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Page 1 I 5 661. The most common cause of congenital adrenal hyperplasia is which of the following? a. 11 hydroxylase deficiency 11 hydroxylase deficiency results in congenital adrenal hyperplasia and excessive adrenal androgen production but is much less common than 21 hydroxylase deficiency. b. 17 hydroxylase deficiency 17 hydroxylase deficiency is an uncommon cause of adrenal hyperplasia and is associated with male pseudohennaphroditism and sexual infantilism, hypertension and hypokalemic alkalosis. c. 21 hydroxylase deficiency The various fonns of 21 hydroxylase deficiency are by far the most common cause of of congenital adrenal hyperplasia. Clinical manifestations include excessive androgen production with masculization of the extemal genitalia and various degrees of salt wasting, depending on the fonn of the deficiency. d. side chain cleavage enzyme deficiency Cholesterol side chain cleavage deficiency is a less common cause of adrenal hyperplasia associated with male pseudohennaphroditism, sexual infantilism and adrenal insufficiency. Death frequently occurs in early infancy from adrenal insufficiency. e. 18 hydroxylase deficiency 18 hydroxylase is an enzyme that catalyzes the conversion of corticosterone to 18-hydroxycorticosterone in the biosynthetic pathway for aldosterone and a deficiency in this enzyme would not result in the congenital adrenal hyperplasia syndrome. Correct answer is: c The Adrenals: Pathophysiology (Disorders of Adrenal Androgen Production). Reference: page 373 668. The most potent physiologic stimulus for insulin secretion is which of the following? a. calcium Calcium is a secretagogue for insulin release in vitro and in vivo but it is not the primary physiologic stimulus for insulin secretion. b. glucose Glucose is the most potent stimulus for insulin release. Insulin levels rise in response to an increase in glucose levels within minutes ofingestion offood. c. glucagon Glucagon has no effect on insulin secretion although insulin itself inhibits glucagon secretion by the A cells of the pancreatic islets. d. amino acids Secretion of insulin does occur in response to amino acids but this effect is much less pronounced than the stimulatory effect of glucose. e. secretin Secretin augments the rate of insulin secretion by potentiating the effects of glucose on the beta cell but is not the primary physiologic stimulus for insulin secretion. Correct answer is: b Endocrine Pancreas: Physiology (Insulin). Reference: page 379 Page 2 / 5 676. Organification of iodine in the thyroid gland may be affected by all of the following agents EXCEPT: a. thyroid stimulating hormone TSH has several regulatory effects on iodide metabolism including enhancing iodide trapping and stimulating the organification of iodide. b. iodine Iodine has several regulatory effects on the uptake and organification process. Iodine depletion enhances iodide transport and stimulates hormone synthesis. Excess iodide, however, inhibits both transport and the organification process. c. propylthiouracil Propylthiouracil is an anti-thyroid drug which acts by inhibiting the oxidation and organification of iodine and by blocking coupling of the iodothyronines. d. propranolol Propranolol is a beta adrenergic antagonist that has no effects on thyroid hormone synthesis or the organification process. Propranolol is very useful in controlling clinical manifestations of thyrotoxicosis and also inhibits the peripheral conversion of T4 to T3. e. thionamides Thionamides are a class of anti-thyroid drugs that includes propylthiouracil and methimazole which act by inhibiting the oxidation and organification of iodine and by blocking coupling of the iodotyrosines. Correct answer is: d Thyroid: Physiology/Inhibitors of Thyroid Hormone Synthesis and Secretion. Reference: page 356 696. The most common cause of adrenal insufficiency is: a. adrenal cortical adenoma Cortisol producing adrenal adenomas may cause Cushing's syndrome but most adrenal cortical adenomas are nonfunctional and are not associated with any affects on cortisol secretion. b. adrenal carcinoma Adrenal cortical carcinomas may produce cortisol and other steroid hormones but are not usually associated with adrenal insufficiency. c. adrenal hemorrhage Bilateral adrenal hemorrhage may cause adrenal insufficiency but this is not the most common cause of Addison's disease. d. idiopathic Adrenal insufficiency may be idiopathic