The neuromyelitis optica presentation and the aquaporin-4 antibody in HIV-seropositive and seronegative patients in KwaZulu-Natal, South Africa

Abstract

Background: The association of the anti-aquaporin-4 (AQP-4) water channel antibody with neuromyelitis optica (NMO) syndrome has been described from various parts of the world. There has been no large study describing this association from southern Africa, an HIV endemic area. HIV patients often present with visual disturbance or features of a myelopathy but seldom both either simultaneously or consecutively. We report our experience of NMO in the era of AQP-4 testing in HIV-positive and HIV-negative patients seen in KwaZulu-Natal, South Africa.

Methods: A retrospective chart review was undertaken of NMO cases seen from January 2005 to April 2016 in two neurology units serving a population of 7.1 million adults. The clinical, radiological and relevant laboratory data were extracted from the files and analysed.

Results: There were 12 HIV-positive patients (mean age 33 years), 9 (75%) were women and all 12 were black patients. Of the 17 HIV-negative patients (mean age 32 years), 15 (88%) were women and 10 (59%) were black people. The clinical features in the two groups ranged from isolated optic neuritis, isolated longitudinally extensive myelitis or combinations. Recurrent attacks were noted in six HIV-positive patients and six HIV-negative patients. The AQP-4 antibody was positive in 4/10 (40%) HIV-positive patients and 11/13 (85%) HIV-negative patients. The radiological changes ranged from longitudinal hyperintense spinal cord lesions and long segment enhancing lesions of the optic nerves. Three patients, all HIV-positive, had tumefactive lesions with incomplete ring enhancement.

Conclusion: This study confirms the presence of AQP-4-positive NMO in southern Africa in both HIV-positive and HIV-negative patients. The simultaneous or consecutive occurrence of optic neuritis and myelitis in an HIV-positive patient should alert the clinician to test for the AQP-4 antibody. It is important to recognise this clinical syndrome as specific therapy is available. We further postulate that HIV itself may act as a trigger for an autoimmune process.

FIGURE 1

(a) and (b) are T2 sagittal images showing high intensity signal in the lower medulla and upper cervical cord; (c) is post-contrast T1 image showing enhancement of the lesion; (d) is a chest radiograph showing features consistent with tuberculosis.

FIGURE 2

a) and (b) are orbital MRI views post-contrast. They show diffuse enhancement of the right optic nerve extending to the chiasm (arrows). Minimal enhancement of the left optic nerve is also present (right arrow in (b)).

FIGURE 3

Images from an HIV-positive patient (a) and (b) are T2 and T1 post-contrast images of the brain, respectively, showing tumefactive lesions. Figure (c) and (d) are corresponding images of the spinal cord.