What is the management for a patient with suspected thyrotoxicosis or severe hypothyroidism due to excessive thyroid hormone intake?

From the Guidelines

Management of suspected thyrotoxicosis or severe hypothyroidism due to excessive thyroid hormone intake requires immediate discontinuation of the thyroid hormone medication and supportive care based on symptom severity. For thyrotoxicosis (thyroid hormone overdose), beta-blockers such as propranolol (20-40mg every 6 hours) should be administered to control sympathetic symptoms like tachycardia, tremors, and anxiety, as supported by the American Association of Clinical Endocrinologists Medical Guidelines for the Evaluation and Treatment of Hyperthyroidism and Hypothyroidism 1. In severe cases, hospitalization may be necessary with IV fluids, cooling measures for hyperthermia, and cardiac monitoring. For patients with underlying cardiac conditions, cardioselective beta-blockers like metoprolol may be preferred. After stopping the excessive thyroid hormone, symptoms typically improve within days to weeks as the exogenous hormone is cleared from the body. TSH and free T4 levels should be monitored until normalized, with the frequency of monitoring depending on the severity of symptoms and the presence of underlying conditions, as outlined in the management of immune-related adverse events in patients treated with immune checkpoint inhibitor therapy: ASCO guideline update 1. The underlying reason for excessive intake should be addressed, whether it was accidental overdose, intentional misuse, or inappropriate prescribing. Patient education about proper medication dosing and the dangers of thyroid hormone misuse is essential to prevent recurrence. Recovery time depends on the half-life of the specific thyroid preparation taken and the duration of excessive intake, with levothyroxine (T4) having a longer half-life (7 days) than liothyronine (T3) (1 day). Key considerations in management include:

• Discontinuation of excessive thyroid hormone intake
• Symptomatic relief with beta-blockers
• Monitoring of TSH and free T4 levels
• Addressing the underlying cause of excessive intake
• Patient education to prevent recurrence
• Consideration of hospitalization in severe cases.

From the FDA Drug Label

The signs and symptoms of overdosage are those of hyperthyroidism [see Warnings and Precautions (5)and Adverse Reactions (6)] . In addition, confusion and disorientation may occur Cerebral embolism, shock, coma, and death have been reported. Seizures occurred in a 3-year-old child ingesting 3. 6 mg of levothyroxine. Symptoms may not necessarily be evident or may not appear until several days after ingestion of levothyroxine sodium. Reduce the levothyroxine sodium dosage or discontinue temporarily if signs or symptoms of overdosage occur. Initiate appropriate supportive treatment as dictated by the patient’s medical status

For a patient with suspected thyrotoxicosis or severe hypothyroidism due to excessive thyroid hormone intake, the management involves:

• Reducing the levothyroxine sodium dosage or discontinuing it temporarily if signs or symptoms of overdosage occur.
• Initiating appropriate supportive treatment as dictated by the patient’s medical status.
• Contacting the National Poison Control Center at 1-800-222-1222 or www.poison.org for current information on the management of poisoning or overdosage. It is crucial to monitor the patient closely and adjust the treatment plan accordingly to prevent further complications 2.

From the Research

Management of Thyrotoxicosis or Severe Hypothyroidism

The management of a patient with suspected thyrotoxicosis or severe hypothyroidism due to excessive thyroid hormone intake involves several key considerations:

• Diagnosis: Accurate diagnosis is crucial, and thyroid function testing, thyroid antibody testing, and radioactive iodine uptake imaging may be necessary to determine the underlying cause of the condition 3.
• Treatment of Hyperthyroidism: Treatment options for hyperthyroidism include antithyroid medications (methimazole and propylthiouracil), radioactive iodine ablation of the thyroid gland, or surgical thyroidectomy 4.
• Treatment of Hypothyroidism: For hypothyroidism, treatment typically involves replacement therapy with levothyroxine, and in cases of pseudomalabsorption, supervised once weekly levothyroxine treatment may be necessary 5.
• Thyroid Emergencies: In severe cases, thyroid-related emergencies such as thyrotoxic storm or hypothyroid coma may require intensive care unit (ICU) admission and treatment with beta-blockers, thyrostatics, and glucocorticoids 6.
• Beta-Blockers: Beta-blockers, such as propranolol, can be used to control symptoms of hyperthyroidism, including nervousness, tremor, and tachycardia, and may also reduce circulating tri-iodothyronine (T3) concentration 7.

Special Considerations

• Conversion of Hypothyroidism to Hyperthyroidism: In some cases, patients with hypothyroidism may develop hyperthyroidism, and recognition of this phenomenon is crucial for prompt diagnosis and treatment 3.
• Pseudomalabsorption: Pseudomalabsorption of levothyroxine can occur in patients with hypothyroidism, and diagnosis can be demonstrated by an oral levothyroxine test, with treatment involving supervised once weekly levothyroxine administration 5.