Moyamoya disease concurrent with Graves' disease treated by direct bypass: clinical features and treatment strategies.

BACKGROUND: Moyamoya disease (MMD) concurrent with Graves' disease (GD) is rare. There is no guideline about optimizing thyroid hormones and the appropriate timing of surgical treatment for MMD with GD.

METHODS: We encountered eight patients with MMD and GD presenting with cerebral ischemia who were treated by direct bypass. Thyroid hormones [free thyroxin (fT4) and free triiodothyronine (fT3)], thyroid-stimulating hormone (TSH), and TSH receptor antibody (TRAb) were measured sequentially. After thyrotoxic conditions were medically optimized, revascularization surgery was performed by superficial temporal artery-middle cerebral artery (STA-MCA) double bypass in all cases. Clinical outcomes were estimated by modified Rankin scale (mRS) at discharge and 3 months after surgery.

RESULTS: In six patients with thyrotoxicosis, the fT4, fT3, and TRAb (range) at the onset of cerebral ischemia were 4.81-10.30 pg/ml, 13.08-31.90 pg/ml, and 3.5-83.8 IU/l, respectively. At surgery, mean (range) fT3 and fT4 were optimized to 3.02 (1.01-4.87) pg/ml and 1.09 (0.41-1.68) ng/dl, respectively. In the thyrotoxic cases, it took 70-310 days (mean, 142 days) to optimize thyroid hormones before surgery. There was no neurological aggravation after surgery, and outcome was excellent at 3 months with mRS scores ≤2 in all cases.

CONCLUSIONS: For MMD concurrent with GD, optimizing thyroid hormones followed by STA-MCA double bypass was successful to prevent cerebral ischemic events.