Infectious disease

1. Septic arthritis
Dr. Noria Ghulam Nabi
IM PGy2
ID block 14/10/2014

2. • Septic arthritis is defined as the infection of 1
or more joints caused by pathogenic
inoculation of microbes.
• It occurs either by direct inoculation or via
haematogenous spread.

3. Diagnosis
• Should be considered in any patient who presents with:
– sudden onset of monoarthritis
– acute worsening of chronic joint disease
– previously painless joint prosthesis that becomes painful
– radiographic loosening or migration of a cemented prosthetic device
• The risk for infection is increased in persons with
– previously damaged joints (e.g., patients with RA), joint prosthesis
– in older adults, and
– in immunosuppressed patients, IV drug abuser/ alcohol use
disorder/DM
– previous intra-articular corticosteroid injection,[8] and the presence of
cutaneous ulcers

4. Common organisms
• Gram-positive organisms are the most
common causes of infectious arthritis in
adults.
– Staphylococcus aureus is the most common
offending organism, regardless of age or
underlying risk factors.
• Gonococcal arthritis is the most common
form of bacterial arthritis in young sexually
active persons in the United States.

5. Less common causes of infectious arthritis:
• Gram-negative infections are more common in older,
immunosuppressed, and postoperative patients, and those
with IV catheters.
• Tuberculous arthritis typically is an indolent, monoarticular
arthritis involving the hip or knee; it does not cause systemic
features, and is not associated with positive TST; Gram stain
and culture of synovial fluid are negative. Diagnosis is made
by synovial biopsy.
• Fungal arthritis typically manifests as subacute monoarthritis
in patients with a systemic fungal infection.

6. • A synovial fluid leukocyte count >50,000/μL is specific
but not sensitive for infectious or crystalline
arthropathy.
• Need an arthrocentesis with Gram stain, polarized
microscopy for crystals, cell count, and differential
• Infectious arthritis can develop in patients with gout or
pseudogout, and the presence of crystals in synovial
fluid does not exclude a concomitant infection.
• X-rays are not helpful in the early diagnosis of acute
native joint infection.

7. Gonococcal infection
• Disseminated gonococcal infection can produce two distinct
syndromes:
– tenosynovitis, polyarthralgia, and dermatitis syndrome; have
cutaneous lesions that progress from papules or macules to pustules
that are sterile on culture. Fever and chills are common.
– purulent gonococcal arthritis; do not have systemic features or
dermatitis.
• Synovial fluid cultures for Neisseria gonorrhoeae are positive
in 50% of infected patients.
• Obtaining culture specimens from the pharynx, GU system,
and rectum, in addition to synovial fluid cultures, increases the
diagnostic yield.
• Evaluate for deficiencies in terminal complement components
for patients with recurrent episodes of disseminated
gonococcal infection.

8. • Analyze joint disease using three parameters:
acuity (acute or chronic), inflammation
(inflammatory or noninflammatory), and
• number of joints involved (monoarticular,
oligoarticular, or polyarticular).

13. Investigations
• Synovial fluid
GS and culture
• Synovial White
cell count
• Blood culture

14. Treatment

15. • Use needle aspiration to drain reaccumulated purulent joint fluid. If this procedure fails, perform
arthroscopy/arthrotomy drainage.
• Manage infected prosthetic joints with surgery plus antibiotics, usually for 6 weeks.
• Suspect tubercular infectious arthritis if the appropriate empiric antibacterial therapy is
unsuccessful.