Ask the Experts - Pathogenesis of Diabetic Ulcers
Ask the Experts - Pathogenesis of Diabetic Ulcers
Please discuss the pathogenesis of diabetic ulcers.
Diabetic foot ulcers are caused by peripheral vascular disease and neuropathy. The pattern of atherosclerosis in patients with diabetes usually involves tibial arteries. There is no "small vessel disease" or microangiopathy, as was once postulated. Peripheral vascular disease leads to reduced oxygen delivery to the foot. Minor wounds become more prone to infection with decreased oxygen delivery. Antibiotic therapy becomes less effective with decreased blood supply carrying antibiotics to the foot.
Diabetic patients have neuropathies: motor, sensory, and autonomic. Motor neuropathy leads to decreased innervation to the interosseus muscles of the foot. This condition results in malalignment of the tendons with subsequent change in the shape of the foot. There is claw toe deformity, midfoot collapse, and prominence of the metatarsal heads on the plantar surface. Sensory neuropathy allows repeated episodes of painless trauma. The abnormal shape of the foot, because of the motor neuropathy, makes the foot more prone to minor trauma. Poorly fitting shoes, walking barefoot, improper trimming of nails, and bath water that is too hot are examples of minor insults that can lead to a wound. Autonomic neuropathy leads to a local decrease in blood flow and can lead to bone resorption, collapse, and further deformity of the foot. Patients experience decreased sweating, with dry skin that cracks if not moisturized. These cracks serve as portals of entry for bacteria.
Most importantly, it must be understood that prevention of foot ulcers is critical to reduce the incidence of amputation in patients with diabetes. Assessment of neuropathy with a 10-g Semmes-Weinstein monofilament should be performed at least yearly. Evaluation of peripheral pulses with noninvasive vascular laboratory evaluation, if pulses are reduced, should be undertaken. Patients must use diabetic footwear if they have neuropathy or peripheral vascular disease. Good foot care is also critically important. Careful bathing of the foot, avoiding fungal infections between the toes, proper nail care, never going barefoot, and moisturizing dry skin are some of the measures that will prevent breaks in the skin. Attention to preventive measures can likely reduce the incidence of amputation.
Please discuss the pathogenesis of diabetic ulcers.
Diabetic foot ulcers are caused by peripheral vascular disease and neuropathy. The pattern of atherosclerosis in patients with diabetes usually involves tibial arteries. There is no "small vessel disease" or microangiopathy, as was once postulated. Peripheral vascular disease leads to reduced oxygen delivery to the foot. Minor wounds become more prone to infection with decreased oxygen delivery. Antibiotic therapy becomes less effective with decreased blood supply carrying antibiotics to the foot.
Diabetic patients have neuropathies: motor, sensory, and autonomic. Motor neuropathy leads to decreased innervation to the interosseus muscles of the foot. This condition results in malalignment of the tendons with subsequent change in the shape of the foot. There is claw toe deformity, midfoot collapse, and prominence of the metatarsal heads on the plantar surface. Sensory neuropathy allows repeated episodes of painless trauma. The abnormal shape of the foot, because of the motor neuropathy, makes the foot more prone to minor trauma. Poorly fitting shoes, walking barefoot, improper trimming of nails, and bath water that is too hot are examples of minor insults that can lead to a wound. Autonomic neuropathy leads to a local decrease in blood flow and can lead to bone resorption, collapse, and further deformity of the foot. Patients experience decreased sweating, with dry skin that cracks if not moisturized. These cracks serve as portals of entry for bacteria.
Most importantly, it must be understood that prevention of foot ulcers is critical to reduce the incidence of amputation in patients with diabetes. Assessment of neuropathy with a 10-g Semmes-Weinstein monofilament should be performed at least yearly. Evaluation of peripheral pulses with noninvasive vascular laboratory evaluation, if pulses are reduced, should be undertaken. Patients must use diabetic footwear if they have neuropathy or peripheral vascular disease. Good foot care is also critically important. Careful bathing of the foot, avoiding fungal infections between the toes, proper nail care, never going barefoot, and moisturizing dry skin are some of the measures that will prevent breaks in the skin. Attention to preventive measures can likely reduce the incidence of amputation.
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