Patient presents with right foot gangrene, manifesting as dry gangrene with clear demarcation.  Symptoms include localized tissue necrosis, black discoloration of the affected digits, and diminished pedal pulse.  Patient reports a history of peripheral artery disease (PAD) and type 2 diabetes mellitus, both contributing factors to the development of foot gangrene.  The patient denies fever, chills, or purulent drainage, suggesting a non-infectious etiology at this time.  Assessment reveals diminished sensation in the affected area, consistent with diabetic neuropathy.  Differential diagnoses considered include critical limb ischemia, diabetic foot ulcer with secondary gangrene, and arterial thrombosis.  Plan of care includes vascular evaluation, debridement of necrotic tissue, wound care management, and optimization of glycemic control.  Medical coding considerations include ICD-10 codes for gangrene (e.g., I70.261 for gangrene, right foot, fifth toe), diabetes (E11.9), and PAD (I73.9).  Patient education provided on foot care, diabetes management, and the importance of follow-up appointments for wound monitoring and potential surgical intervention, such as amputation if necessary.  Prognosis depends on the extent of tissue involvement, adequacy of blood supply, and overall patient health status.  Referral to a vascular surgeon and wound care specialist is initiated.