Cat-scratch disease: a rare cause of osteomyelitis

Cat-scratch disease is a zoonosis caused by Bartonella henselae, characterised by regional lymphadenopathy. Rarer presentations, such as osteomyelitis, can occur. We present an adolescent girl with severe right lumbar pain and fever, without animal contacts or recent travels. On examination, pain on flexion of torso, movement limitation and marked lordosis were noted, but there were no inflammatory signs, palpable masses or lymph nodes. Serological investigations revealed elevated inflammatory markers. Imaging revealed a paravertebral abscess with bone erosion. Several microbiological agents were ruled out. After a second CT-guided biopsy, PCR for Bartonella spp was positive. At this point, the family recalled having a young cat some time before. Cat-scratch disease was diagnosed, and complete recovery achieved after treatment with doxycycline and rifampicin. Cat-scratch disease is a challenging diagnosis in the absence of typical features. However, B. henselae must be investigated if common pathogens are ruled out and response to therapy is poor.