EM@3AM: Diabetic Foot Ulcer
- Feb 17th, 2018
- Cassandra Kennedy
Author: Cassandra L. Kennedy (Flight Paramedic, NREMT-P, San Antonio, TX) and Joshua J. Oliver, MD (EM Attending Physician, San Antonio, TX) // Edited by: Brit Long, MD (@long_brit, EM Attending Physician, San Antonio, TX) and Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)
Welcome to EM@3AM, an emDocs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.
A 58-year-old morbidly obese female patient with uncontrolled diabetes and peripheral arterial disease presents with an open wound to the central plantar aspect of her foot. She reports no pain, does not recall an injury, and is not sure how long she has had the ulcer. On exam, there is a 3.5 cm circular wound with thick yellow material in the center, and the edges of the wound are pink and warm to the touch.
What is the diagnosis, and what are your next steps?
Answer: Diabetic foot ulcer with concern for infection
- Foot infections are a significant cause of mortality in patients with diabetes mellitus. There is evidence that the likelihood of a patient with either type 1 or type 2 diabetes experiencing a diabetic foot ulcer is upwards of 25%.1 Risk factors associated with ulcers are poor glucose regulation, neuropathy, and peripheral vascular disease.1
- Often patients are unaware that an ulcer is developing until infection sets in due to neuropathy and decreased sensation. Diabetics often experience some form of trauma leading to skin breakdown. The presence of other diseases such as peripheral arterial disease and venous stasis leads to swelling and ischemia to the area. This further decreases ability to heal.
- Presentation will differ depending on the extent and depth of tissue involvement. Severe infection may result in systemic signs. However, patients with chronic infections may appear well.
- If the patient is experiencing sensory neuropathy the probability of the wound having gone undiscovered increases tremendously.
- First determine if the patient is sick or not sick. If sick, start treating for sepsis and provide broad-spectrum antibiotics. If the patient looks well and has an ulcer, consider osteomyelitis, which can be acute (more common in pediatric patients with hematogenous spread versus chronic (more common in adults).
- Thorough medical history will help to identify risk factors that may indicate complicated healing, previous diabetic ulcers, glycemic control, neuropathy, significant concurrent disease processes, and social history. Smoking and peripheral vascular disease appear to have the largest impact.1,2
- Examination of the ulcer should include location, size, depth, notation of specific tissue involvement, and the extent of infection if it is present. It is important to note if the ulcer extends to the bone (probe-to-bone test with sterile instrument).1
- Neurologic examination should also be conducted to determine the extent of sensory impairment. Venous and arterial sufficiency should also be noted during exam, obtain an ankle brachial index (ABIs), doppler ultrasound, and consult Vascular Surgery if concern for ischemia.1
- Laboratory tests should include a complete blood count, blood glucose level, electrolytes, renal function, erythrocyte sedimentation rate, and C-reactive protein.2-4 If sick, obtain lactate/VBG.
- ESR > 60 approaches 70% sensitivity for osteomyelitis, while CRP > 3.2 demonstrates a sensitivity of 85%.5
- Wound cultures are not helpful in the ED. These can be obtained by a wound care specialist.
- Radiography or an MRI should be considered if osteomyelitis is suspected. X-ray is the first line test.6,7
- Positive x-ray with probe-to-bone test: If both are negative, the -LR is 0.02.8
- Treatment depends on hemodynamic status of patient: Sick vs. Not Sick.
- Sick patients require resuscitation with fluids and antibiotics.
- If antibiotic therapy is indicated obtain blood and tissue cultures before starting.4 Any regimen should cover MRSA, pseudomonas, and gram negatives. A possible regimen includes Vancomycin 20 mg/kg intravenous (IV), Cefepime 2 grams IV, and Metronidazole 500 mg IV.
- Surgical consultation may be necessary for extensive infection for surgical debridement.3,6,7
- Hospitalization may be necessary for patients with signs and symptoms of systemic infection.
- For patients who appear well, outcomes are still poor with high rates of amputation. They require a multimodal approach with wound care and risk factor modification.
- Vascular Surgery and wound care consultation/follow-up should be considered for patients with poorly controlled diabetes or for those who require revascularization.2,6,7
- Primary goals for these patients are debridement, proper wound care, risk factor modification, and infection control.2,6,7
- Though there is some evidence for the use of Hyperbaric Oxygen Therapy (HBOT) in the treatment of diabetic foot ulcers, not enough evidence exists to initiate HBOT in the Emergency Department.9
- McCulloch D (2017, June 02). Evaluation of the Diabetic Foot. From https://www.uptodate.com
- Armstrong D, McCulloch D, De Asla R. (2018, January 11). Management of diabetic foot ulcers. From http://www.uptodate.com
- Weintrob A, Sexton D. (2016, June 21). Clinical manifestations, diagnoses, and management of diabetic infections of the lower extremities. From http://www.uptodate.com
- Noor S, Zubair M, Ahmad J. Diabetic foot ulcer: A review on pathophysiology, classification and microbial etiology. Diabetes Metab Syndr. 2015 Jul-Sep;9(3):192-9.
- Fleischer, AE et al. Combined clinical and laboratory testing improves diagnostic accuracy for osteomyelitis in the diabetic foot. J Foot Ankle Surg. 2009 Jan-Feb;48(1):39-46.
- Karri VV, Kuppusamy G, Talluri SV, Yamjala K, Mannamala SS, Malayandi R. Current and Emergening therapies in the management of diabetic foot ulcers. Curr Med Res Opin. 2016;32(3):519-42.
- Caravaggi C, Sganzaroli A, Galenda P, Bassetti M, Ferraresi R, Gabrielli L. The management of the infected diabetic foot. Curr Diabetes Rev. 2013 Jan 1;9(1):7-24.
- Conterno, LO et al. Antibiotics for treating chronic osteomyelitis in adults. Cochrane Database Syst Rev. 2013 Sep 6;(9);CD00439.
- Stoekenbroek RM, Santema TB, Legemate DA, Ubbink DT, Van den Brink A, Koelemay MJ. Hyperbaric oxygen for the treatment of diabetic foot ulcers: a systemic review. Eur J Vasc Endovasc Surg. 2014 Jun;47(6):647-55.