Symptoms of thyroid hormone overdose
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Common Symptoms of Thyroid Hormone Overdose
Thyroid hormone overdose, often due to excessive intake of levothyroxine, can cause a range of symptoms. The most frequently reported symptoms include nervousness, tremors, palpitations, tachycardia (rapid heartbeat), diarrhea, fatigue, weight loss, and body temperature dysregulation. Some patients may also experience lethargy, orthostatic hypotension (drop in blood pressure when standing), and hyperhidrosis (excessive sweating) 1678.
Severe and Rare Manifestations
In more severe cases, especially with massive overdoses, symptoms can escalate to seizures, cardiac arrhythmias (including ventricular fibrillation), thyroid storm (a life-threatening state of extreme thyrotoxicosis), and even coma. Cardiac complications such as sinus tachycardia and, rarely, cardiac arrest have been documented. Psychiatric symptoms, including acute psychosis, anxiety, and exacerbation of underlying mental health conditions, may also occur 1567.
Symptom Variability and Delayed Onset
The onset and severity of symptoms can vary widely. Some individuals, even after ingesting large amounts of thyroid hormone, may show only mild or subtle symptoms, or may have a significant delay before symptoms appear. This variability is influenced by factors such as age, underlying health conditions, and the presence of comorbidities. Children often experience milder symptoms, while adults with complex medical histories may be at higher risk for severe outcomes 2345.
Psychiatric and Neurological Effects
Thyroid hormone overdose can worsen psychiatric symptoms, leading to hyperexcitability, mania-like states, or even suicidal ideation. Neurological effects such as seizures and acute psychosis have been reported, particularly in cases of significant overdose or in individuals with pre-existing psychiatric conditions 156.
Conclusion
Thyroid hormone overdose can present with a wide spectrum of symptoms, from mild nervousness and tremors to life-threatening cardiac and neurological complications. The severity and onset of symptoms depend on the dose ingested, patient age, and underlying health status. Prompt recognition and monitoring are essential, especially in adults and those with comorbidities, to prevent serious outcomes.
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