see post #49 of this thread in the nursing student assistance forum for the pathophysiology of pulmonary tb
a pheochromocytoma is a tumor of the endocrine system that produces norepinephrine. if the tumor becomes large enough it also produces epinephrine as well. the tumors come from adrenal medullary cells. if they metastasize they go to the lungs, liver, bones or paraaortic lymph glands.
(page 700, pathophysiology: the biologic basis for disease in adults and children, third edition, by kathryn l. mccance and sue e. heuther)
pheochromocytomas cause excessive production of catecholamines attributable to autonomous functioning of the tumor. other causes of elevated levels of catecholamines include defects in the normal inhibition of tyrosine hydroxylase or defects in the control mechanisms responsible for the regulation of catecholamine synthesis and release. approximately 5% of people with pheochromocytomas have no symptoms, apparently because the tumor is nonfunctioning. such tumors can, however, release catecholamine, especially in response to a stressor."
other pathophysiology information i have on this kind of tumor is that they stem from a chromaffin cell tumor of the adrenal medulla or sympathetic ganglia, but more commonly the right adrenal gland than the left. patients will often have a history of unpredictable episodes of hypertensive crises, paroxysmal symptoms similar to seizure disorders or anxiety attacks, and hypertension that does not respond to conventional treatment. they may occur during pregnancy; when uterine pressure on the tumor causes more frequent hypertensive crises that can result in spontaneous abortion. i have other information that claims pheochromocytomas may occur in the abdomen, thorax, urinary bladder and the neck in association with cranial nerves ix and x. they may be an inherited autosomal dominant trait. they are rare, occurring in only 0.5% of newly diagnosed hypertensive patients. this condition occurs equally among all races and sexes of people. it tends to occur within families and is most common in ages 30 to 50.
these patients will have paroxysms (sudden, periodic attacks) or crises where they experience:
- throbbing headaches
- palpitations and tachycardia
- visual blurring
- nausea and vomiting
- high blood sugar
- high lipid levels
- severe diaphoresis
- a feeling of impending doom
- precordial or abdominal pain
- weight loss
- dizziness when moving to an upright position
- pallor or flushing
- profuse sweating
- irreversible kidney damage
- acute pulmonary edema
- cardiac arrhythmias
- heart failure
(page 600, nurse's 5-minute clinical consult: diseases from lippincott williams & wilkins