Exertional dizziness and autonomic dysregulation

Objectives: To define the clinical characteristics and treatment of dizziness induced by physical exertion and to investigate autonomic nervous system function in exertional dizziness. Study Design: Retrospective case series from a review of 1400 patients evaluated for dizziness at a neurotology referral center, identifying those with predominantly exertional symptoms. Methods: Records of patients with exertional dizziness were screened to eliminate those with known vestibular deficits, cardiopulmonary illnesses, and psychiatric disorders. The clinical characteristics, evaluation results, and treatment of nine patients with purely exertional dizziness were described. Results: The cohort included 4 male and 5 female patients (age range, 13-53 y) with symptoms for 1 to 8 years. Only one patient had a history of autonomic symptoms: phlebotomy-induced syncope in childhood. No patient was taking medications that caused dizziness or orthostasis. All patients experienced "spacey" or "foggy" head sensations without vertigo during exertion. Provocative activities ranged from standing upright for extended periods to running and swimming. On examination, voluntary hyperventilation provoked moderate symptoms in all patients (without nystagmus or anxiety), although no patient had spontaneously occurring, hyper-ventilation-related complaints. Seven patients underwent autonomic testing. Tilt table tests (n = 5) produced severe symptoms in one patient and mild symptoms in two patients. Sodium lactate infusions (n = 6) provoked marked symptoms in four patients and moderate symptoms in one patient. All were treated for autonomic dysregulation. Seven patients improved substantially and resumed all of their premorbid activities. Two improved slightly. Conclusions: In nine patients with exertional dizziness, autonomic challenges were provocative, and medications for autonomic dysregulation were effective. Exertional dizziness may be a clinical manifestation of autonomic nervous system dysregulation.