Cardiovascular autonomic neuropathy (CAN) is a type of dysfunction commonly found in people with diabetes. It results from damage to the nerves that lead to the heart and blood vessels.
Autonomic nerves travel from the brain to signal the heart to beat more forcefully or at a different pace to keep up with the body's needs. In CAN, the heart and blood vessels either do not receive or appropriately respond to these signals, resulting in various symptoms. People with CAN may have increased risk of heart complications, including arrhythmias and heart failure.
This article discusses CAN symptoms, causes, diagnosis, and treatment options.
Symptoms of Cardiovascular Autonomic Neuropathy
CAN symptoms affect a person's quality of life. They commonly include the following:
- Light-headedness or dizziness, especially with standing
- Racing heart
- Exercise intolerance
Many symptoms of CAN occur or worsen when changing position from lying or sitting to standing. Symptoms such as light-headedness and vision disturbance upon standing are known as orthostatic intolerance.
When we stand, blood pools in the legs, causing a temporary decrease in blood pressure. Autonomic nerves signal to the heart to beat faster and harder, and signal the veins in the blood vessels to help keep blood pressure up, as well as to contract the veins to help push the blood back up. Orthostatic intolerance happens where there is a problem with this process.
What Is the Autonomic Nervous System?
The autonomic nervous system controls basic body functions that we rely on without even being aware of them. This includes heartbeat, blood pressure, breathing, and digestion.
CAN is defined as an autonomic disorder in people with diabetes. Poor blood sugar control over time damages nerves throughout the body, leading to neuropathy.
Diabetes and Neuropathy
If you've been diagnosed with diabetes, you have probably been told to monitor changes in your feet. This is because the nerves in the feet may be less sensitive and you could be unaware of a cut or infection there. This is known as peripheral neuropathy.
Other causes of autonomic neuropathy, also known as dysautonomia, include the following:
Some experts have suggested that some of the ongoing symptoms of long COVID after a COVID-19 infection may be related to CAN, but this need further study.
Because the symptoms of CAN can be vague and overlap with symptoms of other disorders, diagnosis can be challenging. Results from several types of tests are combined to arrive at a CAN diagnosis.
These include cardiovascular autonomic reflex testing and cardiovascular sympathetic tests, which measure heart rate variability, blood pressure response, or electrocardiogram findings to various maneuvers.
Nuclear imaging tests, known as heart sympathetic imaging, may have a role in diagnosing CAN in the future.
CAN has been associated with heart disease. People with CAN may have a higher risk of the following:
There is no specific medical treatment to reverse CAN. Treatment instead focuses on preventing further damage and managing symptoms.
Some lifestyle measures, like diet and exercise, may be able to reverse CAN, including:
- Controlling blood sugar to prevent further nerve damage
- Optimizing cardiovascular risk factors, such as cholesterol and blood pressure
- Managing complications like heart failure and coronary artery disease
Lifestyle considerations are important to help manage symptoms. For example, those with orthostatic intolerance can benefit from standing up slowly, staying well-hydrated, exercising, and using compression stockings.
Some medications, such as fludrocortisone, midodrine, or droxidopa, may be used to help alleviate symptoms.
CAN symptoms can be frustrating to live with since they may have a profound effect on everyday life. Having the understanding and support of your treatment team, family, and friends is important.
Joining a support group for people with autonomic disorders, either in person or online, can help connect you with others who may have similar experiences.
CAN is a nervous system condition affecting the nerves that bring signals to the heart and blood vessels. When these nerves become dysfunctional, the heart and blood vessels don't properly keep up with the needs of the body during activities. It can be noticed when standing up or exercising. This condition can result in symptoms that affect daily life, such as fatigue, heart racing, orthostatic intolerance, and difficulty exercising.
CAN is most often a complication of long-standing, uncontrolled diabetes. Treatment involves managing symptoms and controlling risk factors for cardiovascular disease, such as blood sugar, cholesterol, and blood pressure. CAN also increases the risk of heart complications like heart attack and arrhythmias, so prompt treatment is essential.
A Word From Verywell
Because symptoms of CAN overlap with many other conditions, diagnosis can be challenging and take time. Oftentimes, multiple tests and specialist referrals are required. All of this can be overwhelming and frustrating. Specialized centers for autonomic disorders and support groups can be invaluable for people living with CAN.