Objective. We report a case of chronic psychogenic polydipsia with intermittent moderate hyponatremia and comorbid type 2 diabetes in a 52-year-old male patient diagnosed with schizophrenia.
Case report. The patient with a 37-year history of schizophrenia was admitted with signs of psychotic exacerbation including severe auditory hallucinations and dysphoria. His symptoms were increasing over the past 2 weeks in the psychiatric residential facility where he stayed during the past 2 years. He had also a history of drinking bouts. After admission his psychotic symptoms significantly ameliorated, but between 2 and 3 week from admission he developed severe and increasing polydipsia with moderate hyponatraemia (125-130 mmol/l). The latter condition became the target of first-line treatment. Despite fluid restriction behavioral treatment methods turned out to be unsuccessful. All the relevant blood and urine tests were performed. Problems of differential diagnosis are discussed. Besides, the course and management of the patient's symptoms are outlined.
Commentary. A number of pathogenic hypotheses of polydipsia are explored in the analysis of the presented case.