Introduction: There has been a recent increase in the incidence of myositis worldwide. To this date, myositis has been described almost exclusively in children and adolescents. In most cases the causative agents are Gram-positive bacteria. When it involves muscles around the hip, other differential diagnoses such as septic arthritis and transient synovitis need to be excluded amongst others.
Case presentation: We present the case of a 16 year old Caucasian male who suffered from pyomyositis of his left obturator internus muscle. He was pyrexial at 41 degrees C with rigors and severe hip pain, whilst range of motion of his left hip was severely limited. Tenderness over the left pubic bone was significant. After clinical examination and relevant laboratory investigations, it was decided to treat him conservatively with intravenous antibiotics. Blood cultures grew Staphylococcus aureus resistant to amoxicillin and ampicillin. The patient was discharged fifteen days later. At the time of discharge, he was symptom-free.
Conclusion: This form of pyomyositis is a rare pyogenic infection, which may be difficult to diagnose and can easily be missed. Therefore, physicians should familiarise themselves with this condition and consider it as a possible differential diagnosis in patients presenting with an acutely painful hip.