bodies = oxidised denatured Hb. Post: splenectomy causes target cells, Pappenheimer bodies (siderotic granules) and Howell-Jolly bodies (DNA remnants).
A 47 year old woman develops nephritic syndrome and is awaiting further tests to establish the underlying aetiology. Corticosteroids would be most effective in reversing the nephritic syndrome in which condition?
Although there is no known effective treatment for IgA nephropathy, there have been reports of favourable response to long term corticosteroid therapy. 80% adults with minimal change glomerulonephritis (GN) will respond to steroids, although remissions can take up to 16 weeks. Membranous GN does not respond to steroid treatment. No specific treatment is available to cause regression of amyloid deposits.
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