Pheochromocytoma Quiz: What's Your Pheo IQ?

Managing hypertension can be like exploring an iceberg - deceivingly more complex than at first blush, especially for those patients whose blood pressures are stubbornly refractory to your recommendations of multiple medications, and lifestyle changes. Secondary causes of hypertension abound-and we must always keep these in mind. Pheochromocytomas (pheo) are very rare tumors of the adrenal glands that produce excess epinephrine and norepinephrine; they can increase risk of CVA, MI, and death.

Here are a few questions to consider about this intriguing endocrine disorder.

1. What is the classic clinical triad of pheochromocytoma?A. Hyperventilation, paresthesias, and headache

B. Headache, chest pain, and diaphoresis

C. Palpitations, dizziness, and jaw claudication

D. Headache, diaphoresis, and palpitations

Please click here for answer and next question.

Answer: D. The classic triad is headaches, diaphoresis, and palpitations though only ~40% of individuals present with these symptoms. Approximately 10% are diagnosed incidentally-when undergoing imaging for another reason.

2. Which of the following statements about hypertension in patients with pheo is true?

A. All pheo patients have hypertension that is sustained and suboptimally controlled

B. Some patients have paroxysmal hypertension

C. Some patients do not have hypertension

D. B and C

E. None of the above 

Please click here for answer and next question.

Answer: D (B and C). Patients may also have protean presentations. While many patients have episodic hypertension, some have consistently high BP, and still other patients (~10%) are normotensive.

3. Which of the following should be included in your differential diagnosis for pheo?A. Hypothyroidism

B. Primary aldosteronism

C. Hypoglycemia

D. Cushing’s disease

E. Fibromuscular dysplasia

Please click here for answer and next question.

Answer: C. Hypoglycemia. You should keep hypoglycemia in mind, though a patient certainly can also have labile essential hypertension.

4. You’ve been consulted on a 46-year-old woman with suboptimally controlled hypertension, admitted for a heart failure (HF) exacerbation. The inpatient team ordered plasma metanephrines and the results are: 

• Normetanephrine: 136 pg/mL (18 to 111 pg/mL)
• Metanephrine: 68 pg/mL (12 to 60 pg/mL)

What would you do next?

A. Do not conduct these tests when a patient is admitted

B. Consult Endocrinology for further workup; the patient likely has a pheochromocytoma

C. Obtain urine catacholamines and metanephrines

D. Repeat plasma metanephrines as soon as possible

Please click here for answer and next question.

Answer: A. Do not conduct these tests when a patient is admitted. The physical and mental/emotional stress of being acutely ill and hospitalized preclude testing for a pheo while a patient is inpatient because catecholamines may be slightly elevated. The test with the highest sensitivity for a pheo? Plasma metanephrines-with a sensitivity of 96% and specificity of 85%. A 24-hour urinary catecholamines and metanephrines has a sensitivity of 87.5% and a specificity of 99.7%.

5. Pheochromoctyomas are rare. Approximately _____ cases are diagnosed yearly in the US, and these account for approximately ______% of cases of hypertension per year.A. 5,000 and 0.7%

B. 3,000 and 0.5%

C. 1,000 and 0.2%

Please click here for answer and next question.

Answer: C. 1,000 and 0.2%. Pheos are extremely rare-we see about 2-8 cases per 1 million persons each year.

Bonus question: What are catecholamine-producing tumors found outside of the adrenal gland called, and where do they arise from?

Please click here for answer.

Bonus answer: Paraganglioma and Organ of Zuckerkandl

This one probably had you reach back to your medical school and/or board exam-studying days! The organ was named after Dr. Emil Zuckerkandl. This Hungarian-Austrian anatomist in 1901 described a chromafin body at either the bifurcation of the aorta, or the origin of the inferior mesenteric artery.