Causes of persistent dizziness. A prospective study of 100 patients in ambulatory care.

OBJECTIVE: To determine the causes of persistent dizziness in outpatients.
DESIGN: Consecutive adult outpatients presenting with a chief complaint of dizziness.
SETTING: Four clinics (internal medicine, walk-in, emergency room, and neurology) in a teaching hospital. PATIENTS: Of 185 patients presenting during the 10-month study period, 51 (28%) had minimal or no dizziness at 2-week follow-up. Of the remaining 134 patients, 100 completed the study protocol (mean age, 62 years; range, 20 to 85 years). MEASUREMENTS: Evaluation included a detailed study questionnaire, standardized physical examination, vestibular testing by a neuro-ophthalmologist, laboratory tests, audiometry, and a structured psychiatric interview. Data were abstracted onto a standard form and reviewed by three raters. Raters independently assigned diagnoses using explicit criteria, with the final cause determined by consensus.
RESULTS: Primary causes of dizziness included vestibular disorders (54 patients), psychiatric disorders (16 patients), presyncope (6 patients), dysequilibrium (2 patients), and hyperventilation (1 patient); dizziness was multicausal in 13 patients and of unknown cause in 8 patients. Many of those with a single primary cause, however, had at least one other condition contributing to their dizziness; only 52% of patients had a single "pure" cause. Thirty patients had a potentially treatable primary cause, the most common being benign positional vertigo (BPV) (16%) and psychiatric disorders (6%). Central vestibulopathies detected in 10 patients were presumably vascular or idiopathic in origin. No brain tumors or cardiac arrhythmias were found.
CONCLUSIONS: Vestibular disease and psychiatric disorders are the most common causes of persistent dizziness in outpatients. In about 50% of patients with dizziness, more than one factor causes or aggravates symptoms. Life-threatening causes were rare, even in our elderly population.