Question | Answer |
Inf arthritis: pathophys | Bac enter jt fr bloodstream; surround infected ST / bone; synovium vascular / lacks basement mem, bac access to jt; bac trigger inflame response; cartilage / bone destruction |
Inf arthritis incidence | 2-5/100,000 (bimodal: kids, >50 yo) (in RA: 28-38/100,000) |
Inf arthritis risk factors | DM, EtOH, CRF, AIDS, TB; prosthetic joints / recent surg, trauma, older, immunosupp tx, malig, exp to animals; low SES, IVDU |
Inf arthritis: characterize | Large bones > small bones (usu knee); usu monoarticular (poly <20%) |
Inf arthritis Microbiology: | gonococcal and nongonococcal |
Gono arthritis: incidence | 2/3 of infxs arth in pts <40; DGI sequela; F>M (higher risk w/ menses & PG) |
Gono arthritis: 2 presentations | 1. rash, fever, chills, migratory tenosynovitis of knees, ankles, wrists, feet and hands (30-60%) (some = skin lesions: papulovesicular or hemorrhagic, varying size); 2. monoarticular process: KNEE; hip, ankle, wrist or elbow |
Gono arthritis: labs | syn fluid, blood cx not too helpful; cx likely infected mucosal surfaces (cervix, anus, oropharynx); WBC usually normal |
Gono arthritis: Tx: | hospitalize pt; ceftriaxone 1gm (IM or IV) q 24 hours until clinical improvement; po cefixime or cefpodoxime > 1 wk |
Non-gono arthritis: agents | Usu S. aureus (or strep A/B; SP, coag neg staph) |
Non-gono arthritis: common hosts | RA, diabetes, immunosuppressive drugs |
Non-gono arthritis: affected joints | 90% monoarticular; knee>hip>shoulder>wrist>elbow; following bite: small bones / joints of hands / feet; IVDU: spine, SI, sternoclavicular joints |
Non-gono arthritis: Clinical presentation: | mod - severe pain surrounding joint; effusion, spasm, warmth & erythema; chills & fever common (but may be absent) |
Essential for dx / tx of infxs arthritis: | synovial fluid (usu pos as are cx) (Blood cx pos in 50%) |
Nongono arthritis gram pos Rx: | Nafcillin or cefazolin (vanc for MRSA) |
Nongono arthritis: gram neg | esp Enterobacteriaceae; IVDU; & neutropenic (also pseudomonas) ; ceftazidime or genta; IV 2wks & po 4 wks |
Other nongono arthritis agents | spirochetal (congenital: long bones; secondary: diffuse); Lyme; Myco TB |
TB arthritis: Clin presentation | pain & swelling dev in affected joint over mos / yrs; knee & hip > ankle, shoulder, elbow; |
TB arthritis: occurs as: | part of disseminated primary disease or through reactivation; usu a chronic monoarticular process |
TB arthritis: labs | Syn fluid cell counts may be lower (than other infxs arth); AFB found in syn fluid in <20% |
TB arthritis: Tx | same as for pulmonary dz: multiple agents for at least 9 months |
Lyme arthritis: incidence | 70% of untreated Lyme disease pts develop arthritis |
Lyme arthritis: 3 dz patterns | 40% intermittent monoarticular / oligoarticular process: involves knee +/- other large joints; 20% pattern of waxing / waning polyarthralgias; 10% inflame synovitis: evolves into erosions & joint destruction |
Lyme arthrtitis: dx | clinical; serologic (90% Abs to B. burgdorferi) |
Lyme arthrtitis: Tx | oral doxycycline or amox x 1-2 mo; or IV ceftriaxone for 2-4 wks |
Viral arthritis: most common agents | Hep B & C, rubella, & parvovirus (parvo can be confused with RA) |
Viral arthritis: findings | Nondestructive; usually self-limited; No specific tx, except supportive |
Fungal arthritis | often immunocompromised pts; chronic indolent course |
Fungal arthritis: etiologies: | endemic dimorphic fungi in gardeners / occupations w/exp to soil |
Fungal arthritis: Candida | surg procedures, joint injections, critical illness (knee, hip or shoulder); IVDUs: spine, SI joints |
Fungal arthritis: other agents: | Aspergillus, Cryptococcus, Pseudallescheria, dematiaceous fungi |
Fungal arthritis: Labs | cx joint fluid may be neg; Complement fixation, antigen assays, synovial bx: all dx important |
Fungal arthritis: Tx | Ampho B (IV +/- intra-art) |
Infxs arthritis: prosthetic joint: early | Usu Staph epi |
Infxs arthritis: prosthetic joint: late | Usu Staph aureus (often indolent presentation) |
Infxs arthritis: prosthetic joint: dx | Aspiration and growth of organism |
Infxs arthritis: prosthetic joint: Tx | aggressive debridement (early), removal of prosthesis (late), and prolonged Abx tx |
Prosthetic joint infection: on xray usu appears as: | increased lucency around prosthesis |
Prosthetic joint infection: rates highest among: | pts w/ RA, h/o prior joint surgery, immunosuppressive therapy |
Prosthetic joint: prophylaxis? | not recommended (but consider for pts w/ inflame arthritis, DM, immunosuppression or within 2 yrs of joint replacement) |
Bone marrow infection due to blood-borne pathogens = | osteomyelitis |
Osteo often affects whom? | Kids (M > F) |
Osteo bugs | S aureus (no. 1); GAS (kids); GBS & E coli in neonates |
Osteo bugs in IVDU | SA, Pseudomonas, Serratia, Candida |
Osteo bugs after open fx or ORIF | SA, Pseudomonas, coliforms |
Osteo bugs in pts with sickle cell dz | Salmonella |
Imaging for osteo | X-rays (ST swelling, demineralization (10 days - 2 wks), dead bone w/surrounding granulation tissue, periosteal new bone growth later); MRI shows changes earlier; CT radiolucent in cancellous bone & periosteal elevation |
Osteo labs | Elevated WBC and ESR. CRP most sensitive to monitor course |
Chronic osteo: fistulous tracts may develop into: | epdermoid carcinoma |
Chronic osteo: CT is excellent to detect: | sequestra (localized mass of bone, denser than surroundings), cortical destruction, ST abscess, sinus tracts |
Septic joint/osteo: orgs: bone | Bone: GAS, S. aureus |
Septic joint/osteo: orgs: joint | H. flu, GAS, E. coli, NG |
Septic joint/osteo: sx | Fever, joint or bone pain, leukocytosis |
Osteomyelitis after stepping on nail wearing sandals or tennis shoes | Pseudomonas aeruginosa (foam padding in shoes) |
Septic Joint & Osteomyelitis: frequently following: | URI |
Septic Joint & Osteomyelitis: Common Organisms: Bone: | GAS, S. aureus |
Septic Joint & Osteomyelitis: Common Organisms: Joint: | H. flu, GAS, E. coli, N. gono |
Septic Joint & Osteomyelitis: Dx: | Bone scans localize osteomyelitis; Joint aspiration to ID organism |
Septic Joint & Osteomyelitis: Sx: | Fever, joint or bone pain, leukocytosis |
Septic Joint & Osteomyelitis: Dx: | Bone scans localize osteomyelitis; Joint aspiration to ID organism |
Septic Joint & Osteomyelitis: Rx: | Parenteral Abx, I&D |
Infection: prevalence in LBP | Only .01% of all causes of LBP |
Infection: clin features | Fever, leukocytosis; hx of other infections, hematogenous spread |
Infection: includes: | Osteomyelitis; Septic Discitis; Paraspinous abscess; Shingles |