Pyomyositis after vaginal delivery

Abstract

Pyomyositis is a purulent infection of skeletal muscle that arises from haematogenous spread, usually with abscess formation. It can develop after a transient bacteraemia of any cause. This type of infection has never been reported before in the literature after vaginal delivery. A 34-year-old woman had progressive severe pain in the left buttock and thigh and weakness in the left lower limb day 1 post spontaneous vaginal delivery. MRI showed severe oedema of the left gluteus, iliacus, piriformis and adductor muscles of the left thigh and a small fluid collection at the left hip joint. She was diagnosed with pyomyositis. She had fever of 37.9°C immediately postpartum and her risk factors for bacteraemia were a mild IV cannula-associated cellulitis and labour itself. She required prolonged treatment with antibiotics before significant clinical improvement was noted.

Figure 1

An axial MRI T-2 weighted image with fat-saturation which demonstrates diffuse high signal abnormality in the left anterior, posterior and medial compartments of the thigh (TE 32 ms TR 3500).

Figure 2

An axial T-2 weighted sequence with fat-saturation (TE 32 ms TR 3500) which demonstrates no residual signal abnormality on follow-up 10 months later.