A 65-year-old woman comes to the urgent care clinic for evaluation of a left foot wound that has been worsening despite wound care. The patient is a retired nurse and has been performing daily dressing changes to the wound; in addition, she has been using crutches for the past few weeks to minimize weight bearing on the foot. Medical history is significant for type 2 diabetes mellitus with neuropathy and hypertension. She has never smoked cigarettes. Temperature is 36.5 C (97.7 F), blood pressure is 136/82 mm Hg, and pulse is 82/min. Examination of the left foot shows a plantar ulcer, as shown in the exhibit. There is no lower extremity discoloration or edema; dorsalis pedis pulses are present bilaterally and symmetric. Which of the following factors is most likely to have increased this patient's risk for developing her current condition?

Question

A 65-year-old woman comes to the urgent care clinic for evaluation of a left foot wound that has been worsening despite wound care.  The patient is a retired nurse and has been performing daily dressing changes to the wound; in addition, she has been using crutches for the past few weeks to minimize weight bearing on the foot.  Medical history is significant for type 2 diabetes mellitus with neuropathy and hypertension.  She has never smoked cigarettes.  Temperature is 36.5 C (97.7 F), blood pressure is 136/82 mm Hg, and pulse is 82/min.  Examination of the left foot shows a plantar ulcer, as shown in the exhibit.  There is no lower extremity discoloration or edema; dorsalis pedis pulses are present bilaterally and symmetric.  Which of the following factors is most likely to have increased this patient's risk for developing her current condition?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d8bc_7958_bc81_37893bea32f9_MD0003_00 This patient with type 2 diabetes mellitus likely has multiple factors contributing to her plantar foot ulcer, including peripheral neuropathy. Classically a length-dependent axonopathy involving the feet, diabetic neuropathy affects sensory, autonomic, and motor nerve fibers, leading to the following adverse effects: Sensory neuropathy exposes the tissues to increased trauma (eg, friction from shoes due to decreased pain sensation) and pressure (eg, stomping feet due to decreased proprioception), and causes unawareness of tissue injury that can delay treatment. Autonomic neuropathy causes loss of autonomic tone in the arteriolar and capillary circulation, leading to shunting of blood from the arterioles to the veins and decreased tissue perfusion. Motor neuropathy can cause atrophy of the small intrinsic muscles of the feet, leading to unopposed action of the large lower leg muscles, and clawing of the toes with hyperextension at the metatarsal-phalangeal joints. As a result, pressure is redistributed to the metatarsal heads, increasing susceptibility to callus formation, skin breakdown, and ulcer formation. Glycemic control (to slow neuropathy progression) and proper foot care (eg, regular inspection, moisturization, well-fitting shoes) are essential for reducing the risk of foot ulcers in diabetic patients. (Choice B) Venous valve incompetence contributes to venous stasis ulcers, which are commonly located near the ankles and accompanied by surrounding brawny skin discoloration from hemosiderin deposition. In contrast, this patient's ulcer is on the plantar foot, and the skin has no brawny discoloration. venous stasis ulcers (Choice C) Diabetic autonomic neuropathy leads to loss of sympathetic innervation to sweat glands. This results in decreased (not increased) sweating, which contibutes to dry skin that is more suspectible to fissuring. (Choice D) Lack of weight bearing would reduce pressure on the plantar foot surface (eg, metatarsal heads), thereby decreasing (not increasing) risk of ulceration. In fact, foot immobilization and pressure offloading (eg, total contact casting) may be part of diabetic plantar foot ulcer management. Educational objective: Sensory, autonomic, and motor neuropathy can all contribute to plantar foot ulcer formation in patients with diabetic neuropathy. Motor neuropathy can cause intrinsic foot muscle atrophy, toe clawing, and abnormal redistribution of pressure to the metatarsal heads. References: Intrinsic muscle atrophy and toe deformity in the diabetic neuropathic foot: a magnetic resonance imaging study. (http://www.ncbi.nlm.nih.gov/pubmed/12145248) Neuropathy, claw toes, intrinsic muscle volume, and plantar aponeurosis thickness in diabetic feet. (http://www.ncbi.nlm.nih.gov/pubmed/32703177)

A 65-Year-Old Woman Comes to the Urgent Care Clinic for Evaluation