The treacherous and deceptive nature of
pheochromocytoma makes it crucial to detect and treat it promptly; otherwise it will almost certainly be fatal from cardiovascular complications or
metastases.
Hypertension occurring in patients with
pheochromocytomas is sustained in about 50% and paroxysmal in the remainder; however, many patients remain normotensive.
Hypertension attacks may be precipitated by physical activity, postural changes, anxiety, certain foods or wine, some drugs, operative procedures, etc. Cardinal manifestations are paroxysmal
hypertension,
headache, palpitations +/-
tachycardia, inappropriate sweating; anxiety, tremulousness, pallor (rarely
flushing), chest and
abdominal pains;
nausea and
vomiting often occur. Hypercatecholaminemia manifestations are more common and pronounced when paroxysmal
hypertension occurs, but persons with
familial pheochromocytoma may be asymptomatic. Protean manifestations of
pheochromocytoma may simulate many conditions, some of which may have elevated plasma and urine
catecholamines and their metabolites. Baro-reflex failure,
postural tachycardia syndrome,
sleep apnea,
carcinoid,
renal failure, and pseudopheochromocytoma may be diagnostic challenges. The history, physical examination, biochemical testing (after eliminating interfering drugs, when possible) for plasma and urinary metanephrines can usually establish or exclude presence of
pheochromocytomas. Occasionally a
clonidine suppression test is needed to differentiate neurogenic from pheochromocytic
hypertension. Manifestations suggesting hypercatecholaminemia without
hypertension are highly atypical of
pheochromocytoma.
Pheochromocytoma may present as
panic attacks,
pre-eclampsia,
cardiomyopathy,
infection with
fever and leucocytosis, diabetes,
migraine,
shock,
Cushing's syndrome,
multiple organ failure with
lactic acidosis,
neurological manifestations, transitory electrocardiogram abnormalities,
constipation,
intestinal obstruction,
visual impairment, convulsions, etc. The key to diagnosis is always to think of
pheochromocytoma in the differential diagnosis of
hypertension.