Analysis of Posterior Circulation Vascularity in Vestibular Neuritis

BACKGROUND: Vestibular neuritis (VN) is one of the most common causes of acute vertigo. Viral infection is regarded to be the most common etiology of VN, but other various causes including labyrinthine ischemia have not yet been fully elucidated. We assumed that labyrinthine ischemia can develop from various disorders in the posterior circulation including vertebral artery hypoplasia and vertebrobasilar dolichoectasia. METHODS: Fifty-six patients with acute VN and 56 healthy controls were enrolled. Two neurologists independently used magnetic resonance angiography (MRA) to retrospectively investigate the posterior circulation in VN patients. The relation between the presence of VN and abnormalities of posterior circulation vascularity was analyzed. RESULTS: MRA findings of vertebral artery hypoplasia and vertebrobasilar dolichoectasia were present in 15 (27%) and 14 (25%) of the VN patients. However, the frequencies of these findings did not differ significantly from those in the healthy controls (p=0.16). CONCLUSIONS: The frequencies of vertebral artery hypoplasia and vertebrobasilar dolichoectasia did not differ significantly between VN patients and healthy subjects. We suggest that brain MRI and MRA are not essential in acute VN patients without central signs. Large prospective studies are needed to characterize the vascular etiology of vestibular neuritis.

Myasthenia Gravis Aggravated by Steroid-Induced Isolated Mediastinal Tuberculous Lymphadenitis

BACKGROUND: Myasthenia gravis (MG) is occasionally aggravated by chronic infection, of which there are many kinds. CASE REPORT: We report herein the case of a 56-year-old woman with MG aggravated by the activation of isolated mediastinal tuberculous lymphadenitis (MTL) during corticosteroid administration. The possibility of MTL had been disregarded in the differential diagnosis of aggravation of MG weakness, because MTL without pulmonary manifestations is uncommon even in areas where tuberculosis is endemic. CONCLUSIONS: This case suggests that chronic infections such as tuberculosis should be considered in myasthenic patients with progressive exacerbation if definite evidence for aggravating factors of MG is not obtained.