Diabetes mellitus as a predictor for late recovery of vestibular neuritis

The time course of recovery in vestibular neuritis varies between individuals. The aim of this study was to identify the predictors for the early or late recovery of vestibular neuritis. The inclusion criteria were patients 1) who had an acute onset of vertigo lasting at least 24 hours, 2) with a horizontal-torsional unidirectional spontaneous nystagmus, and 3) with a canal paresis of 20% or more on the bithermal caloric tests. The primary endpoint for this study was an early or late recovery of vestibular neuritis as a dependent variable. A functional level scale was used to define the late recovery (5 or more points) at seven days after the symptom onset. The secondary endpoint was the duration of hospitalization. One hundred twenty eight patients met the inclusion criteria for this study, and among them, 71 patients had an early recovery. Multiple logistic regression analysis showed that diabetes mellitus was the only independent significant variable for the prediction of a late recovery of vestibular neuritis. In addition, the diabetes mellitus was a predicting variable for long duration of hospitalization. Diabetes mellitus was a predictor for a late recovery of vestibular neuritis. Neurology Asia 2014; 19(4) : 393 – 397 Address for correspondence: Sung Eun Kim, M.D., PhD. Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundaero 875, Haeundae-gu, Busan, 612-896 Korea. Tel: +82-51-797-1195, Fax: +82-51-797-1196, E-mail: [email protected] INTRODUCTION Vestibular neuritis is defined as a sudden unilateral deficit of the peripheral vestibular organ without auditory symptoms and is a common cause of peripheral vertigo. It causes a sudden onset of rotational vertigo, nausea, vomiting, gait and postural imbalance with a tendency to fall toward the side of the affected ear and spontaneous nystagmus. 3 Signs and symptoms result from an imbalance of the tonic discharge between the impaired and intact vestibular afferents. The acute stage of severe vertigo lasts for several days to a few weeks in most patients and gradually decreases due to proprioceptive and visual substitution for the unilateral vestibular deficit thereafter combined with a central vestibular compensation of the imbalance in vestibular tone. The time course of recovery varies between individuals and almost 50% of patients with vestibular neuritis report sustained dizziness and disequilibrium. In previous study it has been reported that a recovery could be retarded by aging and psychological factors such as anxiety and depression. Diabetes mellitus (DM) is a common metabolic disorder. Its main pathophysiology is a hyperglycemia caused by reduced insulin secretion or insulin resistance. Complications of DM affect many organ systems and the risk of complications increases with the timely duration of DM. Diabetic neuropathy is a common and intractable neurological complication, and is associated with axonal atrophy, demyelination and loss of peripheral nerve fibers. This may result from microvascular injuries with the involvement of nerve supplying small blood vessels. Some reports have been presented about the relationship between a delayed recovery or severity and DM in viral diseases. DM has been associated with an increased disease severity, higher extra-hepatic manifestations and decreased response to antiviral therapy in patients with a chronic HCV infection. In addition, the incidence and severity of herpes zoster increase in patients with DM compared with those without DM. However, there was no study about the effect of DM on recovery of vestibular neuritis yet. The aim of this study was to follow the recovery during the first one week after the onset of vestibular neuritis, and to identify the predictors for an early recovery of vestibular neuritis. We evaluated the demographic and laboratory Neurology Asia December 2014 394 differences including DM between patients with early and late recovery of vestibular neuritis and assessed the significance of DM for the recovery time of vestibular neuritis.