Diagnostic Challenges in Fahr's Disease: A Rare Case of Extensive Basal Ganglia Calcifications

Fahr's disease, or primary familial brain calcification (PFBC), is a rare neurodegenerative disorder characterized by bilateral intracranial calcifications, often involving the basal ganglia, cerebellum, and subcortical white matter. Clinical manifestations may include seizures, cognitive decline, movement abnormalities, and psychiatric symptoms. Although Fahr's disease is often idiopathic with an autosomal dominant inheritance, similar imaging findings may arise from non-hereditary secondary causes such as metabolic, infectious, or toxic conditions. Identifying the underlying etiology is essential for guiding management. We present the case of a 48-year-old African-American male with a history of intellectual disability, psychiatric illness, and gait instability, who was brought to the emergency department after a witnessed generalized tonic-clonic seizure. Non-contrast computed tomography (CT) imaging of the head revealed extensive bilateral calcifications involving the basal ganglia, cerebellum, and cerebral white matter. Laboratory findings showed marked hypocalcemia, low parathyroid hormone levels, and borderline elevated phosphate. No history of prior neck surgery or known familial endocrine disorder was reported. The patient was treated with calcium and vitamin D supplementation, antiepileptic therapy, and continued psychiatric management. He was discharged to subacute rehabilitation (SAR) with plans for follow-up in neurology and endocrinology clinics. This case illustrates the diagnostic complexity of intracranial calcification syndromes. While certain clinical and imaging features raised suspicion for idiopathic Fahr's disease, the presence of metabolic abnormalities suggested a secondary etiology related to long-standing hypoparathyroidism. The absence of a definitive family history and social support, together with the chronicity of symptoms, added further ambiguity to the diagnostic picture. Whether the calcifications resulted primarily from an idiopathic process or developed in the context of longstanding, unrecognized hypoparathyroidism remains uncertain, though the latter was the leading hypothesis. A complete workup, including metabolic investigation and genetic evaluation when feasible, is critical in such cases. In patients presenting with seizures and neuropsychiatric symptoms alongside extensive intracranial calcifications, both idiopathic and secondary causes of Fahr's disease should be considered. This case highlights the importance of integrating clinical, biochemical, and imaging data to guide diagnosis and management. Early identification and treatment of modifiable factors, even when the etiology is unclear, may improve patient outcomes.