Pyomyositis in HIV: A Series of 12 Cases

Abstract

Background: Pyomyositis is a bacterial infection of the large skeletal muscles presenting with muscle pain and swelling. It is commonly seen in the tropics but is being recognised more in end-stage HIV/AIDS. In HIV-associated pyomyositis, leukocytosis and bacteraemia is rare due to deranged immune response. Surgical drainage, antibiotic treatment and HAART are the mainstay of treatment. Objective: To describe pyomyositis in HIV positive patients, their CD4+ cell counts, clinical stages of pyomyositis and anatomical sites affected. Design: Cross sectional, prospective, descriptive, consecutive entry study. Setting: Kisumu District Hospital and Nairobi Rheumatology Clinic between January 2002 to December 2007. Subjects: Twelve patients with HIV infection and pyomyositis. Main Outcome Measures: CD4+ cell counts, clinical stage and site of pyomyositis. Results: Twelve patients (six males and six females) were enrolled with mean age of 39.3 years (24-52). Pyomyositis was localised in the following regions:two each in gluteal and calf, six in the thigh and one each in the right arm and abdominal wall. CD4+ cell counts were low with a mean of 166.8 cells/µl (1.0-433) (normal range is 355-1600 cells/µl), indicating severe immunosuppression. They also had leucocytopaenia with a mean white blood cell count of 3.67 ~ 103/µl (1.5-7.1 ~ 103/µl) with a mean neutrophil count of 62.7% (43-78). Random blood sugar and creatine kinase levels were all normal. The co-morbidities comprised one case of deep venous thrombosis (DVT) and five of oral candidiasis. Pus swab grew Staphylococcous aureus in eight instances and Streptococcous pyogenes in four. Conclusion: Pyomyositis in HIV positive patients tends to occur at low CD4+ cell counts. Staphylococcus aureus was the most common causative organism.