Dysautonomia is an umbrella term for conditions that disrupt the autonomic nervous system, the network that controls involuntary functions like heart rate, blood pressure, digestion, and temperature regulation. There isn’t one universally agreed-upon list of exactly 15 types, but medical centers and patient organizations recognize at least 15 distinct forms. Here’s a breakdown of each one, what it does to the body, and how the types differ from one another.
1. Postural Orthostatic Tachycardia Syndrome (POTS)
POTS is one of the most commonly diagnosed forms of dysautonomia, particularly in younger women. It causes an abnormal spike in heart rate when you stand up: at least 30 beats per minute in adults or 40 beats per minute in adolescents within the first 10 minutes of standing. Blood pressure may stay relatively stable, but the racing heart brings lightheadedness, brain fog, fatigue, and sometimes nausea. Many people with POTS also experience exercise intolerance, meaning even mild physical activity feels disproportionately exhausting.
2. Neurogenic Orthostatic Hypotension
Where POTS is defined by heart rate, neurogenic orthostatic hypotension is defined by blood pressure. It’s diagnosed when standing causes a sustained drop in systolic blood pressure of at least 20 mmHg or diastolic pressure of at least 10 mmHg within three minutes. The “neurogenic” label means the drop is caused by nerve damage rather than dehydration or medication side effects. The autonomic nerves that normally tighten blood vessels when you stand fail to fire properly, so blood pools in the legs and not enough reaches the brain. Dizziness, blurred vision, and fainting are the hallmark symptoms.
3. Neurocardiogenic Syncope (Vasovagal Syncope)
This is the most common cause of fainting worldwide. The autonomic nervous system overreacts to a trigger, causing a sudden drop in heart rate and blood pressure that reduces blood flow to the brain. Common triggers include standing for long periods, heat exposure, seeing blood, having blood drawn, fear of bodily injury, and straining during a bowel movement. Most episodes are preceded by warning signs: warmth, nausea, tunnel vision, or feeling pale and sweaty. For many people, vasovagal syncope is an occasional nuisance, but frequent episodes can significantly interfere with daily life and may overlap with other forms of dysautonomia.
4. Inappropriate Sinus Tachycardia (IST)
IST produces a resting heart rate above 100 beats per minute that has no identifiable cause. Unlike POTS, the elevated heart rate isn’t limited to standing. It can persist while sitting or lying down. People with IST often feel heart palpitations, chest discomfort, shortness of breath, and fatigue. The condition is thought to involve the heart’s natural pacemaker cells firing too quickly or responding too aggressively to adrenaline, but the exact mechanism is still poorly understood.
5. Multiple System Atrophy, Parkinsonian Type (MSA-P)
Multiple system atrophy is a rare, progressive neurodegenerative disorder that typically appears in people in their 50s and advances over 5 to 10 years. The parkinsonian type causes symptoms that resemble Parkinson’s disease: slow movement, muscle stiffness, tremors, and balance problems. It also produces severe autonomic dysfunction, including blood pressure instability, bladder problems, and erectile dysfunction. Compared to the cerebellar subtype, MSA-P tends to involve more widespread cognitive difficulties, particularly with mental processing speed, working memory, and executive function.
6. Multiple System Atrophy, Cerebellar Type (MSA-C)
The cerebellar subtype of MSA primarily affects coordination rather than movement speed. It causes loss of balance, difficulty swallowing, slurred or quivering speech, and unusual eye movements. Autonomic failure is still a core feature, so blood pressure and bladder control are affected just as they are in MSA-P. Disease onset tends to occur slightly later than in MSA-P, and the disease duration is somewhat longer, though the overall prognosis remains serious for both types.
7. Pure Autonomic Failure
Pure autonomic failure (PAF) is a rare degenerative condition that damages the autonomic nervous system without initially affecting movement or cognition. Symptoms include severe orthostatic hypotension, reduced sweating, elevated blood pressure when lying down, and changes in bladder and sexual function. PAF progresses slowly, and many people live with it for years. However, a portion of PAF patients eventually develop a broader neurological condition like Parkinson’s disease or multiple system atrophy. Doctors monitor for warning signs of this conversion, such as worsening bladder problems or subtle changes in movement.
8. Autoimmune Autonomic Ganglionopathy (AAG)
AAG is an autoimmune condition in which the body produces antibodies that attack the communication hubs of the autonomic nervous system. Specifically, these antibodies target the nicotinic acetylcholine receptor in autonomic ganglia, the relay stations where nerve signals are passed along to organs. This disrupts signaling across every branch of the autonomic system at once, so symptoms can include orthostatic hypotension, dry eyes and mouth, severe constipation or diarrhea, bladder dysfunction, and abnormal pupil reactions. Higher antibody levels correlate with more severe symptoms. Because it’s autoimmune in origin, AAG can sometimes improve with immune-targeted treatments.
9. Baroreflex Failure
Your baroreceptors are pressure-sensing nerves in the neck and chest that continuously report blood pressure levels to the brain, which then adjusts heart rate and vessel tone to keep things stable. When these sensors fail, blood pressure becomes wildly volatile. Baroreflex failure causes episodes of severe high blood pressure with a racing heart in response to stress, exercise, or pain, followed by periods of low blood pressure and a slow heart rate during rest. Headache and profuse sweating often accompany the high-pressure surges. The condition can result from surgery, radiation therapy to the neck, or tumors that damage the baroreceptor nerves.
