Fahr's Syndrome Misdiagnosed As Delusional Disorder: A Case Report.

Fahr's disease is a rare neurological disorder that is characterized by bilateral basal ganglia calcification. In the present study, a 49-year-old male patient presented with delusional beliefs. He had normal neurologic examination. Follow-up mental status examination and clinical findings revealed delusional disorder. After three weeks, the patient presented to the clinic with postural tremor in the hands, and gait difficulties. A cranial CT scan showed that he had bilateral basal ganglia, thalamus, and centrum semiovale calcifications. The case illustrates the importance of considering organic etiologies before diagnosing a patient, particularly one who has late-onset presentation of psychosis.