Autonomic neuropathy is caused by damage to nerves that help control involuntary body functions such as heart rate and blood pressure, sweating and thermoregulation, digestion, urination, and some sexual functions.
Heart and circulatory system
Diabetic autonomic neuropathy may damage nerves in the heart and circulatory system, resulting in:
- A sudden drop in blood pressure when you suddenly sit down or stand up (upright hypotension).
- A rapid heart rate when not exercising (resting tachycardia).
- Heart attack without symptoms of chest pain (silent heart attack) Without symptoms of chest pain, a heart attack may go unnoticed and lead to serious heart damage. A heart attack in people with diabetes and kidney disease may only present with elevated blood sugar levels, weakness that remains after eating, constantly shorter breaths, nausea, and occasional leg swelling.
Sweating and thermoregulation
Autonomic neuropathy may affect the nerves that control sweating.
- Decreased sweating is common, especially in the hands and feet. It may be difficult to recognize when blood glucose is dropping because sweating is one of the main symptoms of hypoglycemia. Dry skin that is more prone to breakage, injury, and infection may occur. Heavy sweating on the trunk, face, or neck may occur at night or during meals.
- A change in the body’s ability to regulate body temperature may make the patient more susceptible to chills or fever-related illnesses, such as pyrexia or heat exhaustion.
Digestive system
Nerve damage to the stomach and intestines may result in:
- Constipation. This occurs when waste products in the intestines pass through the bowel abnormally slowly. This is the most common digestive problem in people with diabetes.
- Delayed gastric emptying after a meal (gastroparesis). This can be the cause of frequent flatulence, burping, heartburn, nausea, or vomiting.
- Diarrhea. This occurs when waste products from the intestines pass through the bowel unusually quickly. It is most common at night.
- Abdominal pain.
Sexual function and urination
Nerve damage can lead to bladder and sexual function problems. Common problems include:
- Difficulty determining if the bladder is full of urine (diabetic cystopathy) or difficulty emptying the bladder completely.
- Frequent urinary tract infections. Nerve damage may disrupt the proper emptying of the bladder, increasing the risk of infection.
- Men who have difficulty getting or maintaining an erection during sexual intercourse (impotence).
- Decreased vaginal wetness and reduced clitoral sensitivity in women.
Autonomic neuropathy is usually not life-threatening, but can be disabling. Certain problems caused by diabetic autonomic neuropathy can be treated effectively.