Tricia Moo-Young, M.D., Richard A. Prinz, M.D.
1 Which of the following statements regarding the anatomy of the adrenal gland is false?
A The arterial supply arises from the inferior phrenic artery, the renal artery, and the aorta.
B The left adrenal vein, joined by the inferior phrenic vein, drains into the left renal vein.
C The right adrenal vein enters directly into the inferior vena cava.
D The arterial supply arises from the inferior phrenic and renal arteries.
E The adrenal vein is longer on the left side.
Ref.: 1, 2
Comments
The arterial supply of the adrenal gland arises from three sources. Superiorly, branches are given off by the inferior phrenic artery, whereas the middle branches originate from the aorta. Along the medial and inferior aspect of the gland are contributory branches given off by the ipsilateral renal artery. The venous drainage of the adrenal gland differs by side. The left adrenal vein is joined by the inferior phrenic vein before it drains into the left renal vein and can measure 2 cm long. Variably, the left inferior phrenic vein will drain separately into the left renal vein. On the right, the adrenal vein enters directly into the inferior vena cava posteriorly and is shorter and broader than the left one. This shorter configuration can make ligation technically more challenging for the adrenal surgeon.
Answer
D
2 What enzyme is responsible for the conversion of norepinephrine to epinephrine?
A Tyrosine hydroxylase
B Monamine oxidase
C Catechol O-methyltransferase
D Phenylethanolamine-N-methyltransferase (PNMT)
E Dopamine β-hydroxylase.
Ref.: 1, 2
Comments
Histologically, the adrenal gland is divided into two components: the centrally located medulla and the peripherally located cortex. The adrenal cortex arises from the mesoderm and accounts for approximately 90% of the total adrenal mass. Histologically, the cortex is made up of three zones, the glomerulosa, fasciculata, and reticularis. Each zone corresponds to the synthesis of mineralocorticosteroids, corticosteroids, and sex steroids. The medulla is composed of chromaffin cells derived from ectodermal neural crest cells. The chromaffin cells are innervated by sympathetic fibers traveling from the sympathetic chain. They secrete the vasoactive catecholamines epinephrine and norepinephrine. Norepinephrine is converted to epinephrine by the enzyme PNMT. This enzyme is exclusively located within the adrenal medulla and is not found in ectopic adrenal medullary tissue. Thus, ectopic pheochromocytomas are incapable of producing epinephrine since they lack this enzyme.
Answer
D
3 What is the rate-limiting enzyme of catecholamine synthesis?
A Tyrosine hydroxylase
B Monamine oxidase
C Dopamine β-hydroxylase
D Dopa decarboxylase
E PNMT
Ref.: 1, 2
Comments
Tyrosine hydroxylase is the rate-limiting enzyme in catecholamine synthesis. The first step in catecholamine synthesis involves the conversion of L-tyrosine into dihydroxyphenylalanine (L-dopa) by the enzyme tyrosine hydroxylase. Dopa decarboxylase then converts L-dopa into dopamine. Dopamine is subsequently converted to norepinephrine by the enzyme dopamine β-hydroxylase. PNMT is the enzyme located exclusively in the adrenal gland and is responsible for the conversion of norepinephrine into epinephrine.
Answer
A
4 Aldosterone secretion is under the control of all of the following except:
A Potassium
B Adrenocorticotropic hormone (ACTH)
C Angiotensin II
D Heparin
E Epinephrine
Ref.: 1-3
Comments
Aldosterone synthesis is under the control of angiotensin II, potassium, and to a lesser extent, ACTH. Its synthesis is inhibited by somatostatin, dopamine, atrial natriuretic factor, and heparin. Aldosterone synthase (CYP11B2) is restricted to the zona glomerulosa, where aldosterone is primarily synthesized. Angiotensin II and potassium stimulate aldosterone secretion by increasing the transcription of CYP11B2. ACTH increases aldosterone secretion by no more than 10% to 20% over baseline values and does so by stimulating the earlier pathways of adrenal steroidogenesis. Epinephrine plays no direct regulatory role in aldosterone synthesis.