10. Familial Dysautonomia (Riley-Day Syndrome)
Familial dysautonomia is an inherited condition caused by mutations in the ELP1 gene. Nearly all affected individuals carry two copies of the same mutation. It disrupts the development of both autonomic and sensory nerves from birth, so symptoms appear in infancy: difficulty feeding, poor temperature regulation, and absence of tears when crying. Older children experience autonomic crises involving episodes of vomiting, blood pressure spikes triggered by excitement or stress, and prolonged breath-holding that can cause the skin to turn blue or lead to fainting. The condition is most common in people of Ashkenazi Jewish descent.
11. Diabetic Autonomic Neuropathy
Diabetes is the most common identifiable cause of autonomic nerve damage. Prolonged high blood sugar gradually injures the small nerve fibers that regulate heart rate, digestion, bladder function, and blood vessel tone. Cardiac autonomic neuropathy is one of the most dangerous consequences, as it can mask the chest pain of a heart attack and increase the risk of fatal heart rhythm problems. Digestive symptoms like gastroparesis (delayed stomach emptying), constipation, and diarrhea are also common. Up to 80% of people with Parkinson’s disease experience some degree of autonomic dysfunction too, making these secondary forms collectively very widespread.
12. Postprandial Hypotension
Postprandial hypotension is a sudden drop in blood pressure after eating. During digestion, the body diverts a large volume of blood to the intestines. Normally, the autonomic nervous system compensates by increasing heart rate and constricting blood vessels elsewhere. When that compensation fails, blood pressure falls, causing lightheadedness, dizziness, or fainting within 30 to 75 minutes of a meal. It’s most common in older adults and people who already have another form of dysautonomia or Parkinson’s disease. Eating smaller, more frequent meals and reducing carbohydrate intake at each sitting can help reduce episodes.
13. Autonomic Dysreflexia
Autonomic dysreflexia occurs almost exclusively in people with spinal cord injuries at or above the mid-chest level (T6). A painful or irritating stimulus below the level of the injury, such as a full bladder, skin irritation, or constipation, triggers a massive, uncontrolled spike in blood pressure. Because the brain can’t send calming signals past the injury, the response spirals. Blood pressure can rise to dangerously high levels, causing a pounding headache, flushing and sweating above the injury, and a slow heart rate. It’s a medical emergency because the blood pressure elevation can cause a stroke or seizure if the triggering stimulus isn’t quickly identified and removed.
14. Cerebral Salt Wasting Syndrome
This type of dysautonomia involves excessive sodium loss through the kidneys following brain injury, neurosurgery, or certain neurological conditions. Sodium loss pulls water out of the bloodstream, reducing blood volume and causing low blood pressure, dizziness, and fatigue. It’s distinct from a similar-looking condition called syndrome of inappropriate antidiuretic hormone (SIADH), and telling them apart matters because the treatments go in opposite directions: cerebral salt wasting requires fluid and salt replacement, while SIADH requires fluid restriction.
15. Secondary Dysautonomia From Other Conditions
Many people develop autonomic dysfunction as a consequence of another disease rather than as a standalone diagnosis. The list of conditions that can damage or disrupt the autonomic nervous system is long and spans nearly every category of medicine. Amyloidosis deposits harmful proteins that damage autonomic nerves. Ehlers-Danlos syndrome, a connective tissue disorder, appears frequently alongside POTS and other autonomic symptoms. Sjögren’s disease, an autoimmune condition, causes autonomic dysfunction in roughly half of patients. Parkinson’s disease affects autonomic function in up to 80% of cases.
Other established causes include Chiari malformation, which can impair cerebrospinal fluid flow and disrupt autonomic signaling; mast cell activation disorders, which trigger autonomic symptoms through abnormal immune cell behavior; mitochondrial diseases, which starve nerves of energy; and toxic exposures from alcohol, chemotherapy drugs, or heavy metals that directly poison autonomic nerve fibers. Paraneoplastic syndromes, where antibodies meant to fight a tumor accidentally attack the nervous system, can also cause severe dysautonomia. Celiac disease, sarcoidosis, Fabry disease, and chronic inflammatory demyelinating polyneuropathy round out the more common secondary causes.
How These Types Are Diagnosed
Testing for dysautonomia typically centers on measuring how your cardiovascular system responds to specific challenges. The tilt table test is the most widely used tool: you lie flat on a motorized table while your blood pressure and heart rate are continuously recorded beat by beat, then the table tilts you upright to simulate standing. Doctors watch for the blood pressure drops that define orthostatic hypotension, the heart rate spikes of POTS, or the combined crash of vasovagal syncope. Some forms of orthostatic hypotension only appear after prolonged standing, so the test protocol may be extended. Initial orthostatic hypotension, by contrast, requires an active standing test because passive tilting doesn’t reproduce the sudden gravity shift of getting up on your own.
Beyond the tilt table, a full autonomic reflex screen measures sweat output to assess the nerves controlling temperature regulation, and specialized breathing and heart rate tests evaluate the vagus nerve’s influence on the heart. For autoimmune autonomic ganglionopathy, a blood test measuring antibodies against the ganglionic nicotinic acetylcholine receptor can confirm the diagnosis, with levels above 0.2 nmol/L considered significant. Distinguishing between types often comes down to the pattern: which parts of the autonomic system are failing, how severely, and whether the damage is in the brain, the spinal cord, or the peripheral nerves themselves.