Bone and Joint

Acute Osteomyelitis and Septic Arthritis

• Refer to Infectious Diseases and Orthopaedics. These services should also be involved in the management of chronic osteomyelitis.
• Unless the patient has sepsis and/or neurological deficits, diagnostic cultures must be taken before initiating antimicrobial treatment.
• For acute swelling of a single joint, see Hospital HealthPathways.
• For osteomyelitis associated with ulceration see Infected ulcers.
• Empiric treatment of vertebral osteomyelitis differs from non-vertebral osteomyelitis and septic arthritis – consult Infectious Diseases.
• Diseases notifiable in New Zealand include all forms of tuberculosis.

Pathogens

• Common: S. aureus, Streptococcus species
• Other: Enterobacteriaceae (mainly coliforms), Pseudomonas aeruginosa

Drug Treatment

• Duration: Variable. Usual total duration of treatment is approximately:
  • 6 to 8 weeks for acute osteomyelitis.
  • 4 to 6 weeks for septic arthritis of a native joint (significantly longer for a prosthetic joint).
• Consult with Infectious Diseases about the duration of IV therapy, follow-on oral antimicrobials (where appropriate), and total duration of treatment.

Empiric

Non-vertebral osteomyelitis and septic arthritis

flucloxacillin HMLSchedNZFPMLnoids Flucloxacillin F: 0.9 Half life: 1 hour Elimination: renal fe: 0.7

IV 2 g every six hours

• fe = 0.7, consider adjusting dose if CrCl reduced.
• Risk of hepatotoxicity is increased in females, patients > 55 years old, high doses, and courses longer than 14 days duration.

If risk factors for MRSA, add:

vancomycin HMLSchedNZFPMLnoids Vancomycin F: n/a Half life: 6 hours Elimination: renal fe: 0.9 Additional points: TDM

See dosing guidelines.

• fe = 0.9, adjust dose if CrCl reduced.
• Must be given diluted (1 g in at least 200 mL) and slowly (≤ 1000 mg/hour) to minimise infusion reactions.

Mild penicillin allergy

cefazolin HMLSchedNZFPMLnoids Cefazolin F: n/a Half life: 2 hours Elimination: renal fe: 0.9

IV 2 g every eight hours

• fe = 0.9, consider adjusting dose if CrCl is reduced.

If risk factors for MRSA, add:

• fe = 0.9, adjust dose if CrCl reduced.
• Must be given diluted (1 g in at least 200 mL) and slowly (≤ 1000 mg/hour) to minimise infusion reactions.

Severe penicillin allergy

• fe = 0.9, adjust dose if CrCl reduced.
• Must be given diluted (1 g in at least 200 mL) and slowly (≤ 1000 mg/hour) to minimise infusion reactions.

Vertebral osteomyelitis

Consult Infectious Diseases/Clinical Microbiology.

Pathogens Known

S. aureus

Methicillin susceptible S. aureus (MSSA)

See empiric treatment.

Methicillin resistant S. aureus (MRSA)

• fe = 0.9, adjust dose if CrCl reduced.
• Must be given diluted (1 g in at least 200 mL) and slowly (≤ 1000 mg/hour) to minimise infusion reactions.

Streptococcus (Note: check susceptibility)

benzylpenicillin HMLSchedNZFPMLnoids Benzylpenicillin F: n/a Half life: 1 hour Elimination: hydrolysis fe: 0.9 (Penicillin G)

IV 1.8 g (3 megaunits) every four hours

• fe = 0.8, consider adjusting dose if CrCl is reduced.

Mild penicillin allergy (Note: check susceptibility)

• fe = 0.9, consider adjusting dose if CrCl is reduced.

Severe penicillin allergy (Note: check susceptibility)

• fe = 0.9, adjust dose if CrCl reduced.
• Must be given diluted (1 g in at least 200 mL) and slowly (≤ 1000 mg/hour) to minimise infusion reactions.

Enterobacteriaceae (mainly coliforms)

Treat according to known or local susceptibilities.

Pseudomonas aeruginosa (suspect if penetrating foot injury through a shoe)

Consult Infectious Diseases/Clinical Microbiology.

Topic Code: 99210

must be prescribed or recommended by a consultant.