Psychogenic polydipsia--an unusual cause of hyponatremic coma and seizure

Polydipsia in the chronically mentally ill: a review

Polydipsia, or excessive intake of water, is reviewed in the chronically mentally ill from a nursing perspective. The purpose of this article is to review research related to excessive water ingestion, the magnitude and types of problems that these patients experience, and the treatment interventions reported. Future research and practice should focus on understanding the patient's experience of polydipsia and how it relates to the patient's level of functioning, testing assessment tools, and determining appropriate interventions.

Long-term neurologic outcome in psychogenic water drinkers with severe symptomatic hyponatremia: the effect of rapid correction

PURPOSE

The purpose of our study was to ascertain the safety of rapidly correcting acute symptomatic hyponatremia in psychogenic water drinkers, particularly in regard to any delayed adverse neurologic sequelae.

PATIENTS AND METHODS

We reviewed the medical records of all known psychogenic water drinkers (34) in our hospital from 1977 to 1989. Using seizure as a marker of severity, we identified 13 patients having a total of 27 episodes associated with severe hyponatremia. We evaluated the charts of those patients in detail to assess the mode of treatment, rate of correction, and long-term neurologic outcome. None of the patients experienced respiratory arrest before treatment, which was initiated within 2 hours of seizure.

RESULTS

For all 27 episodes, the initial serum sodium level (mean +/- SE) was 110.9 +/- 1.2 mmol/L, and the rate of correction (mean +/- SE) was 1.65 +/- 0.2 mmol/L/hour. All but one episode were corrected "rapidly" (initial correction rate of 0.7 or more mmol/L/hour) to 120 to 130 mmol/L within 12 hours. The absolute change in the serum sodium level was 15.1 +/- 1.2 mmol/L in 12 hours, 21.6 +/- 1.4 mmol/L in 24 hours, and 25.9 +/- 1.4 mmol/L in 48 hours. In no instance did therapy induce hypernatremia. All patients recovered immediately after treatment. There was no clinical or radiologic evidence of adverse neurologic sequelae immediately after treatment or after 6 years of follow-up.

CONCLUSION

In this series of male psychogenic water drinkers, early "rapid" correction of acute symptomatic hyponatremia by raising the serum sodium level 15 mmol/L in 12 hours while maintaining an absolute change in the serum sodium level of 26 mmol/L within 48 hours produced no long-term neurologic sequelae.

Diurnal variation of urinary excretion for patients with psychosis, intermittent hyponatremia, and polydipsia (PIP syndrome)

Ten patients [8 men and 2 women, mean age (SD) 37.6 +/- 6.5 years] with psychosis, intermittent hyponatremia, and polydipsia (PIP syndrome) underwent serial determinations at 6:00 AM, 12 noon, 6:00 PM, and 12 midnight of levels of urinary creatinine concentration (UCR), urinary specific gravity (SPGR), and urinary osmolality (UOSM) on 8 consecutive Thursdays. Diurnal variation (p less than 0.015) was present in the case of each parameter of urinary excretion (UCR, SPGR, and UOSM). These three parameters remained very low throughout the day (mean UCR 19.0 mg/dl, mean SPGR 1.0033, and mean UOSM 112.6 mosmol/kg), which is consistent with severe and persistent hyposthenuria, and each parameter correlated well with the other two parameters (r between 0.78 and 0.93, p less than 0.001). The 6:00 PM (UC6PM) value for UCR correlated best with the daily mean UCR (UCM), providing the simple linear regression UCM = 0.7615 X UC6PM + 6.1503 (r = 0.912, p = 0.0005) for the 10 PIP patients. Twenty-four-hour urinary volume (24UV) could then be estimated using UCM and values of 17.5 and 12.5 mg creatinine/kg body weight for male and female PIP patients, respectively, to calculate the daily urinary excretion of urinary creatinine. The group mean 24UV was 6963 ml, with a range of 4934-9884 ml. We hope that information about the diurnal variation of urinary excretion (21.6%, 20.5%, 27.4%, and 30.4% of 24UV excreted in consecutive quartiles commencing with the 12 midnight to 6:00 AM quartile), coupled with the utilization of the equation UCM = 0.7615 X UC6PM + 6.1503 (r = 0.912, p = 0.0005) to estimate UCM as an index of 24UV in the PIP syndrome, will provide tools to better elucidate the relationship between psychosis and water dysregulation.

Psychogenic polydipsia and water intoxication--concepts that have failed

Ten patients (8 men, 2 women; mean age 38.7 +/- 8.1 years), 7 of whom had schizophrenic disorders and 3 of whom had bipolar disorder (manic-depressive illness), manifested psychosis, intermittent hyponatremia, and polydipsia (PIP syndrome). The relationship between serum sodium and urinary water excretion among the 10 PIP patients is described in detail. The success of lithium in improving serum sodium levels and in decreasing urinary water excretion among the three PIP patients with bipolar disorder and the failure of changes in urinary water excretion to explain changes in serum sodium levels among the 10 PIP patients argue against "psychogenesis" as the explanation for the polydipsia and excessive water intake as the sole explanation for hyponatremia or complications ascribed to water intoxication.