Septic arthritis

Q: Septic Arthritis most commonly occurs via? (select one) 

 A) hematogenous seeding 
 B) direct inoculation 
 C) extension of infection


Answer: A

The cause of hematogenous seeding for septic arthritis is most common particularly if bacteremia occurs with Staphylococcus aureus which has a high propensity to adhere to the synovial tissues. The synovial membrane does not carry any limiting basement membrane and thus has a very high risk to acquire infection. This piece of knowledge becomes extremely important in patients with blood cultures positive for Staphylococcus aureus, though other organisms can also cause septic arthritis. Clinical exam in such instances is essential.

Direct inoculation via bites, trauma, post-surgery,  procedures like arthroscopy, and unsterile intra-articular injection is also common.

Extension of infections from osteomyelitis or diverticulitis may occur due to the dissection of infection into the adjacent joints. In ICU, line infections may extend into joints, particularly after subclavian and femoral line insertions.


#infectiousdiseases
#rheumatology


References:

1. Goldenberg DL. Septic arthritis and other infections of rheumatologic significance. Rheum Dis Clin North Am 1991; 17:149. 

2. Mader JT, Shirtliff M, Calhoun JH. The host and the skeletal infection: classification and pathogenesis of acute bacterial bone and joint sepsis. Baillieres Best Pract Res Clin Rheumatol 1999; 13:1. 

3. Balato G, Di Donato SL, Ascione T, et al. Knee Septic Arthritis after Arthroscopy: Incidence, Risk Factors, Functional Outcome, and Infection Eradication Rate. Joints 2017; 5:107. 

4. Aglas F, Gretler J, Rainer F, Krejs GJ. Sternoclavicular septic arthritis: a rare but serious complication of subclavian venous catheterization. Clin Rheumatol 1994; 13:507. 

5. Fromm SE, Toohey JS. Septic arthritis of the hip in an adult following repeated femoral venipuncture. Orthopedics 1996; 19:1047. 

6. Messieh M, Turner R, Bunch F, Camer S. Hip sepsis from retroperitoneal rupture of diverticular disease. Orthop Rev 1993; 22:597.