Sunday, July 3, 2011

Postural tachycardia syndrome (PoTS): few doctors have heard of it, let alone know how to diagnose and treat it

Fainting after standing up is a common symptom among people who have postural tachycardia syndrome (PoTS). The condition causes blood to drain to the abdomen and legs upon standing, causing dizziness as the heart fights to maintain blood supply to the brain.

The Ottawa Citizen:

A summer’s evening in London and 21-year-old Sophie Mortimer was squashed between tourists and commuters on the Piccadilly subway line. As she stood, swaying, she felt increasingly light-headed. Just before the train pulled into the station, she fainted.

“It was a family of American tourists who carried me off the Tube,” Mortimer recalls. “I woke up on the platform and the Underground staff gave me water and called an ambulance.” At the hospital, doctors said she might have glandular fever, although they also said she “looked too healthy.”

But Mortimer, a student at the London School of Economics, was not at all healthy. She had indeed had a lengthy bout of glandular fever a year before, and the symptoms — sleeping 14 hours a night and difficulty concentrating on her degree — had lingered on.

Her family doctor dismissed the faint as post-viral, but Mortimer knew something else was wrong. Nearly three years after her first fainting fit in 2007, she was diagnosed with a condition that makes it hugely difficult to go from sitting to standing without fainting or feeling dizzy. Postural tachycardia syndrome (PoTS) was discovered only 15 years ago, and few doctors have heard of it, let alone know how to diagnose and treat it.

The name may be tricky but the explanation is simple. Normally, when someone stands up, the blood, which gravity dictates should sink below the abdomen and pool around the ankles, miraculously remains waist high. If you have PoTS, this doesn’t happen. Gravity wins and blood drains down into the abdomen and legs. The heart races to try to get blood back to the brain, and the result is fainting and dizziness. Which is what happened to Sophie on the homebound train.

A condition of the autonomic nervous system that controls all our bodily functions, PoTS is surprisingly common, particularly among young women; one estimate puts the number of people with the condition at 1.7 per cent, and studies estimate that one in 100 teenagers is affected. Yet it is so little known by doctors that it is often misdiagnosed as anxiety or depression, or dismissed as “all in the mind”.

Dr. Blair Grubb, professor of medicine and pediatrics at the University of Toledo in Ohio, and a world authority on fainting and autonomic disorders, explains: ... Read more>>


Anonymous said...

The main characteristic of ME/POTS/CFS is not delayed muscle recovery. The cardinal signs of these conditions are low blood volume, reduced orthostatic cerebral blood flow, increased orthostatic sympathetic outflow, and in a subset of patients, elevated angiotensin II mediated reductions in Neuronal nitric oxide activity. Parasympathetic withdrawal is the consequence.

Charles said...

Delayed muscle recovery is not the cardinal sign of CFS/ME/POTS, etc. The cardinal signs are abnormal circulatory control that manifests are reduced orthostatic cerebral blood perfusion, increased orthostatic sympathetic drive, parasympathetic withdrawal, and in a subset of patients, elevated angiotensin II-mediated reductions in neuronal nitric oxide activity. Any reduction in peripheral muscle recovery is likely a consequence of disordered circulatory control.


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