Primary pyomyositis in North India: a clinical, microbiological, and outcome study

BACKGROUND/AIMS: Pyomyositis is an infective condition with primary involvement of the skeletal muscles. There is sparse recent literature on patients with pyomyositis. METHODS: This study was carried out at emergency services of a tertiary care center located in subtropical area of Indian subcontinent. RESULTS: Sixty-two patients of primary pyomyositis formed the study cohort. Mean age of occurrence was 29.9 ± 14.8 years. There were 54 men. Twelve patients had underlying medical diseases. Muscle pain was seen in all 62 patients. Forty-eight patients (77.4%) had the fever. Most common site of involvement was thigh muscles (n = 29, 46.8%). Forty-nine patients (79%) presented in the suppurative stage of illness. Patients with comorbidities were older (age: median 36 years [interquartile range (IQR), 25 to 47] vs. 24 years [IQR, 16 to 35], p = 0.024), had higher culture positivity with gram-negative organisms (8/9 [88.89%] vs. 6/29 [20.69%], p = 0.001). Importantly, higher number of these patients received inappropriate antibiotics initially. Patients with positive pus culture result had higher complication rate (32/38 [84.21%] vs. 10/18 [55.56%], p = 0.044). Six patients (9.7%) had in-hospital mortality. Lower first-day serum albumin, initial inappropriate antibiotic therapy, and advanced form of the disease at presentation were associated with increased in-hospital mortality. CONCLUSIONS: Primary pyomyositis is not an uncommon disease entity. Patients with comorbidities were more likely to receive initial inappropriate antibiotic therapy. Patients with positive pus culture report had the higher rate of complications. Lower first-day serum albumin, initial inappropriate antibiotic therapy and advanced form of the disease at presentation were associated with increased in-hospital mortality.