[A 9-year-old boy with 'pinpoint pain' caused by pyomyositis]. / Een jongen van 9 met 'pinpoint'-pijn door pyomyositis.

BACKGROUND: Pyomyositis is a rare bacterial infection of striated muscle, usually caused by Staphylococcus aureus. CASE DESCRIPTION: A healthy 9-year-old boy was referred to us because of pain in the hip and fever. We noticed he could point to the pain with one finger; this is referred to as 'pinpoint pain'. An MRI indicated a diagnosis of pyomyositis of the iliacus muscle and piriformis. The infection was caused by S. aureus. The boy recovered completely and swiftly with antibiotic therapy. CONCLUSION: This specific type of pyomyositis in the hip is rare, especially in children. Being able to localise the pain with one finger is a typical characteristic of this condition. MRI is the investigation of first choice to confirm this diagnosis.