| What is septic infectious arthritis? | Articular manifestations due to presence of pathogen within a joint, major cases bacteria, most common is S.areus, could be virus/fungi/mycobacterium.
Hematogenous seeding of vascular synovial membrane after bacteremia, may also arise from penetrating cutaneous trauma following plant-thorn wound/animal bite.
Rarely due to corticosteroid joint injection or intraarticular procedures, typical is acute, very painful monoarthritis with fever.
Irreversible loss of function develops in 25-50% of pt related to delayed dx and tx, can be life threat in 10% of cases |
| What is the difference between gonococcal and non-gonococcal arthritis? | Non gonococcal vs Gonococal
Age (risk increases with age vs sexually active young adults)
Gender (no difference vs 4x more in women)
Menstuation (no increased risk vs increased risk)
SLE (risk for nisseria menigitidis vs N.gonorrhea)
Presentation (single joint vs migratory polyarthritis)
Tenosynovitis and polyarthralgia(uncommon vs common)
Pustular dermatitis (abscent vs does occur)
Culture positivity (nearly 90% vs <50%) |
| What is non-gonococcal arthritis? | Emergency because joint can be destroyed if tx is postponed for a few days, pt with advanced age, RA, and those with immunocompromised /abnormal joint structure or joint prosthesis are at increased risk of joint infection. |
| What are the risk factors for non-gonococcal arthritis? | Old age (>80 years), RA, immunosuppressed, AIDS, Chronic renal failure, organ transplant, hypogammaglobulinemia, prosthetic join, previous intra-articular corticosteroid injections, DM, OA, low socioeconomic status, alcoholism, IV drug use, cutaneous ulcer, hemoglobinopathy, trauma to joint, SLE. |
| How are clinical symptoms and dx of non-gonococcal arthritis? | Acute swollen joints often large joints like ankle/knee, fever, sweats, rigors, joint swollen, warm, red and tender.
Clinical presentation vary according to virulence of causative organism, low for mycobacterial/fungal joints.
If other joint issue exists, one joint stand out of the others, polyarthritis occurs for 20% of pt mostly with chronic disease/immunosuppression.
In pt with RA, use of anti-inflammatory drugs mask the joint pain and swelling leads to dx delay |
| How is DD of septic arthritis? | Acute monoarthritis is septic arthritis until proven otherwise. |
| How is dx of non-gonococcal arthritis? | Arthrocentesis (synovial fluid gram stain, WBC, and culture. Staph/strep are 91% of infections, gram - are in old and immunocompromised pt, gram + 71% of cases are +, 40-50% of cases are gram - and <25% gonococcal, microscopy for only 50% of cases)
Lab markers (WBC, ESR, CRP)
Imaging (Radio normal early stages, only swelling, structural damage severity differs according to agent, include juxta-articular osteoporosis, diffuse joint space narrowing due to cartilage destruction and erosions, at late stages appear badly destroyed, MRI/CT assesses inflammation, destruction and periarticular soft tissue masses) |
| What are possible microbes in different pt backgrounds? | Staph Aureus (RA, OA, IV drug use)
Klebsiella (alcoholism, malignancy, immunosupressed)
Gram - (malignancy, immunosuppressed)
Pseudomonas (IV drug use)
Encapsulated microbe (complement defect)
Salmonella, Niesseria meningitidis, adn Strep Pneumo (SLE)
HIV no specific gram. |
| What are the outcomes of septic arthritis? | Duration of symptoms, type of organisms, type of joint drainage, per-existing joint problems, co-existing osteomyelitis, baseline joint condition |
