Septic arthritis

1. SEPTIC ARTHRITIS & TOM SMITH ARTHRITIS

2. Introduction A joint inflammation due to an infection usually involving synovial joints. 50% of cases- children less than 5 years. 30% of cases- children less than 2 years.

3. Common sites(Adults) Knee- 53% Hip- 20% Elbow- 17% Shoulder- 10%

4. Common sites(Children) Knee- 39% Hip- 32%

5. CAUSATIVE ORGANISMS Staphylococcus aureus Hemophilus influenza Streptococcus E. coli Proteus

6. MODES OF SPREAD Direct invasion. Local spread from adjacent tissues. Spread from metaphyseal osteomyelitis. Hematogenous spread.

7. Predisposing Factors-General factors Rheumatoid arthritis. SLE Immunosuppressive drug therapy. Diabetes mellitus. Immunodeficiency disorders. Chronic debilitating disorders- liver failure and renal failure.

8. Predisposing factors- Local factors Previous joint trauma. H/o arthritis to the same joint. Degenerative joint disease. Crystal induced joint disease.(gout and pseudogout)

9. PATHOLOGY Bacteria rapidly gains access to the joint cavity and settles in the synovial membrane. Acute inflammatory reaction occurs with formation of serous or seropurulent exudate. Articular cartilage is eroded and destroyed due to the action of bacterial toxins and by enzymes released from the synovium and inflammatory cells. In late cases- extensive erosion due to synovial proliferation and ingrowth .

10. If untreated- spread to the underlying bone or burst out of the joint to form abscesses and sinuses. With healing: Complete resolution. Partial loss of cartilage and fibrosis of joint. Loss of articular cartilage and bony ankylosis . Bone destruction and permanent deformity of the joint.

11. Clinical Features- Symptoms Fever Pain over joint. Reluctance to move joint( pseudoparesis ).

12. Signs In neonates: Few clinical signs. Child may not have fever. Loss of spontaneous movement of extremity. Hip-flexion, abduction, and external rotation.

13. In children: signs of local inflammation are present. Rapid pulse and swinging fever. Overlying skin-red. Swelling may be present. Local rise of temperature and marked tenderness over joint. All movements of joint- restricted.

14. In adults: Often a superficial joint( knee, wrist or ankle). Joint is painful, swollen, and inflamed. Movements are restricted.

15. PHYSICAL EXAMINATION Decreased or absent range of motion. Signs of inflammation: joint swelling, warmth, tenderness and erythema. Joint orientation as to minimize pain (position of comfort): Hip: abducted, flexed and externally rotated. Knee, ankle and elbow: partially flexed. Shoulder: abducted and internally rotated

16. Investigations Blood investigations X- ray USG Diagnostic aspiration MRI

17. BLOOD INVESTIGATIONS Leucocytosis >12,000. ESR>40 mm/hr. CRP- elevated. Blood culture-may be positive.

18. X-ray In early stages- usually normal. Later on- joint space widening may be present and subluxation of the joint may be present. In late stages- irregularity of the joint.

19. Septic arthritis of the ankle

20. USG Can be used to detect even the smallest amount of joint effusion. Non invasive, inexpensive and easy to use. Can be used to guide joint aspiration.

21. JOINT ASPIRATION In early cases- fluid may be clear. Sample sent for Gram staining, microscopy, culture, and antibiotic sensitivity. Normal synovial fluid leucocyte count: under 300/ml. Leucocyte count>50,000 per ml with 90% PMN- strongly suggestive of septic arthritis.

22. streptococci

23. H. influenzae

24. MRI Can detect infection and extent of infection. Useful in diagnosing infections that are difficult to access. Also useful in differentiating between bone and soft tissue infections and in detecting joint effusion.

25. Differential Diagnosis Acute osteomyelitis. Trauma Irritable joint Hemophilic joint. Rheumatic fever Gout and pseudogout Gaucher’s disease.

26. Treatment IV fluids- to prevent dehydration. Analgesics- for pain. Joint must be rested either on splint or in a widely split plaster.

27. Antibiotics Broad spectrum IV antibiotics are started immediately and then depending on microbiological investigations, specific antimicrobial therapy is started. First line antibiotics: Benzyl penicillin, flucloxacillin, and augmentin . Second line antibiotics: Vancomycin, Clindamycin, Fusidin, and Teicoplanin. Hemophilus infection- cephalosporins.

28. Duration of treatment: IV antibiotics given for minimum of 2 weeks. Oral antibiotics: Children-2-4 weeks. Adults- 4-6 weeks.

29. Drainage: Indication of Surgical Drainage: 1-Joints that do not respond to antimicrobial therapy and daily arthrocentesis 2-. Any joint with limited accessibility, including the sternoclavicular or the hip joint 3-Patients with underlying disease, including diabetes, rheumatoid arthritis, immunosuppression , or other systemic symptoms, should be treated more aggressively with earlier surgical intervention

30. Drainage In septic arthritis of hip- surgical drainage is always done. Best approach- anterolateral Joint is opened through a small incision and washed with normal saline. Small drain is left in place after incision is closed. Suction-irrigation is continued for another 2 or 3 days.

31. In knee- arthroscopic debridement and copious irrigation. In adults- repeated closed aspiration of joint may be done. But if no improvement within 48 hours- open drainage is necessary.

32. Complications Joint Destruction Coxa magna Pathological Dislocation Acute Osteomyelitis Septicemia Secondary osteoarthritis Avascular necrosis

33. TOM SMITH ARTHRITIS

34. Septic arthritis of the hip. Seen in infants. Head of femur is completely destroyed by the pyogenic process.

35. Transphyseal vessels are present in early infancy before the formation of the growth plate This may account for the frequency of septic arthritis of the hip in the neonate In children, about a third of long-bone osteomyelitis is associated with septic arthritis of the adjacent joint.

36. Clinical features Onset is acute with rapid abscess formation. Can be mistaken for a superfical infection. Can present later with complaints of limp without any pain. O/E: Affected leg is shorter and hip movements are increased in all directions. Telescopy test-positive.

37. X-ray- complete absence of the head and neck of femur. Condition resembles DDH; complete absence of head and neck and normally developed round acetabulum.

38. Treatment Acute surgical emergency. Open drainage of hip joint is the most effective method of treatment in septic arthritis of the hip. Arthroscopic drainage can also be attempted.