Hyponatremia Presenting with Recurrent Mania

Primary psychogenic polydipsia (PPD) is a chronic, relapsing condition in which there is a disturbance in thirst control primarily due to an underlying disorder such as a psychogenic condition. It is characterized by an increase of fluid intake along with excretion of excessive amounts of dilute urine exceeding 40 to 50 mL/kg of body weight. PPD is typically seen in patients with schizophrenic symptoms due to elevated levels of dopamine that stimulate the thirst center or in patients with a psychiatric history receiving anticholinergic drugs. There are many reported cases of PPD related to an underlying schizophrenia disorder, but rarely is PPD seen in bipolar patients. We herein report a case of recurrent mania in a patient from a community hospital, who presented with chronic hyponatremia due to PPD. The patient had a history of bipolar disorder type 1 and was admitted to the hospital four times within three weeks with hyponatremia and presenting symptoms of mood lability, psychomotor agitation, pressured speech, racing thoughts, sleeping disturbances, distractibility, and inflated self-esteem. These were the same circumstances and manic presentation in her subsequent medical admissions. Due to her repeat manic presentation and consistently low sodium levels, we believe that her manic symptoms were a result of hyponatremia due to PPD. This patient serves as a unique case wherein switching medications and treating with oral sodium chloride did not prevent the manic episodes as she continues to become hyponatremic secondary to PPD. Due to the difficulty in managing and diagnosing a patient like this, case studies are helpful in studying treatment and maintenance for future cases.