Digging into autonomic dysfunction and POTS

This post was written by Lyndsay Butt, NP, PPG – Specialty Pediatrics.

You may not have heard of it, but autonomic dysfunction is a prevalent health problem that continues to be underdiagnosed, mistreated and underrepresented within healthcare systems. Sadly, many patients tend to have a late diagnosis, and the symptoms associated with autonomic dysfunction can be chronic and persistent. Patients and their families often feel frustrated because they frequently get told their symptoms are psychological or anxiety related. In reality, autonomic dysfunction falls on a spectrum that includes orthostatic hypotension, postural orthostatic tachycardia syndrome (POTS) and neurocardiogenic syncope. Each condition plays a vital role on the blood pressure mechanism. Let’s take a look at each disorder and where it falls on the spectrum:

• Orthostatic hypotension: A drop in blood pressure with a change in position
• POTS: A drop in blood pressure and an increase in heart rate
• Neurocardiogenic syncope: A drop in blood pressure and a drop in heart rate

Interestingly enough, the same individual can be on each end of the spectrum in one day, depending on the symptoms they experience. However, for the moment, we are going to dig a little deeper into POTS.

A closer look at POTS and those affected

POTS typically occurs when there is a drop in blood pressure with an increase in the heart rate. Technically this happens when the volume of blood diminishes. This reduction, in turn, causes a decrease in the rate of blood flow back to the heart, causing tachycardia (an increased heart rate) and orthostatic intolerance.

Additionally, the disorder is more prominent in females than males and commonly seen anywhere from 9-19 years of age, with peak occurrences between the ages of 12-16 due to hormone changes and linear growth during puberty. These shifts affect the blood pressure mechanism, so when there is a drop in blood pressure, an individual may experience any of the following symptoms:

• Headaches
• Blurred, spotty or tunnel vision
• Near fainting (near syncope)
• Blacking out (syncope)
• Dizziness
• Lightheadedness
• Numbness
• Tingling
• Racing or pounding of the heart
• Chest discomfort
• Shortness of breath
• Feeling cold and clammy or hot and sweaty

Moreover, the normal compensatory response of the body is to have an increase in heart rate when there is a drop in blood pressure. With these symptoms, patients can experience an exaggerated increase in heart rate with no fall in blood pressure. These symptoms usually occur following a change in posture from sitting/lying down to standing, but they can also happen after meals, any exertional activity or prolonged standing.

Lastly, POTS symptoms tend to be worse during the early morning hours, in hot weather, during menses, and if there is a fever or illness. Most POTS patients cannot tolerate standing while taking a warm shower and must sit down to bathe. A simple act of showering can exhaust these patients to the point of needing to lie down and rest afterward. These symptoms may also become exacerbated by any emotional, psychological and physical stress. Though this may seem overwhelming, it’s important to note that POTS is not life-threatening. It is treatable and curable. While these symptoms can be debilitating at times for patients, they are manageable (with or without medication), and many go on to lead a normal quality of life.

Diagnosis

There is a form of autonomic testing to help diagnose POTS. It is called the Tilt-Table test. Fortunately, this test can be more sensitive and specific than a random sampling of heart rate changes during a clinical assessment. The Tilt-Table test can also help decipher which medication (if needed) would be best suited for a patient.

When diagnosing POTS, the heart rate and blood pressure are measured while lying down, sitting and standing. POTS is definitive when the patient experiences symptoms along with a 30 beat per minute increase in their heart rate or a maximum heart rate greater than 120 beats per minute, occurring within the first 10 minutes of standing or an upright tilt.        

When a patient experiences heart palpitations like racing or pounding, or blacking out, it is essential to rule out any life-threatening conditions associated with the heart. We do this by way of an echocardiogram and an electrocardiogram. These tests can identify any arrhythmias or hypertrophic cardiomyopathy. Once we rule out these conditions, we can look at autonomic dysfunction and how it’s affecting the patient.

Treatment and symptom management

The first line of treatment for an autonomic dysfunction, specifically POTS, is increasing fluid and salt intake. Patients who experience these symptoms need to consume at least 64, but preferably 80 ounces of fluid daily. To keep that extra fluid on board and not urinated out of the body, we need to increase the sodium intake. We recommend POTS patients get at least 1-2 grams of sodium daily with a maximum of 4 grams. Also, because it can be challenging to measure the sodium when simply added to your diet, we sometimes recommend patients try eating ramen noodles, macaroni and cheese, chicken noodle soup or other processed foods that are high in sodium.

If processed foods aren’t an option, salt tablets are available and can be purchased over the counter or by prescription. However, the excess salt can upset the stomach, so we always advise patients to take it with meals or dissolve them in a clear carbonated beverage. It’s best to take these tablets first thing in the morning with breakfast in hopes of getting ahead of any symptoms. We also warn patients to take the sodium tablets consistently, not just when they don’t feel well.

Remember, the excess intake of fluid and salt helps maintain adequate blood pressure, minimizing the symptoms associated with POTS. It’s also essential that patients remain physically active if they can tolerate it. If patients stand for long periods, we recommend compression stockings to help prevent blood pooling in the legs, lowering the blood flow rate back to the heart, causing a decrease in blood pressure. After maintaining optimal fluid and salt intake a patient still experiences symptoms, we can discuss medication options.