# Moyamoya Syndrome: Differential Diagnosis in Patients With Central Nervous System Symptoms and Hyperthyroidism

## TL;DR

This paper reports a rare case of moyamoya syndrome caused by Graves' disease, highlighting the importance of considering underlying conditions during diagnosis.

## Contribution

The paper presents a novel case linking moyamoya syndrome with Graves' disease and emphasizes the need for differential diagnosis.

## Key findings

- Moyamoya syndrome was diagnosed in a patient with Graves' disease and central nervous system symptoms.
- Treating the underlying Graves' disease resolved the patient's moyamoya-related symptoms.
- The case underscores the importance of identifying primary illnesses in moyamoya syndrome diagnosis.

## Abstract

Moyamoya syndrome, known as secondary moyamoya disease, is associated with various primary illnesses, such as brain tumor, meningitis, autoimmune disease, and thyrotoxicosis, and their relations are not clear. We report a rare case of moyamoya syndrome in a patient with Graves' disease. An 18-year-old woman was admitted to our hospital due to convulsions. She had symptoms of palpitations and fatiguability for half a year and transient numbness in her left upper extremity and dysarthria for a month. In physical findings, tachycardia and diffuse thyroid swelling were noted. A blood test revealed thyrotoxicosis and antithyroid antibody, and a diagnosis of Graves' disease was obtained. Brain magnetic resonance imaging (MRI) showed bilateral internal carotid artery occlusion. We finally diagnosed the patient with moyamoya syndrome caused by Graves' disease. Moyamoya disease or syndrome can cause symptoms like a stroke, sometimes requiring neurosurgical treatment. In our case, the therapy for Graves' disease resolved the symptoms. When diagnosing moyamoya disease, it is necessary to confirm whether there are any background diseases, such as Graves' disease.