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diabetic foot

Pathology: 1) neuropathy (sensory & motor) a) motor neuropathy appears 1st b) more common than angiopathy c) non painful d) Charcot joint: neuropathic osteoarthropathy 1] X-ray 2] bone scan negative 3] indium-labeled WBC scan negative 2) angiopathy a) poor prognosis b) ischemic ulcers painful c) pallor with elevation or dependent rubor d) limb-threatening e) posterior tibial artery much bigger than dorsalis pedis thus better indicator of ischemic potential 3) combination of neuropathy & angiopathy 4) diabetic foot ulceration a) mixed infection with Staphylococcus aureus, anaerobes & aerobic gram negative organisms b) osteomyelitis 1] diagnosis is difficult 2] if bone can be probed through ulcer, likelihood of osteomyelitis is high c) risk factors [4] 1] loss of protective sensation due to peripheral neuropathy 2] peripheral vascular disease 3] foot deformities 4] prior ulceration &/or amputation (greatest risk factor) d) also see grading of diabetic foot ulcer 5) callus formation a) increased formation of keratin b) calluses prone to crack & act as entry points for cutaneous bacteria c) foot ulcers may originate from callus-induced lesions 6) loss of sweating results in dryness & cracking of skin Laboratory: 1) ankle/brachial index by doppler ultrasound 2) bone biopsy for suspected osteomyelitis Radiology: 1) radiographs may be helpful in diagnosis of osteomyelitis if there are erosive changes contiguous with the ulcer, especially if worsening with time 2) magnetic resonance imaging (MRI) is recommended if further imaging (after radiograph) is needed [5] 3) bone scan a) may show multiple areas of increased radioactive uptake unrelated to osteomyelitis b) overlying cellulitis confounds interpretation of bone scan Management: 1) prevention a) foot inspection 1] 4 times per year 2] all diabetics at least yearly [1] 3] inspect for sensation, ulcers, calluses, foot deformities, pain, abnormal pressure sensation, peripheral pulses [1] b) 10 gram monofilament test defines loss of protective sensation c) nightly self inspection d) extra depth & custom-molded shoes for patients with foot deformity or history of ulceration e) patients must NOT go barefoot f) callouses indicate pressure points in footwear g) petroleum jelly or lanolin relieves dry, cracking skin of neuropathic foot h) no benefit of therapeutic shoes [2] 2) ulceration a) reduce pressure - molded cast, removable splint, sandal with molded insert, keeping off foot c) prolonged courses of antibiotics may be necessary d) debridement if evidence of sinus tract 3) infection a) extensive spreading cellulitis, tissue ischemia, & sepsis portend life-threatening infection b) antibiotic coverage should include 1] Staphylococci (including MRSA) 2] Streptococci 3] gram negative organisms (including Pseudomonas) 4] anaerobes [1] (see pathology) c) treatment of cellulitis d) treatment of osteomyelitis [5] - adjunctive rifampin for diabetic foot osteomyelitis associated with improved amputation-free survival [10] 4) ischemia: hyperbaric oxygen does not improve outcomes in diabetic patients with ischemic foot ulcers [9] 5) glycemic control is key to optimizing healing [1]

Related

diabetes mellitus diabetic foot infection diabetic foot ulcer; diabetic foot lesion; diabetic lower extremity lesion

General

diabetes mellitus complication syndrome sign/symptom chronic neurologic disease

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 15, 16. American College of Physicians, Philadelphia 1998, 2009, 2012
  2. Journal Watch 22(12):93, 2002 Effect of therapeutic footwear on foot reulceration in patients with diabetes: a randomized controlled trial. Reiber GE et al, JAMA 287:2552, 2002 PMID: 12020336
  3. Diabetic Foot Disorders Clinical Practice Guideline American College of Foot and Ankle Surgeons http://www.acfas.org/pubresearch/cpg/diabetic-cpg.htm
  4. Geriatric Review Syllabus, 7th edition Parada JT et al (eds) American Geriatrics Society, 2010 - Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013
  5. Lipsky BA et al Executive Summary: 2012 Infectious Diseases Society of America Clinical Practice Guideline for the Diagnosis and Treatment of Diabetic Foot Infections Clin Infect Dis. (2012) 54 (12): 1679-1684 PMID: 22619239 http://cid.oxfordjournals.org/content/54/12/1679.full
  6. American Diabetes Association. (9) Microvascular complications and foot care. Diabetes Care. 2015 Jan;38 Suppl:S58-66 PMID: 25537710 - American Diabetes Association. Microvascular complications and foot care: standards of medical care in diabetes-2021. Diabetes Care 2021 Jan; 44:S151 PMID: 33298422
  7. Game FL Osteomyelitis in the diabetic foot: diagnosis and management. Med Clin North Am. 2013 Sep;97(5):947-56. Review. PMID: 23992902
  8. Peters EJ, Lipsky BA. Diagnosis and management of infection in the diabetic foot. Med Clin North Am. 2013 Sep;97(5):911-46. Review. PMID: 23992901
  9. Santema KTB, Stoekenbroek RM, Koelemay MJW et al. Hyperbaric oxygen therapy in the treatment of ischemic lower-extremity ulcers in patients with diabetes: Results of the DAMO2CLES multicenter randomized clinical trial. Diabetes Care 2018 Jan; 41:112 PMID: 29074815 http://care.diabetesjournals.org/content/41/1/112
  10. Wilson BM, Bessesen MT, Doros G et al. Adjunctive rifampin therapy for diabetic foot osteomyelitis in the Veterans Health Administration. JAMA Netw Open 2019 Nov 1; 2:e1916003. PMID: 31755948 https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2755865
  11. Schmidt BM, Holmes CM. Updates on diabetic foot and Charcot osteopathic arthropathy. Curr Diab Rep 2018 Aug 15; 18:74 PMID: 30112582
  12. ElSayed NA, Aleppo G, Aroda VR, et al. 12. Retinopathy, neuropathy, and foot care: standards of care in diabetes - 2023. Diabetes Care. 2023;46:S203-S215. PMID: 36507636
  13. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Diabetes and Foot Problems https://www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/foot-problems