Reversible Facial Congestion After Elevation of Both Arms

Reversible facial congestion after elevation of both arms

A 77-year-old man was referred to the endocrinology clinic for evaluation of subclinical hyperthyroidism. Physical examination revealed an enlarged thyroid with no palpable nodules or cervical lymphadenopathy. When the patient raised both arms, he developed reversible facial congestion.

What is the name of this sign and what’s the diagnosis?