Catastrophic Parasitic Meningoencephalitis Due to Halicephalobiasis: Case Report

Halicephalobus gingivalis is a free-living nematode and facultative parasite, rarely known to affect the central nervous system (CNS). We report the 6th case of Halicephalobiasis in humans worldwide and the first case of catastrophic meningoencephalitis caused by Halicephalobus gingivalis in Australasia, in a 73-year-old woman on long-term immunosuppressive drugs for rheumatoid arthritis. Her initial presentation and normal blood profile did not lead to a clinical suspicion of meningitis. A rapid deterioration in her neurological state to a GCS score of 6 was noted within 48 hours. Broad-spectrum antimicrobials and antivirals were commenced to treat possible severe meningoencephalitis, with the addition of an anti-helminthic therapy at a later stage. Due to medical futility and poor prognosis, multisystem organ supports were withdrawn and focus was changed to comfort care and she died on day 8 of admission. All human cases have reportedly led to death within ten days. Diagnosis through detection of parasites in the CSF is difficult as nematodes tend to be invasive and there is no immunoassay or polymerase chain reaction (PCR) test readily available. All cases have been diagnosed post-mortem and it is paramount that further research is conducted in this area of clinical parasitology for earlier detection and institution of therapy to achieve clinically meaningful outcomes.