An Overview of Postural Orthostatic Tachycardia Syndrome

You have probably never heard of postural orthostatic tachycardia syndrome or POTS, even though it affects many people, including teens, and was identified in the early 1990s. The National Dysautonomia Research Foundation describes children with these disorders as invisible to outsiders, who may think that they are faking their symptoms.

That it isn't more well known can be even more frustrating because POTS can cause such debilitating symptoms, including dizziness, headaches, and fatigue.

Definition and Characteristics

Postural orthostatic tachycardia syndrome (POTS) is caused by alterations or dysfunction in the autonomic nervous system (dysautonomia).

You may not be familiar with the autonomic nervous system, but are likely familiar with some other conditions which are related to dysfunction of the autonomic nervous system. These may include irritable bowel syndrome, fibromyalgia, and chronic fatigue syndrome.

In addition to the central nervous system (our brain and spinal cord), we have an autonomic nervous system that helps to involuntarily control many things our body does, such as:

• Dilating our pupils when we go into a dark room
• Increasing saliva production when we eat
• Causing us to sweat when we get hot

The autonomic nervous system also helps regulate our heart rate and blood pressure. These roles are especially important when we change position, like going from supine (lying down) or sitting to a standing position.

When we stand up, many things happen in our bodies that we don't notice, or at least we don't notice when they happen correctly. In response to a large amount of blood moving to our lower body, which initially drops our blood pressure, the autonomic nervous system increases our heart rate, constricts or tightens blood vessels and increases our blood pressure, all to maintain blood flow to our brain. Muscles in our legs and abdomen also compress veins in these parts of our body and help with the process.

POTS is thought to occur when this system doesn't work properly, causing affected people to get dizzy when they stand, among other symptoms.

POTS is most common in women, especially women between the ages of 15 and 50 years of age (menarche to menopause). Although it is not known what causes POTS, it often begins after a prolonged viral illness, like the flu or mono.

Symptoms

The classic definition of POTS in teenagers is feeling lightheaded and having a heart rate that rises more than 40 beats per minute (or a heart rate above 120 beats per minute), within 10 minutes of standing up.

In addition to often feeling dizzy, other symptoms of POTS can include:

• Headaches
• Weakness, fatigue, and exercise intolerance
• Nausea and abdominal discomfort
• Tachycardia (fast heart rate) and palpitations
• Near syncope (feeling like you are going to faint)
• Blurred vision
• Anxiety
• Sweating inappropriately
• Trouble sleeping
• Difficulty concentrating

In addition to having classic symptoms, tilt-table testing can be done to help diagnose teens with POTS. A tilt test can also be done after a teen has been supine (lying down) for 5 minutes, measuring her heart rate and blood pressure, and then after she has been standing for 3, 5, 7, and 10 minutes.

Dizziness and Fainting vs. POTS

Dizziness and even fainting (syncope) are actually common symptoms in teens.

In fact, it is thought at least 15% of teens will faint at least once before they reach adulthood, usually around the age of 15 years. Fortunately, most of these teens with dizziness and fainting won't have POTS. Instead, they will have more common disorders, such as:

• Vasovagal syncope - Also called postural syncope, vasovagal syncope can be caused when you are standing for too long in one place (blood pools in your arms and legs, especially if you aren't moving them much) or in response to pain or fear.
• Transient orthostatic intolerance - Transient orthostatic intolerance can occur when you are sick with the flu, a stomach virus, or other medical conditions, causing you to be a little dehydrated and get dizzy when you stand up.
• Orthostatic hypotension - Like POTS, orthostatic hypotension occurs when you stand up.

The big difference between the conditions above and POTS is that with POTS the symptoms may occur daily and are often disabling.

In addition to treating any underlying dehydration, the best treatments for these causes of syncope are usually countermeasures to help prevent them from occurring. At the first sign that your teen feels like she might faint, it is usually recommended that he or she sit, squat, or lie down. Getting enough salt and water in their diet is also important.

Subtypes of POTS

Not everyone with POTS has the same symptoms, and it appears that there are three primary forms or subtypes of the condition, each of which is related to different underlying mechanisms. Understanding the specific subtype of POTS may help guide your healthcare provider to the best treatment choices. These include:

• Neuropathic POTS
• Hyperadrenergic POTS
• Hypovolemic POTS

Treatments

Since POTS can be so debilitating, finding effective treatments are important. The primary initial goals are usually volume expansion (with fluids and salt), exercise, and education. Treatments may include:

• Elevating the head of your child's bed by 4-6 inches.
• Encouraging your child to drink at least 2 to 3 liters of noncaffeinated, clear liquids each day and to stay well hydrated.
• Increasing the amount of salt in your child's diet—up to 3-5g/d, as compared to the usual 1500-2300mg of salt for teens without POTS.
• Avoiding big meals and instead of eating more frequent, but smaller meals (big meals increase the amount of blood in the gut.)
• An exercise or reconditioning program to include aerobic activity and lower body strengthening that gradually increases the amount of exercise your child gets each day. This is especially important since many experts believe that bed rest and deconditioning may play a role in actually causing POTS.

Medications

Medications are also sometimes used to help teens with POTS, including metoprolol (a beta-blocker), midodrine (an alpha-agonist), or fludrocortisone (a mineralocorticoid that can help increase salt and water retention), are examples of medications which may be used.

Although older tricyclic antidepressants are thought to make POTS worse, newer SSRI antidepressants (such as Prozac) are considered a possible treatment.

Ivabradine is a newer treatment which appears to be helpful for some people with POTS.

Coming up With a Treatment Plan

There is no definitive treatment plan for teens with POTS. Some journal articles don't even agree on whether or not some treatments, like beta-blockers or SSRIs, are even helpful. Getting help will likely include some trial and error to find the best treatments that work for your teen with POTS.

What You Need to Know About POTS

• Although there is no cure for POTS, many teens do seem to outgrow it. At least 500,000 people in the United States are thought to have POTS.
• Fainting during exercise is a red flag for a serious cause of syncope, especially in kids with a family history of sudden death. An evaluation by your pediatrician and/or a pediatric cardiologist should be done immediately.
• POTS is sometimes associated with having hypermobility syndrome, a Chiari malformation, or chronic fatigue.
• The quality of life is diminished for young people with POTS and up to half of the teens and young adults with the syndrome are at risk of suicide. Finding a good therapist that your child can be open with can be an important part of the treatment plan.
• A pediatric neurologist can be helpful to diagnose and treat your child with POTS. Specialty POTS clinics are also available in some Children's Hospitals.