Back pain in children and adolescents — formative SAQs

SAQ 1 (10 marks) — The three-year-old who refuses to walk and holds her back

Stem: A three-year-old girl is brought to the emergency department refusing to walk and holding her lower back stiff. She is mildly febrile at 38.1 degrees Celsius and irritable, and her mother reports she has been reluctant to sit for two days. Her CRP is 42 milligrams per litre and her ESR is 48 millimetres per hour. A plain radiograph of the lumbar spine is reported as normal. Outline your assessment, investigations, and management. [1] [7]

Model answer

Assessment and red-flag screen (2 marks). This child has back pain in a pre-school child, which is itself a red flag — back pain under five years is uncommon and an organic cause is sought by default. She has two further red flags: a fever and the systemic picture of irritability. The refusal to walk in the young child is the presenting feature of discitis, the classic spinal infection of this age, and the workup is directed at the spinal infection regardless of the normal temperature. The normal plain radiograph does not exclude the diagnosis, because the early discitis is radiographically occult. [1] [7]

Investigations (3 marks). The inflammatory markers are already raised and provide the baseline for tracking the response. A blood culture is drawn before any antibiotic is given, to identify the organism. The definitive investigation is an urgent magnetic resonance imaging of the spine, which reveals the disc-space inflammation and the adjacent endplate oedema that the plain film misses, and which excludes a vertebral osteomyelitis, an epidural abscess, and a tumour. The ACR Appropriateness Criteria confirm the MRI as the modality for the suspected spinal infection in the child. The plain film is reviewed for a destructive lesion, and the MRI frames the extent and the complication. [11] [7]

Immediate management (5 marks). The blood culture and the MRI are obtained, and the child is managed with empirical intravenous antibiotics targeting Staphylococcus aureus, the commonest organism in the spinal infections of childhood. The choice of antibiotic follows local guidelines, and the duration is typically two to four weeks intravenously with a step-down to oral guided by the clinical and the inflammatory-marker response. The child is immobilised for comfort, and the analgesia is provided. The infectious-diseases team is involved for the antibiotic guidance, and the orthopaedic team is involved if an abscess, a neurological deficit, or a progressive deformity demands surgical intervention. The family is counselled on the diagnosis, the duration of therapy, and the safety-net. [7] [11]