Fever of unknown origin in a patient initially presenting with traveller's diarrhoea

A 17-year-old male presented with diarrhoea and malaise following his return from Kenya and Tunisia. He was managed as a case of traveller's diarrhoea. Stool cultures were negative for pathogenic bacterial growth. Two weeks later he presented with worsening lower back pain. MRI of lumbosacral spine suggested L1 osteomyelitis. CT-guided spinal aspirate grew no organisms and repeat viral serology and blood cultures (including tuberculosis screening) were negative. He was treated with a 6-week course of ceftriaxone. Back pain did not improve and a repeat MRI scan 8 weeks after his antibiotic course indicated progressive changes in L1 extending to L2 with an intradiscal abscess. Repeat CT-guided spinal aspirate grew Salmonella arizonae sensitive to cotrimoxazole and ceftriaxone. He was treated with intravenous ceftriaxone and cotrimoxazole for 12 weeks. A 4-month follow-up MRI scan showed progressive improvement of the L1/L2 discitis with resolution of intradiscal fluid.