Articular involvement in human Brucellosis: A retrospective analysis of 304 cases

Abstract

Brucellosis is a zoonosis which in humans is caused by one of four species of the Brucella genus: B. melitensis, B. abortus, B. suis and B. canis. B. abortus is the species prevalent in North America and Europe and B. melitensis in most developing countries. Differences in disease manifestations may be accounted for either by differences in the species or by differences in the host. Articular involvement in brucellosis, although recognized since 1904, has been variably emphasized. Three hundred and four cases of human Brucellosis caused by B. melitensis, the prevalent species in Perú, were seen during a 12-yr period in one Lima hospital. Fever, malaise and hepatomegaly were the most frequent findings. Diagnosis was greatly improved when cultures were done in the biphasic Ruiz-Castañeda medium, rather than in trypticase soy broth. Serologie diagnosis is still important, and it should include standard tube testing, detection of IgG blocking antibodies and fractionation with 2-ME in chronic cases. The disease may take one of three courses: acute, (<8 wk), chronic (>8 wk) or undulant (periods of remissions and exacerbations). Four syndromes were recognized in a total of 33.8% of patients with Brucellosis. The most frequent pattern (in ~46.6% of patients with arthritis) was sacroiliitis, usually non-destructive and either uni-or bilateral. The second most frequent articular syndrome was peripheral arthritis (38.8%), manifested either as a single large lower extremity joint or as an asymmetric pauciarthritis. Rarely patients presented with a rheumatoidlike arthritis. Mixed arthritis (7.8%) was a combination of the first two. The above forms occurred in patients with an acute or undulant course. Spondylitis was the least common form of arthritis (6.8%), and differed significantly from the other forms of arthritis in the duration of symptoms (chronic course), age of patients (older individuals) and the paucity of fever and malaise. It also tended to be destructive. The arthritis usually resolved with the combined regimen of tetracycline (2 g p.o. for 21 days) and streptomycin (1 g i.m. for 21 days) without sequelae. Illustrative cases of these syndromes are presented. The relatively benign nature of most of the patients with brucellar arthritis lead us to postulate that they are for the most part reactive arthritides. Host factors are thought to be important in determining the response to the infection, but they are yet to be identified. Our own genetic studies have failed to identify an increased frequenty of B27 or CREG antigens in the patients with sacroiliitis. The demonstrations of circulating immune complexes in these patients however favors an immunopathogenic mechanism as responsible for some of the manifestations of this disease.