Kuchel and colleagues2,11 considered this disorder to be a form of "hyperadrenergic-essential hypertension," but could not explain why it occurs. Many entities, such as anxiety, hyperthyroidism, hyperdynamic β-adrenergic circulatory state, cluster or migraine headaches, hypertensive encephalopathy, coronary insufficiency, renovascular hypertension, central nervous system lesions (stroke, tumor, hemorrhage, compression of lateral medulla, trauma), seizure disorder, carcinoid, drugs (cocaine, lysergic acid diethylamide, amphetamine), tyrosine ingestion combined with monoamine oxidase inhibitors, baroflex failure, and factitious hypertension, can occasionally manifest as paroxysmal hypertension and should be considered where clinically appropriate. Other entities can on rare occasion manifest as paroxysmal hypertension,1 but are rare in the absence of any other signs or symptoms suggestive of them.