We would like to present a case and associated images highlighting the diagnostic use of Magnetic Resonance Imaging (MRI) in non mobile infants.

A previously mobile 13-month-old toddler presented following a fall with subsequent reluctance to weight-bear. A fractured femur was suspected, but not confirmed on x-ray. She deteriorated further, evidencing reluctance to sit and screaming episodes when supine but not when lying prone. Inflammatory markers were raised and an MRI performed 14 days later revealed lumbar discitis with associated vertebral osteomyelitis. She received intravenous antibiotics followed by oral antibiotics for 6 weeks and made a good recovery.

Methods Diagnostic use of early MRI.

Results Discitis is rare in children. A high index of clinical suspicion is required, the mean duration of symptoms can be 24 days prior to presentation and diagnosis delayed by a further 12 days post presentation. Long-term morbidity includes chronic back pain, premature ankylosis and degenerative changes which can be reduced by early diagnosis and treatment.

Key messages Although rare, discitis should be suspected in children refusing to weight bear.

Early MRI is the investigation of choice.

Erythrocyte sedimentation rate is the most accurate investigation correlating with the clinical course of Discitis.