Pots means postural orthostatic tachycardia syndrome. It is rare but complex condition that is caused by orthostatic intolerance which is the intolerance to change from supine position to an upright position. This change in position causes an abnormal increase in heart rate, that is often accompanied by a sharp fall in blood pressure. The orthostatic tachycardia syndrome is a disabling disease that was described since 1940. Patients are often unable to work, retain jobs or attend schools. Pots disease is common and it affects an unknown number of patients mostly in the age range of 12 to 50 years who are mostly female.
Causes of pots disease
Heart problems: since the heart is the central blood pump, a weak or irregular heart can cause pots disease. The conditions that can weaken or cause an irregular heart are; arrhythmia, heart failure and pregnancy. These three conditions can make the heart unable to provide adequate blood pressure. If the heart is not pumping the blood strongly enough, the pressure drops significantly.
Hypovolemia: another possible cause of pots disease that is not associated with the heart is anemia, dehydration or dialysis which causes insufficient blood volume in the bloodstream. This condition is known as Hypovolemia.
Blood vessels conditions: The blood vessels may also cause pots disease. The blood vessels do not just have the role of ensuring passive conduction of the blood, they also squeeze to raise the blood pressure, and if this action is prevented for some reason, the blood pressure falls. The loss of this function of the blood vessels is as a result of different medications. Numerous types of medications affect blood vessels negatively including most of the medications used for blood pressure, in psychiatry and for heart pain. Heat, from a hot shower or from a fever can also dilate blood vessels and cause orthostasis.
Nervous system problems: The nervous system usually senses and responds to regulate blood pressure. There are several neurological mechanisms of controlling blood pressure which affect heart pumping, blood vessels, kidneys etc. If something is wrong with this control system then, the blood pressure may fluctuate.
Ear vestibular problems: vestibular disorders interact with blood pressure and heart rate control. The vestibular system is the main source of information about uprightness and the whole system is localized in the inner ear.
Symptoms of pots disease
The onset of pots disease symptoms is gradual.
Increased heart rate: This is the main and most common sign of pots disease. When changing from the supine to upright position, the heart rate may vary with more than 30 beats per minute and cause a heart rate that is greater than 120 beats per minute within 10 minutes of standing up. Pots disease often causes a temporary blood pressure rise when an individual stands up as a result of rapid acceleration of the heart rate.
Reactive hypoglycemia: Reactive hypoglycemia is a common problem among individuals with pots disease. It is the abnormal lowering of the blood sugar levels. It occurs as a result of complex series of neural and hormonal interactions. Lowering of blood sugar levels is not the only cause of symptoms, because pots disease patient's bodies produce excess adrenaline and other stress hormones.
Frequent urination: Frequent urination is a main and common symptom of pots disease. This pots disease symptom is sometimes misdiagnosed as diabetes insipidus, which is a disease that is caused by the reduced production of a pituitary hormone called vasopressin. Other symptoms include;
- Weight loss
- Night sweat
- Localized back pain
- Tingling in the legs
- Numbness of the palms and soles
Diagnosis and tretament
The most essential aspect of evaluation is the patient’s history. The pots disease patient has to elicit all the relevant information about the onset of symptoms. That is, were they sudden or gradual and what makes the symptoms worse or better should be the core questions. This should be followed by a careful physical exam.
Pots disease is correctly diagnosed on the basis of the heart rate increase and heart waveform signature revealed by electrocardiogram, not on the basis of a drop in blood pressure, as is the case with orthostatic hypotension and neuro-mediated hypotension.
Adding a lot of extra salt to the diet increases the blood volume and pressure due to the increase in fluid retention that is caused by the extra salt. However, high salt intake should be tried under the supervision of a doctor. Pots disease patients should avoid garlic and nitrates as they lower the blood pressure. Regular exercise is also recommended. The medical treatments for pots disease include; florinef, midodrine and beta blockers.