Diabetic foot ulcers (DFUs) typically occur on the weight-bearing surface of the foot or the digits as a result of sensory neuropathy, bony abnormalities, and/or repeated mechanical forces (shear, friction, or direct pressure). Because patients with diabetes often present with other co-morbidities, including peripheral arterial disease (PAD), it is imperative to distinguish DFUs from other types of wounds in order to effectively diagnose and treat. A thorough vascular examination is a critical part of managing patients with DFUs, and if pedal pulses are diminished or absent, timely referral to a vascular specialist is warranted. If pedal pulses are present, DFUs can be treated with standard care as described below. However, even in the presence of palpable pedal pulses, referral to a vascular specialist should be considered for cases in which a wound fails to progress in a given period of time, or if the patient is at particularly high risk for amputation.
Clinical Guideline: Pulses are palpated with the ungloved finger directly over the dorsalis pedis and posterior tibial arteries, after removal of the patient’s socks. If pulses are diminished and confirmed with a Doppler, note that a positive Doppler sound does not equate to normal blood flow. In this case, perfusion is reduced and referral to a vascular specialist for further testing is indicated.
Patients with hyperglycemia can have impaired healing of wounds due to any etiology (e.g. surgical incisions, venous, pressure, or trauma); however, these wounds are not termed diabetic wounds. Rather, they are classified according to their etiology, for example, a non-healing pressure ulcer on a patient with diabetes. This becomes important in coding for reimbursement. The American Diabetes Association guidelines for patients with diabetes recommend that hemoglobin A1c levels be 53 mmol/mol or <7%.1 Hyperglycemia is known to impede wound healing by several mechanisms, (Table 5-1) as well as to increase the risk of infection; therefore, management of blood glucose levels is an integral component of treating any patient with diabetes who has a diabetic foot ulcer or non-healing wound.2
TABLE 5-1Impaired cellular function associated with diabetes |Favorite Table|Download (.pdf) TABLE 5-1 Impaired cellular function associated with diabetes
Impaired neutrophil and macrophage function
Excessive deposition of matrix proteins (collagen and fibronectin)
Reaction of glucose with proteins to form advanced glycosylation end-products (AGEs)
Decreased endothelial cell response to angiogenic stimuli
Interference with cell communication and need for keratinocyte migration
Decreased keratinocyte migration
Failure of timely and rapid wound contraction
Impaired endothelial function (nitric oxide)
Diagnostic Clue: The guidelines to help determine if infection is a result of poor glucose control or if the hyperglycemia is contributing to the infection are (1) if the patient’s hemoglobin A1c is normal and blood glucose ...