Autonomic neuropathy occurs when blood is shunted away from peripheral cutaneous capillary beds, which may occur in patients with PAD associated with diabetes. Motor neuropathy leads to changes in gait and thus more pressure on one leg, leading to ulceration. The loss of protective sensation and proprioception resulting in increased force with each step may lead to formation of calluses at pressure areas, which decreases elasticity and increases skin ischemia. Patient has diabetic neuropathy.
Acute occlusion of a lower extremity artery may occur with chronic PAD and development of an acute thrombosis. It is called “critical limb ischemia” when the chronic development of peripheral artery occlusive disease in the lower extremity becomes severe. It is manifested by ischemic ulcers of the foot. Ischemic ulcers often begin as minor traumatic wounds and fail to hail because the blood supply is insufficient to meet the increased demands of the healing tissue. Ulcerations caused by ischemia are typically lcated at the termination of arterial branches. They are commonly found on the tips of the toes and between the digits. They can also form at increased focal pressure, such as lateral malleolus and metatarsal heads. In addition to ulcers, patient can present a gangrenous digit or foot. Gangrene can either be dry or wet. Dry gangrene is characterized by a hard, dry texture, often with a clear demarcation between viable and black, necrotic tissue. This form of gangrene is common in patients with PAD. Wet gangrene is characterized by its moist appearance, gross swelling, and blistering. Wet gangrene is a surgical emergency. Pt presented in the ED with wet gangrene, and dry gangrene post op.
(Neschis, 2016)
Ischemia sufficient to threaten a limb occurs when arterial blood flow is insufficient to meet the metabolic demands of resting muscle or tissue. Once patient’s body is unable to maintain the metabolic needs, it goes into anaerobic metabolism, which is seen in labs as high lactic acid. Acute thrombosis of sites of stenosis in which the blood flow impairment was hemodynamically significant can occur and present with acute symptoms., such as pain, pallor, paresthesias, paralysis, pulselessness, and poikilothermia(coldness). Symptoms of parethesias and paralysis may indicate advanced ischemia that is affecting nerve pathways of the extremity. Patient had ischemic ulcer in L foot, and signs of parethesias, pulselessness, and pain.