Controversies in Hypertension VI: Paroxysmal Hypertension

Paroxysmal hypertension is characterized by a sudden and significant increase in blood pressure that may have coexisting hyperadrenergic symptoms (headache, palpitations, diaphoresis) with or without an obvious precipitating cause. Pheochromocytoma is suggested, although less than 1% of such patients have the tumor. Four syndromes should be considered, including labile hypertension, panic attacks, pseudopheochromocytoma, and baroreflex failure. Labile hypertension includes paroxysms that are provoked by obvious stress or anxiety; they may be asymptomatic or have hyperadrenergic symptoms. Similarly, panic attacks are precipitated by fear or anxiety. Pseudopheochromocytoma is characterized by paroxysms without obvious precipitating stress or anxiety, although anxiety may result from the paroxysm, and the paroxysms are invariably symptomatic; abnormal repression of emotions underlies most cases. Afferent baroreflex failure presents as symptomatic hypertensive paroxysms often precipitated by emotional or environmental stress alternating with periods of frank hypotension; orthostatic hypotension frequently coexists. No guidelines specify therapy of paroxysmal hypertension and no randomized controlled trials with hard endpoints exist for this syndrome. We discuss in detail the 4 pheochromocytoma mimics in the differential diagnosis of paroxysmal hypertension with recommendations on diagnosis and therapy.