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

To determine the causes of persistent dizziness in outpatients.

Consecutive adult outpatients presenting with a chief complaint of dizziness.

Four clinics (internal medicine, walk-in, emergency room, and neurology) in a teaching hospital.

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).

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.

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.

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.