Haycocknema perplexum myositis: the first description of subclinical disease and a proposed distinctive triad to evoke clinical suspicion

Introduction Haycocknema perplexum is an exceedingly rare cause of parasitic myositis endemic to Australia, more specifically, Tasmania and North Queensland. There is a paucity of literature regarding this diagnosis, with only nine previously described cases. Diagnosis This report details two cases of biopsy-confirmed H. perplexum myositis from Townsville University Hospital and describes the first-ever case of subclinical infection. There is limited known information regarding the H. perplexum life cycle and a definitive host which has hindered the development of a non-invasive diagnostic test. A review of the previously described cases has identified the hallmark features of this enigmatic condition: a triad of serological markers including deranged hepatic function, persistent eosinophilia and an elevated creatine kinase. Conclusions This report aimed to raise awareness of H. perplexum myositis and the possibility of subclinical infection, which suggests a protracted disease course. Further research is required to identify a non-invasive diagnostic test, given that early diagnosis and timely initiation of albendazole treatment may drastically limit patient disability.