Secondary Fahr’s disease: A differential to be considered in a COVID-19 pneumonia patient with neuropsychiatric presentations

Background, aim. Fahr’s disease is a rare neurodegenerative disease caused by intracranial classifications. This case report aims to accentuate the importance of considering rare disease like Fahr’s disease as the differential diagnosis of neuropsychiatric deficits, especially in patients with a history of thyroidectomy. Case presentation. A 50-year-old female who underwent thyroidectomy 5 years previously presented with incoherent speech, behavioural problems, and hand stiffness. On evaluation, several neurobehavioral deficits and carpopedal spasms were observed, along with low Mini-Mental State Examination (MMSE), Hachinski, Activities of Daily Living (ADL), and Instrumental Activities of Daily Living Scale (IADL) score of 22, 4, 13, and 12, respectively. Clinically significant labo-ratory abnormalities include low serum calcium of 4.7 mg/dl, low thyroid stimulating hormone (TSH) level of 0.113 mIU/l, and low parathyroid hormone (PTH) level of 1.2 pg/ml. In addition, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) reverse transcription-polymerase chain reaction (RT-PCR) test showed a positive result. Meanwhile, brain computerized tomography (CT)-scan results showed multiple bilateral calcifications in the basal ganglia, bilateral corti-cal-subcortical calcifications in the frontal lobe, and subcortical calcification in the left frontal lobe. Results. The patient was diagnosed with Fahr’s disease secondary to post-thyroidectomy hypoparathyroidism and coro-navirus disease 2019 (COVID-19). The patient was treated with calcium lactate, levothyroxine, donepezil, favipiravir for COVID’s infection, vitamin B1, B6, and B12. Conclusions. Fahr’s disease should be considered in patients with neuropsychiatric deficits and spasm disorders, especially in patients with a history of thyroidectomy. Routine follow-up CT-scans after thyroidectomy are recommended.