Answer
E
5 Congenital adrenal hyperplasia (CAH) is most commonly caused by a deficiency of which of the following enzymes?
A 21-Hydroxylase
B 17α-Hydroxylase
C 11β-Hydroxylase
D 5α-Reductase
E 21β-Hydroxylase
Ref.: 1, 2
Comments
The most common form of congenital adrenal hyperplasia is due to mutations or deletions of CYP21A2, the gene that encodes for 21-hydroxylase. This enzyme defect accounts for more than 90% of cases of CAH. In most patients, it is manifested as a salt-wasting form in which lack of the 21-hydroxylase enzyme impedes downstream synthesis of aldosterone. Clinically, this becomes apparent within the first few months of life with the development of hypovolemia and hyperkalemia. There is excess production of ACTH because of the lack of negative feedback on steroid synthesis. Upstream precursors accumulate as a result of lack of the 21-hydroxylase enzyme and are then shunted into the sex steroidogenesis pathway. This leads to the presence of ambiguous genitalia in females. The diagnosis is made by finding elevated levels of 17-hydroxyprogesterone, the 21-hydroxylase substrate, and by genetic testing.
Answer
A
6 What is the most common cause of primary adrenal insufficiency (Addison disease)?
A Tuberculosis
B Kaposi sarcoma
C Cytomegalovirus
D Lymphoma
E Autoimmune disorder
Ref.: 1, 2
Comments
More than 150 years ago, Thomas Addison described a clinical condition that involved salt wasting, skin hyperpigmentation, and histopathologic destruction of the adrenal gland. In the 1850s, tuberculous adrenalitis was the most common cause of primary adrenal insufficiency. Because of the decreased incidence of advanced tuberculosis, the current most common cause is autoimmune Addison disease. Clinical symptoms of the disorder can include nausea and vague abdominal pain, musculoskeletal complaints, and postural dizziness. The most characteristic feature of Addison disease is hyperpigmentation of the skin and mucous membranes. Autoimmune Addison disease is typically associated with other autoimmune disorders such as type 1 diabetes mellitus.
Answer
E
7 A 55-year-old male patient is currently being treated in the surgical intensive care unit for ventilator-associated pneumonia following partial hepatectomy. His laboratory values are as follows: hemoglobin, 8 g/dL; white blood cell count, 8 × 103 cells/µl; and blood glucose, 34 mg/dL. In postoperative week 2, increasing pressor requirements develop suddenly in this patient, whose sepsis had been resolving despite broadening his antibiotic coverage and blood cultures being negative. You suspect adrenal insufficiency. What initial laboratory test can assist in making the diagnosis?
A Serum cortisol
B 24-hour urine cortisol
C Serum chemistry panel
D Cosyntropin stimulation test
E Serum troponin levels
Ref.: 1, 2
Comments
See Question 8.
Answer
C
8 The patient described in Question 7 has worsening hypotension despite escalation in intravenous norepinephrine. What should be the immediate next step in the management of this patient?
A Addition of vasopressin
B Intravenous fluids
C Cosyntropin stimulation test
D Hydrocortisone injection
E Blood transfusion
Ref.: 1, 2
Comments
Acute adrenal insufficiency is a life-threatening emergency. In the critically ill patient population it can develop in either the acute or chronic phase of the illness. In the intensive care setting, if acute hypotension refractory to pressor support and not demonstrated to be cardiogenic in origin develops suddenly, acute adrenal insufficiency should be excluded. Although the cosyntropin stimulation test is the definitive means of diagnosing adrenal insufficiency, this test can take up to 24 hours to return. Thus, in the acute setting, evidence of hyperkalemia, hyperglycemia, and refractory hypotension is sufficient to begin empirically treating these patients with steroids until the diagnosis can be confirmed. The first step in the management of a hypotensive patient suspected of having adrenal insufficiency is volume resuscitation followed by empirical steroid replacement. Corticosteroid replacement in patients with acute adrenal insufficiency should include the intravenous administration of either hydrocortisone, 100 mg every 6 to 8 hours, or dexamethasone, 4 mg every 24 hours. Dexamethasone is long acting and does not interfere with the administration of a cosyntropin stimulation test. Maintenance therapy in patients with chronic adrenal insufficiency can be achieved with oral prednisone, 5 mg daily, and the mineralocorticoid fludrocortisone, 0.1 mg/day. Blood transfusion will not reverse this patient’s condition, and it is not generally recommended for patients with a hemoglobin level greater than 7 g/dL.
