Diagnosis and treatment of diabetic autonomic neuropathy

Diabetic autonomic neuropathy (DAN) is associated with a markedly reduced quality of life and poor prognosis. The manifestations of DAN cause multiple symptoms and involve the 1) cardiovascular system: resting tachycardia, reduced heart rate variability and circadian rhythm of heart rate and blood pressure, painless myocardial ischemia/infarction, orthostatic hypotension, exercise intolerance, perioperative instability, sudden death; 2) respiratory system: reduced ventilatory drive to hypercapnia/hypoxemia, sleep apnea; 3) gastrointestinal tract: esophageal motor dysfunction, diabetic gastroparesis, gallbladder atony, diabetic enteropathy, colonic hypomotility, anorectal dysfunction; and 4) genitourinary tract: diabetic cystopathy, erectile dysfunction. Treatment is based on four cornerstones: 1) causal treatment aimed at near-normoglycemia; 2) treatment based on pathogenetic mechanisms; 3) symptomatic treatment; and 4) avoidance of risk factors and complications. Pharmacologic treatment of symptomatic DAN may be difficult, due to limited efficacy and frequent adverse reactions. First-line treatments include midodrine for orthostatic hypotension, prokinetic drugs for gastroparesis, broad-spectrum antibiotics for diabetic diarrhea, and sildenafil for erectile dysfunction. Prior to an adequate symptomatic treatment a thorough risk-benefit estimate, aimed at maintaining the patient's quality of life, is required.