Infection Risk

Hyperglycemia weakens several parts of the immune response. Neutrophils do not move toward pathogens or destroy them as effectively, and altered cytokine signalling can blunt a coordinated inflammatory response. High glucose also impairs wound healing. When peripheral arterial disease is present, reduced blood flow limits oxygen delivery, immune-cell access, and antibiotic penetration into affected tissue. Infection and hyperglycemia then reinforce each other. Stress hormones released during infection raise blood glucose, while persistent hyperglycemia further compromises host defence. A glucose trend that is unexpectedly high despite the person following their usual regimen may be an early clue to infection. Neuropathy adds another risk. A person may not feel a blister, a foreign object in a shoe, a burn, or the pressure injury that becomes a foot ulcer. Absence of pain is therefore not reassurance. It can be the reason the infection has advanced before it is noticed.