The natural cushioning and compliance of the foot are diminished. As toes claw, weight remains concentrated on metatarsal heads. Sensory neuropathy with its attendant vibratory and proprioceptive loss lead to frequent foot injury, unrecognized and not felt by the patient. Autonomic and sympathetic nervous system deficits cause vasodilation, arteriovenous shunting, and edema. This leads to decreased local nutrition, and dry hyperkeratotic skin which fissures and ulcerates.
Pathogenic bacteria can easily penetrate.
Vascular insufficiency Atherosclerosis occurs more frequently and aggressively in the diabetic. More peripheral and smaller vessels are involved. Venous stasis from congestive heart failure increases edema of the lower extremities, impairs collateral circulation. The neuropathy, arthropathy, metabolic abnormalities and angiopathy allow pressure sores and injuries. The malnutrition, hyperglycemia, decreased peripheral microvasculature, anaerobic metabolism, and poor wound healing all help to create a hospitable environment for the bacteria.