Acute psychosis in a patient with bipolar disorder revealing primary hyperparathyroidism case report

Introduction

Primary hyperparathyroidism (PHPT) is characterized by the excessive secretion of parathyroid hormone, leading to hypercalcemia with systemic effects, including neuropsychiatric manifestations such as mood disturbances, cognitive impairment, anxiety, and psychosis. Although these symptoms are well described in the literature, their interpretation becomes challenging in patients with pre-existing psychiatric disorders, particularly bipolar disorder. This raises an important clinical question: where does hyperparathyroidism begin and where does the psychiatric disorder end? Symptoms may be misinterpreted as a primary psychiatric relapse, delaying the diagnosis and treatment of an underlying metabolic condition. The relationship between PHPT, hypercalcemia, and psychiatric symptomatology remains clinically relevant but often under-recognized, making differential diagnosis particularly difficult.

Objectives

The present work aims to describe a case of a patient with a diagnosis of bipolar disorder and multiple hospitalizations who was concomitantly diagnosed with primary hyperparathyroidism. We further analyze the evidence supporting the differential diagnosis and diagnostic challenges of acute psychosis in PHPT, particularly in patients with bipolar disorder, as well as clinical outcomes following PHPT treatment, highlighting the importance of considering medical conditions in complex psychiatric presentations.

Methods

We present a chronological case report including patient history, diagnostic findings, treatment interventions, and potential clinical outcomes. Additionally, we conducted an evidence-based review using a PubMed search, selecting the most relevant studies on this topic published in the last decade.

Results

We report a 48-year-old woman diagnosed with Bipolar Affective Disorder in 2018, with four previous psychiatric hospitalizations due to severe affective episodes with psychotic features.

During her first admission, hypercalcemia and elevated parathyroid hormone (PTH) were incidentally detected, suggesting possible PHPT; however, endocrine follow-up and treatment adherence were inconsistent. Over subsequent years, she experienced recurrent psychiatric relapses requiring hospitalization, initially without confirmed metabolic abnormalities.

In late 2024, reassessment confirmed PHPT with serum calcium 12.0 mg/dL, phosphorus 2.1 mg/dL and PTH 323.5 pg/mL. A multidisciplinary approach was initiated, including hydration, monitoring, imaging, and cinacalcet therapy. Despite recommendations, she was lost to follow-up and was re-hospitalized in 2025 with severe behavioral disorganization, confusion, hetero-aggressive behavior and acute psychotic symptoms. Laboratory evaluation revealed marked hypercalcemia (total calcium 14.2 mg/dL; corrected calcium 13.0 mg/dL) with significantly elevated PTH (819.5 pg/mL). Following psychiatric stabilization, she underwent right unilateral parathyroidectomy and was discharged three days postoperatively.

Neuropsychiatric manifestations in PHPT often improve after curative parathyroidectomy, although mechanisms linking hypercalcemia to acute psychosis remain unclear. The patient has remained clinically stable over a 6-month follow-up. However, questions remain regarding the long-term prognosis and the extent to which PHPT contributed to previous bipolar relapses.

Conclusions

This case highlights the diagnostic complexity of distinguishing primary psychiatric relapse from secondary neuropsychiatric manifestations of metabolic disorders such as PHPT. It underscores the importance of systematic medical evaluation in patients with atypical, recurrent, or treatment-resistant psychiatric presentations. Early identification and treatment of endocrine abnormalities may significantly improve clinical outcomes and reduce psychiatric morbidity. Greater awareness of the interaction between metabolic and psychiatric conditions is essential for accurate diagnosis and effective multidisciplinary management.

References

No references.