Answer
B
9 A 45-year-old woman with known Addison disease is due to undergo laparoscopic cholecystectomy. Which of the following is the correct stress corticosteroid dosage that she should receive preoperatively?
A Hydrocortisone, 25 mg on the day of the procedure only
B Hydrocortisone, 50 to 75 mg on the day of the procedure, followed by a 2-day taper to the maintenance dose
C Hydrocortisone, 100 mg on the day of the procedure, followed by a rapid 5-day taper to the maintenance dose
D Hydrocortisone, 100 mg on the day of the procedure only
E Hydrocortisone, 50 to 75 mg on the day of the procedure, followed by a 6-week taper to the maintenance dosage
Ref.: 1, 2
Comments
In patients with adrenal insufficiency, supplemental corticosteroids are required during physiologic stress such as illness, trauma, anesthesia, and surgical procedures. One standard dose should not be applied to all patients with adrenal insufficiency but should be individualized to the daily maintenance dose and the procedure or stress that they are undergoing. There is no benefit to excessive dosing (>200 mg/day of hydrocortisone) or an extended duration of dosing. In fact, deleterious effects secondary to undue corticosteroid exposure have been seen. In this patient, the appropriate dose, relative to the surgical procedure, is her daily maintenance dose that morning, 50 to 75 mg of hydrocortisone intravenously before induction of anesthesia, and her steroid dose tapered back to the maintenance dosage over the next 2 days.
Answer
B
10 The initial biochemical screening tests for incidentally discovered adrenal nodules include all of the following except:
A ACTH
B Low-dose dexamethasone test
C Serum aldosterone
D Serum renin
E Late-night salivary cortisol level
Ref.: 1-3
Comments
Work-up of an incidental adrenal mass includes screening and secondary confirmatory testing. Screening tests include (1) a low-dose dexamethasone test or 24-hour urine cortisol (or both), (2) a morning serum aldosterone and renin level, and (3) fractionated urine metanephrines. Confirmatory tests are done when the results of initial testing are equivocal and include but are not limited to a high-dose dexamethasone test, serum catecholamines, and salt-loading aldosterone suppression testing. Measurement of the serum ACTH level is performed once a diagnosis of hypercortisolism is established. Cortisol levels follow a circadian rhythm, which explains why random cortisol levels are not useful in the screening of these patients. When there is normal diurnal variation, cortisol should be at its lowest late at night. In patients suspected of having Cushing syndrome, an elevated serum cortisol level at 11 PM can be an early, albeit not definitive factor in diagnosis of the condition. For its simplicity and relative accuracy, measurement of late-night salivary cortisol levels has gained popularity in recent years. It is more costly than standard testing and should be repeated over several evenings for improved accuracy. With repeated measurements, levels less than 1.3 ng/mL on radioimmunoassay exclude the diagnosis of Cushing syndrome.
Answer
A
11 A 32-year-old woman has a 5-year history of poorly controlled hypertension. She is taking three different medications, including a diuretic, β-blocker, and potassium supplements. What should be the next step in establishing the diagnosis of surgically correctable hypertension?
