Polidipsie

Polidipsie, also referred to as polydipsia in many languages, is a condition characterized by excessive thirst and an increase in fluid intake. It can be a normal physiological response to heat, physical activity, or dry mouth, but it may also indicate an underlying disorder affecting thirst regulation or urine concentration.

Common causes include physiological polydipsia due to dehydration or dry environments, diabetes mellitus with osmotic diuresis, and diabetes insipidus (central or nephrogenic) which impairs the kidney’s ability to concentrate urine. Psychogenic or primary polydipsia is associated with certain psychiatric conditions and can lead to excessive water drinking. Medications such as diuretics and anticholinergics, and, less commonly, chronic kidney disease or electrolyte disturbances can contribute.

Diagnosis relies on clinical history and laboratory tests. Key measurements are serum electrolytes and osmolality, urine osmolality, and glucose levels to screen for diabetes. A structured water deprivation test helps distinguish primary polydipsia from diabetes insipidus, while vasopressin/desmopressin testing can differentiate central from nephrogenic DI. Imaging or endocrine evaluation may be pursued if an underlying disorder is suspected.

Treatment targets the underlying cause. For diabetes mellitus, glycemic control is essential. Central diabetes insipidus is treated with desmopressin; nephrogenic diabetes insipidus may respond to fluid management, low-salt diet, and sometimes thiazide diuretics or other agents. Psychogenic polydipsia requires behavioral therapy and structured fluid restriction. In dehydration, rehydration with appropriate electrolytes is indicated. Monitoring is needed to prevent hyponatremia or other electrolyte disturbances.

Prognosis varies with cause; timely identification and management of the underlying condition generally improves symptoms and reduces complication risk.