Recurrent short-lasting headache associated with paroxysmal hypertension: a clonidine-responsive syndrome

The clinical syndrome of hypertension, headache, palpitation, diaphoresis, flushing, and emotional lability is classically associated with pheochromoc ytoma. Two patients are presented with this constellation of symptoms in wh om investigations for pheochromocytoma were unrevealing. Headache was the p resenting and most prominent complaint, with daily episodes of short-lastin g, intermittent, and paroxysmal attacks. Each paroxysm of headache was asso ciated with a dramatic increase in systolic and diastolic blood pressure. A fter failure to control the labile fluctuations in blood pressure and heada che with several classes of anti-hypertensive medications used in combinati on, a prompt and persistent response occurred after the administration of c lonidine. The pathophysiology of this syndrome and the mechanism of clonidi ne action are reviewed in the context of a possible failure of the barorece ptor reflex.