A Computed tomography (CT) of the abdomen and pelvis
B Urine catecholamines
C Serum aldosterone and renin levels
D Renal ultrasound
E Saline suppression testing
Ref.: 1, 2
Comments
The most likely diagnosis in this patient is primary hyperaldosteronism. There is general consensus that all patients with young age, poorly controlled hypertension, and a history of hypokalemia should undergo evaluation for an aldosterone-secreting adenoma. The initial step is measuring the aldosterone-to-renin ratio. This test should be performed after discontinuing such interfering medications as spironolactone. An aldosterone-to-renin ratio of greater than 25 to 30 (e.g., a serum aldosterone level of ≥15 ng/dL with a renin level of <0.5 ng/mL) is suggestive of the diagnosis. The diagnosis is then confirmed by doing a 24-hour urine aldosterone, sodium, and potassium test with the patient ingesting a high-salt diet. A 24-hour urinary aldosterone level greater than 12 mcg in 24 hours is considered positive. After establishing the biochemical diagnosis, the next step is to determine whether there is laterality of the disease. Only at this time should diagnostic imaging be ordered.
Answer
C
12 Biochemical testing confirms the diagnosis of primary hyperaldosteronism in the patient in Question 11. Diagnostic imaging reveals a 1.5-cm area of fullness in both adrenal glands. The next step in management should be:
A Imaging repeated in 6 months
B Long-term management with spironolactone
C Bilateral cortical-sparing adrenalectomies
D Selective venous sampling
E Laparoscopic ultrasound
Ref.: 1, 2
Comments
The next step to assist in localization is selective venous sampling. The test is done by performing simultaneous measurements of serum cortisol and aldosterone in the cannulated adrenal veins and the peripheral circulation. Confirmation of successful cannulation is established by documenting a greater than fivefold elevation in cortisol concentration relative to the peripheral circulation. Lateralization is confirmed by an unbalanced ratio of aldosterone to cortisol when comparing one side with the other. Typically, most authors recommend at least a fourfold difference between the two sides rather than an absolute value of elevation above normal. Intraoperative ultrasound can facilitate intraoperative localization of adrenal tumors, particularly via laparoscopy. However, an operation is not the next step in this patient.
Answer
D
13 The most common cause of hyperaldosteronism is:
A Bilateral idiopathic adrenal hyperplasia
B Aldosterone-producing adenoma
C Familial hyperaldosteronism type I
D Adrenocortical carcinoma
E Unilateral adrenal hyperplasia
Ref.: 1, 2
Comments
The most common cause of hyperaldosteronism is bilateral idiopathic hyperplasia (60% to 70%). The second most common cause is an aldosterone-producing adenoma (35%). The remaining subtypes include unilateral adrenal hyperplasia (2%), carcinoma (<1%), and familial hyperaldosteronism types I and II (<1%). It is important to distinguish which subtype of hyperaldosteronism that a patient has because some types, including bilateral idiopathic hyperplasia, are managed nonoperatively.
Answer
A
14 A patient being evaluated for hyperaldosteronism has elevated aldosterone and renin levels. What is the probable cause of this condition?
A Cirrhosis
B Aldosterone-secreting adenoma
C Familial hyperaldosteronism type II
D Metastatic renal cell cancer
E Bilateral idiopathic hyperplasia
Ref.: 1, 2
Comments
This patient has secondary hyperaldosteronism as a result of increased renin production by the kidney. This condition can result from reduced intravascular volume as is seen in congestive heart failure, cirrhosis, nephrosis, renovascular hypertension, Bartter syndrome, and pregnancy. Adrenal function is normal, and treatment is directed at the underlying condition.
Answer
A
15 The most common endogenous cause of Cushing syndrome is:
A Adrenocortical carcinoma
B ACTH-hypersecreting pituitary adenoma
C Cortisol-hypersecreting adrenal adenoma
D Ectopic ACTH-producing tumor
E Adrenal hyperplasia
Ref.: 1, 2
Comments
Overall, the most common cause of Cushing syndrome is the exogenous use of corticosteroids. Among the endogenous types of Cushing syndrome, an ACTH-hypersecreting pituitary adenoma is the most common (70%). Adrenal adenomas and ectopic adrenocorticotropic hormone-producing tumors each account for 10% of the endogenous causes of Cushing syndrome.
