Thyroid Storm in a Toddler Presenting as a Febrile Seizure.

Although simple febrile seizures are relatively common and benign in toddlers, it is important to rule out any underlying critical disease that necessitates further intervention and treatment. Thyroid storm, the extreme manifestation of hyperthyroidism, is relatively rare and not often considered in the differential diagnosis of a febrile seizure despite its high mortality rate. Here, we report 1 of the youngest patients with thyroid storm, who initially presented with a febrile seizure. After reevaluation, the 2-year-9-month-old patient was discovered to have thyromegaly, which led to recognition that her persistent tachycardia and widened pulse pressure were likely signs of thyrotoxicosis. Laboratory results were consistent with primary hyperthyroidism due to Graves' disease. Thyroid storm was then diagnosed on the basis of clinical features including gastrointestinal and central nervous system disturbances. Treatment with methimazole, propranolol, hydrocortisone, and Lugol's iodine solution was used. This medication regimen was safe and effective with restoration of a euthyroid state after 2 months and no recurrence of seizures. Improved awareness of hyperthyroidism and thyroid storm can lead to prompt diagnosis and treatment of this endocrine emergency, thus reducing mortality and morbidity. Pediatricians should consider this diagnosis in children with febrile seizures and suggestive vital signs and physical examination findings.