elective surgery

Question 1

Management of deep infection of joint replacement

Answer 1

If a fulminant infection is diagnosed early (within the first 2‐3 weeks) surgical washout & debridement and prolonged parenteral antibiotic therapy (around 6 weeks) can be attempted to salvage the artificial joint. This strategy is around 50% successful. Deep infections present for longer than 3 weeks or so tend not to be salvageable by washout as the infecting bacteria adhere to the foreign surfaces and form a Biofilm which prevents the patient’s immune system attacking. In this situation, removal of the infected implants and all foreign material (including cement) which requires extensive surgery is usually required. The patient is usually left without a joint for around 6 weeks and given parenteral antibiotics. Once the infection is under control (wound healed, clean and dry, CRP reduced) a revision (re‐do) joint replacement is performed with more complex joint replacement components. This strategy is around 80‐90% successful in eradicating infection however throughout this process the soft tissues scar and lose elasticity. The joint inevitably stiffens and the overall functional outcome is usually compromised.

Question 2

common organisms causing early prosthetic valve infection

Answer 2

Common virulent organisms which produce an early prosthetic infection include Staph. aureus and gram negative bacilli including coliforms.

Question 3

common organisms causing late prosthetic valve infection

Answer 3

Some organisms cause a more indolent or “low grade” infection which is inevitably diagnosed late (up to a year after surgery) and often requires surgical intervention. Such bacteria include Staph. epidermidis (also known as coagulase negative staphylococci) and enterococcus. Organisms associated with late onset haemotogenous infection Include Staph. aureus, beta haemolytic Streptococcus and Enterobacter.