2. PHEOCHROMOCYTOMA
Pheochromocytoma is a tumor that is usually benign and originates
from the chromaffin cells of the adrenal medulla.
In 80% to 90% of patients, the tumor arises in the medulla; in the
remaining patients, it occurs in the extra-adrenal chromaffin tissue
located in or near the aorta, ovaries, spleen, or other organs.
Pheochromocytoma may occur at any age, but its peak incidence is
between ages 40 and 50 years
3. Pheochromocytoma is the cause of high blood pressure in 0.2% of
patients with new onset of hypertension.
Pheochromocytoma may occur in the familial form as part of multiple
endocrine neoplasia type 2;
4. Clinical Manifestations
The nature and severity of symptoms of functioning tumors of the
adrenal medulla depend on the relative proportions of epinephrine
and norepinephrine secretion.
The typical triad of symptoms comprises headache, diaphoresis, and
palpitations.
Hypertension and other cardiovascular disturbances are common.
Other symptoms may include tremor, headache, flushing, and anxiety.
5. Hyperglycemia may result from conversion of liver and muscle
glycogen to glucose by epinephrine secretion; insulin may be required
to maintain normal blood glucose levels.
The clinical picture in the paroxysmal form of pheochromocytoma is
usually characterized by acute, unpredictable attacks lasting seconds
or several hours.
During these attacks, the patient is extremely anxious, tremulous, and
weak.
The patient may experience headache, vertigo, blurring of vision,
tinnitus, air hunger, and dyspnea.
6. Other symptoms include polyuria, nausea, vomiting, diarrhea,
abdominal pain, and a feeling of impending doom.
Palpitations and tachycardia are common.
Blood pressures exceeding 250/150 mm Hg have been recorded.
7. Such blood pressure elevations are life-threatening and may cause
severe complications, such as cardiac dysrhythmias, dissecting
aneurysm, stroke, and acute renal failure.
Postural hypotension occurs in 70% of patients with untreated
pheochromocytoma.
8. Assessment and Diagnostic Findings
Pheochromocytoma is suspected if signs of sympathetic nervous
system overactivity occur in association with marked elevation of
blood pressure.
These signs can be associated with the “five Hs”: hypertension,
headache, hyperhidrosis (excessive sweating), hypermetabolism, and
hyperglycemia.
9. Factors that may elevate catecholamine levels must be controlled to
obtain valid results; these factors include consumption of coffee or tea,
use of tobacco, emotional and physical stress, and use of many
prescription and over-the-counter medications (eg, amphetamines,
nose drops or sprays, decongestant agents, and bronchodilators).
10. Imaging studies, such as CT scans, MRI, and ultrasound, may also be
carried out to localize the pheochromocytoma and to determine
whether more than one tumor is present.
I-metaiodobenzylguanidine (MIBG) scintigraphy may be required to
determine the location of the pheochromocytoma and to detect
metastatic sites outside the adrenal gland.
11. SURGICAL MANAGEMENT
The definitive treatment of pheochromocytoma is surgical removal of
the tumor, usually with adrenalectomy.
Bilateral adrenalectomy may be necessary if tumors are present in both
adrenal glands.
Administration of antihypertensive medications
Intravenous fluid administration
Corticosteroid replacement is required if bilateral adrenalectomy has
been necessary.
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