M00.9
DESCRIPTION
Septic arthritis may occur as a result of haematogenous seeding of the synovium during transient periods of bacteraemia.
Septic or pyogenic arthritis is often part of a generalised septicaemia which may involve more than one joint and is caused by pyogenic micro-organisms. The organisms involved vary:
- Neonates – S. aureus , Group B Streptococci, E. coli , fungi.
- Infants/children – S. aureus , H. influenzae , Group A Streptococci, S. pneumoniae , Kingella kingae .
- Adolescents (sexually active) – N. gonorrhoea .
- Chronic septic arthritis – Brucella , tuberculosis, atypical mycobacteria, fungi and other uncommon organisms.
DIAGNOSTIC CRITERIA
The diagnosis is largely clinical and confirmed by finding pus in the joint space.
CAUTION
Do not carry out needle aspiration in haemophiliacs.
Clinical
- Fever, local pain, loss of function and toxic looking child.
- Subtle, non-specific signs of sepsis early in the course of the disease, especially in neonates.
- Local tenderness, warmth, swelling at a joint with restriction of passive and active movement.
- Malaise, irritability, feeding problems and pseudo-paralysis.
- If lower extremities are involved, development of a limp or refusal to bear weight.
Investigations
- Blood cultures prior to antibiotic administration.
- Aspiration of pus from the joint space under ultrasound guidance, if possible, and submit for microscopy, Gram stain, culture and sensitivity.
- Raised CRP and white-cell count and/or ESR.
GENERAL AND SUPPORTIVE MEASURES
- Septic arthritis of the hip (emergency) requires prompt open surgical drainage at the time of presentation, in consultation with an orthopaedic surgeon.
- Manage most infections of other sites by repeated aspiration or open drainage (not antibiotic instillation), if frank pus is obtained on initial diagnostic aspiration.
- Immobilise affected limb in position of function.
- Identify other effects of septicaemia or haematogenous spread and treat appropriately.
- Supportive and symptomatic care.
MEDICINE TREATMENT
Antibiotic therapy
- Minimum duration of therapy: 4–6 weeks.
IV antibiotics
Initiate IV antibiotic treatment immediately.
Adjust antibiotic therapy based on culture results or if response to empiric antibiotic treatment is unsatisfactory.
Continue with IV antibiotics until there is evidence of good clinical response and laboratory markers of infection improve. Once clinical improvement and inflammatory markers are normalising, patients can be switched to oral antibiotic therapy.
Neonates:
- Cloxacillin, IV, 50 mg/kg/dose.
- If 1ˢᵗ week of life: 12 hourly.
- If 2ⁿᵈ–4ᵗʰ week of life: 8 hourly.
- If > 4 weeks old: 6 hourly.
PLUS
- Cefotaxime, IV, 50 mg/kg/dose.
- Preterm: 12 hourly.
- If 1ˢᵗ week of life: 8 hourly.
- If > 2 weeks old: 6 hourly.
1 month to < 3 months
- Cloxacillin, IV, 50 mg/kg/dose 6 hourly.
PLUS
- Ceftriaxone, IV, 80 mg/kg/dose 12 hourly.
Infants > 3 months and children:
- Cloxacillin, IV, 50 mg/kg/dose 6 hourly.
If Gram negative organisms are seen on Gram stain, or when clinically suspected, e.g. sickle cell disease:
ADD
- Ceftriaxone, IV, 80 mg/kg/dose 12 hourly.
Special Circumstances
If MRSA, replace cloxacillin with vancomycin.
- Vancomycin IV, 15mg/kg/dose administered over 1 hour given 6 hourly.
Where available, vancomycin doses should be adjusted on the basis of therapeutic drug levels.- Trough levels (taken immediately prior to next dose), target plasma level 15-20mcg/mL.
Oral antibiotics
- Can transition to oral therapy once there is sustained clinical improvement, resolution of fever and CRP < 30mg/L.
- Duration: 2-4 weeks of treatment.
Antibiotics according to sensitivities:
- Clindamycin, oral, 6 mg/kg/dose 6 hourly.
OR
For children able to swallow a capsule:
- Flucloxacillin, oral, 12.5–25mg/kg/dose, 6 hourly.
PLUS
Corticosteroids
- Dexamethasone, IV, 0.15mg/kg 6 hourly for 4 days.
For pain and inflammation:
Refer Pain control .
REFERRAL
- Multi-organ involvement.
- Failure to achieve progressive improvement on treatment.