Septic Arthritis

Author: Helia Mansouri Dana



Infectious arthritis, also known as septic arthritis, occurs as a result of bacterial, fungal, or viral infection of joints, most commonly seen in large joints such as the knee or the hip (J. W. Smith, Chalupa, and Hasan 2006; Shirtliff and Mader 2002). This disease often arises as a result of the infection of the synovial space following bacterial entry into the bloodstream (bacteremia) (Visser and Tupper 2009).

The inflammation associated with septic arthritis is as a result of the host immune response against the microbial invasion of the joint, and may lead to cartilage and tissue damage if left untreated (Shirtliff and Mader 2002). Generally, the incidence of septic arthritis is 2 to 5 per 100000 individuals, while this can increase up to 20 fold in individuals with articular conditions or prosthetics (Kaandorp et al. 1995). 



The onset of septic arthritis can be due to various modes of transmission, each of which are associated with particular bacterial species that cause the infection (J. W. Smith, Chalupa, and Hasan 2006). The most common bacterial causative agents are Streptococci spp., Gram-negative cocci, and Staphylococcus aureus (J. W. Smith, Chalupa, and Hasan 2006; I. D. M. Smith et al. 2018). This is not an exhaustive list of bacterial species and many pathogenic or even commensal bacteria of the microbiota may lead to an infection in the joints (Shirtliff and Mader 2002).

Viral arthritis can be caused by mumps, rubella, poliovirus, arenavirus, and Hepatitis B virus, with higher prevalence of Hep B in men, and the remaining viral infections majorly observed in multiple small and large joints in women (J. W. Smith and Sanford 1967; J. W. Smith, Chalupa, and Hasan 2006).



  • Pain and swelling in a single joint (but may be multiple)
  • Limited range of motion in affected joint
  • Fever
  • Lack of coordination
  • Walking abnormalities (if sacroiliac joint is affected)

(Hassan et al. 2017)


Risk Factors 

  • Diabetes
  • Articular diseases such as osteoarthritis and rheumatoid arthritis
  • Old age
  • Immune deficiency
  • Alcohol and drug abuse
  • Prosthetic joints
  • Skin infections
  • Recent joint surgeries

(Wu et al. 2017; Singh and Yu 2017)



Clinical Features

Patients are typically presented with fever, local pain, warmth, swelling and decreased range of motion in the affected joint (J. W. Smith, Chalupa, and Hasan 2006; Shirtliff and Mader 2002). Typically, only one joint is affected but it must be noted that polyarticular inflammation may also be present (I. D. M. Smith et al. 2018). Many of the clinical features overlap with other articular disorders such as rheumatoid arthritis, thus a detailed history of the patient as well as further testing of the synovial fluid and blood tests are required to confirm diagnosis (Hassan et al. 2017; Shirtliff and Mader 2002).

Pathological Features

Synovial fluid must be taken and tested for bacterial culture and Gram staining, as well as a white blood cell (WBC) count (Hassan et al. 2017). A high level of WBCs in the synovial fluid (greater than 50000/µL) are also indicative of an infection in the joint, but must be taken into account alongside patient history, Gram staining results, and reduced glucose levels in synovial fluid (below 50%) (Tarkowski 2006). Radiographs and ultrasonography can also be used for imaging to attain additional clues about the condition of the joint (Hassan et al. 2017). 



Non-Pharmaceutical Treatment

Initial treatment of septic arthritis usually requires drainage of the synovial fluid and aspirations using a needle, or may be done via surgery for inaccessible joints (Smith et al. 2006). Operative management involves either arthrotomy or arthroscopy of the knee with thorough irrigation and debridement of all infected tissue (Elsissy et al., 2020).

Pharmaceutical Treatment

Intravenous treatment with antibiotics is recommended in order to control bacterial growth and infection, followed by oral antibiotic treatment (Tarkowski 2006). Additionally, Methicillin-resistant Staphylococcus aureus (MRSA) is a major etiologic agent of septic arthritis, with MRSA joint infection associated with more severe outcomes (Ross 2017). The initial and general antibiotic regimen should cover methicillin-resistant Staphylococcus aureus and gram-negative and gram-positive organisms (Elsissy et al., 2020).

The antibiotic regimen should be specified following the culture results of the infected joint (Elsissy et al., 2020). Recommended antibiotics include cefuroxime, ceftriaxone, and for Staphylococcus aureus methicillin resistant strains, vancomycin (Smith et al. 2006). To prevent damage by host inflammatory responses, corticosteroids, namely dexamethasone, need to be used in addition to antibiotics (Verba, Sakiniene, and Tarkowski 1997, Odio et al. 2003). 


