We retrospectively analyzed the clinical records of 137 patients who were treated at our clinic for acute low-tone sensorineural hearing loss of unknown cause over a period of 8 years. The analyses of the clinical records indicated the following clinical characteristics: female preponderance; peak incidence during the fourth decade of life; frequent accompanying tinnitus, sensation of ear fullness, and/ or autophony; suspicion of bilateral involvement; and association with autonomic imbalance. The hearing in most of the patients completely recovered, but some selected patients experienced fluctuating hearing loss or progression to Meniere's disease. Our results suggest that a subgroup of patients with severe initial hearing loss should be carefully followed up, although it is difficult to predict the outcome of this disorder.

Fifty patients (14 men and 36 women ranging in age from 16 to 66 years) with acute low-tone sensorineural hearing loss (ALHL) were retrospectively analyzed in this study. The glycerol test and the orthostatic test were performed. On the glycerol test, 43.8% of 16 ears of the 14 men and 33.3% of 39 ears of the 36 women with ALHL had a positive result. On the orthostatic test, 42.9% of the 14 men and 52.7% of the 36 women with ALHL had a positive result. In addition, 28.6% of the 14 men and 33.3% of the 36 women had hypotension with a systolic blood pressure of 100 mm Hg or less. Our results suggest that endolymphatic hydrops as shown by the glycerol test and an underlying autonomic imbalance and/or insufficient blood circulation as shown by the orthostatic test may be important factors in the causation of ALHL.

The long-term therapeutic efficacy of isosorbide, an oral hyperosmotic diuretic, was clinically evaluated in 30 patients (14 males and 16 females) who were followed up in our clinic for more than 2 years. The patients ranged in age from 14 to 73 years, with a mean age of 49.2 years. Isosorbide was given orally, continuously or intermittently, for 27-297 weeks, depending on each patient’s condition. The efficacy of the drug was determined according to the evaluation criteria of the American Academy of Ophthalmology and Otolaryngology (AAOO) and the American Academy of Otolaryngology, Head and Neck Surgery (AAO-HNS) for Ménière’s disease. Definitive episodes were successfully controlled in 15 of the 20 patients (75%) who received isosorbide continuously according to both the AAOO and the AAO-HNS criteria. Of the 10 patients who were given the drug intermittently, definitive episodes were successfully controlled in 6 patients (60%) according to the AAOO and in 7 patients (70%) according to the AAO-HNS criteria. During the treatment periods, hearing improved in 6 patients (20%), and tinnitus subjectively lessened in 15 patients (50%). Although some patients complained of abdominal discomfort, the side effects of this drug were minimal. Among the patients who responded well to the treatment, the doses of isosorbide could be tapered to a daily dose of 30 ml, less than one half of the usual daily dose of this drug. The results suggest that most patients should be asked to continue this medical treatment for at least several months before a decision can be made regarding whether the medical response is good or poor. We believe that the long-term use of isosorbide is often efficacious in stabilizing the disabling symptoms of Ménière’s disease.

The temporal bone pathology of a 71-year-old man with bilateral sensorineural hearing loss and facial paralysis caused by diffuse metastatic leptomeningeal carcinomatosis is described. The origin of this malignant disease was an extremely rare entity, a transitional cell carcinoma of the renal pelvis. Histopathologic study of the temporal bone demonstrated that tumor cells filled the internal auditory meatus, infiltrated into the Rosenthal's canals, and reached the scala tympani of the basal turn of the bilateral cochleas. The vestibulocochlear nerve and facial nerve trunks in the internal auditory meatus had been destroyed by the bilateral tumor invasion. Case reports of temporal bone metastases of leptomeningeal carcinomatosis published since 1965 were reviewed. In leptomeningeal carcinomatosis, it is suggested that tumor cells infiltrate the internal auditory meatus of both ears simultaneously from the cerebrospinal fluid, involving the seventh and eighth nerve trunks, and then cause bilateral sensorineural hearing loss and facial paralysis.

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