08.09 ID
08.09 Infectious disease [PDF link]: Animal & human bites, Cellulitis, Sepsis, Necrotising fasciitis, Nematode infections (Ancylostoma braziliense, Strongyloides stercoralis, Toxocara canis), Threadworms (Enterobius vermicularis), Lemierre's syndrome, Post-splenectomy sepsis, Pyrexia of unknown origin (fever of unknown origin, PUO, FUO), Spinal epidural abscess, Side effects of antimicrobials
Other notes
Sepsis 6: Blood cultures, urine output, VBG for lactate. Antibiotics, IV fluids (bolus if in shock), oxygen if needed
Diabetic foot infections (DFI)
Definition: DFI involves skin and soft tissue infections in the context of diabetes mellitus, which may lead to osteomyelitis, bacteraemia and sepsis
Risk factors / pathophysiology: Diabetics have increased risk of developing skin and soft tissue infections due to
(1) neuropathic damage resulting in reduced sensation → patients are unaware of minor injuries that allow for entry of pathogens into skin and soft tissue → development of infected ulcers
(2) peripheral vascular disease – reduced blood supply hinders the healing process
Diabetic foot infections are often polymicrobial
Superficial wounds often grow common skin organisms such as Staph aureus, Staph epidermidis, Strep agalactiae, Strep pyogenes.
Deep or chronically infected ulcers are more likely to grow multiple organisms including enterococci (eg E. faecalis), Ps. aeruginosa, and anaerobes.
Diagnosis / Investigations:
Diagnosis is clinical.
See also IWGDF/IDSA classification system
If there is clinical suspicion of osteomyelitis, plain XR first ± MRI for further evaluation
Bone biopsy (and cultures) can help to confirm OM and guide abx therapy.
Management:
Diabetic patients should undergo annual review to screen for diabetic foot disease
Check dorsalis pedis pulse and posterial tibial artery pulse
Neuropathy: a 10 g monofilament used to assess sensation
Diabetic patients should be taught to check their feet regularly, and also to practise preventative feet care
Eg avoid going barefoot even at home, to trim their toenails carefully, etc.
Fungal toenails should be treated
Choice of antibiotic therapy
Options depend on (1) severity, (2) any recent exposure to abx, (3) considerations of specific types of organisms that need to be covered for
Refer to local policy regarding choice of antibiotics (too many options to discuss here)
