Abstract
Purpose :
There are approximately 214 million malaria cases annually. Of the African children with cerebral malaria (CM) 15% die and 30% have long-term neurological sequelae. Diagnosis of CM can be difficult. Retinal changes closely reflect cerebral changes, thus helping CM diagnosis. Clinical signs of malarial retinopathy (MR) (retinal whitening; vessel discoloration; hemorrhages; papilledema) not only help detect CM but also predict severity. However, one-third of CM patients are MR-negative by funduscopic examination. Also, on autopsy, 30% of patients dying of coma and positive for malaria parasitemia end up having alternative diagnosis. Therefore it is important to detect subtle retinal changes in funduscopy negative patients. This study used hand-held optical coherence tomography (HH-OCT) for the first time for this purpose.
Methods :
Five funduscopy-negative patients with CM were recruited from the Queen Elizabeth Central Hospital, Blantyre, Malawi. All underwent full medical assessments, dilated funduscopy, photography, fluorescein angiography and HH-OCT scans (7 x 7 x 2mm volume for each A scan, 1000 A scans per B scan, 140 or 210 B scans) for fovea and optic nerve on admission once they had been stabilised after treatment. OCT findings were compared with those observed in retinopathy positive CM patients (n=26) and local age-matched children were used as controls.
Results :
HH-OCT showed that all 5 retinopathy negative patients had the changes typically observed in MR. Four had hyper-reflective vessel walls with hypo-reflective lumina, 3 had hyper-reflective vessels with hyper-reflective lumina and one had numerous hyper-reflective capillaries. The hyper-reflective vessels and capillaries are consistent with parasitized erythrocytes segregating on the vessel walls, as described histologically.
Conclusions :
HH-OCT can detect subclinical retinal changes in patients with CM. OCT may increase the accuracy of CM diagnosis in funduscopy negative patients, enabling specific therapeutic intervention. In the future, studies of HH-OCT in a larger number of retinopathy negative patients and correlation with autopsy findings are necessary.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.