Basal Ganglia Calcification With Treatment-Resistant Hypocalcaemia and Persistent Psychosis in an 18-Year-Old: A Case Report.

Basal ganglia calcification (BGC) in young adults represents a pathological finding requiring systematic investigation, contrasting with incidental age-related calcification in elderly populations. We report an 18-year-old male patient who presented to the emergency department with a first episode of generalized tonic-clonic seizure with subsequent imaging revealing extensive bilateral BGC involving the basal ganglia, thalami, and cerebellum. His inpatient stay was complicated by treatment-resistant hypocalcaemia. A retrospective review revealed that hypocalcaemia had been documented eight months prior to this presentation. The patient had been suffering from new-onset psychotic symptoms beginning 12 months prior, which were poorly responsive to multiple antipsychotics and had initially been managed as primary functional psychosis. This presentation suggested that the neurological, psychiatric, and metabolic presentations are organically interlinked. Comprehensive screening for autoimmune encephalitis and infectious aetiologies was negative, with genetic testing for pseudohypoparathyroidism currently ongoing. Pseudohypoparathyroidism emerges as the leading hypothesis based on treatment-resistant hypocalcaemia, elevated parathyroid hormone (PTH) levels, and extensive calcification. The temporal sequence, psychosis (12 months) → documented hypocalcaemia (eight months) → seizure, suggests that long-standing calcium dysregulation and progressive BGC may have contributed to the psychiatric presentation, ultimately manifesting as seizure. This case demonstrates that investigating treatment-resistant psychiatric symptoms for organic causes and recognizing BGC in young patients as pathological red flags may facilitate earlier diagnosis before acute neurological complications.