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A 36-year-old woman with type 1 diabetes presented with a 4-week history of a dry, black great toe and third toe on the right foot (Figure 213-1). She said that she noticed severe maceration between the first and second interspace approximately 6 weeks ago. Subsequently, the toes changed color and became very painful. Two days ago, she noticed a foul odor from both toes. The patient reported smoking since she was 13 years old. On physical examination, there were no palpable pulses in the right foot. The patient was admitted for IV antibiotics and revascularization was performed. Subsequently, the toes were partially amputated and the wounds healed without any complications. Her physicians attempted to help her to quit smoking without success.

Figure 213-1

Dry gangrene of the first and third toes in a 36-year-old woman with poorly controlled diabetes demonstrating the typical demarcation of the necrotic eschar from the normal tissue. (Courtesy of Richard P. Usatine, MD.)

Dry gangrene develops following arterial obstruction and appears as dark brown/black dry tissue. Peripheral arterial disease is common in patients with diabetes and dry gangrene is most commonly seen on the toes. The nonviable tissue becomes black in color from the iron sulfide released by the hemoglobin in the lysed red blood cells.

Mummification necrosis.

  • Peripheral arterial disease (PAD) is a common finding in patients with diabetes. PAD is an important factor leading to lower-extremity amputation in patients with diabetes.1
  • Thirty percent of diabetic patients with an absent pedal pulse will have some degree of coronary artery disease.1

  • PAD manifests in the lower extremity in two ways: macro- and microvascular diseases.
  • The pattern of occlusion in the macrovascular tree is distal and multisegmental.2
  • Multiple occlusions occur below the trifurcation of the popliteal artery into the anterior tibial artery, posterior tibial artery, and peroneal artery.
  • Risk factors, such as hypercholesteremia, hyperlipidemia, and hypertension, are often associated with patients with PAD and, therefore, poor wound healing.3,4

  • Diabetes.
  • Dyslipidemia.
  • Smoking.
  • Neuropathy.

Clinical Features

  • Dry, black eschar, which most commonly begins distally at the extremities (Figures 213-1 and 213-2).
  • There is a clear demarcation between healthy tissue and necrotic tissue (Figures 213-1 and 213-2).
  • Foul odor.
  • Pain may be present.
  • Trauma is the most common etiology.
  • Nonpalpable pulses are common. Palpable pulses do not preclude the presence of limb-threatening ischemia. Also, the dorsalis pedis pulse is reported to be absent in 8% of healthy individuals, and the posterior tibial pulse is absent in 2% of the population.
  • Smoking is commonly associated with this problem.
  • Associated trophic skin changes (e.g., absent pedal hair and thin shiny skin).
  • Indicators of vascular insufficiency include pallor upon elevation of the limb and rubor upon dependency, along with ...

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