18 Vertigo and Disequilibrium Vertigo and disequilibrium can be due to otologic, neurologic, psychiatric, metabolic, and cardiac etiologies, so patients with these symptoms may require evaluation by multiple clinicians. A thorough clinical history is sufficient to diagnose a majority of patients presenting with imbalance, although imaging can also be indicated. Vertigo is often described as an acute intense rotary spinning sensation, whereas disequilibrium, dizziness, and giddiness are often thought of as less intense chronic sensations of imbalance. Rather than being separate entities, however, vertigo and disequilibrium may be part of a continuum of movement sensations and may be present in the same patient suffering from a single diagnostic entity. Medications that can cause vertigo and disequilibrium are listed in Table 18.1 . Eye movements seen on neurovestibular examination are listed in Table 18.2 Labyrinthitis is a common cause of vertigo that usually arises during or after a viral upper respiratory infection. Symptoms of vertigo may be intense, and there may be associated sensorineural hearing loss and/or tinnitus. Nystagmus is typical; however, other neurologic findings would not be expected. A change in any position can worsen dizziness symptoms, but the symptoms do not arise in a specific inciting position. Alcohol ingestion can cause acute nausea and can exacerbate preexisting vestibular conditions. It affects both the peripheral vestibular system and the central nervous system. Examination will often reveal obvious signs of alcohol use, as well as nystagmus. Chronic alcohol usage can lead to cerebellar atrophy with resulting ataxia. Gait is often more affected than limb and ocular control. Benign paroxysmal positional vertigo is a common cause of peripheral vertigo. Canalithiasis, with free-floating otoconia in the endolymph of the membranous labyrinth, is the most commonly accepted etiology, occurring mainly in the posterior semicircular canal, but in some patients affecting the lateral semicircular canal. Posterior canal symptoms include vertigo of brief duration, with associated rotational geotropic (toward the ground) torsional nystagmus, which is fatigable and precipitated by head movement. Diagnosis is made by inducing fatigable nystagmus with the Dix-Hallpike maneuver, which entails taking the patient from the sitting position to the lying position with the neck extended and head hanging and turned to one side or the other.
Vertigo and Disequilibrium: Inner Ear
Labyrinthitis
Alcohol-Induced Vestibulopathy
Benign Paroxysmal Positional Vertigo
Drug | Type of Dizziness | Mechanism |
Aminoglycosides Platinum compounds (cisplatinum) | Vertigo, Disequilibrium | Damage to vestibular hair cells |
Antiepileptics Carbamazepine Phenytoin Primidone | Disequilibrium | Cerebellar toxicity |
Tranquilizers Barbiturates Antihistamines Tricyclic amines | Intoxication | CNS depression |
Antihypertensives, diuretics | Near-syncope |
