Clinical management of a patient with a 12-year history of a balance disorder.

A 69-year-old man presented with a 12-year history of balance difficulties. He had been admitted to a hospital 12 years earlier for treatment of nausea, vomiting, and left-upper-quadrant pain, and he was given intravenous fluids and antibiotics. Treatment alleviated his symptoms, but he noticed that once he was out of bed, he was unable to maintain his balance and had to hold on to the IV pole. Ever since then, his symptoms had persisted.

At the office, the patient reported that he had no balance difficulty while lying down or sitting--only when standing or walking. He said the intensity of symptoms fluctuated and that periods of more severe imbalance were becoming more frequent. He was unable to walk steadily while looking at the horizon; he had less difficulty when he looked down as he walked. He reported a possible decline in his hearing, but he experienced no tinnitus or aural fullness. His medical history also included epilepsy, for which he was taking phenytoin and phenobarbital, and prostate cancer. His family history was not contributory. A review of the hospital chart from 12 years earlier revealed that he had not received an ototoxic antibiotic.

A clinical neurotologic examination revealed that the patient's pupils were irregularly sized and did not respond to light. He said he had been aware of these abnormalities for many years. He performed the regular Romberg test with some difficulty, and he was unable to perform the sharpened Romberg test with either foot forward. Moreover, when he was standing, both of his knees were in flexion and he tilted to one side. When he walked, he exhibited an exaggerated sway from side to side, and it appeared that he would have fallen if a wall or piece of furniture had not been present to prevent a fall.

Electronystagmography (ENG) was performed while the patient remained on the phenytoin and phenobarbital. No spontaneous, positional, or neck-torsion nystagmus was observed. The alternate binaural bithermal (ABB) test yielded generally hypoactive responses in both ears; these responses might have been influenced by the drugs. The ABB test elicited a reduced vestibular response left and a directional preponderance (DP) left. The simultaneous binaural bithermal test elicited a type 4 response, with a left-beating warm response consistent with the DE

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A sinusoidal vertical-axis rotation test showed a low gain at 0.16 Hz and a phase lag at 0.16 Hz. There was abnormal symmetry to the right at 0.08 and 0.32 Hz. Ocular fixation suppression of 0.08-Hz rotation-induced nystagmus was excellent. In all, the rotation test showed an incomplete central vestibular compensation of a peripheral vestibular disorder.

Findings on audiologic testing did not contribute to the evaluation, but small-pixel ultrathin-slice computed tomography of the temporal bones detected evidence consistent with otosclerosis in the otic capsule. The metabolic evaluation revealed an exaggerated response of the blood sugars to a glucose load. The simultaneous insulin levels were elevated at hyperinsulinemic levels.

The patient was placed on etidronate 400 mg/day for 2 weeks every 6 weeks plus supplemental calcium and vitamin D daily to address the otosclerosis. He was referred to a nutritionist to address the metabolic factors. He returned 7 months later and said that he no longer had any problem with his balance. He was pleased to report that he had been able to stand on a ladder to hang ornaments on his Christmas tree. In fact, he had even been mountain climbing without any difficulty.

A follow-up sinusoidal vertical-axis rotation test showed improvement in the gains, as all data points were normal, although the test continued to show a lag at 0.16 Hz. The previous abnormal symmetry had disappeared, indicating a complete central vestibular compensation of a peripheral vestibular disorder. This finding was consistent with his vestibular symptoms. The patient's 2-hour postprandial blood sugar and insulin levels had moved into the normal range.

The patient was switched to risedronate 30 mg twice weekly; he was maintained on calcium with vitamin D, and sodium monofluorophosphate was added. He was seen again at 12 and 21 months into treatment, and his symptoms had not returned.

This case had several interesting points:

* The patient's history was consistent with ototoxicity secondary to the use of ototoxic antibiotics. However, his stance and gait did not support such a provisional diagnosis, and his hospital records revealed no use of ototoxic antibiotics.

* The reduced caloric responses were consistent with the long-term use of phenobarbital, and they might have represented some effect of the phenytoin.

* The sinusoidal vertical-axis rotation test was more helpful in the diagnosis than the ENG because its diagnostic information was not adversely affected by the drug he was taking. The absence of universally lowered gains is not consistent with ototoxicity. The rotation test was also helpful in monitoring the response to medical treatment.

* The illness that triggered the patient's symptoms was inflammatory, and it might have led to the otosclerosis through the release of tumor necrosis factor alpha. (1,2)

* Treatment of both the otosclerosis and the abnormal metabolic factors led to a rapid reversal of a 12-year history of a disabling balance disorder.

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References

(1.) Adams JC. Clinical implications of inflammatory cytokines in the cochlea: A technical note. Otol Neurotol 2002; 23(3):316-22.

(2.) Karosi T, Jokay I, Konya J, et al. Detection of osteoprotegerin and TNF-alpha mRNA in ankylotic stapes footplates in connection with measles virus positivity. Laryngoscope 2006; 116(8): 1427-33.

Kenneth H. Brookler, MD, FRCSC; Mohamed A. Hamid, MD, PhD

From Neurotologic Associates, PC, New York City (Dr. Brookler), and the Cleveland Hearing and Balance Center, Beachwood, Ohio (Dr. Hamid).