Cerebral malaria: insight into pathology from optical coherence tomography

PurposeWe aimed to investigate structural retinal changes in malarial retinopathy (MR) using hand-held optical coherence tomography (HH-OCT) to investigate its diagnostic potential.MethodsChildren with MR (n=43) underwent ophthalmoscopy, fluorescein angiography and HH-OCT during admission, one month (n=31) and one year (n=8) post-discharge. Controls were comatose patients without malaria (n=6) and age/sex-matched healthy children (n=43). OCT changes and retinal layer thicknesses were compared.ResultsOn HH-OCT, hyper-reflective areas (HRAs) were seen in the inner retina of 81% of MR patients, corresponding to ischaemic retinal whiteningon fundus photography. Cotton wool spots were present in 37% and abnormal hyper-reflective dots, co-localized to capillary plexus, in 93%. Hyper-reflective vessel walls were present in 84%, and intra-retinal cysts in 9%. Vascular changes and cysts resolved within 48 hours. HRAs developed into retinal thinning at one month (p=0.027) whichwas more pronounced after one year (p=0.009).ConclusionsIschaemic retinal whitening is located within inner retinal layers, distinguishing it from cotton wool spots. Vascular hyper-reflectivity may represent the sequestration of parasitized erythrocytes in vessels, a key CM feature. The mechanisms of post-ischemic retinal atrophy and cerebral atrophy with cognitive impairment may be similar in CM survivors. HH-OCT has potential for monitoring patients, treatment response and predicting neurological deficits.