Orbital Loiasis Masquerading as Orbital Cellulitis: A Case Series

Abstract

Background: Orbital loiasis is a rare ocular disease which is sparsely reported in the literature. It is caused by the human filarial parasite, Loa loa, which is rarely found in other continents except in Africa and among African immigrants. The ocular presentation of orbital loiasis is similar to orbital cellulitis, thus, a high index of suspicion is required to make a diagnosis.

Methods: A retrospective description of the patients diagnosed and treated for orbital loiasis in a tertiary health facility in Ogun State, Nigeria between 1998 and 2013 was done. Data on the demographic characteristics, place of residence of the patients, symptoms, signs, and results of ancillary investigations were retrieved from the records.

Result: Three cases of presumed orbital loiasis were seen within the study period. All the patients presented with sudden onset of ocular pain with proptosis without the history of shifting body or facial swellings or visible worm in their eyes. Other features recorded in all the three patients included severe axial proptosis, eyelid oedema with mechanical ptosis, conjunctival injection with chemosis and restriction of ocular motility in all positions of gaze. Full blood count revealed eosinophilia while the radiological investigation was neither in keeping with sinusitis, thyroid-related orbital disease or orbital pseudotumor. Treatment was switched to Diethylcarbamazine  when there was no satisfactory clinical response to the initial antibiotics and all the patients had a good outcome.    

Conclusion: Orbital loiasis should be suspected when orbital cellulitis cases appear to be recalcitrant to treatment with antibiotics, particularly when there is eosinophilia on peripheral blood film.