Severe, disabling dizziness after intratympanic aminoglycoside treatment for dizziness.

Unlike all other installments of VESTIBULOLOGY CLINIC in this series, this one features no electronystagmography (ENG) tracings. This omission is made deliberately to underscore the fact that in the case presented here, ENG was not performed prior to perfusion with an intratympanic amninoglycoside.

A 69-year-old woman reported that she experienced dizziness one morning as she awoke briefly and turned over. She went back to sleep, and when she awoke again, she experienced a severe rotary dizziness that lasted 30 minutes before subsiding. Later, she arose from bed and ate breakfast. Shortly thereafter, she again experienced rotary vertigo, which was then accompanied by nausea and vomiting, for 90 minutes. At that point, the woman took a nap for a couple of hours. When she awoke, her nausea was gone, but the rotary dizziness remained.

The woman went to the emergency room, where she was treated with intravenous fluids, phenergan, and meclizine. She spent the night in the hospital for dehydration. The spinning feeling, which remained continuous, was marked by both an off-balance feeling and an up-and-down sensation. She experienced no symptoms while she was lying down and sitting and when she was not moving. A 1-week course of diazepam was added to her regimen, but it produced a lifeless feeling and was discontinued early. Later, the meclizine was replaced by dexamethasone while she continued to take phenergan, but these drugs provided no benefit.

The patient said that she believed she had had a hearing problem in her right ear for about 22 years, which was of gradual onset and slowly progressive. She added that just prior to the onset of that hearing loss, she had experienced tinnitus in the right ear, which manifested as an intermittent pulsatile sound that became louder when she was upset. She also reported a 40-year history of either right forehead or right nuchal headaches, but they had improved by 90% since the onset of the dizziness. Finally, she reported that she had also felt a right nuchal heaviness for the previous 22 years.

Five months following her first visit, a Dix-Hallpike test revealed that nystagmus occurred only when her head was down and to the left. No other vestibular testing was undertaken. Audiology revealed a symmetric binaural high-tone sensorineural hearing loss and a normal binaural speech reception threshold and normal discrimination. Based on this information, she received a left intratympanic aminoglycoside perfusion for 3 consecutive days.

Three days following the final perfusion, the woman found that she had great difficulty getting out of bed because she could not maintain her balance. She said the degree of dizziness was worse than it was before the perfusions. She was also unable to focus her eyes while she was driving.

She enrolled in a vestibular rehabilitation program, but after 2 weeks she was told that she could expect no benefit from it. She was able to walk on a treadmill indoors, but was unable to walk outside. She had a constant feeling of imbalance and a feeling that her surroundings were moving whenever she moved.

ENG findings

Two months later she underwent ENG, which revealed a spontaneous left-beating nystagmus of 3.20[degree]/sec. There was no response to either warm or cool stimuli in either ear. The patient did not report any dizziness during the irrigations. Sinusoidal vertical-axis rotation testing revealed low gains at all four frequencies, which was consistent with a hypoactive vestibular system.

Six months after the aminoglycoside perfusions, we again evaluated her in our vestibular laboratory. At that examination, she had a direction-fixed, left-beating nystagmus in all positions except the 30[degrees] supine. Again, she exhibited no response to warm, cool, or icewater stimuli binaurally.

From all the information available prior to ENG, it is likely that the source of this patient's dizziness was the right ear, which had a markedly reduced vestibular function. Because of the commonly held belief that the source of dizziness during the Dix-Hallpike maneuver is almost always the undermost ear, this patient's left ear was subjected to the aminoglycoside perfusions. (The idea that the undermost ear is not always the source of dizziness was discussed in a previous VESTIBULOLOGY CLINIC. [1]) Had ENG been performed prior to the perfusion, the hypoactive right ear would have been identified. This finding in the ear opposite the one that would be expected during the Dix-Hallpike maneuver could have given us pause to proceed with a chemical vestibular labyrinthine destructive procedure on the ear suggested by the maneuver.

From Neurotologic Associates, P.C., New York City.

Reference

(1.) Brookler K. Positional nystagmus in only one position. Ear Nose Throat J 1999;78:834.