A case report of pyogenic sacroiliitis in a 9-month-old child.

A very rare condition, pyogenic sacroiliitis is responsible for 1-2% of all osteoarticular infections in children. Diagnosis is often delayed in the pediatric population due to non-specific signs and symptoms during presentation, difficulty in assessing the joint, more common differential diagnosis and low yield diagnostic findings in conventional radiography. A delayed diagnosis of this condition can lead to permanent joint damage. A 9-month-old presented to the emergency department with a history of fever, being unsettled and clingy along with refusal to weight bear over the past few days. On initial assessment, she was found to be tachycardic and afebrile with abnormal posture of her left leg held in external rotation at the hip joint. On examination, she refused to weight bear, presented with alternating tenderness of her left and right hip joints and spinal tenderness at the L5 position. Investigations done showed slightly raised inflammatory counts, normal hip and pelvic radiographs, normal hip ultrasound and blood culture growing staphylococcus aureus and Magnetic Resonance Imaging spine showing right sacroiliitis leading the diagnosis of pyogenic sacroiliitis. This case report highlights the importance of examination of the back and the importance of avoiding fixation error by history. Although rare, clinicians should consider the diagnosis of sacroiliitis in children who present with fever, being unsettled with decreased and painful movements around the pelvic region.