Reluctance to sit or stand

An 11 month old infant presented with a four week history of reluctance to sit or stand. He had no fever, tenderness, or other abnormalities on examination, including that of the lower limbs, hips, and spine. Investigations revealed normal full blood count, inflammatory markers, and blood culture. Radiological investigations included a normal radiograph and ultrasound scan of the hips. A magnetic resonance imaging scan of the lower limbs and pelvis performed under general anaesthetic was normal, and that of the spine confirmed a diagnosis of lumbar discitis. Identifying the aetiological agent in discitis is difficult as blood cultures are usually negative, but Staphylococcus aureus is reportedly the most common causative organism. Serological investigations in this child were negative.