Acute Psychosis Related to Primary Hyperparathyroidism in a Patient With Bipolar Disorder

Primary hyperparathyroidism (PHPT) can cause hypercalcemia secondary to high parathyroid hormone secretion. Hyperparathyroidism- and hypercalcemia-related acute psychotic symptoms can be challenging to diagnose in patients with mental health-related disorders, and it should be considered a possible differential in these patients besides medications. It can sometimes be the first manifestation of the disease, and diagnosis can be challenging, especially in patients with a previous psychiatric history without checking their biochemistry profile. The hypercalcemia severity can vary from mild to severe, and signs and symptoms may also vary depending on the calcium levels. Hypercalcemia can cause neuropsychiatric dysfunction, and patients may present with confusion, agitation, delusions, and hallucinations. We present a case of a 54-year-old patient with a previous history of bipolar disorder and a recent diagnosis of depression and schizophreniform disorder, who presented to the emergency department with acute agitation, violent behavior, and disorientation. She was being managed by the community mental health team at a local behavioral health hospital for new onset psychosis over the past few months. She was refusing blood tests prior to hospital admission. Calcium level on laboratory tests was 3.54 mmol/l, and parathyroid hormone level was 45 pg/ml. She was managed with intravenous fluids initially, followed by zoledronic acid (4 mg intravenously over 15 minutes). She was then commenced on cinacalcet 30 mg twice daily initially, which was later increased to 60 mg twice daily. Ultrasound of the neck demonstrated a large left parathyroid mass, and she underwent left parathyroidectomy as an urgent outpatient. She has remained asymptomatic, and her psychiatry symptoms resolved following parathyroidectomy.