Abstract
A 19-year-old Caucasian male presented acutely describing several episodes of profound paralysis. At the time of admission he had recovered completely and his neurological examination and routine biochemistry were normal. A diagnosis of thyrotoxic periodic paralysis was made after the thyroid function tests returned confirming hyperthyroidism. He was given β blockers and received a block and replacement regime before proceeding on to radioactive iodine therapy. He suffered a relapse of hyperthyroidism and paralysis following the radioiodine and required carbimazole for a short time before becoming permanently hypothyroid. Euthyroidism is now maintained with thyroxine replacement therapy and he has had no further episodes of paralysis.