# Diabetic autonomic neuropathy | Symptoms, Causes, Tests and Treatment | OSANG > Diabetic autonomic neuropathy occurs in approximately 20-40% of diabetic patients, and the incidence increases as the duration of disease increases. Cardiac autonomic ne… - Official page: https://osns.co.kr/en/encyclopedia/diabetic-autonomic-neuropathy - Organization: OSANG Neurosurgery ## Page content Neurological Conditions ## Diabetic autonomic neuropathy Diabetic Autonomic Neuropathy · E10.43 Diabetic autonomic neuropathy (DAN) is a common complication of diabetes in which oxidative stress and metabolic abnormalities caused by chronic hyperglycemia damage autonomic nerve fibers, causing dysregulation of the autonomic nervous system throughout the body, including cardiovascular, digestive, urinary, and sweating functions. ## At a glance Diabetic autonomic neuropathy occurs in approximately 20-40% of diabetic patients, and the incidence increases as the duration of disease increases. Cardiac autonomic neuropathy (CAN) is the most clinically important and increases the risk of asymptomatic myocardial infarction, arrhythmia, and sudden death. Orthostatic hypotension, gastroparesis, bladder dysfunction, and abnormal sweating are also common symptoms. Controlling blood sugar is the key to prevention and suppressing progression, and early detection is possible through heart rate variability testing. - 01Definition and Overview - 02Classification - 03Mechanism of occurrence - 04cardiac autonomic neuropathy - 05Other autonomic involvement - 06diagnosis - 07treatment ## Definition and Overview Diabetic autonomic neuropathy (DAN) is one of the common chronic complications of diabetes. It occurs when chronic hyperglycemia and the resulting metabolic abnormalities gradually damage autonomic nerve fibers. The autonomic nervous system regulates involuntary body functions such as cardiovascular, digestive, urinary, sweating, and pupil reactions, so when damaged, various symptoms appear throughout the body. Diabetic autonomic neuropathy occurs in approximately 20-40% of diabetic patients, and the longer the duration of diabetes, the higher the incidence. In the case of type 1 diabetes patients, approximately 50% of patients with type 1 diabetes show autonomic dysfunction over 25 years or more. The poorer the blood sugar control, the greater the risk, and a 1% increase in glycated hemoglobin (HbA1c) significantly increases the risk of autonomic neuropathy. ## Classification Diabetic autonomic neuropathy is classified as follows depending on the organ system involved. Cardiac autonomic neuropathy (CAN) is the most clinically significant form. Heart rate control disorders, exercise intolerance, and orthostatic hypotension occur, and the risk of asymptomatic myocardial infarction and sudden death increases. Gastrointestinal autonomic neuropathies include gastroparesis, esophageal motility disorder, diabetic diarrhea, constipation, and fecal incontinence. Genitourinary autonomic neuropathies include bladder dysfunction (neurogenic bladder), male erectile dysfunction, female sexual dysfunction, and retrograde ejaculation. Sudomotor dysfunction includes distal anhidrosis and compensated proximal hyperhidrosis. Pupil abnormalities include reduced pupil dilation in dark places and impaired dark adaptation. ## Mechanism of occurrence Chronic hyperglycemia damages autonomic nerve fibers through several pathways. Activation of the polyol pathway results in sorbitol and fructose accumulation, causing osmotic stress in nerve cells. Accumulation of advanced glycation end products (AGEs) directly damages nervous tissue and blood vessels. Increased oxidative stress leads to mitochondrial dysfunction and neuronal cell death. A decrease in neurotrophic factor (nerve growth factor, NGF) reduces the maintenance and regeneration ability of autonomic nerve fibers. Damage to the endoneurial vasculature reduces the blood supply to the nerve, resulting in ischemic damage. Because small-diameter unmyelinated autonomic nerve fibers (C fibers) are damaged before myelinated large-diameter fibers, there is an initially asymptomatic stage in which abnormalities are detected only through heart rate variability tests. ## cardiac autonomic neuropathy Cardiac autonomic neuropathy is the most clinically important among diabetic autonomic neuropathies. According to studies, the 5-year mortality rate in diabetic patients with cardiac autonomic neuropathy is approximately 3.5 times higher than in patients without cardiac autonomic neuropathy. Initially, resting tachycardia (heart rate >100 beats/min) appears. This is because parasympathetic nerve damage occurs before sympathetic nerve damage, which reduces the parasympathetic nerve's inhibitory effect on heart rate. In heart rate variability tests, the heart rate change (R-R interval variability) according to the breathing cycle decreases. As the disease progresses, the sympathetic nerves are also damaged, slowing down the normal increase in heart rate and blood pressure during exercise. Painless myocardial infarction may occur, and may be first discovered as an electrocardiogram abnormality or heart function abnormality without chest pain. Orthostatic hypotension (a decrease in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg when standing) occurs due to impaired sympathetic vasoconstrictor response. Orthostatic hypotension is reported in approximately 6-32% of diabetic patients. ## Other autonomic involvement ### Gastrointestinal autonomic neuropathy Gastroparesis occurs in approximately 5-12% of diabetic patients. Gastric emptying is delayed, causing feelings of fullness, nausea, vomiting, and abdominal distension after a meal. It becomes a factor that makes blood sugar control more difficult. Diagnosis is made using gastric scintigraphy. Constipation (occurring in approximately 60% of diabetic patients) and nocturnal diarrhea (occurring in approximately 20% of diabetic patients) are common diabetic bowel dysfunction. ### Urinary autonomic neuropathy Neurogenic bladder abnormalities in bladder