Answer
B
16 A 55-year-old male smoker with no previous medical history comes to the surgical clinic after having recently undergone CT for nonspecific abdominal pain. A 2.5-cm left adrenal mass was identified on CT. What is the next step in management of the incidental adrenal mass in this patient?
A Magnetic resonance imaging (MRI)
B CT-guided fine-needle aspiration (FNA) biopsy
C Biochemical work-up
D Observation and follow-up CT in 6 months
E CT of the lung
Ref.: 1, 2
Comments
Despite no previous history suggesting an underlying biochemical syndrome, the first step in management of an incidental adrenal lesion is to complete a functional evaluation. If the lesion is nonfunctional, the next step in management is to distinguish benign from malignant disease. MRI can be useful in this regard, but most times an index of suspicion for a malignant process can be garnered from CT alone. Image-guided biopsy is not believed to be useful in helping differentiate benign from malignant adrenal lesions. According to the National Institutes of Health (NIH) State-of-the-Science Conference on the work-up of adrenal incidentalomas, FNA is recommended in patients with a history of malignancy and no other signs of metastases. Before percutaneous biopsy it is imperative that the presence of a pheochromocytoma be excluded since a life-threatening pheochromocytoma crisis can occur with this intervention. Metastatic lung cancer should be considered in the differential diagnosis, but CT of the lung should not be the initial step in this patient.
Answer
C
17 A 66-year-old woman has a 3.8-cm left adrenal mass noted on CT. On review of the CT scan, which of the following suggests a benign lesion?
A Mass larger than 3 cm
B Rapidity of washout of contrast material of less than 50% at 10 minutes
C Unilateral lesions
D Heterogeneous enhancement
E Less than 10 Hounsfield units (HU)
Ref.: 1, 2
Comments
In the evaluation of nonfunctional tumors there are a number of radiographic findings that can assist the clinician in determining whether a lesion is likely to be benign or malignant (Table 18-1). Measurement of Hounsfield units on computed tomography is a commonly used parameter and is associated with acceptable rates of specificity and sensitivity when other features such as size, shape, or growth are considered. Less than 10 HU on unenhanced CT is indicative of a benign lesion. When intravenous contrast material is administered and delayed imaging is performed, the rapidity of washout of the contrast agent can be measured. Typically, benign lesions have rapid washout, with more than 50% of the initial attenuation value lost at 10 minutes on delayed imaging. Less than 50% washout suggests malignancy or pheochromocytoma. The reported sensitivity and specificity of assessing lesions by Hounsfield units with washout percentages are 98% and 92%, respectively.
TABLE 18-1 Adrenal Incidentalomas: Imaging Characteristics of Benign versus Malignant Lesions
Answer
E
18 The patient in Question 17 undergoes repeated CT in 1 year, followed by MRI. CT shows that the lesion has grown from 3.8 to 4.1 cm during that period. Characteristics on CT reveal a low-attenuation lesion with less than 10 HU. MRI shows a hyperintense lesion on T1-weighted in-phase MRI. What is the probable diagnosis in this patient?
A Adrenocortical adenoma
B Pheochromocytoma
C Adrenocortical carcinoma
D Myelolipoma
E Aldosteronoma
Ref.: 1, 2
Comments
The imaging characteristics described are typical of myelolipoma. These lesions are composed of erythroid, myeloid, and an abundant amount of adipose tissue. On non–contrast-enhanced CT, they are low attenuation and consistent with nearly pure fat. On MRI they are hyperintense on T1-weighted in-phase images. On T2-weighted images, malignant lesions are typically hyperintense and benign lesions are isointense relative to the liver. Generally, myelolipomas are benign and slow growing. There is no indication to surgically remove these lesions unless they are causing symptoms of compression or pain.
Answer
D
19 A 58-year-man has ACTH-independent hypercortisolism from a 5-cm left adrenal mass. He is initially seen in acute hepatic failure associated with corticosteroid psychosis and abdominal peritonitis. In this acute setting which of the following pharmacologic agents will assist in the management of this patient?