but this is not the most common cause. e. exogenous cortisol administration and subsequent withdrawal The most common cause of adrenal insufficiency is exogenous cortisol administration with suppression of adrenal cortical function. Adrenal insufficiency may occur with withdrawal of exogenous cortisol or during periods of stress when cortisol replacement therapy is inadequate. Correct answer is: e Adrenals: Pathophysiology (Adrenal Insufficiency). Reference: page 377 Page 3 I 5 978. The best initial test to evaluate a patient with suspected Cushing's syndrome is: a. Plasma ACTH Plasma ACTH levels are useful in differentiating ACTH-dependent from primary adrenal causes of Cushing's syndrome once the presence of hypercortisolism has been established. Plasma ACTH should not be measured as an initial screening test for Cushing's syndrome. b. Plasma cortisol Loss of the diumal rhythm in cortisol secretion is one of the characteristics of Cushing's syndrome. However, because of the variability in the plasma cortisol levels, measurement of AM and PM cortisol levels is not a very reliable test for screening patients with Cushing's syndrome. c. 24 hour urine free-cortisol The best initial test to evaluate a patient for suspected Cushing's syndrome is measurement of cortisol excretion in the urine over a 24 hour time period. Elevated levels are present in more than 90% of patients with Cushing's syndrome. d. High dose dexamethasone test The high dose dexamethasone test has been used primarily to differentiate pituitary from nonpituitary causes of ACTH-dependent Cushing's syndrome. It is not generally used as an initial screening test for persons with suspected hypercortisolism. e. Correct answer is: c Endocrine System: Adrenal Pathophysiology section Reference: page 373 910. Which test is most appropriate for evaluating patients with suspected renal trauma. a. Intravenous urogram While the intravenous urogram can demonstrate renal trauma, from the standpoint of extravasation, renal parenchymal defects or non-function, significant renal trauma can exist and not be well demonstrated on the intravenous urogram. Additionally, the intravenous urogram by and large provides only infonnation about the kidneys. In the unstable trauma patient, clearly a one shot intravenous urogram is preferable to no study at all; however, the test does not provide the same infonnation as the CT scan. b. CT with contrast Reference: Section, Radiographic Imaging for Genitourinary Diseases c. MRI The role of MRI in trauma has not been delineated. At this point in time, the infonnation obtained from an MRI does not appear to be any better than a CT scan with contrast. MRI is significantly more expensive, significantly more cumbersome with regards to handling of the trauma patient, and at this point has no place. d. Ultrasound Ultrasound is extremely insensitive with regards to the demonstration of renal trauma. e. Nuclear renal scan Nuclear renal scan can be quite sensitive with regards to the demonstration of extravasation. However, no anatomic infonnation is provided. Correct answer is: b Section, Radiographic Imaging for Genitourinary Diseases Reference: page 660 Page 4/5 913. Which of the following is correct concerning autonomic dysreflexia? a. Rarely occurs after spinal cord injury. Autonomic dysreflexia is a long term sequelae of spinal cord injury. b. Can be treated with alpha-agonists. Autonomic dysreflexia involves an excessive sacral afferent feed back which initiates an uncontrolled sympathetic response. It is treated by eliminating its cause and also can be treated with non-selective alpha antagonists. c. Produces a marked decrease in blood pressure. Uncontrolled sympathetic response is associated with high blood pressure. d. Usually occurs in patients with spinal cord injury above T6. Reference: Section on Physiology of Voiding and Voiding Dysfunction. e. Is of little concern to patients with spinal cord injury. Uncontrolled and severe autonomic dysreflexia can be associated with significant elevations in systemic blood pressure and has been associated with cerebral vascular accident Correct answer is: d Section on Physiology of Voiding and Voiding Dysfunction. Reference: page 662 916. All of the following statements about urinary tract infections are correct EXCEPT: a. They are rare in young and middle aged males This is a true statement. Urinary tract infections indeed are rare in young to middle aged males. b. Their incidence