MRI findings of the brain in human African trypanosomiasis: a case series and review of the literature.

Human African Trypanosomiasis (HAT) is a neglected tropical disease that affected 3797 people worldwide in 2014. Without treatment mortality approaches 100%. Due to its low incidence and non-specific clinical features, diagnosis can be challenging and the role of MRI in diagnosis of HAT has not been evaluated outside of case reports. We carried out a retrospective, institutional review of three patients presenting with neurological stage (Stage 2) HAT presenting to the Hospital of Tropical Diseases, London between 2004 and 2016. MRI brain was performed in both the acute and follow-up stages of their infection. In addition to confirming that the most common MRI abnormality is weighted fluid-attenuated inversion recovery (T2W FLAIR) high signal intensity in the supratentorial white matter, this series has identified radiological findings not previously reported in the literature. In the acute stages, restricted diffusion can be seen in the internal capsules and splenium of the corpus callosum and microhaemorrhages not related to melarsoprol have been identified. Furthermore, the signal abnormality appears to be largely reversible upon treatment with regression associated with mild atrophy demonstrated on follow-up MRI post-treatment. We conclude that although direct microscopy remains the mainstay of diagnosis with serological and polymerase chain reaction (PCR) testing providing useful adjuncts, MRI brain can be helpful in assessing neurological involvement and may provide important prognostic information post-treatment.