A pheochromocytoma is a rare, catecholamine-secreting tumor that may precipitate life-threatening hypertension.
Pheochromocytomas are rare, reportedly occurring in 0.05–0.2% of hypertensive individuals. This accounts for only a portion of cases, however, as patients may be completely asymptomatic. A retrospective study from the Mayo Clinic revealed that in 50% of cases of pheochromocytoma, the diagnosis was made at autopsy. [21] Approximately 10% of pheochromocytomas are discovered incidentally.
Pheochromocytomas occur in people of all races, although they are diagnosed less frequently in blacks. Pheochromocytomas may occur in persons of any age, but the peak incidence is from the third to the fifth decades of life. Approximately 10% occur in children. Fifty percent of pheochromocytomas in children are solitary intra-adrenal lesions, 25% are present bilaterally, and 25% are extra-adrenal
Clinical signs associated with pheochromocytomas include the following:
Hypertension: Paroxysmal in 50% of cases
Postural hypotension: From volume contraction
Hypertensive retinopathy
Weight loss
Pallor
Fever
Tremor
Neurofibromas
Tachyarrhythmias
Pulmonary edema
Cardiomyopathy
Ileus
Café au lait spots
- Diagnostic tests for pheochromocytoma include the following:
Plasma metanephrine testing: 96% sensitivity, 85% specificity [1]
24-hour urinary collection for catecholamines and metanephrines: 87.5% sensitivity, 99.7% specificity [2]
- Test selection criteria include the following:
Use plasma metanephrine testing in patients at high risk (ie, those with predisposing genetic syndromes or a family or personal history of pheochromocytoma)
Use 24-hour urinary collection for catecholamines and metanephrines in patients at lower risk
Surgical resection of the tumor is the treatment of choice and usually cures the hypertension. Careful preoperative treatment with alpha and beta blockers is required to control blood pressure and prevent intraoperative hypertensive crises. [4]
Preoperative medical stabilization is provided as follows:
Start alpha blockade with phenoxybenzamine 7-10 days preoperatively
Provide volume expansion with isotonic sodium chloride solution
Encourage liberal salt intake
Initiate a beta blocker only after adequate alpha blockade, to avoid precipitating a hypertensive crisis from unopposed alpha stimulation
Administer the last doses of oral alpha and beta blockers on the morning of surgery.
(Medscape)