Abstract Details

Neuromyelitis Optica (NMO) is an autoimmune inflammatory disorder of the central nervous system. Pathogenic aquaporin 4 (AQP4) antibodies are present in 65-88% of cases. It presents with recurrent optic neuritis and/or longitudinally extensive transverse myelitis. Brain lesions are typically non-specific and asymptomatic; the distribution corresponds with regions of high AQP4 expression.

A 50-year-old female with seropositive NMO was on maintenance Rituximab every 6-12 months for the past 10-years. She was admitted for two spinal cord relapses, 2 months apart, treated with intravenous steroids and plasma exchange (PLEX). On the 3^rdmonth of admission, she was found unresponsive and hypothermic (34°C). Preliminary bloods showed a normal serum glucose and hypo-osmolar hyponatraemia consistent with an SIADH. MRI showed no clear new lesion. CSF was acellular with raised protein and markedly low orexin. Given prior regular Rituximab and recent immunotherapy, an extensive screen for atypical autoimmune and infectious processes was performed and was negative. EEG demonstrated no epileptiform features. She eventually responded to a prolonged course of intravenous steroids and PLEX for a hypothalamic relapse. On the 7^thmonth of admission, after further Rituximab, whilst on 20/15mg prednisolone alternate days, she had a remarkably similar relapse. 

The hypothalamus plays a central role in homeostasis. In this case, hypothalamic dysfunction secondary to NMO manifests as a combination of thermal dysregulation, endocrinopathies, autonomic dysfunction and disorders of alertness. A multitude of clinical manifestations may co-exist given the proximity of the hypothalamic nuclei. This case demonstrates aggressive activity in spite of combination immunotherapy.