A Etomidate
B Mitotane
C Erythromycin
D Vincristine
E Intravenous vitamin A
Ref.: 1, 2
Comments
Etomidate, a commonly used induction agent for general anesthesia, is a potent inhibitor of the 11-hydroxylase enzyme. It is the only inhibitor of steroid synthesis that can be given parenterally. It is the treatment of choice for control of hypercortisolism in critically ill patients unable to take oral medications. Its onset of action is very rapid (<1 minute), and its half-life is only 3 to 5 hours. The drug is administered as a continuous infusion, with nonhypnotic doses ranging between 0.2 and 0.6 mg/kg/h. The infusion is titrated according to the decline in serum cortisol levels. Once the cortisol levels are brought within a physiologic range, some patients may require hydrocortisone supplementation to avoid the development of adrenal insufficiency. Mitotane, a multiple enzyme inhibitor of cortisol, is a derivative of the insecticide DDT (dichlorodiphenyltrichloroethane). Its onset of action takes several days to achieve, and its dose must be titrated slowly because of associated toxic side effects. It is available only in an oral formulation. For these three reasons, mitotane is not indicated in the acute treatment of critically ill patients with refractory hypercortisolism. The other drugs listed have no role in the management of hypercortisolism.
Answer
A
20 According to the most current recommendations, which size cutoff should be used to select patients with adrenal incidentalomas for surgery?
A 3 cm
B 4 cm
C 5 cm
D 6 cm
E 2 cm
Ref.: 3
Comments
The 2002 NIH Consensus Conference suggests that surgical resection should be considered for any nonfunctional incidentalomas 6 cm or larger. It is estimated that lesions larger than 6 cm have a 25% risk of harboring a malignancy. Observation is appropriate for lesions 4 cm or smaller. The risk for malignancy in a lesion smaller than 4 cm is 2%. Management recommendations for lesions between 4 and 6 cm are controversial. In more current studies, evidence has started to emerge that a lower threshold of 4 cm is appropriate. With improved imaging and increased use of laparoscopy in adrenal surgery, current practice has shown that more benign tumors are being removed because of lowering of the size criteria.
Answer
D
21 What is the most likely diagnosis in a patient who has elevated free cortisol and plasma ACTH levels and both low- and high-dose dexamethasone administration fail to suppress cortisol production?
A Bilateral adrenal hyperplasia
B Pituitary tumor
C Adrenal adenoma
D Ectopic ACTH-producing tumor
E Exogenous corticosteroids
Ref.: 1, 2
Comments
Failure to suppress cortisol production after the administration of high-dose dexamethasone concomitant with elevated plasma ACTH levels suggests that the hypothalamic-pituitary-adrenal axis is not intact. This scenario suggests the presence of an ectopic source of ACTH. Ectopic adrenocorticortropic hormone-producing tumors account for 10% to 15% of cases of Cushing syndrome. Thoracic tumors are more common than abdominal tumors as a cause of ectopic ACTH syndrome. Of those arising in the mediastinum, primary lung carcinoids are the most common. Following in frequency are small cell lung cancer and thymic tumors. In approximately 20% of patients the site of ACTH production is never found.
Answer
D
22 An increased risk for deep venous thrombosis has been associated with which of the following conditions?
A Hyperaldosteronism
B Pheochromocytoma
C Primary adrenal insufficiency
D Bilateral adrenal hyperplasia
E Hypercortisolism
Ref.: 4
Comments
There is a documented increased risk of 1.9% for deep venous thrombosis in patients with Cushing syndrome in the nonoperative setting. In postoperative Cushing patients, the risk for venous thromboembolism ranges between 0% and 5.6%. Chronic glucocorticoid excess produces a metabolic syndrome that is associated with increased morbidity and mortality. The elevated risk for venous thromboembolic disease is thought to in part be due to the increased prevalence of cardiovascular disease, glucose intolerance, and obesity. Some researchers have postulated that the hypercortisolism is associated with a hypercoagulable state independent of these associated risk factors.
