Abstract
The phenomenon of psychogenic polydipsia appears to have received little attention in the last two decades after a period of intense scrutiny. The reduced focus appears to have resulted in lower recognition of the condition in everyday psychiatric practice. We discuss a case of increased water consumption on a background of acute psychotic exacerbation to re-emphasize the importance of recognizing this relatively common phenomenon in day-to-day psychiatric practice. Psychogenic polydipsia with resulting hyponatraemia and concurrent mental state changes can have serious implications unless diagnosed early by the vigilant clinician.
A 42 year old female accountant with a long history of bipolar affective disorder (BPAD), presented to hospital with a psychotic manic relapse. The current relapse had been precipitated in the context of work stressors and non-compliance with medication. This presentation was characterized by paranoid delusions, increased pressure of speech, energy and libido with decreased requirement for sleep. The family reported an increase in water intake amounting to several litres a day since the onset of psychosis. At admission, her serum sodium level was 123 mmol/L. Serum and urine osmolality were consistent with dilutional hyponatraemia. Dilutional anaemia was additionally diagnosed with a haemoglobin of 108 g/L. Management involved the antipsychotic Olanzapine (10 mg/day), PRN Lorazepam (6 mg/day) for management of agitation, and fluid restriction (2 L/day). She also received oral supplementation with sodium chloride tablets. She did not require hypertonic saline infusion. Over the subsequent 8 days her serum sodium returned to 137 mmol/L, her haemoglobin was 128 g/L and her manic psychosis abated significantly. She was transferred to an open psychiatric unit where she no longer required close monitoring of her fluid intake and was discharged a week later. She continues to maintain improvement at 8 month follow up.
This patient has several characteristics typical of a patient with polydipsia, intermittent hyponatraemia and psychosis syndrome. Women are more commonly affected representing 60-80% of all patients [1]. Affective symptoms, exacerbation of psychosis, higher IQ scores, paranoia, good response to neuroleptic medication and less emotional deterioration being other characteristic features [2].
Epidemiological studies indicate that the prevalence of polydipsia ranges between 6–17% amongst chronically ill psychiatric patients [2]. Prevalence amongst acutely unwell patients with psychosis is less well documented. Amongst patients with polydipsia and psychosis the frequency of hyponatraemia ranges between 3.7–63.2% [3]. These rates, however, do not appear to be reflected in everyday psychiatric practice. This could possibly be because most patients with symptomatic hyponatraemia and polydipsia are likely to be treated in medical wards as opposed to acute psychiatric units. We suspect that lack of familiarity may have contributed to decreased pick up rates. In this unit itself, following an educational session on polydipsia, recognition of polydipsic symptoms increased. We also wonder whether the ready availability of beverages (e.g. cordial, carbonated drinks and coffee) on acute inpatient units masks the hyponatraemia that might otherwise accompany the copious consumption of water.
The etiology of polydipsia in psychosis still remains controversial with both psychological and pathophysiological processes implicated in its genesis [3]. However the complications of hyponatraemia can be life threatening, ranging from headaches and blurred vision to seizures, cerebral oedema, renal failure or congestive heart failure [4]. One article postulates that 18% of the deaths of schizophrenic patients under the age of 53 may be related to water intoxication [5]. Even more common and less severe symptoms such as confusion, lethargy and psychosis may be misconstrued as new or altered psychiatric symptoms, and therefore go without proper treatment.
The discussion of this case emphasizes the importance of recognizing this potentially life threatening problem. We also wonder whether changes in the cultural milieu of psychiatric wards with the increased availability of beverages other than water masks this condition to some extent. Nevertheless, psychogenic polydipsia and the consequent hyponatraemia are as worthy today of recognition and treatment as they have been in the past.