LAUSR

Sir, The spectrum of neuromyelitis optica (NMO) broadly covers uncommon lesions located outside the core opticospinal lesions. Apart from the optic nerve, relapses involving the cranial nerves and cortical meningeal enhancement have rarely been described in NMO [1,2]. We report the first case of a typical patient with NMO suffering from a clinical relapse involving the eighth cranial nerve and associated with local meningeal enhancement. A 53-year-old Caribbean female was referred to our center in December 2013 with a 9-month history of relapsing neurological complaints. She became blind temporarily in the right eye without perception of light in June 2013 and then recovered in a few days without treatment. Six months later, she suddenly developed intractable vomiting without hiccup and mild cervical sensory myelitis that resolved in few days. She simultaneously developed unilateral right sensorineural hearing loss accompanied by tinnitus and vertigo. The vestibular syndrome regressed in 2 weeks but the cochlear symptoms persisted. She was referred in March 2014 for a subacute third relapse, associated with difficulty in swallowing liquids, tracheal aspiration and nasal regurgitation. As in the two previous episodes, the symptoms resolved in a few days. Clinical examination disclosed right visual acuity of 20/30 with papillitis and Marcus Gunn’s sign, a pyramidal syndrome and suspended D2-12 extralemniscal anesthesia. Puretone audiometry confirmed a right threshold hearing loss of 30 dB in the higher frequencies. Rinne and Weber tests confirmed the sensorineural hearing loss. Spinal magnetic resonance imaging was normal. Brain magnetic resonance imaging disclosed an edematous right optic nerve with gadolinium uptake. The brainstem was normal but the right eighth cranial nerve and the adjacent meninges were prominently enlarged and gadolinium enhanced along the cisternal and intracanalicular nerve segment, giving a tumor-like appearance (Fig. 1a). Lumbar puncture disclosed no cells and 0.87 g/L proteins without intrathecal IgG synthesis. Complete laboratory investigations, including blood tests with inflammatory parameters including antineutrophil cytoplasmic antibody, angiotensin-converting enzyme, serologies, whole-body computed tomography scan and salivary accessory gland biopsy, were all normal. Anti-aquaporin-4 antibodies were positive with a cell-based assay (Inserm U1028, Lyon, France). She received high-dose steroids followed by six infusions of mitoxantrone over 1 year. At last follow-up, 1 year later, auditory function was almost normal and no relapse had occurred. Control magnetic resonance imaging demonstrated a normal right eighth nerve (Fig. 1b). Cranial nerve attacks occurring in NMO spectrum disorder are mostly oculomotor palsies associated with brainstem lesions [3]. Vestibulocochlear signs, mainly hearing loss and vestibular ataxia, occur in 2.5% and 1.7% of NMO relapses, respectively [4], but these clinical signs are related to central lesions.