Answer
E
23 Which of the following is not an associated feature of Cushing syndrome?
A Dyslipidemia
B Psychosis
C Hyperkalemia
D Nephrolithiasis
E Facial plethora
Ref.: 1, 2
Comments
Patients with Cushing syndrome can have a wide variety of symptoms. Classically, patients will have newly diagnosed or poorly controlled hypertension, glucose intolerance, and truncal obesity. Additional signs and symptoms include easy bruising, proximal muscle weakness, decreased libido, nephrolithiasis, and a static flushed facial appearance (facial plethora). Nephrolithiasis occurs in up to 50% of patients with Cushing syndrome. The underlying pathogenesis is not yet clearly defined. There is evidence that patients with Cushing syndrome have elevated urinary uric acid secretion, which could contribute to increased stone formation. Hyperkalemia is not a feature of Cushing syndrome; in fact, hypokalemia is more likely to occur given the weak mineralocorticoid effect of cortisol.
Answer
C
24 Which of the following is not a clinical feature of pheochromocytoma?
A Headache
B Hypoglycemia
C Anxiety
D Pallor
E Facial plethora
Ref.: 1, 2
Comments
Pallor, headache, and a sense of impending doom are all relatively common symptoms of patients with pheochromocytoma. Hyperglycemia is also a relatively common feature in such patients. The insulin-producing islet cells of the pancreas are under inhibitory control by α2 receptors. Thus, with catecholamine excess, a relative hypoinsulinemia can develop and lead to hyperglycemia. Flushing, nausea, and fever can occur rarely.
Answer
B
25 A 22-year-old man with a history of multiple endocrine neoplasia type IIA (MEN-IIA) is found on biochemical surveillance to have elevated serum catecholamines. CT reveals a 1-cm left adrenal mass and right adrenal fullness but no discrete mass. What is not appropriate management of this patient?
A Bilateral adrenalectomy
B Left adrenalectomy with cortical-sparing right adrenalectomy
C Left adrenalectomy
D Bilateral cortical-sparing adrenalectomy
E Observation
Ref.: 2
Comments
Considerable controversy exists around the appropriate surgical management of pheochromocytomas in patients with MEN. If at initial evaluation only one side shows evidence of a mass and unilateral adrenalectomy is performed, the chance of a contralateral pheochromocytoma developing over an interval of 12 years is 52%. Patients with multiple endocrine neoplasia type II should not undergo prophylactic removal of the contralateral side if no mass or presence of pheochromocytoma is confirmed. When the laterality of the pheochromocytoma is at question and the patient’s disease is relatively asymptomatic, observation in young patients has been the favored approach by some surgeons because nearly a fourth of patients will experience at least one episode of acute adrenal insufficiency requiring hospitalization. This is a special concern in young patients, in whom the reliability of taking medications regularly or adjusting for physiologic stressors is highly variable. Alternatively, surgeons have begun performing laparoscopic cortical-sparing procedures in these patients, in whom the success rate of avoiding exogenous steroid dependence is reported to be between 65% and 100%. Thus, in the patient described here, it would be appropriate to perform a left adrenalectomy, a left adrenalectomy with cortical-sparing removal of the right, or bilateral cortical-sparing adrenalectomy. Adrenal vein sampling in these patients preoperatively can be a useful adjunct to assess the prevalence of bilateral pheochromocytomas when imaging is not able to lateralize the side of active disease.
Answer
A
26 Which of the following biochemical tests for the work-up of pheochromocytomas has the highest sensitivity?
A Urinary norepinephrine
B Urinary vanillylmandelic acid
C Urinary total metanephrines
D Plasma free metanephrines and normetanephrine
E Urinary epinephrine
Ref.: 1, 2
Comments
Elevated plasma free metanephrine and normetanephrine levels have the highest sensitivity among all the tests listed. However, its specificity (risk for false-positive results) is lower than that of the others listed. The specificity of plasma free metanephrines can be improved by using a cutoff value of at least four times the upper limit of normal. Table 18-2 illustrates the specificity of the other biochemical tests performed for the evaluation of pheochromocytoma.
