Description

A 14-month-old boy, independently mobile for 1 month, presented after refusing to walk for 2 days. He was afebrile, with no preceding coryzal illness. A diagnosis of transient synovitis was made. Owing to the lack of improvement and ongoing symptoms for 5 weeks, he underwent blood tests, which showed a C reactive protein of 7, an erythrocyte sedimentation rate of 38 and a platelet count of 511.

Apart from the inability to weight bear, he was systemically well in himself. Septic arthritis, osteomyelitis1 and leukaemia were deemed unlikely diagnoses. Serial blood tests showed static infection markers. A pelvic X-ray and an ultrasound of the hips were unremarkable.

In view of the possible hip pathology, the child was booked for an MRI of his pelvis, with a plan to include the spine if the oral sedation lasted long enough. The spinal MRI showed L4/L5 discitis (figure 1).

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Figure 1

MRI of the spine showing an ill-defined disc at L4–L5.

Forty-eight hours into intravenous flucloxacillin, he started walking again. His blood cultures were negative. He continued on intravenous antibiotics for 6 weeks.

Discitis was not in our top differentials. It is an uncommon disease in toddlers. It is believed to be of infectious aetiology with the haematogenous transfer of the causative organism (most likely Staphylococcus aureus) to the disc space, despite sterile blood cultures.2 Management involves immobilisation and antibiotic therapy.3 It is a self-limiting illness, but awareness of this condition must be raised, with the aim of facilitating its diagnosis and management.