Pheochromocytoma stems from a chromaffin cell tumor of the adrenal medulla or sympathetic ganglia, occurring more commonly in the right adrenal gland than in the left. Extra-adrenal pheochromocytomas may be located in the abdomen, thorax, urinary bladder, neck, and in association with the 9th and 10th cranial nerves.

Pheochromocytoma may be inherited as an autosomal dominant trait.

Pheochromocytoma produces the same complications as those of severe, persistent hypertension, cerebrovascular accident (CVA), retinopathy, heart disease, and irreversible kidney damage. Commonly, the disorder is diagnosed during pregnancy when uterine pressure on the tumor induces more frequent attacks of hypertensive crisis. Such attacks can prove fatal for mother and fetus as a result of CVA, acute pulmonary edema, cardiac arrhythmias, or hypoxia. In such patients, the risk of spontaneous abortion is high, but most fetal deaths occur during labor or immediately after birth. Cholelithiasis is commonly associated with this disorder.

Patients with pheochromocytoma have an increased risk of serious complications and death during invasive diagnostic testing and surgery. After adrenalectomy, severe hypotension resulting in circulatory collapse and shock may occur.

The cardinal sign of pheochromocytoma is persistent or paroxysmal hypertension. The patient’s history may reveal unpredictable episodes of hypertensive crisis, paroxysmal symptoms suggestive of seizure disorder or anxiety attacks, hypertension that responds poorly to conventional treatment and, in some cases, hypotension or shock resulting from surgery or diagnostic procedures.

The patient may detail attacks that include headache, palpitations, visual blurring,
nausea, vomiting, severe diaphoresis, feelings of impending doom, and precordial or abdominal pain. The attacks may be precipitated by any activity or condition that displaces the abdominal contents, such as heavy lifting, exercise, bladder distention, or pregnancy. Severe attacks may be triggered by the administration of opiates, histamine, glucagon, and corticotropin although, sometimes, no precipitating event is found.

The patient may also report mild to moderate weight loss caused by increased metabolism. In addition, she may have symptoms related to orthostatic hypotension, such as dizziness, light-headedness, or faintness when rising to an upright position.