Background: Fahr's syndrome (or Fahr's disease) is a rare, neurological disorder characterized by bilateral calcification in the cerebellum, thalamus, basal ganglia, and cerebral cortex as a result of calcium and phosphorus metabolism disorder. The patients may be asymptomatic and clinical symptoms represent a wide range of neurologic manifestations and nonspecific neuropsychiatric disorders. We report an unusual case of Fahr's syndrome which was asymptomatic and incidentally diagnosed by generalized tonic-clonic seizure in a patient with SARS-CoV-2 (COVİD-19) pneumonia.

Case presentation: The patient was a 68-year-old female and admitted to our emergency department suffering from cough and fatigue. After thorax computed tomography (CT) and SARS-CoV-2 PCR test, she was diagnosed as COVID-19 pneumonia. In the intensive care unit, the patient had a tonic-clonic convulsion starting from the left arm and spreading to the whole body. Fahr's syndrome was diagnosed after a cranial CT scan and blood metabolic panel test.

Conclusions: As a result of the clinical, radiological, and biochemical evaluations, the patient was diagnosed incidentally as Fahr's syndrome associated with hypoparathyroidism. Seizures could be induced by hydroxychloroquine that was in the COVID-19 treatment or the inflammation caused by COVID-19 pneumonia. The association between the mortality of COVID-19 pneumonia and Fahr's syndrome is unknown which needs further research.

Keywords: (SARS-CoV-2) COVID-19 disease; Fahr’s syndrome; Hypoparathyroidism.