Levothyroxine poisoning in children: a multicenter study from Türkiye

This study aimed to investigate the clinical features, laboratory findings, treatment approaches, and follow-up strategies employed in the management of pediatric patients with levothyroxine poisoning.

This multicenter retrospective study included patients aged ≤18 years who presented with acute, single-episode levothyroxine ingestion to the pediatric emergency departments of six tertiary care centers between 2010 and 2023. Clinical data, laboratory findings, symptom onset and severity, and treatment modalities were extracted from medical records. Thyroid function tests (TFTs) were interpreted according to the age-specific reference ranges of each center. Treatment decisions, including gastric decontamination and pharmacologic therapy, were evaluated based on documented clinical indications.

A total of 45 patients were included in the study. The median age was 3.83 years (interquartile range [IQR]: 2.2-6.1). Levothyroxine ingestion was accidental in 80% (n = 36) of cases and intentional (suicidal) in 20% (n = 9). The median ages for accidental and suicidal ingestions were 3.0 years (IQR: 2.0-4.2) and 15.0 years (IQR: 13.7-16.9), respectively (p < 0.001). The median total ingested levothyroxine dose was 500 μg (IQR: 212.5-1112.5). Symptoms were reported in 33.3% (n = 15) of patients, with tachycardia being the most common (100%, n = 15), followed by hypertension (26.7%, n = 4) and agitation (20.0%, n = 3). The median levothyroxine dose among symptomatic patients was 1100 μg (IQR: 450-2250), significantly higher than that of asymptomatic patients 312.5 μg (IQR: 187.5-750) (p = 0.003). TFTs were abnormal in 51.1% (n = 23) of patients. Treatment was initiated in 55.6% (n = 25) of patients; activated charcoal was administered to 51.1% (n = 23), and gastric lavage to 26.7% (n = 12). Among the three patients with moderate symptoms, one received propranolol, methimazole, and corticosteroids, whereas the other two were treated with propranolol alone. An asymptomatic patient with markedly abnormal TFTs received corticosteroids. No fatal outcomes were reported.

Levothyroxine poisoning in children is generally asymptomatic. When symptoms do occur, they are typically mild to moderate in severity, and the overall prognosis is favorable.