Septic Arthritis Causes

1. See Also
   1. Septic Joint
   2. Prosthetic Joint Infection
2. Causes: General
   1. Staphylococcus aureus
      1. Most common cause of Septic Arthritis in all ages
3. Causes: Septic Arthritis Causes based on age
   1. Infant (age <3 months, contiguous spread from Osteomyelitis)
      1. Staphylococcus aureus (common)
      2. Neisseria gonorrhoeae (common)
      3. Enterobacteriaceae
      4. Group B Streptococcus
   2. Children (age 3 months to 14 years)
      1. No cause identified in one third of cases
      2. Staphylococcus aureus (27%)
      3. Streptococcus (14%)
         1. Streptococcus Pyogenes
         2. Streptococcus Pneumoniae
      4. HaemophilusInfluenzae (<3% of cases, much less common in U.S. since start of Hib Vaccine)
      5. Gram Negative Bacilli
         1. Kingella kingae (preschool children
   3. Adults with STD risk
      1. Neisseria gonorrhoeae (most common)
         1. See Gonococcal Arthritis
         2. Gonorrrhea is a still a leading cause in young adults with Septic Arthritis
         3. More common in women by a factor 3-4
         4. Typically Migratory Arthritis
         5. Hands, wrists, ankles are most often affected
      2. Staphylococcus aureus
      3. Streptococcus
      4. Gram Negative Bacilli
      5. Syphilis
   4. Adults with no STD risk
      1. Gram Positive organisms (91% of cases)
         1. Staphylococcus aureus (50%)
         2. Streptococcus species (esp. Streptococcus Pyogenes)
      2. Gram Negative Bacilli (esp. elderly and Immunocompromised)
         1. Escherichia coli
         2. Klebsiella
         3. Enterobacter
      3. References
         1. Ryan (1997) Br J Rheumatol 36: 370-3 [PubMed]
   5. Older Patients
      1. Gram Negative Bacteria (esp. Escherichia coli) causes up to 30% of cases
4. Causes: Iatrogenic or Trauma related Septic Arthritis
   1. Joint Aspiration or injection
      1. Staphylococcus aureus
   2. Joint Trauma or wound
      1. Gram Negative Bacilli
      2. Anaerobic Bacteria
      3. Staphylococcus aureus
      4. Polymicrobial infections
   3. Joint prosthesis
      1. Early infection
         1. Staphylococcus epidermidis
      2. Late Infection
         1. Gram Positive Cocci (e.g. pneumococcus)
         2. Anaerobic Bacteria
         3. Pseudomonas
   4. Penetrating, moist wounds through plastic, Rubber
      1. Pseudomonas aeruginosa
   5. Umbilical catheter (UAC or UVC) use in the newborn
      1. Risk of septic hip
   6. Dog or Cat Bite (esp. fingers, toes)
      1. Capnoctyophaga
      2. Pasteurella multocida
   7. Decomposed wood in soil or dust (monoarticular knee, ankle, or elbow)
      1. Blastomyces dermatitidis
5. Causes: Septic Arthritis related to Comorbid Medical Conditions
   1. Intravenous Drug Abuse (esp. sternoclavicular joint, sacroiliac joint)
      1. Atypical Gram Negative Bacilli (e.g. Pseudomonas)
      2. Staphylococcus aureus
   2. Rheumatoid Arthritis (Oligoarticular infections are more common)
      1. Staphylococcus aureus
      2. Streptococcus (esp. pneumococcus)
      3. Gram Negative Bacilli
      4. Fungus (esp. candida)
   3. Gout
      1. Gram-Negative Bacteria (e.g. Pseudomonas, Escherichia coli)
   4. Systemic Lupus Erythematosus or Sickle Cell Anemia (Functional Asplenia)
      1. Salmonella
      2. Proteus
      3. Neisseria gonorrhoeae
   5. Hemophilia
      1. Staphylococcus aureus
      2. Streptococcus
      3. Gram Negative Bacilli
   6. Hemoglobinopathy (e.g. Sickle Cell Anemia)
      1. Salmonella
   7. Immunodeficiency or Diabetes Mellitus
      1. Staphylococcus aureus
      2. Mycobacterium species
      3. Fungus (esp. candida)
      4. Gram-Negative Bacteria (e.g. Pseudomonas, Escherichia coli)
6. Causes: Chronic Monoarticular Arthritis
   1. Brucella
   2. Nocardia
   3. Mycobacterium
   4. Fungus
7. Causes: Acute Polyarticular Septic Arthritis
   1. See Polyarticular Joint Pain Causes
   2. Neisseria gonorrhoeae (most common)
   3. Lyme Disease
   4. Acute Rheumatic Fever
   5. Syphilis
   6. Methicillin-Sensitive Staphylococcus Aureus
   7. Group B Streptococcus
   8. Virus Infection
      1. Viral Hepatitis
      2. Parvovirus B19
      3. Rubella
      4. Chikungunya
8. Causes: Septic Arthritis related to Occupation or Travel
   1. Gardening or agricultural
      1. Sporothrix schenckii
      2. Brucella
      3. Nocardia
      4. Pantoea agglomerans
   2. Marine related (e.g. cleaning fish tank, esp. wrist, fingers)
      1. Mycobacterium marinum
   3. Immigrant
      1. Mycobacterium tuberculosis
9. References
   1. Gilbert (2012) Sanford Guide to Antimicrobials
   2. Earwood (2021) Am Fam Physician 104(6): 589-97 [PubMed]
   3. Stimmler (1996) Postgrad Med 99(4):127-39 [PubMed]