function are reported in approximately 43-87% of diabetic patients. Decreased bladder sensation causes excessive fullness, and decreased detrusor muscle contraction causes repeated residual urine and urinary tract infections. ### abnormal sweating It is characterized by anhidrosis of the distal part (mainly the feet and legs) and compensatory hyperhidrosis of the proximal part (mainly the trunk). Gustatory sweating, which is excessive sweating of the face and neck after a meal, can also occur in diabetic autonomic neuropathy. ## diagnosis The American Diabetes Association (ADA) guidelines recommend the following five tests using heart rate variability as standard evaluation methods. Deep breathing HRV: Measures the maximum-minimum heart rate difference during deep breathing 6 times per minute. Valsalva manual test: Measures heart rate changes during forced expiration. Stand-to-stand test (30:15 ratio): Measures the heart rate ratio between the 30th and 15th moments after standing up. Changes in blood pressure when standing: Check for orthostatic hypotension. Blood pressure changes during grip strength: Evaluating blood pressure response to static exercise. If abnormalities are confirmed in three or more of these, clinically confirmed cardiac autonomic neuropathy is diagnosed. ## treatment Blood sugar control is the most important treatment for prevention and progression. In type 1 diabetes, intensive blood sugar control has been confirmed in a randomized controlled trial to reduce the incidence of cardiac autonomic neuropathy by approximately 53%. For orthostatic hypotension, non-pharmacological methods (compression stockings, sufficient fluid intake, increased salt intake, head elevation) are first applied, and if necessary, fludrocortisone or midodrine is used. For gastroparesis, gastric motility stimulants such as metoclopramide and domperidone are used. PDE-5 inhibitors are effective for erectile dysfunction. ## Frequently asked questions ### Q01What is diabetic autonomic neuropathy? If diabetes persists for a long time, high blood sugar gradually damages autonomic nerve fibers. The autonomic nerve controls functions that occur automatically without conscious awareness, such as heart rate, blood pressure, digestion, urination, and sweating. When this nerve is damaged, various symptoms appear. This is diabetic autonomic neuropathy. It occurs in approximately 20-40% of diabetes patients, and the longer the disease period, the higher the frequency of occurrence. ### Q02What are the symptoms of diabetic autonomic neuropathy? If there is a problem with heart and blood pressure control, orthostatic hypotension, which causes a person to feel dizzy or faint when sitting or standing up, occurs. On the digestive side, gastroparesis, which slows down stomach emptying, causes a feeling of fullness, nausea, and vomiting after a meal. Constipation and diarrhea may appear alternately. Sweating abnormalities (sweating too much or not at all), bladder dysfunction (difficulty passing urine or a feeling of residual urine), and erectile dysfunction in men are also common symptoms. ### Q03How is diabetic autonomic neuropathy diagnosed? Heart rate variability (HRV) testing is the most basic screening test. Autonomic function is assessed through heart rate and blood pressure responses, such as heart rate changes during deep breathing, Valsalva maneuver, and orthostatic response. Orthostatic hypotension is checked through a standing tilt test. Additional tests are performed depending on symptoms, such as sweating function tests and gastric emptying tests (gastric scintigraphy). For patients with type 1 diabetes and type 2 diabetes who have been diagnosed with diabetes for more than 5 years, an autonomic nerve test is recommended from the time of diagnosis. ### Q04Why is cardiac autonomic neuropathy dangerous? If you have cardiac autonomic neuropathy, your heart rate may not be maintained consistently, and even if you have a myocardial infarction, you may experience a painless myocardial infarction in which you do not feel chest pain. Studies have shown that diabetic patients with cardiac autonomic neuropathy have an approximately 3.5 times higher risk of death than those without. There is also an increased risk of complications during anesthesia and an increased risk of arrhythmias during exercise. Early detection and active blood sugar management are important. ### Q05Can diabetic autonomic neuropathy be treated or prevented? Strictly controlling blood sugar within the target range is the most effective prevention and progression control method. In type 1 diabetes, intensive glycemic control has been reported to reduce the risk of cardiac autonomic neuropathy by approximately 53%. Depending on the symptom, fludrocortisone or midodrine is administered for orthostatic hypotension, gastric motility stimulants for gastroparesis, and drug treatment for bladder dysfunction. Regular autonomic function tests are recommended to detect autonomic nerve abnormalities early. ### Q06How often should I get autonomic tests if I have diabetes? According to the American Diabetes Association guidelines, it is recommended that patients with type 2 diabetes begin testing autonomic function from the time of diagnosis, and patients with type 1 diabetes start testing autonomic function 5 years after onset, with regular evaluations annually thereafter. Heart rate variability testing is non-invasive and highly reproducible, making it suitable for follow-up testing. If you have autonomic symptoms, it is best to get tested as soon as possible, regardless of the timing. ## Related articles - delirium - Cervical radiculopathy - Cervical disc herniation - dystonia This article provides general medical information and does not replace an individual diagnosis or treatment plan. Please seek a medical assessment if symptoms persist. ## Important notice This Markdown alternative helps search and AI tools understand the public page accurately. It provides general health information and does not replace an individual diagnosis or treatment.