View source for Polydipsia

{{short description|Excessive thirst or excess drinking}}
{{For|the term formerly used in reference to compulsive drinking of alcohol|Dipsomania}}
{{Infobox medical condition (new)
| name            = Polydipsia
| field           = [[Endocrinology]], [[psychiatry]]
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'''Polydipsia''' is excessive [[thirst]] or excess drinking.<ref name="pathophys">Porth, C. M. (1990). ''Pathophysiology: Concepts of altered health states''. Philadelphia: J.B. Lippincott Company.</ref> The word derives {{ety|el|''πολυδίψιος'' ({{grc-transl|πολυδίψιος}})|very thirsty}},<ref>{{LSJ|poludi/yios|πολυδίψιος|ref}}</ref> which is derived {{ety|grc|''πολύς'' ({{grc-transl|πολύς}})|much, many||''δίψα'' ({{grc-transl|δίψα}})|thirst}}.  Polydipsia is a nonspecific [[symptom]] in various medical disorders. It also occurs as an [[List of abnormal behaviours in animals|abnormal behaviour in some non-human animals]], such as [[Polydipsia in birds|in birds]].<ref>{{cite journal |author1=Hamm R.J. |author2=Porter J.H. |author3=Kaempf G.L. | year = 1981 | title = Stimulus generalization of schedule-induced polydipsia | journal = Journal of the Experimental Analysis of Behavior| volume = 36 | issue = 1| pages = 93–99 | doi=10.1901/jeab.1981.36-93|pmid=16812235 |pmc=1333055}}</ref>

==Causes==
===Diabetes===
Polydipsia can be characteristic of [[diabetes mellitus]], often as an initial symptom. It is observed in cases of poorly controlled diabetes, which is sometimes the result of low patient [[adherence (medicine)|adherence]] to [[anti-diabetic medication]].<ref name="pathophys" />

[[Diabetes insipidus]] ("tasteless" diabetes, as opposed to diabetes mellitus) can also cause polydipsia.<ref name="pathophys" />

===Other physiological causes===
It can also be caused by a change in the [[osmolality]] of the [[extracellular fluid]]s of the body, [[hypokalemia]], decreased [[blood volume]] (as occurs during major [[hemorrhage]]), and other conditions that create a water deficit.<ref name="pathophys" /> This is usually a result of [[osmotic diuresis]].{{cn|date=January 2025}}

Polydipsia is also a symptom of [[anticholinergic]] poisoning. Zinc is also known to reduce symptoms of polydipsia by causing the body to absorb fluids more efficiently (reduction of diarrhea, induces constipation) and it causes the body to retain more sodium; thus a zinc deficiency can be a possible cause. The combination of polydipsia and (nocturnal) [[polyuria]] is also seen in (primary) [[hyperaldosteronism]] (which often goes with hypokalemia).
[[Antipsychotics]] can have side effects such as [[Chlorpromazine#Indications|dry mouth]] that may make the patient feel thirsty.{{cn|date=January 2025}}

===Primary polydipsia===
{{main article|Primary polydipsia}}

Primary polydipsia describes excessive thirst and water intake caused in the absence of physiological stimuli to drink. This includes both [[Primary polydipsia|psychogenic primary polydipsia]] and non-psychogenic primary polydipsia, such as in patients with [[Autoimmune hepatitis|autoimmune chronic hepatitis]] with severely elevated [[globulin]] levels.<ref>{{Cite journal|last=Tobin|first=M. V.|last2=Morris|first2=A. I.|date=1988-04-01|title=Non-psychogenic primary polydipsia in autoimmune chronic active hepatitis with severe hyperglobulinaemia.|url= |journal=Gut|language=en|volume=29|issue=4|pages=548–549|doi=10.1136/gut.29.4.548|issn=1468-3288|pmid=3371724|pmc=1433532}}</ref>

Psychogenic polydipsia is an excessive water intake<ref name="pathophys" /> seen in some patients with mental illnesses such as [[schizophrenia]], or with developmental disabilities. It should be taken very seriously, as the amount of water ingested exceeds the amount that can be excreted by the kidneys,<ref name="pathophys" /> and can on rare occasions be life-threatening as the body's [[Sodium#Biological role|serum sodium]] level is diluted [[Hyponatremia|to an extent]] that seizures and cardiac arrest can occur.{{cn|date=January 2025}}

While psychogenic polydipsia is generally not found outside the population of serious mental disorders, there is some anecdotal evidence of a milder form (typically called 'habit polydipsia' or 'habit drinking') that can be found in the absence of psychosis or other mental conditions. The excessive levels of fluid intake may result in a false diagnosis of [[diabetes insipidus]], since the chronic ingestion of excessive water can produce diagnostic results that closely mimic those of mild diabetes insipidus.  As discussed in the entry on [[diabetes insipidus]], "Habit drinking (in its severest form termed psychogenic polydipsia) is the most common imitator of diabetes insipidus at all ages. While many adult cases in the medical literature are associated with mental disorders, most patients with habit polydipsia have no other detectable disease. The distinction is made during the water deprivation test, as some degree of urinary concentration above isosmolar is usually obtained before the patient becomes dehydrated."  However, prior to a water deprivation test, consideration should be given to a psychiatric consult to see whether it is possible to rule out psychogenic polydipsia or habit polydipsia.{{cn|date=January 2025}}

==Diagnosis==
Polydipsia is a symptom (evidence of a disease state), not a disease in itself. It is often accompanied by [[polyuria]] (excessive urination) and [[Hyponatremia|low sodium levels]]. Investigations directed at diagnosing [[diabetes insipidus]] and [[diabetes mellitus]] can be useful. Blood serum tests can also provide useful information about the osmolality of the body's extracellular fluids. A decrease in osmolality caused by excess water intake will decrease the serum concentration of [[hematocrit|red blood cells]], [[blood urea nitrogen]] (BUN), and sodium.<ref name="pathophys" />

==See also==
{{col div|colwidth=30em}}
* [[Adipsia]]
* [[Human homeostasis]]
* [[Polydipsia in birds]]
* [[Polyphagia]]
* [[Potomania]]
* [[Primary polydipsia]]
* [[Water intoxication]]
* [[Hyponatremia]]
* [[Diabetes insipidus]]
* [[Diabetes mellitus]]
* [[Polyuria]]
{{colend}}

==References==
{{reflist}}

== External links ==
{{Medical resources
|   ICD10       = {{ICD10|R|63|1|r|50}}
|   ICD9        = {{ICD9|783.5}}
|   MedlinePlus = 003085
}}
{{General symptoms and signs}}

[[Category:Symptoms and signs: Endocrinology, nutrition, and metabolism]]
[[Category:Thirst]]