septic arthritis

Question 1

why septic arthritis is dangerous

Answer 1

Consider septic arthritis in any acutely inflamed joint, as it can destroy a joint in under 24h. Inflammation may be less overt if immunocompromised (eg from medica- tion) or if there is underlying joint disease. The knee is affected in >50% cases.

Question 2

risk factors

Answer 2

• pre existing joint disease
• DM
• immunosuppression
• chronic renal failure
• recent joint surgery
• prosthetic joints (infections here are particularly hard to treat)
• IV drug use
• alcohol use disorder
• presnce of cutaneous ulcers
• > 80 y/o

Question 3

definition of septic arthritis

Answer 3

A septic joint will be painful, hot, swollen, and restricted.

Diagnosis is based on the opinion of the clinician experienced in the management of musculoskeletal disease.

In all cases of suspected native joint sepsis, the joint should be aspirated.

In all cases of suspected joint sepsis, empirical antibiotic therapy should be commenced once appropriate cultures have been taken.

Definition:
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.

Question 4

organisms causing septic arthritis

Answer 4

The predominant causative organisms of septic arthritis are staphylococci or streptococci.

In sexually active patients, gonococcal arthritis may be suspected. In older and immunocompromised people, gram-negative organisms are more common than among young people, although staphylococci and streptococci still predominate. Anaerobic organisms rarely cause septic arthritis except in the case of penetrating trauma.[9]

Community-associated MRSA is becoming more common in many parts of the world and should be suspected in patients recently discharged from hospital, nursing home residents, those with leg ulceration, and those with indwelling urinary catheters.

Tuberculous arthritis should be suspected in immunocompromised people and in patients who originate from areas where tuberculosis is prevalent.

Question 5

symptoms

Answer 5

hot, swollen, tender, restricted joint

usually accompanied by fever

Question 6

investigations

Answer 6

1st investigations:

• synovial fluid gram stain and culture
• synovial fluid white cell count
• blood culture
• white cell count
• ESR
• CRP
• plain radiograph
• ultrasound