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The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 31

39. How are mast cell disease, Ehlers Danlos Syndrome and POTS connected?

I’m answering this question in two parts because there is a lot of information to relay and it’s important that it is done clearly.

Let’s talk about what EDS and POTS are first.

Ehlers Danlos Syndrome (EDS) is a connective tissue disease. It can be, and often is, inherited. About 1 in 5000 people have some form of EDS.

There are several subtypes of EDS. The ones you hear about most are called classical, vascular, and hypermobility. The different forms of EDS used to be distinguished by numbers (like Type I, Type II, etc) but now they use descriptive terms instead. Types I and II EDS are now called classical EDS (cEDS); type IV EDS is now called vascular EDS (vEDS); and type III EDS is now called hypermobility type (hEDS or htEDS). There are also other rare variants of EDS.

Each of these subtypes has distinguishing features that make them unique from the other forms of EDS. All forms of EDS cause major systemic dysfunction of connective tissue, the pieces of you that hold your body together and keep everything in the right place. Generally, in EDS patients, their connective tissues tear easily and heal slowly. They usually (but do not always) show hypermobility in their joints (being double jointed or overly flexibility). Skin that is very stretchy or that heals very poorly is common.

Because you have connective tissues holding your whole body together, EDS can affect your entire body. All patients are at risk for symptoms that specifically impact their joints, muscles and bones. VEDS can significantly affect life span because it increases the risk of an aneurysm or a blood vessel bursting. HEDS patients often have cardiovascular, GI, and neurologic symptoms. CEDS patients often display the trademark skin stretchiness and many have extraordinary difficulties in healing incisions and wounds. Of course, many EDS patients have other symptoms, and there is a lot of symptom overlap among these forms. I am just generalizing here.

There is no cure and treatment is largely about managing symptoms and complications. EDS is usually diagnosed by a geneticist. There are genetic markers for most forms of EDS that can be found with genetic testing. However, the most common form of EDS, hypermobility type EDS (hEDS), does not have a known genetic marker. For this reason, geneticists often assess how hypermobile a patient is and then uses that to support the diagnosis of hEDS.

Postural orthostatic tachycardia syndrome (POTS) is a form of orthostatic intolerance, which means symptoms and problems caused specifically by standing up. POTS patients have a big jump in heart rate when they stand up (increase of 30 beats per minute or heart rate over 120 beats/minute in adults) that is not due to a drop in blood pressure. POTS is a form of dysautonomia, an umbrella term that covers several conditions in which the body is not able to control some of the body’s automatic functions like heart rate and blood pressure. (For those wondering, automatic is not a typo, and I did not mean to write autonomic, which is related here.)

There are multiple types of POTS. I’m just going to cover neuropathic POTS and hyperadrenergic POTS as they are the most applicable here. POTS can be a primary or secondary condition. It can cause very severely disabling symptoms and effects. It can cause a huge array of symptoms, including dizziness; fainting; exhaustion; inability to exercise; nausea; vomiting; major GI disturbances (both diarrhea and constipation); inappropriate sweating; chest pain; coldness, numbness, pain and weakness of extremities; and anxiety. Some patients are unable to stand up at all.

Neuropathic POTS, the most frequently described, is thought to be the result of the veins in the legs not being able to pump blood effectively. When you stand up from a sitting position or laying down, a lot of blood that was in your torso quickly moves into your legs. This happens to everyone. In most people, the veins in your legs are able to tighten and squeeze effectively to pump that blood out of the legs and get it back to your heart. In neuropathic POTS, your veins don’t seem to be able to do this as well so the blood gets stuck in your legs. Your body interprets this as having low blood pressure even though you have enough blood and it’s just not where your body expects it. In response to the “low blood pressure”, your heart starts beating very fast to try and get enough oxygenated blood to every place in your body that needs it.

Hyperadrenergic POTS is less common but relatively more common in mast cell patients. In this form, the body makes too much adrenaline (and often other similar molecules like noradrenaline). These molecules work together to cause the nervous system to tell the heart to beat way too fast in response to standing up and that blood moving into your legs. In patients with hyperadrenergic POTS, blood pressure is often increased while the heart rate is also increased instead of being normal or low as in neuropathic POTS.

The second part of this question (question 39) will be up in a day or two. Sorry for the length but I don’t think there’s a way to answer this question both clearly and with brevity.