A Case of Transient Central Hypothyroidism Coinciding With Reversible Cerebral Vasoconstriction Syndrome.

Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by reversible segmental constriction and dilation of the major cerebral arteries and is typically unrelated to endocrine dysfunction. Central hypothyroidism (CH), a rare form of hypothyroidism caused by insufficient thyroid-stimulating hormone secretion from the pituitary gland, is usually associated with pituitary pathology. Here, we report a case of transient CH coinciding with RCVS, which to our knowledge has not been previously described in the literature. A 45-year-old woman presented with recurrent cerebral infarction characterized by total aphasia, right hemiplegia, and conjugate deviation. During the recurrent episode, endocrinological evaluation revealed CH with a blunted thyroid-stimulating hormone response to thyrotropin-releasing hormone stimulation, while other pituitary hormones remained normal. She was treated with levothyroxine and verapamil, leading to gradual improvement in both thyroid function and neurological deficits. Follow-up imaging demonstrated resolution of vascular stenosis, and levothyroxine was discontinued once thyroid function normalized. We hypothesize that transient vasoconstriction of small pituitary arteries, undetectable on imaging, may have contributed to reversible pituitary dysfunction. This case cautiously indicates a possible association between RCVS and CH, suggesting that endocrine evaluation would be helpful when managing patients with RCVS.