Dizziness accounts for an estimated 5 percent of primary care clinic visits. The physician who encounters this complaint should investgate only after classifying it into one of four categories: vertigo, disequilibrium, presyncope, or lightheadedness. Each one has a distinct differential diagnosis. The differential diagnosis of dizziness can be narrowed with easy-to-perform physical examination tests, including evaluation for nystagmus, the Dix-Hallpike maneuver, and orthostatic blood pressure testing. Laboratory testing and radiography play little role in diagnosis and, in fact, final diagnosis is not obtained in about 20 percent of cases. Romberg test and observation of gait can lead the physican to consider vestibular dysfunction. Ataxia is indicative of cerebellar dysfunction, and the patient’s gait is usually slow, wide-based, and irregular.
When nystagmus accompanies the complaint of dizziness, lesions of the labyrinth and cranial nerve VIII (vestibulocochlear) should be suspected. When nystagmus is not spontaneously present but is only provoked by maneuvers such as Dix-Hallpike maneuver, a vertebral apparatus cause is suspected.
The referenced article by Post et al is a good review of the issue.
ROBERT E. POST, MD, Virtua Family Medicine Residency, Voorhees, New Jersey
LORI M. DICKERSON, PharmD, Medical University of South Carolina, Charleston, South Carolina
Am Fam Physician. 2010 Aug 15;82(4):361-368.
Kevin A. Kerber, MD and A. Mark Fendrick, MD The Evidence Base for the Evaluation and Management of Dizziness. J Eval Clin Pract. 2010 February; 16(1): 186–191.