Onchocerciasis identified with anterior segment ocular examination and FDG-PET/CT imaging

Background

Ocular onchocerciasis, commonly known as “river blindness,” is a parasitic infection caused by the filarial nematode Onchocerca volvulus. Although presentation within the United Kingdom is extremely rare, with no reports evident within the literature, it is the second leading cause of infectious blindness worldwide. Diagnosis is traditionally made through skin snip biopsy, serological testing and, where available, quantitative-polymerase chain reaction. Diagnostic imaging is not traditionally utilised due to limited availability within endemic regions.

Case Report

In this case, of a man presenting to a tertiary London ophthalmology unit with recurrent anterior uveitis, both anterior segment ocular examination with paracentesis, demonstrating microfilariae, and fluorodeoxyglucose – positron emission tomography / computed tomography, demonstrating an onchocercoma, play a crucial role in allowing targeted ultrasound-guided fine needle aspiration which confirmed the diagnosis.

Conclusion

This case highlights the role of anterior segment examination and diagnostic imaging in the diagnosis of infectious diseases. It also demonstrates novel anterior segment ocular imaging findings of in vivo microfilariae as seen in ocular onchocerciasis.