Doctor, I’m Dizzy!
Abstract & Commentary
Source: Baloh RW. Vestibular Neuritis. N Engl J Med. 2003;348:1027-1032.
Differentiating central from peripheral causes of vertigo is a recurrent clinical challenge that behooves reinforcement. Bedside examination usually suffices, based on the characteristics of the nystagmus, the presence of associated symptoms (or their absence), and results of the head-thrust test. In contrast to centrally originating nystagmus, which is purely unidirectional (horizontal, vertical, or rotational) and which changes direction with change in direction of gaze, nystagmus of peripheral origin is typically horizontal with a rotational component, does not change direction with change in gaze, and demonstrates a positive head-thrust test. Centrally caused vertigo often precludes standing upright without assistance, whereas patients with peripheral vertigo can stand, though they will lean to the side of the lesion. In association with an otherwise normal neurological examination, these characteristics permit a confident diagnosis of peripherally originating vertigo precluding the necessity for expensive imaging procedures. Electronystagmography and audiography are even less rarely required.
Performance of the head-thrust test is straightforward. Have the patient hold his head forward but looking 10° to one side and ask him to continuously fixate on your nose. Quickly jerk the head slightly to that side and watch for corrective saccades. Repeat with the eyes looking to the opposite side. If corrective saccades are present, they indicate that the eyes are moving with the head rather than fixating on the nose and are a sign of vestibulopathy. If the "catch-up" saccades occur with the eyes in one direction but not the other, you have documented an ipsilateral peripheral vestibular lesion, either in the labyrinth or eighth nerve.
Prolonged vertigo, lasting hours to days when associated with unilateral hearing loss, suggests labyrinthitis, labyrinthine infarction, or perilymph fistula. In the absence of hearing impairment, prolonged vertigo suggests vestibular neuritis (neuronitis), whereas in association with neurologic signs and symptoms brainstem or cerebellar infarction is to be considered. Vertigo in Ménière’s disease rarely lasts longer than 4-5 hours and is associated with hearing loss, which, however, may not be present initially.
Vertigo is best treated acutely with antihistamines (promethazine, dimenhydrinate, meclizine), anticholinergic or antidopaminergic agents, or GABA-enhancing agents (diazepam, lorazepam). Intramuscular or intravenous administration may be necessary due to the nausea commonly accompanying vertigo. Recovery is otherwise spontaneous, although dizziness and a sense of imbalance may last for weeks to months. Vestibular exercises, including eye-and-head coordination and balance exercises, should begin as soon as possible as they may shorten the recovery period. Antiviral agents and prednisone are of no proven benefit and long-term use of antihistamines should be avoided as they interfere with the central compensation mechanisms needed for recovery.
Commentary
Dizziness and vertigo are among the most common complaints seen by neurologists, and benign paroxysmal positional vertigo (BPPV) is one of their most frequent causes. Resulting from otolithic debris in the lumen of, most commonly, the posterior semicircular canal, BPPV may be easily cured in the majority of instances by the Epley1 or Semont2 maneuvers. Regardless of the maneuver chosen, additional enhancements such as mastoid vibration or post-treatment positional restriction adds little. Significantly, neither patient age nor duration of symptoms affects treatment outcome, and the maneuver is recommended even in the elderly with long-standing symptoms.3 Furthermore, the Semont maneuver benefits patients with a typical BPPV history even in the absence of demonstrable nystagmus on Dix-Hallpike testing.4 Overall, 90% of BPPV patients benefit, but there is a 50% 5-year recurrence rate,5 underscoring the importance of self-treatment. Radtke’s modified Epley procedure6 is preferred (more effective) than Brandt-Daroff exercises.7 — Michael Rubin, MD, Professor of Clinical Neurology, New York Presbyterian Hospital-Cornell Campus, Assistant Editor, Neurology Alert.
References
1. Epley JM. Otolaryngol Head Neck Surg. 1992;107: 399-404.
2. Semont A, et al. Adv Otorhinolaryngol. 1988;42:290-293.
3. Wolf M, et al. Clin Otolaryngol. 1999;24:43-46.
4. Haynes DS, et al. Laryngoscope. 2002;112:796-801.
5. Nunez RA, et al. Otolaryngol Head Neck Surg. 2000;122:647-652.
6. Radtke A, et al. Neurology. 1999;53:1358-1360.
7. Bronstein AM. Curr Opin Neurol. 2003;16:1-3.
Differentiating central from peripheral causes of vertigo is a recurrent clinical challenge that behooves reinforcement.
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