Clinics in rheumatic diseases最新文献

The results from animal studies of bacterial joint infection have demonstrated pathogenic changes in synovium, cartilage, and bone which lead to joint destruction. Mechanisms responsible for the changes in these articular components remain to be more completely defined in order to develop methods to prevent articular destruction. Eradication of the active infectious process with early institution of antibiotics and adequate drainage is required but is not sufficient to prevent chronic destructive processes initiated by the acute bacterial infection. Biochemical effects of changes in the anabolic and catabolic functions of the cells in bone, cartilage, and synovium and the control mechanisms for these functions undoubtedly hold the key to prevention of destruction in infectious arthritis. Much less is understood about the pathogenic changes and mechanisms in infections caused by anaerobic bacteria, mycobacteria, fungi or viruses. Application of advances in immunological, morphological and biochemical techniques to animal models of infectious arthritis provides the opportunity to increase understanding of pathogenic mechanisms and to develop innovative methods of treatment.

Most of the data for this paper were taken from a 30-year follow-up of septic arthritis and a 25 year series of osteomyelitis seen in Dallas, Texas. A specific bacterial aetiology was determined in about 70% of patients with septic arthritis, utilizing culture of multiple fluids. The aetiological agent was influenced by the age of the patient. In the newborn Staph. aureus, group B streptococci and gram-negative organisms are found most commonly. In the older infant H. influenzae becomes a prominent pathogen, and in those over 2 years of age staphylococci, streptococci, H. influenzae and N. gonorrhoea are the predominant organisms. Ninety-three per cent of arthritis was monoarticular. A slightly higher percentage (78%) of children with osteomyelitis had a specific bacterial aetiology determined. Staph. aureus was the most common pathogen found at all ages, averaging 53% of all cases and in all age groups, and followed in frequency by various types of streptococci. Diagnosis was delayed in osteomyelitis compared to septic arthritis. In the Dallas patients a single bone was involved in 316 compared to 24 with polyosteal disease.

In both infections the initial antibiotic chosen is determined by the gram strain of material obtained from joint aspiration, pus, or other secretions. If no specific bacterial aetiology is found, treatment is begun for the most likely organism considering the age of the patient and the clinical situation. Recently oral therapy has been used extensively in specific instances after an initial period of parenteral therapy. A limited number of follow-up studies have shown that the age of the patient, the bone and/or joint involved, and the organism responsible all influence the long-term results in both septic arthritis and osteomyelitis. The poorest long-term prognosis is in the neonate, especially where the hip joint is involved either alone or with a concomitant osteomyelitis.

Although initially considered a localized epidemic form of arthritis, Lyme disease is now known to have protean manifestation (skin, joint, heart, nervous system) and worldwide distribution. It is caused by infection with the spirochaete Borrelia burgdorferi and is transmitted by a variety of hard ticks and, in some localities, fleas. Antigenic variation between isolates may determine the differences in clinical expression observed between cases in North America and Europe. The reservoir in the animal kingdom is primarily in deer and mice but house pets have also been implicated. The disease is easily treated with oral antibiotics (tetracycline or penicillin) at an early stage but requires parenteral penicillin and can become refractory to medication at late stages. Prompt diagnosis assures the best outcome. Whereas the classic rash, erythema chronicum migrans, is pathognomonic, diagnosis in its absence may rest on serological tests. Bacteriological isolation is seldom successful and is lengthy (Shrestha et al, 1985). Since cloning of the DNA for several of B. burgdorferi antigens has been accomplished, utilization of hybridization techniques may allow rapid detection of the presence of the organism and confirm difficult cases in the future.