Article Text

Rare disease
Obturator internus pyomyositis presenting as a pararectal abscess
  1. Gillian Duthie1,
  2. Caroline Corry2,
  3. Fraser Munro1,
  4. James Robb3
  1. 1
    Royal Hospital for Sick Children, Paediatric Surgery, 9 Sciennes Road, Edinburgh EH9 1LT, UK
  2. 2
    Royal Hospital for Sick Children, Radiology Department, 9 Sciennes Road, Edinburgh EH9 1LT, UK
  3. 3
    Royal Hospital for Sick Children, Orthopaedics, 9 Sciennes Road, Edinburgh EH9 1LF, UK
  1. Gillian Duthie, gduth01{at}


This report describes two children who presented with fever, hip pain and a limp, and were subsequently found to have a primary pyomyositis of the obturator internus muscle. A clinical diagnosis of septic arthritis of the hip was made initially, but in both children MRI showed a pararectal abscess, which required incision and drainage. Staphylococcus aureus was cultured from pus from the abscesses and both children made a full recovery subsequently. This report highlights the main features of this unusual entity and emphasises the need for early imaging in the child with an unexplained limp.

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  • Competing interests: none.

  • Patient consent: Patient/guardian consent was obtained for publication.