Psychogenic polydipsia is commonly encountered in patients with psychiatric disorders, particularly in those with schizophrenia.
Patients present with water-seeking and excessive drinking, sometimes accompanied by hyponatremia and water intoxication.
Neuropsychiatric manifestations of hyponatremia include headache, nausea, cramping, hyporeflexia, dysarthric speech, lethargy, confusion, seizures, and delirium. Coma and sudden death can ensue.
Complications of psychogenic polydipsia include incontinence and enuresis, bladder dilation and hydronephrosis, renal and congestive heart failure, and osteoporosis and associated pathologic fractures.
Diagnosis is one of exclusion. Other medical causes of polydipsia, polyuria, and/or hyponatremia need to be ruled out.
Management includes fluid restriction and behavioral and pharmacologic therapy. Serum sodium should be vigilantly and frequently monitored, with judicious use of hypertonic saline to treat symptomatic or severe hyponatremia.
Polydipsia is excessive or abnormal thirst, accompanied by intake of excessive quantities of water or fluid. Psychogenic polydipsia (PPD), also known as primary polydipsia, is characterized by excessive volitional water intake and is often seen in patients with psychiatric disorders and/or neurodevelopmental disorders. There may be no physical effects, but hyponatremia can occur.
History and exam
Key diagnostic factors
- medical history of psychiatric disorder or neurodevelopmental disorder
- water-seeking and drinking
Other diagnostic factors
- nausea or vomiting
- lethargy or confusion
- seizures, delirium, or coma
- psychiatric disorders
- neurodevelopmental disorders
1st investigations to order
- plasma osmolality
- urine osmolality
- urine sodium
- serum sodium
- 24-hour urine volume
- serum BUN
- water restriction test
Investigations to consider
- vasopressin test
- plasma antidiuretic hormone
severe hyponatremia (<125 mEq/L) or with neurologic symptoms
hyponatremia (125-130 mEq/L) or with GI symptoms
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