Thyrotoxic periodic paralysis (TPP) is an uncommon but potentially life-threatening complication of hyperthyroidism characterized by sudden, reversible muscle weakness due to an intracellular potassium shift. While hypokalemia is a typical feature, normokalemic presentations are exceedingly rare. We report a 46-year-old Hispanic woman with poorly controlled hyperthyroidism who presented with acute bilateral lower-extremity weakness and areflexia. The initial potassium level was within the normal range. The patient was clinically and biochemically thyrotoxic. She was treated with methimazole, dexamethasone, propranolol, lisinopril, and cautious electrolyte replacement, resulting in progressive improvement and complete recovery of motor strength. Although TPP predominantly affects Asian males, this case illustrates that it can occur in other ethnicities and in females. Acute flaccid paralysis in hyperthyroid patients, even with normal serum potassium, should prompt suspicion for TPP to avoid unnecessary neurologic workups and delays in therapy. Early recognition and prompt administration of β-blockers and antithyroid therapy are critical to prevent complications and recurrence.
Vincent et al. (Sat,) studied this question.