[Diabetic Autonomic Neuropathy]

Diabetic autonomic neuropathy is a clinically important component of diabetic neuropathy involving the cardiovascular, gastrointestinal, genitourinary, sudomotor, pupillary, and glucose counterregulatory systems. Cardiovascular autonomic neuropathy (CAN) has been extensively studied and is clinically relevant because of its association with adverse cardiovascular and renal outcomes. Early CAN is frequently silent and may only be recognized by reduced heart rate variability or abnormal cardiovascular autonomic reflex testing. As CAN progresses, patients develop resting tachycardia, reduced exercise tolerance, orthostatic or postprandial hypotension, abnormal nocturnal blood pressure regulation, and perioperative hemodynamic instability. Non-cardiovascular manifestations include gastroparesis, bowel and bladder dysfunction, erectile dysfunction, sudomotor and pupillary abnormalities, and impaired hypoglycemic awareness. The underlying mechanisms involve chronic hyperglycemia, glycemic variability, dyslipidemia, insulin resistance, oxidative and mitochondrial stress, inflammation, microvascular injury, and impaired axon-glial support. Clinically, evaluation should begin with a systematic symptom review, neurological examination, supine and standing blood pressure measurements, and heart rate assessment, followed by organ-specific testing if indicated. Treatment was based on comprehensive risk factor control and symptom-directed management.