Nongonococcal Infectious Arthritis
Nongonococcal infectious arthritis is an acute or subacute illness with potentially significant morbidity and mortality. Bacteria, mycobacteria, and fungi can cause the disease. Both healthy individuals and individuals with predisposing conditions can be infected. Nongonococcal infectious arthritis is typically a monoarticular disease, but, in approximately 10% of patients, it affects multiple joints. Without treatment, the condition results in joint destruction.
Infectious arthritis ensues when foreign organisms invade the synovium or joint space. These organisms invade the joint via (1) hematogenous dissemination from a distant site; (2) periarticular infection, such as osteomyelitis or adjacent soft-tissue infection; or (3) direct introduction through penetrating trauma or procedural intervention, such as arthrocentesis or surgical repair.
The yearly incidence of bacterial arthritis varies from 2-10 cases per 100,000 persons in the general population to 30-70 cases per 100,000 persons in patients with rheumatoid arthritis.
Mortality occurs in 10-15% of cases.
Joint destruction occurs in 25-50% of cases.
No inherent racial predilections for infectious arthritis are recognized.
Sex is not an independent risk factor to predispose individuals to infectious arthritis.
Age older than 80 years has been shown in some studies to be an independent risk factor for susceptibility to bacterial arthritis.
The clinical course of bacterial arthritis is typically acute in onset.
Patients with joint prostheses are the exception. These patients’ symptoms may persist for weeks or months before a diagnosis is made.
Individuals with mycobacterial or fungal arthritis also tend to have a much more indolent or subacute prodrome before the diagnosis is considered.
The sternoclavicular and sacroiliac joints are preferentially involved in patients who abuse parenteral drugs.
Joint pain, swelling, erythema, and loss of motion are common presenting symptoms.
The most commonly affected joint in persons with bacterial arthritis is the knee.
The shoulder, hip, elbow, and wrist joints are infected less frequently.
Approximately 10% of individuals with bacterial arthritis have infection in multiple joints, particularly in the presence of a preexisting destructive joint disease (eg, rheumatoid arthritis) or compromising medical conditions (eg, diabetes, glucocorticoid therapy).
During the first 24 hours of hospitalization, 78% of patients with nongonococcal bacterial arthritis exhibit fever; however, the fever rarely exceeds 39°C (102.2°F).
The patient may have decreased range of motion in the joint.
Swelling, tenderness to palpation, erythema, warmth to touch, and pain upon movement of the affected joint are common physical examination findings.
The presence of a preexisting, chronic, inflammatory, destructive arthritis, especially rheumatoid arthritis, is correlated with infectious arthritis. The recent introduction of anti–tumor necrosis factor (TNF) agents in the treatment of inflammatory arthritis may additionally predispose this population to infectious arthritis.
A person undergoing immunosuppressive therapy, such as with corticosteroids or cytotoxic agents, is more likely to become infected.
A person who has a prosthetic joint has greater risk of infection.
Elderly individuals are particularly at risk for infectious arthritis.
Comorbid nonarticular conditions, such as diabetes mellitus, immunodeficiency diseases, cancer, or intravenous drug abuse, also increase the risk of infectious arthritis.
Gram-positive cocci, especially Staphylococcus aureus, are the predominant etiologic agents. Streptococcal species are also common, especially group A streptococci.
If a prosthetic joint was implanted within the preceding 6 months, Staphylococcus epidermidis and S aureus are major pathogens.
Gram-negative bacilli are more common in elderly patients with chronic medical conditions.
Pseudomonas aeruginosa and methicillin-resistant S aureus are more prevalent in the infectious arthritis that affects individuals who abuse intravenous drugs.
Salmonella species exhibit a predilection for individuals with systemic lupus erythematosus.
Consider Pasteurella multocida subsequent to a cat bite or Eikenella corrodens after a human bite.
In addition to the common pathogen Mycobacterium tuberculosis, nontuberculous species, such as Mycobacterium kansasii, may spread from a pulmonary focus and infect a joint.
Mycobacterium marinum should be considered in individuals exposed to aquatic or marine environments.
Candida organisms, including Candida albicans and Candida parapsilosis, are causative in debilitated hospitalized patients or in patients on long-term antibacterial therapy.
Sporothrix schenckii may infect the hand or wrist joints of a person frequently exposed to moist soil, rose thorns, or the outdoors.