Infectious Arthritis
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Contents |
More Specific Terms
- fungal arthritis
- HIV-associated arthritis
- infectious arthritis in the elderly
- tuberculous arthritis
- viral arthritis
Introduction
- Generally, inflammation of a joint caused by bacterial invasion.
Etiology
-
- most common cause in patients < 40 years of age
- may produce an arthritis- dermatitis syndrome indistinguishable from Neisseria gonorrhoeae
- most common cause of non- gonococcal septic arthritis
- affects native & prosthetic joints
- medical emergency [3]
- coagulase negative Staphylococcus
- Streptococcus pneumoniae
- Streptococcus pyogenes
- Streptococcus agalactiae
- Haemophilus influenzae
- gram negative bacilli
- Escherichia coli
- Salmonella, especially osteomyelitis
- Pseudomonas
- Hemophilus influenza
- more common in elderly, immunosuppressed, post-op, & in patients with intravenous catheters
- Brucella preferentially involves spine
- tuberculosis preferentially involves spine
- Mycobacterium marinum
- Borrelia burgdorferi ( Lyme disease)
- viral arthritis:
- Sporothrix schenckii
- Histoplasma
- Crytococcus
- Blastomyces
- prosthetic joint infection
- sources of infection
- injection drug use associated with subacute septic arthritis
- septic sacroiliitis, sternoclavicular joint & pubic symphysis involvement
- gram-negative bacilli
Pathology
- hematogenous spread from another primary site of infection
- contiguous spread to joint from soft tissue or adjacent bone
Clinical-manifestations
- acute onset monoarthritis
- worsening of chronic joint disease in a single joint
- onset generally over a few days
- fever, shaking chills uncommon
- affected joint may be warm, erythematous, swollen & painful with limited joint mobility
- pain on passive range of motion in the absence of trauma
- pain & swelling less in elderly & in patients receiving corticosteroids
- joints commonly affected
- knee is involved in 1/2 of the cases
- hips
- shoulders
- wrists
- ankles
- elbows
- spine - involves vertebral body & adjacent intervertebral disk space
- in drug abusers ( Staphylococcus aureus, Pseudomonas)
- migratory arthragia, tenosynovitis (wrist or ankle) & skin pustule = disseminated gonococcal infection
- overlying skin infection in a patient who has recently undergone arthroplasty suggests prosthetic joint infection
Diagnostic-criteria
- acute monoarticular arthritis.
- positive gram stain/ culture from synovial fluid (exception Neisseria gonorrhoeae)
Laboratory
-
- WBC 10,000-100,000/ mm3 ( bacterial)
- differential > 90% neutrophils
- synovial fluid Gram stain, culture & sensitivity
- serum & joint fluid glucose - joint fluid often < 50% fasting serum glucose
- "string test": normal synovial fluid when gently pushed from syringe will form a 5-10 cm "string". With infection, the "string" will be shorter
- polarized microscopy of joint fluid for crystals
- septic arthritis can develop in patients with crystalline arthritis
- crystals in synovial fluid does not exclude infection
- complete blood count ( CBC) may show leukocytosis
- blood cultures
- if disseminated gonococcal infection, also wound culture (skin pustule), urethral culture or cervical culture, rectal culture, throat culture
Radiology
- plain films of joint (rarely helpful [3])
- soft tissue swelling & distention of joint capsule early
- joint destruction may be observed as a late manifestation
- evidence of co-existing osteomyelitis may be present
- bone scan may be useful, but is non-specific
- magnetic resonance imaging ( MRI)
Differential-diagnosis
Management
- joint aspiration & drainage daily until fluid ceases to accumulate
- arthroscopic or open drainage may be necessary if joint fluid cannot be completely evacuated by aspiration
- antibiotic therapy
- determined by clinical condition & laboratory studies
- empiric antibiotic therapy
- no organisms seen on gram stain
- ceftriaxone, if risk for gonorrhea even if cultures negative [3]
- nafcillin + ceftazidime if low risk for gonorrhea
- nafcillin or oxacillin +/- gentamicin; cefazolin 2nd line
- vancomycin or linizolid if high-risk of MRSA [3] teicoplanin 2nd line
- ceftriaxone of cefotaxime; fluoroquinolone 2nd line
- ceftazidmine + gentamicin if Pseudomonas
- ceftazidmine + gentamicin for IV drug users [3]
- duration of therapy:
- surgery + antibiotics for infected prosthesis
- splinting of joint may provide symptomatic relief
- passive range of motion exercises once pain has diminished followed by active exercise to restore strength & joint mobility
- bony fusion may be required with severely damaged weight-bearing joints
- poor outcomes are common even with aggressive management
- glucocorticoids
- persistent synovitis & effusion after cure of infection may respond to a single intra-articular glucocorticoid injection
- document negative cultures after completion of antibiotics prior to glucocorticoid injection
- administration of dexamethasone 0.2 mg/kg IV every 8 hours for 12 doses improved outcomes in children [4]; 1st dose administered 15-20 minutes before 1st dose of parenteral antibiotics [4]
More General Terms
Additional Terms
References
- Harrison's Principles of Internal Medicine, 11th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1987, pg 1462
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 877-78
- Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15 American College of Physicians, Philadelphia 1998, 2006, 2009
- Journal Watch 23(23):187, 2003 Odio CM et al Double blind, randomized, placebo-controlled study of dexamethasone therapy for hematogenous septic arthritis in children. Pediatr Infect Dis J 22:883, 2003 PMID: [1]
- National Guideline Clearinghouse The diagnosis of periprosthetic joint infections of the hip and knee. American Academy of Orthopaedic Surgeons (AAOS) ngc-guideline: [2]
