An 11-year-old boy who lived on a farm presented with a 2-week history of fever, vomiting and pain in the right hip that extended into the right buttock. The patient was non-weight bearing on the right leg, with restricted movement of the right hip. CRP was elevated. The pelvic radiograph at presentation was normal. Clinical examination had revealed tenderness on deep palpation of the right iliac fossa, and an abdominal ultrasound obtained to exclude appendicitis was negative. No hip joint effusion was seen on ultrasound.
MRI image study was requested.Axial T1wFS image post IV gadolinium and coronal STIR images at the level of Sacrum given below.

Axial T1wFS image post IV gadolinium

coronal STIR image

What is the Diagnosis?


Sacral osteomyelitis associated with pyogenic sacroiliitis

Axial and coronal STIR and T2w images showed a focal lesion with surrounding high signal in the right sacral alum and less well-defined high signal in the right iliac bone also. The sacral lesion was associated with cortical loss at the inferior aspect of the right sacroiliac joint and a low signal central bony sequestrum. The adjacent iliacus, pectineus, obturator internus, psoas and gluteus maximus muscles were thickened and of high signal. There was marked enhancement post-gadolinium of the bony sacral lesion and the anterior soft tissue collection.

Sacral osteomyelitis is rare and diagnosis is often delayed due to a variable clinical presentation, low suspicion of examining clinician, lack of awareness of diagnostic procedure, and rare findings on plain radiographs. The rate of complications increases with delay in diagnosis, and includes abscess or sequestrum formation, prolonged period of sepsis, long-term joint deformity, disability or even death .
Presentation is often a triad of fever, low back pain and difficulty weight-bearing, associated with an elevated C-reactive protein. The most common causative agent is Staphlococcus aureus.Brucellosis and other atypical organisms are associated with sacral osteomyelitis.
The plain radiograph is rarely helpful. An ultrasound examination is useful to exclude a hip joint effusion. Tc99-MDP bone scan is a sensitive test, but lacks specificity. CT clearly shows bone and soft tissue involvement, and may have a role in aspiration or biopsy. MRI has emerged as the imaging modality of choice due to its increased sensitivity and specificity.



  1. Anonymous Says:
  2. i guess viral infection

  3. Anonymous Says:
  4. abces on anterior face of psoas muscle..and
    colitis and some mesenteral adenopathies...GAbriela Paraschiv

  5. Anonymous Says:
  6. most probably a psoas abscess..

  7. Anonymous Says:
  8. Psoas abscess

  9. Anonymous Says:
  10. brucellosis

  11. Anonymous Says:
  12. Osteomyelitis- staphylococcus aureus

  13. Anonymous Says:
  14. Psoas Ascess due to Brucellosis

  15. Anonymous Says:

  17. al shabahi Says:
  18. septic arthraitis of the hip joint

  19. Anonymous Says:
  20. Acute osteomyelitis

  21. Anonymous Says:
  22. The Ex Rays Didnt Dhow Nothing Wrong So Whats causing The Pain


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