Pheochromocytoma. Update on diagnosis, localization, and management.

Pheochromocytoma, although rare, is associated with a high degree of morbidity and mortality if not recognized. A high degree of suspicion in patients with new-onset hypertension; hypertension with sudden worsening or development of diabetes mellitus; or a family history of MEN, neuroectodermal tumors, or simple pheochromocytoma should prompt biochemical confirmation with either 24-hour urine catecholamines (norepinephrine and epinephrine) or total MET (NMET plus MET). Following confirmation of the diagnosis, radiologic studies with CT and (if needed) MIBG are employed to localize the tumor. Surgical removal is the only definitive therapy. Medical management with alpha-blocking agents, to control symptoms and prevent a hypertensive crisis, is generally advocated for 2 weeks preoperatively and intraoperatively. Occasionally, beta-blockers, employed only after adequate alpha-blockade, are necessary to control tachycardia and tachyarrhythmias. High-dose MIBG and combination chemotherapy have been used adjunctively to treat malignant pheochromocytoma, although neither modality provides lasting satisfactory results. Normal urine assays performed 2 weeks postoperatively ensure the complete removal of all tumor. Additionally, lifelong follow-up (yearly initially) is necessary to detect any signs of benign recurrence or malignancy because these have been reported to occur as long as 41 years after the initial surgical resection. Biochemical evidence of excess catecholamine production usually precedes the clinical manifestations of catecholamine excess when these tumors recur.

Acute adrenal insufficiency.

Acute adrenal insufficiency is a rare disorder associated with high morbidity and mortality if allowed to progress unrecognized. A constellation of nonspecific symptoms including weakness, easy fatigue, nausea, anorexia, and weight loss are typical features of adrenal insufficiency. The index of suspicion should be particularly high if the patient has hyperpigmentation; hyponatremia and/or hyperkalemia; a history of autoimmune disease (hypothyroidism, diabetes) or recent prior use of exogenous steroids or if the patient is on anticoagulant therapy. Any decline in clinical status (hypotension, fever, decreasing mental status), especially in the setting of an acute intercurrent illness, should be treated aggressively, even before laboratory confirmation of the diagnosis. Diagnostic testing is fairly straightforward and readily available. The development of purified synthetic corticosteroid preparations has provided a safe and effective means of replacement. Early awareness, recognition, and intervention remain significant steps in altering the course of acute adrenal insufficiency.