Bacterial infections: osteoarticular brucellosis

Osteoarticular brucellosis has been documented extensively from the Middle East and Spain in the last 5 years, but it has only been reported infrequently from the UK and USA. Brucella melitensis from goat and sheep is the most frequently isolated organism. Peripheral articular pain, particularly of the large joints, is the commonest osteoarticular manifestation, while effusions that seldom yield organisms on culture, also occur frequently. Sacroiliitis which most frequently is unilateral, often presents acutely and dramatically with severe pain that is poorly localized to the lower back and buttock, leading to difficulty in walking and even standing. Tapping the heel and springing the sacrum is probably the best way of localizing the pain to the sacroiliac joint in this acute stage. Lack of awareness of this pattern of presentation could lead to misdiagnosis. Spondylitis is the third major manifestation of osteoarticular brucellosis. It occurs in older patients and is insidious and chronic in onset and course. The lumbar spine is most frequently involved, although cervical involvement is frequently associated with more complications, particularly compressive neurological deficits. Osteomyelitis occurs unusually. Several large series have been reported among children. In them peripheral large joint involvement in association with systemic features predominate while sacroiliitis may occur unusually. Plain X-rays often demonstrate vertebral damage, involving the upper anterior margin most frequently. CT scans define better vertebral damage that is characterized by bony sclerosis and the less frequently encountered extradural extension and para-vertebral abscess formation. Technetium bone scan is the most sensitive technique for detecting acute sacroiliitis and other sites of early osteoarticular involvement. A four-fold rise in Brucella agglutination titre is the most frequently utilized diagnostic aid. A 6 week culture in a CO2-enriched medium is recommended for growing Brucella. Tetracycline or doxycycline 200 mg per day for 6 weeks is the mainstay of most medical treatment schedules. Combination with streptomycin for 3 weeks or rifampicin for 6 weeks is recommended, to reduce significantly the failure and relapse rate. Spinal involvement is associated with an increased failure and relapse rate while they occurred least among those with no osteoarticular involvement. Surgical intervention to stabilize the spine and relieve neurological compression may become necessary. With the use of these various measures, the outlook for complete recovery is good.