Microsporidial polymyositis in human immunodeficiency virus−infected patients, a rare life‐threatening opportunistic infection: Clinical suspicion, diagnosis, and management in resource‐limited settings

Abstract

Myositis in HIV-infected patients with low CD4 counts should be evaluated using muscle biopsy. A high index of suspicion is required for early diagnosis of microsporidial myositis in HIV-infected patients. Early diagnosis and immediate, aggressive treatment are the keys to favorable outcomes in these patients.

Infective myositis

“…Microsporidia are easily identified as ovoid and refractile spores (<4 microns) within the myofibers by modified Gömöri trichrome stain (69) (Figure 5). Definitive diagnosis is by transmission electron microscopy (Figures 6 and 7) that helps in species identification and the presence of polar filaments (77). Other methods include immunofluorescence antibody staining methods/serological tests (IFA, ELISA, and immunoblot) and PCR (78).…”

Secondary myopathy due to systemic diseases

“…A rare protozoic infection with muscle involvement is neosporosis . In immune‐compromised patients, microsporidia, obligate intracellular parasites, may manifest as focal or generalized myositis . Focal myositis may be also a rare manifestation of Lyme disease (Lyme myositis) .…”

Presumptive neural microsporidiosis in a young adult German Shepherd dog from rural Australia

“…This dog initially appeared to respond to treatment with TMS, pyrimethamine and fenbendazole and did not show any adverse effects. Treatment was extrapolated from the human literature as there is very little available information concerning treating canine microsporidiosis 3,15,16 . Fenbendazole was used rather than albendazole, which is the benzimidazole of choice in human patients.…”

“…They were continued once a presumptive diagnosis of microsporidiosis was made. This combination of drugs has been used successfully for cases of microsporidial polymyositis in humans, 16 although it is possible that monotherapy with fenbendazole would have been appropriate. Sulphonamides and pyrimethamine have been demonstrated in an in vitro study to be ineffective against E. cuniculi 18 .…”