Hyperadrenergic, Neuropathic, and Hypovolemic POTS
Postural orthostatic tachycardia syndrome (POTS) is the most common form of dysautonomia, characterized by malfunction of the autonomic nervous system. The range of potential symptoms of POTS is broad in both scope and severity. Sometimes practitioners will refer to three subtypes of POTS to help think about the possible mechanism and treatment options. These are not used by all practitioners, so don’t worry if you haven’t heard these terms. There is a lot of overlap between these subtypes: hyperadrenergic POTS, neuropathic POTS, and hypovolemic POTS, and so it is possible that one person could identify with symptoms and taking medications described for each type of POTS. This is common and nothing to be concerned about.
Hyperadrenergic POTS is characterized by elevated levels of plasma norepinephrine levels (neurotransmitter of the sympathetic NS) >600 pg/mL and >10 mmHg rise in systolic blood pressure while standing for 10 minutes (Low et al. 2009). In hyperadrenergic POTS, the sympathetic nervous system is overactivated.
The most prominent symptoms associated with hyperadrenergic POTS include:
The most common comorbidity with hyperadrenergic POTS is mast cell activation syndrome (Wang et al. 2021). Identifying and treating mast cell activation syndrome, if present, can help to decrease these symptoms. There are a number of other potential causes of hyperadrenergic POTS, which are rare. These include a single point mutation in the norepinephrine reuptake receptor (Lambert et al. 2008), baroreflex failure, and a tumor on the adrenal glands called pheochromocytoma (Benarroch 2012).
Treatments for hyperadrenergic POTS focus on rebalancing the autonomic nervous system, typically by decreasing the activity of the sympathetic nervous system. These medications include:
Neuropathic POTS is characterized by a decrease in sympathetic innervation, particularly in the legs (Mar and Raj 2020), and is often associated with small fiber neuropathy. Normally, these small fiber nerves regulate constriction of the blood vessels in the limbs and abdomen. Because these nerves are damaged in neuropathic POTS, however, activation of the sympathetic nervous system leads to less release of norepinephrine from these small fibers. Because norepinephrine is a vasoconstrictor, neuropathic POTS is often associated with excessive blood pooling in the hands and feet. This decreases blood circulation and causes less blood to return to the heart (low venous return) which causes the heart rate to increase in order to compensate. Neuropathic POTS often occurs following infection, surgery or trauma and may be an autoimmune form of POTS, as autoantibodies to the ganglionic acetylcholine receptor have been associated with this POTS subtype (Li et al. 2014).
The most prominent symptoms of neuropathic POTS include:
Treatments for neuropathic POTS tend to focus on decreasing blood pooling and moving blood back up toward the heart and brain. These include:
Hypovolemic POTS is characterized by abnormally low blood levels, including both red blood cells and plasma (Raj et al. 2005). While not often measured, the plasma deficit in POTS is approximately 13% and may be related to low levels of circulating renin and aldosterone which typically help to increase blood volume and blood pressure (Raj et al. 2005). As a result, people with this type of POTS have their kidneys excreting too much sodium and water, which contributes to this low blood level. Low blood volume leads to less blood return to the heart, which causes an increased heart rate and force of contraction in an attempt to keep blood circulation at normal levels.
What symptoms are typically associated with hypovolemic POTS?
What are the typical non-pharmacological treatments?
What are the typical medications to increase blood volume?
Check out this page for more information on medications for POTS that includes dosages and other administration information.
To hear Dr. Cathy Pederson’s episode discussing this topic, listen to The POTScast Episode 88: Three Types of POTS.