Diabetic autonomic neuropathy

Autonomic neuropathy is caused by damage to the nerves that help control the involuntary functions of the body (autonomic nervous system), such as heartbeat and blood pressure, sweating and temperature regulation, digestion, urination, and some aspects of sexual function.

Heart and circulatory system problems

Diabetic autonomic neuropathy may damage the nerves in the heart and circulatory system, causing a:

• Sudden drop in blood pressure when you sit or stand up suddenly (orthostatic hypotension).
• Rapid heart rate when you are not exercising (resting tachycardia).
• Heart attack that causes no chest pain (silent heart attack). Without the symptom of chest pain, a heart attack may be ignored, which can result in severe damage to the heart. The only signs of a heart attack in a person with diabetes and neuropathy may be a rising blood sugar level, weakness that does not go away after eating, increasing shortness of breath, nausea, and occasionally swelling in the legs.

Sweating and temperature regulation problems

Autonomic neuropathy may affect the nerves that control sweating.

• Reduced sweating is common, especially in the hands and feet. It may be difficult to recognize when your blood sugar is dropping because sweating is one of the main symptoms of low blood sugar. You can develop dry skin that may be more prone to cracking, injury, and infection. Profuse sweating of the torso, face, or neck may occur at night or while eating.
• Changes in the body's ability to regulate temperature may make you more prone to body chilling (hypothermia) or heat-related illness, such as heatstroke or heat exhaustion.

Digestive system problems

Damage to the nerves of the stomach and intestines may cause:

• Constipation, because of abnormally slow passage of waste through the intestines. This is the most common digestive problem in people with diabetes.
• Delayed stomach-emptying after a meal (gastroparesis). This may cause frequent bloating, belching, heartburn, nausea, or vomiting.
• Diarrhea, because of abnormally fast passage of waste through the intestines. Diarrhea is more common at night.
• Abdominal pain.

Sexual function and urination problems

Nerve damage may cause problems with the bladder and sex organs. Common problems include:

• Difficulty knowing when the bladder is full (diabetic cystopathy) and difficulty emptying the bladder completely.
• Frequent urinary tract infections (UTIs). Nerve damage can disrupt the proper emptying of the bladder, which increases the risk of infection.
• For men, difficulty in achieving or maintaining an erection during intercourse (impotence).
• For women, decreased moisture in the vagina and reduced sensation of the clitoris.

While not usually life-threatening, autonomic neuropathy can be disabling. There are effective treatments for some of the problems caused by diabetic autonomic neuropathy.