Epidemiology

 Although hematogenous infections with virulent organisms such as S. aureus, H. influenzae, and pyogenic streptococci occur in healthy persons, there is an underlying host predisposition in many cases of septic arthritis. Patients with rheumatoid arthritis have the highest incidence of infective arthritis (most often secondary to S. aureus) because of chronically inflamed joints; glucocorticoid therapy; and frequent breakdown of rheumatoid nodules, vasculitic ulcers, and skin overlying deformed joints. Diabetes mellitus, glucocorticoid therapy, hemodialysis, intravenous drug use, and malignancy all carry an increased risk of infection with S. aureus and gram-negative bacilli. Tumor necrosis factor inhibitors (e.g., etanercept, infliximab), which increasingly are used for the treatment of rheumatoid arthritis, predispose to mycobacterial infections and possibly to other pyogenic bacterial infections and could be associated with septic arthritis in this population. Pneumococcal infections complicate alcoholism, deficiencies of humoral immunity, and hemoglobinopathies. Pneumococci, Salmonella species, and H. influenzae cause septic arthritis in persons infected with HIV. Persons with primary immunoglobulin deficiency are at risk for mycoplasmal arthritis, which, while rare, results in permanent joint damage if tetracycline and replacement therapy with IV immunoglobulin are not administered promptly. IV drug users acquire staphylococcal and streptococcal infections from their own flora and acquire pseudomonal and other gram-negative infections from drugs and injection paraphernalia.

Clinical Manifestations

 Patients with acute septic arthritis usually present with joint pain often with limitation of passive and active joint movement, joint swelling, and/or erythema. Approximately 90% of patients present with involvement of a single joint—most commonly the knee; less frequently the hip; and still less often the shoulder, wrist, or elbow. Small joints of the hands and feet are more likely to be affected after direct inoculation or a bite. Among IV drug users, infections of the spine, sacroiliac joints, and sternoclavicular joints (Fig. 1) are more common than infections of the appendicular skeleton. Poly articular infection is most common among patients with rheumatoid arthritis and may resemble a flare of the underlying disease.

Fig1. Acute septic arthritis of the sternoclavicular joint. A man in his forties with a history of cirrhosis presented with a new onset of fever and lower neck pain. He had no history of IV drug use or previous catheter placement. Jaundice and a painful swollen area over his left sternoclavicular joint were evident on physical examination. Cultures of blood drawn at admission grew group B Streptococcus. The patient recovered after treatment with IV penicillin. (Courtesy of the late Francisco M. Marty, MD, Brigham and Women’s Hospital, Boston; with permission.)

The usual presentation consists of moderate to severe pain that is uniform around the joint, effusion, muscle spasm, and decreased range of motion. Fever in the range of 38.3–38.9°C (101–102°F) and some times higher is common but may not be present, especially in persons with rheumatoid arthritis, renal or hepatic insufficiency, or conditions requiring immunosuppressive therapy. The inflamed, swollen joint is usually evident on examination except in the case of a deeply situated joint such as the hip, shoulder, or sacroiliac joint. Cellulitis, bursitis, and acute osteomyelitis, which may produce a similar clinical picture, should be distinguished from septic arthritis by preservation of passive range of motion and less-than-circumferential swelling. A focus of extraarticular infection, such as a boil, pneumonia, or endocarditis, should be sought. Peripheral-blood leukocytosis with a left shift and elevation of the erythrocyte sedimentation rate or C-reactive protein level are common.

Plain radiographs show evidence of soft tissue swelling, joint space widening, and displacement of tissue planes by the distended capsule. Narrowing of the joint space and bony erosions indicate advanced infection and a poor prognosis. Ultrasound is useful for detecting effusions in the hip, and CT or MRI can demonstrate infections of the sacroiliac joint, the sternoclavicular joint, and the spine very well.

Laboratory Findings

 Specimens of peripheral blood and synovial fluid should be obtained before antibiotics are administered. Blood cultures are positive in up to 50–70% of S. aureus infections but are less frequently positive in infections due to other organisms. The synovial fluid is turbid, serosanguineous, or frankly purulent. Gram-stained smears confirm the presence of large numbers of neutrophils. Levels of total protein and lactate dehydrogenase in synovial fluid are elevated, and the glucose level is depressed; however, these findings are not specific for infection, and measurement of these levels is not necessary for diagnosis. The synovial fluid should be examined for crystals because gout and pseudogout can resemble septic arthritis clinically, and infection and crystal-induced disease occasionally occur together. Organisms are seen on synovial fluid smears in nearly three-quarters of infections with S. aureus and streptococci and in 30–50% of infections due to gram-negative and other bacteria. Cultures of synovial fluid are positive in >90% of cases. Inoculation of synovial fluid into bottles containing liquid media for blood cultures increases the yield of a culture, especially if the pathogen is a fastidious organism or the patient is taking an antibiotic, but should be interpreted in the context of the Gram’s stain result. Pathogen nucleic acid amplification based assays (NAAT) or MALDI-TOF mass spectrometry, when available, can be useful for the diagnosis of partially treated or culture-negative arthritis. Inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein tend to be elevated in septic arthritis but are nonspecific. Serum procalcitonin elevation is only ~50% sensitive and should not be used to rule out infectious arthritis. Synovial fluid procalcitonin might be useful, although data are limited.

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المجمع العلمي يواصل تنظيم أنشطته القرآنية في محافظتي كربلاء وصلاح الدين

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أكثر من قرن على صناعتها.. متحف الكفيل يرمم قطعة أثرية هندية

قسم الشؤون الفكرية ينظّم ندوة عن البعد الحضاري لزيارة الأربعين ويصدر عددًا جديدًا من مجلة الرياحين

المزيد

الآخبار الصحية

العنب.. فاكهة صغيرة بمفعول "خارق" للقلب والدماغ

دراسة تحدد "الحلقة المفقودة".. تسبب ارتفاع ضغط الدم

هذه الأطعمة تحمي دماغك من الشيخوخة وتزيد حدة الذكاء

خبراء يحذرون من مخاطر "الدهون المخفية" على القلب

المزيد

الآخبار التكنلوجية

الأرصاد الجوية تلجأ إلى الذكاء الاصطناعي.. لأي غرض؟

في منزلك.. "تعديل بسيط" يخفض ضغط الدم بشكل طبيعي

"ميزة جديدة" من إنستغرام تنافس تيك توك.. طال انتظارها

غوغل في مأزق.. بيانات 2.5 مليار مستخدم بقبضة القراصنة

المزيد

مواضيع ذات صلة

Gonococcal Arthritis

Acute Bacterial Arthritis

Streptococcus pyogenes

Treatment of Staphylococci

Enzymes and Toxins of Staphylococci

Rocky Mountain Spotted Fever

Human Ehrlichiosis

Antimicrobial Susceptibility Testing and Therapy of Neisseria and Moraxella catarrhalis

Laboratory Diagnosis of Neisseria and Moraxella catarrhalis

Spirillum Minus

Streptobacillus moniliformis

Myositis and Myonecrosis