TABLE 18-2 Biochemical Tests for Pheochromocytoma
|
Test |
Sensitivity (%) |
Specificity (%) |
|
Plasma free metanephrines and normetanephrines |
99 |
85-89 |
|
Urinary total metanephrines |
71-77 |
93-99 |
|
Urinary epinephrine |
29 |
99 |
|
Urinary norepinephrine |
50 |
99 |
|
Urinary dopamine |
8 |
100 |
|
Urinary vanillylmandelic acid |
64 |
95 |
Answer
D
27 A 44-year-old man is due to undergo laparoscopic adrenalectomy for pheochromocytoma. Which of the following agents should not be given as the initial or only medication to help achieve appropriate preoperative adrenoreceptor blockade?
A Phenoxybenzamine
B Amlodipine
C Prazosin
D Atenolol
E Metyrosine
Ref.: 1, 2
Comments
Preoperative catecholamine receptor blockade is done to reduce the incidence and magnitude of intraoperative fluctuations in blood pressure and the development of arrhythmias. A β-blocker such as atenolol should never be administered before the use of an α-blocker because β-blockade can cause severe vasoconstriction and hypertension from inhibition of the vasodilator action of epinephrine. Prazosinand phenoxybenzamine are both α-blockers and have been used routinely for preoperative α-blockade in patients with pheochromocytoma. Infrequently, calcium channel blockers can be used as a substitute or as an adjunct to an α-blocker. The benefit of these agents is that coronary vasospasm is reduced and, when given in conjunction with an α-blocker, they can reduce the dosage of α-blocker needed. Metyrosine is an inhibitor of catecholamine synthesis that is also not commonly used in the preparation of patients with pheochromocytoma for surgery. The main limitations of metyrosine are its lack of widespread availability and patient tolerance of associated side effects.
Answer
D
28 The patient in Question 27 demonstrates signs of confusion and complains of sweating and headache several hours following his operation. His blood pressure is 130/65 mm Hg, his heart rate is 100 beats/min, and his respiratory rate is 12 breaths/min. What is the most likely cause of his symptoms?
A Dehydration
B Postoperative bleeding
C Hypoglycemia
D Narcotic overdose
E Incomplete removal of the pheochromocytoma
Ref.: 1, 2
Comments
In the postoperative setting, patients with pheochromocytoma should be monitored closely for signs or symptoms associated with hypoglycemia. Profound hypoglycemia can develop in these patients as a result of the rebound hyperinsulinemia that occurs with removal of the inhibitory catecholamine effect. Liver glycogen stores may be severely depleted in these patients because catecholamines promote glycogen breakdown. Thus, the patient’s ability to respond acutely to the hypoglycemia is impaired. It is unpredictable in which patients hypoglycemia will develop, so those with pheochromocytoma are usually administered a prophylactic dextrose infusion postoperatively.
Answer
C
References
1 Lal G, Clark OH. Thyroid, parathyroid and adrenal. In Brunicardi FC, Andersen DK, Billiar TR, et al, editors: Schwartz’s principles of surgery, ed 9, New York: McGraw-Hill, 2010.
2 Duh QY, Yeh MW. The adrenal glands. In Townsend CM, Beauchamp RD, Evers BM, et al, editors: Sabiston textbook of surgery: the biological basis of modern surgical practice, ed 18, Philadelphia: WB Saunders, 2008.
3 NIH state-of-the-science statement on management of the clinically inapparent adrenal mass (“incidentaloma”). NIH Consens State Sci Statements. 2002;19:1-25.
4 Van Zaane B, Nur E, Squizzato A, et al. Hypercoagulable state in Cushing’s syndrome: a systematic review. J Clin Endorinol Metab. 2009;94:2743-2750.