Pyomyositis in Children: A 15-year Retrospective Study From a Tertiary Care Pediatric Hospital in Portugal.

BACKGROUND

Pyomyositis is a primary infection of the skeletal muscle, commonly occurring in tropical countries in children. Treatment is still controversial, with antibiotics plus drainage being the main option.

METHODS

Retrospective, unicentric study of pyomyositis in a tertiary care Pediatric Hospital, from January 2008 to December 2022. Predisposing factors, clinical, laboratory and radiological results, treatment and evolution were analyzed.

RESULTS

Twenty-nine patients were identified, 75.9% male, median age of 8 years old (0.8;17). The most common predisposing factors were intense physical activity (37.9%), followed by trauma (31.0%). Pain (100.0%), functional impairment (82.8%) and fever (65.5%) were the most frequent symptoms. The most affected sites were the pelvis (51.6%) and the upper leg (22.6%). Magnetic resonance imaging had 100% sensitivity, whereas 40.7% of ultrasounds were inconclusive. Blood cultures were positive in 40.0% of cases and pus in 33.3%. Methicillin-sensitive Staphylococcus aureus was the most common isolated organism (36.0%). Most patients were treated with intravenous flucloxacillin plus clindamycin (55.2%) for a median of 14 days (7;30) and a median total duration of 29 days (14;72). Drainage was only performed in 20.7% of patients, of which 6/15 were in the suppurative phase. All patients improved without functional impairment at 6-month follow-up.

CONCLUSION

Pyomyositis' symptoms can be nonspecific. Methicillin-sensitive Staphylococcus aureus was the most common isolated organism, and many patients can be treated conservatively, without drainage, even in the suppurative phase.