increases in females with increasing age. This is a true statement. Incidence of UTI does increase in females with increasing age. c. The longer a patient is hospitalized, the less likely he is to develop a UTI. Reference: Section on Urinary Tract Infection d. Nursing home patients are more likely to develop UTls than elderly patients who reside at home. This is a true statement. in fact, studies have shown that nursing home patients are much more likely to develop UTls as compared to aged matched patients who reside at home. e. N/A N/A Correct answer is: c Section on Urinary Tract Infection Reference: page 665 --- --- Page 5 I 5 925. The most common cause of male infertility is: a. Ductal obstruction Testicular causes of infertility comprise the bulk of male infertility patients. About 40% of this category have a varicocele, and surgical correction may increase sperm production. Pre testicular infertility is the result of abnormal hormone production which adversely effects spermatogenesis. Isolated gonadotropin deficiency or increased production of prolactin can result in abnormal poor spermatogenesis. Testicular causes of infertility include problems with delivery of the sperm and are commonly related to obstructive b. Endocrine abnormalities Testicular causes of infertility comprise the bulk of male infertility patients. About 40% of this category have a varicocele, and surgical correction may increase sperm production. Pre testicular infertility is the result of abnormal hormone production which adversely effects spermatogenesis. Isolated gonadotropin deficiency or increased production of prolactin can result in abnormal poor spermatogenesis. Testicular causes of infertility include problems with delivery of the sperm and are commonly related to obstructive c. Varicocele Reference: Section on Male Infertility d. Environmental toxins Testicular causes of infertility comprise the bulk of male infertility patients. About 40% of this category have a varicocele, and surgical correction may increase sperm production. Pre testicular infertility is the result of abnormal hormone production which adversely effects spermatogenesis. Isolated gonadotropin deficiency or increased production of prolactin can result in abnormal poor spermatogenesis. Testicular causes of infertility include problems with delivery of the sperm and are commonly related to obstructive e. Ductal agenesis Testicular causes of infertility comprise the bulk of male infertility patients. About 40% of this category have a varicocele, and surgical correction may increase sperm production. Pre testicular infertility is the result of abnormal hormone production which adversely effects spermatogenesis. Isolated gonadotropin deficiency or increased production of prolactin can result in abnormal poor spermatogenesis. Testicular causes of infertility include problems with delivery of the sperm and are commonly related to obstructive phenomena. Correct answer is: c Section on Male Infertility Reference: page 667 942. The testicular tumor most often treated with definitive radiation therapy is: a. Embryonal cell carcinoma Embryonal cell carcinoma is a frequently encountered testicular tumor, is one of the non-seminomatous varieties of testicular carcinoma. Embryonal carcinoma does not respond to radiotherapy. b. Teratoma. Teratoma is another of the non-seminomatous germ cell tumors. Teratoma and teratocarcinoma are not shown to be radiosensitive. c. Yolk sac tumor. Yolk sac tumor is the term given to the juvenile embryonal tumor, in essence, this is a non-seminomatous germ cell tumor seen in the young boy. These tumors have not been shown to be radiosensitive. d. Seminoma. Seminoma is the most common tumor seen in carcinoma of the testis comprising 35% of tumors. Syncytiotrophoblastic elements are seen in 10-15%. Approximately 5-10% of seminomas are classified as anaplastic seminomas. These tumors tend to present with a higher stage than classic seminoma. Their pattem seems to follow the line of non-seminomatous germ cell tumors more than true seminoma. True seminoma is a radiosensitive tumor and is treated with definitive radiation therapy. e. Choriocarcinoma Choriocarcinoma is a non-seminomatous germ cell tumor comprised of syncytiotrophoblastic elements. Its presence is hailed by elevated levels of human chorionic gonadotropin (beta HCG). These tumors are not radiosensitive. Correct answer is: d See Section on GU TumorslTestis Reference: page 677