Unfortunately there is not one simple cause of POTS. Normally, it is difficult to distinguish between the causes of POTS and its symptoms. Here are some of the possible causes:
Cervical Stenosis- a narrowing of the spinal canal, which compresses the spinal cord and the nerve roots.
Chiari Malformation- This is what I have. The cerebral tonsils protrude into the spinal cord, which limits the flow of cerebral spinal fluid (CSF). Some researchers and physicians believe that their is a link between Ehlers-Danlos syndrome, POTS, and Chiari 1 malformation.
Ehlers-Danlos Syndrome (EDS)- a connective tissue disorder which causes veins to distend in response to blood pressure. It causes blood to pool in the lower limbs. I will post an entry with more details of this disorder.
Liver disease- it coincides with vasodilation and hypovolemia
Mast-cell activation disorders- increased urinary methylhistamine is present in these patients. Vasodialator histamine and plasma prostaglandin 2 may contribute to symptoms. Beta-blockers should not be prescribed to patients with these disorders because they can activate mast-cells
Nitric Oxide (NO) deficiency- NO controls the blood vessel size and the blood vessel leakiness.
Norepinephrine transporter deficiency- the enzyme that reuses norepinephrine does not properly function, and thus it is overused and becomes depleted. They go from too much of the chemical to not enough, causing a crash.
The Nutcracker Phenomenon (NC)- the congestion of the left renal vein due to its compression by the aorta and the superior mesenteric artery. There will be another post on this cause later.
B Vitamin deficiencies- Especially B: 1, 3, 6, 9, and 12.
Syringomyelia- a cyst that grows within the spinal cord. Occurs between the ages of 25 and 40 and comes on suddenly.
Viruses- about 50% of POTS patients acquire the disease from viruses like the Epstein-Barr virus (Mono). Half of these patients will recover within 2-5 years.
Head Injuries- like car accidents or a bad fall
Rapid Weight loss
There are probably many more causes of POTS, but for now, these are the majority of the causes that researchers know about. Almost all of these causes are treatable, so keep that hope up!