Polydipsia R63.1

The word polydipsia is derived from the Greek and literally means "much thirsty/many thirst". In medicine, polydipsia refers to pathologically increased thirst. It can be caused by both organic and psychogenic disease patterns. Due to the resulting increase in drinking, polydipsia is often accompanied by polyuria (increased urination). Polydipsia can have harmless causes, but it can also be an expression of a potentially life-threatening disease, so that it should be taken seriously in any case.

Possible underlying conditions include:

• Primary polydipsia
• Psychogenic diseases
• Diabetes mellitus
• Diabetes insipidus
• Psychogenic diseases
• Diseases of the parathyroid gland
• Cushing's syndrome
• Liver, thyroid or kidney diseases
• Increased alcohol consumption or alcohol-related diseases
• Pharmacological side effects (e.g. taking diuretics)
• Rather short-term polydipsia: infections, fever, diarrhoeal diseases

The diagnosis depends on the underlying suspicion of the corresponding underlying diseases.

Basically, however, urine examination and the taking of various laboratory parameters are obligatory (e.g. blood glucose, HbA1c, electrolytes, plasma osmolality). For differentiation, the so-called thirst test is available, which can distinguish very precisely between psychogenic and organic causes as well as between central and renal diabetes insipidus. A further differentiation is made by means of the ADH test. Imaging procedures can also be used depending on the underlying condition (e.g. exclusion of a brain tumour).

An important and potentially life-threatening hazard is dehydration (drying out) and increased electrolyte loss with resulting electrolyte disorders.

Therapeutic treatment depending on the underlying disease.

1. Herold G et al (2018) Internal Medicine, Herold Verlag, pp. 581, 584, 588, 620, 631, 641, 729, 745, 771, 772, 803, 804