Related Experiment Video
Updated: Aug 14, 2026

Electromagnetic Source Imaging in Presurgical Evaluation of Children with Drug-Resistant Epilepsy
Published on: September 20, 2024
Seizure in a child after an acute ingestion of levothyroxine
Ben T Tsutaoka1, Susan Kim, Stephen Santucci
1California Poison Control System, San Francisco Division, University of California, 94143-1369, USA. btsutaoka@calpoison.org
Background:
Unintentional ingestion of thyroid hormone preparations is a common occurrence reported to poison control centers. These incidents rarely result in serious outcomes. We report a case of a tonic-clonic seizure occurring in a child after ingestion of a maximum of 3.6 mg of levothyroxine.
Case Report:
A 3.5-year-old boy ingested up to 41 tablets of 88 microg levothyroxine, which was not discovered until the following day. On the third day after the ingestion, he had a single 5- to 10-minute tonic-clonic seizure. Laboratory results were total thyroxine greater than 24.0 microg/dL; free thyroxine, 5.5 ng/dL; and thyroid-stimulating hormone, 0.03 mU/L. On the following day, the patient had diarrhea and was hyperactive; heart rate was 144 beats per minute, and mild hyperreflexia was noted on neurological examination. Symptoms were resolved 3 days later.
Conclusion:
This is the second case report of a seizure occurring in a child after an unintentional ingestion of levothyroxine. The maximum amount possibly ingested is much lower than that previously reported. Pediatric ingestion of less than 5 mg of levothyroxine may result in serious outcomes.
Related Concept Videos
Seizures l: Introduction
Seizures: Classification
Seizures are typically classified into two main categories: focal and generalized seizures.
Focal Seizures
Focal seizures originate from specific regions of the brain. These seizures are further sub-classified into two types:
Graves Disease II: Pathophysiology
Epilepsy and Seizures: Overview
Various factors can trigger epilepsy, including genetic factors, brain damage, metabolic causes, and unknown etiology. Diagnosis of epilepsy involves electroencephalography (EEG), which...
Goiter
Antiepileptic Drugs: Modulators of Neurotransmitter Release Mediated by SV2A Protein
SV2A is a transmembrane glycoprotein located predominantly in the brain, modulating the release of neurotransmitters for neuronal communication. Both levetiracetam and brivaracetam exhibit a high affinity for...

