PHYSICAL EXAMINATION

VS: T 98.7°F, P 128/min, R 17/min, BP 146/95 mm Hg, BMI 25

LABORATORY STUDIES

Blood test:

24-Hour urine specimen:

Abdominal CT: Tumors on adrenal glands

DIAGNOSIS

Pheochromocytoma

PATHOPHYSIOLOGY OF KEY SYMPTOMS

The patient’s symptoms are consistent with marked activation of the sympathetic nervous system. The duration and intermittent nature of the episodes, however, are more consistent with an endocrine action rather than an autonomic nervous system action.

The sympathetic nervous system consists of the sympathetic nerves and the adrenal medulla. Norepinephrine is a neurotransmitter at the postganglionic sympathetic nerve terminals. The adrenal medulla receives preganglionic sympathetic nerves from the spinal cord (Fig. 73-1), but, rather than function as a postganglionic nerve, the adrenal medulla secretes the catecholamines epinephrine and norepinephrine into the bloodstream, where they act as hormones.

FIGURE 73–1 Distribution of sympathetic nerves.