Excessive Thirst in ME
Please see Blog Post about thirst by Irish ME patient Patrick Usher, a long but very well-written blog post which recently appeared in Health Rising.org; you might want to take it in smaller chunks or read about the Gist of the post further below.
The blog post includes a talk about thirst in ME by Video which ME patient Patrick Usher gave to the Irish ME Trust (IMET) .
The Gist of Patrick Usher's Blog Post about Excessive Thirst in M.E.
by Health Rising
Many ME patients suffer from polydipsia – a condition that involves unquenchable thirst, dilute urine, a worsening of thirst during post-exertional malaise (PEM) and, at least in some patients, the development of hyponatraemia (low blood sodium).
Patrick Ussher, an Irish ME patient, used to suffer from this symptom at its most extreme – to the point that he developed life-threatening hyponatraemia and was hospitalised.
In the hospital, he was diagnosed with a mental health condition, ‘psychogenic polydipsia’, in which it is assumed that patients drink enormous quantities of water in the absence of physiological needs and because they are mentally ill.
After his hospital stay, Patrick managed to resolve his extreme thirst through his own research and later wrote a (free) book about what might be causing thirst in ME (details to follow).
In Patrick’s hypothesis, excessive thirst in ME is mainly caused by the low blood volume that is characteristic of the illness. Research has consistently found that ME patients do not have enough blood, with some patients short by a litre or more. The most significant reason for this reduction in blood volume appears to be the suppression of the renin-angiotensin-aldosterone axis, a hormonal system which controls salt levels in the body.
The brain actually has two distinct thirst centres: osmotic (triggered when the body’s water content is too low) and hypovolemic (triggered when the plasma blood volume drops by 10%). It is this little-known second thirst centre that is likely being triggered continuously in ME patients.
Crucially, the hypovolemic thirst centre is not ‘looking’ for water in order to be ‘quenched’. Blood is salty stuff and, in order to boost blood volume, the ingested fluids need to be appropriately salty.
Patrick believes that most ME patients fall into the understandable trap of just drinking pure water in response to their thirst (for who doesn’t drink water when they are thirsty?).
When this water is excreted by the kidneys, though, the blood volume will remain low and, as a result, the thirst will continue – and even grow – as sodium levels and blood volume continue to drop.
When Patrick switched from drinking pure water to drinking ORS (oral rehydration solutions), he experienced a profound decrease in his thirst along with a significant improvement in his quality of life.
In previous research, ORS has been shown to increase blood volume as effectively as a saline IV in POTS patients.
Later on, Patrick researched ‘psychogenic polydipsia’ in detail. He found that it is a condition which has received little research and which is generally regarded as a ‘medical mystery’.
In fact, several leading academics have suggested that the supposed ‘psychogenic’ basis might be a mistake and that the real mechanisms simply haven’t been identified yet.
When Patrick researched the earliest papers into the condition from the 1940s and 50s, he came across several intriguing patient case studies.
Those patients had symptoms reminiscent of ME such as ‘aching everywhere’ and profound ‘weakness of the legs’. Among other reasons, this led Patrick to believe that, at least in many patients, what has always been termed ‘psychogenic polydipsia’ may have been a misreading of the biomedical thirst experienced in ME patients.
Patrick’s book challenges the psychogenic basis of ‘psychogenic polydipsia’ (also known as ‘primary polydipsia’) and instead maps out a model of ‘hypovolemic thirst’ which can explain the symptoms in organic terms.
The book is called ‘The Myth of Primary Polydipsia: Why Hypovolemic Dehydration Can Explain the Real Physiological Basis of So-Called Psychogenic Water Drinking’. It is available on Amazon and from themythofprimarypolydipsia.com as a PDF download.
At its most extreme, this symptom can lead to hyponatraemia-induced coma and death.
Despite this, the current diagnosis of ‘psychogenic water drinking’ offers only stigmatisation and no practical help. If ‘hypovolemic dehydration’ could re-explain these symptoms in organic terms, it would not only lead to much-needed medical help but also to greater awareness about the biomedical nature of ME among future medical students.
Patrick is looking for doctors/medical researchers who may wish to work on a hypothesis paper or other similar collaborations.
~ the gist of Patrick Usher’s blog post about thirst by healthrising dot org
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