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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
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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
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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
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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
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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