Articles on Misdiagnosis

Eberst-Ledoux, J., Tournadre, A., Mathieu, S., Mrozek, N., Soubrier, M., & Dubost, J.-J. (2012). Septic arthritis with negative bacteriological findings in adult native joints: A retrospective study of 74 cases. Joint Bone Spine, 79(2), 156–159.

Keane, B., Top, J., & Burbridge, M. (2018). Septic Arthritis Versus Lyme Arthritis: A Case of Diagnostic Difficulty. Hospital Pediatrics, 8(3), 170–172.

Song, S. J., Bae, D. K., Noh, J. H., Seo, G. W., & Nam, D. C. (2011). A Case of Adult Onset Still’s Disease Misdiagnosed as Septic Arthritis. Knee Surgery & Related Research, 23(3), 171–176.



Elsissy JG, Liu JN, Wilton PJ, Nwachuku I, Gowd AK, Amin NH. Bacterial Septic Arthritis of the Adult Native Knee Joint: A Review. JBJS Rev. 2020 Jan;8(1):e0059. doi: 10.2106/JBJS.RVW.19.00059. PMID: 31899698. 

Hassan, Ahmed S., Allison Rao, Augustine M. Manadan, and Joel A. Block. 2017. “Peripheral Bacterial Septic Arthritis: Review of Diagnosis and Management.” JCR: Journal of Clinical Rheumatology 23 (8): 435–442.

Kaandorp, C. J., D. Van Schaardenburg, P. Krijnen, J. D. Habbema, and M. A. van de Laar. 1995. “Risk Factors for Septic Arthritis in Patients with Joint Disease. A Prospective Study.” Arthritis and Rheumatism 38 (12): 1819–25.

Odio, Carla M., Tobias Ramirez, Gloria Arias, Arturo Abdelnour, Isabel Hidalgo, Marco L. Herrera, Willy Bolaños, Jorge Alpízar, and Patricio Alvarez. 2003. “Double Blind, Randomized, Placebo-Controlled Study of Dexamethasone Therapy for Hematogenous Septic Arthritis in Children.” The Pediatric Infectious Disease Journal 22 (10): 883–89.

Ross JJ. Septic Arthritis of Native Joints. Infect Dis Clin North Am. 2017 Jun;31(2):203-218. doi: 10.1016/j.idc.2017.01.001. Epub 2017 Mar 30. PMID: 28366221.

Shirtliff, Mark E., and Jon T. Mader. 2002. “Acute Septic Arthritis.” Clinical Microbiology Reviews 15 (4): 527–44.

Singh, Jasvinder A., and Shaohua Yu. 2017. “The Burden of Septic Arthritis on the U.S. Inpatient Care: A National Study.” PLoS ONE 12 (8).

Smith, I. D. M., K. M. Milto, C. J. Doherty, S. G. B. Amyes, A. H. R. W. Simpson, and A. C. Hall. 2018. “A Potential Key Role for Alpha-Haemolysin of Staphylococcus Aureus in Mediating Chondrocyte Death in Septic Arthritis.” Bone & Joint Research 7 (7): 457–67.

Smith, J. W., P. Chalupa, and M. Shabaz Hasan. 2006. “Infectious Arthritis: Clinical Features, Laboratory Findings and Treatment.” Clinical Microbiology and Infection 12 (4): 309–14.

Smith, J. W., and J. P. Sanford. 1967. “Viral Arthritis.” Annals of Internal Medicine 67 (3): 651–59.

Tarkowski, Andrej. 2006. “Infectious Arthritis.” Best Practice & Research Clinical Rheumatology, Infection and Musculoskeletal Conditions, 20 (6): 1029–44.

Verba, V., E. Sakiniene, and A. Tarkowski. 1997. “Beneficial Effect of Glucocorticoids on the Course of Haematogenously Acquired Staphylococcus Aureus Nephritis.” Scandinavian Journal of Immunology 45 (3): 282–86.

Visser, Shaun, and Jennifer Tupper. 2009. “Septic until Proven Otherwise.” Canadian Family Physician 55 (4): 374–75.

Wu, Chia-Jung, Chien-Cheng Huang, Shih-Feng Weng, Ping-Jen Chen, Chien-Chin Hsu, Jhi-Joung Wang, How-Ran Guo, and Hung-Jung Lin. 2017. “Septic Arthritis Significantly Increased the Long-Term Mortality in Geriatric Patients.” BMC Geriatrics 17 (August).


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