What are the causes and symptoms of thyrotoxicosis (a condition characterized by hyperthyroidism)?

From the Guidelines

Thyrotoxicosis is primarily caused by thyroiditis or Graves' disease, with symptoms including weight loss, palpitations, heat intolerance, tremors, anxiety, and diarrhea, and its management depends on the underlying cause, with beta-blockers and supportive care being essential components of treatment. The condition is characterized by excess thyroid hormone in the body, leading to hypermetabolic symptoms. According to the most recent and highest quality study 1, the management of thyrotoxicosis involves:

• Checking TSH every 4-6 weeks as part of routine clinical monitoring for asymptomatic patients on immune checkpoint inhibitor therapy
• Using TSH and FT4 for case detection in symptomatic patients
• Considering TSH receptor antibody testing if there are clinical features and suspicion of Graves’ disease
• Managing symptoms with beta-blockers, such as atenolol or propranolol, and supportive care, including hydration and rest
• Holding immune checkpoint inhibitor therapy until symptoms resolve to baseline in cases of moderate to severe symptoms
• Considering endocrine consultation for unusual clinical presentations or difficulty titrating hormone therapy Some key points to consider in the management of thyrotoxicosis include:
• Thyroiditis is a self-limiting process that can lead to permanent hypothyroidism after an average of 1 month after the thyrotoxic phase and 2 months from initiation of immunotherapy 1
• Graves' disease is a rare cause of thyrotoxicosis, but it can be diagnosed by laboratory tests, including measurement of TSH receptor antibodies 1
• Radioactive iodine therapy or thyroidectomy may be considered for definitive treatment in cases of recurrence or medication intolerance
• Supportive measures, such as adequate hydration, rest, and avoiding caffeine and other stimulants, are essential components of treatment
• Severe cases presenting with thyroid storm require intensive care with higher doses of antithyroid drugs, beta-blockers, corticosteroids, and cooling measures. The symptoms of thyrotoxicosis can be masked if the patient is taking beta-blockers, and routine laboratory monitoring may show high free T4 or triiodothyronine (T3) levels, with low/normal TSH 1. Overall, the management of thyrotoxicosis requires a comprehensive approach that takes into account the underlying cause, symptoms, and potential complications, with the goal of improving morbidity, mortality, and quality of life.

From the FDA Drug Label

Thyrotoxicosis: Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism. Therefore, abrupt withdrawal of propranolol may be followed by an exacerbation of symptoms of hyperthyroidism, including thyroid storm. The causes of thyrotoxicosis are not directly stated in the label, but the symptoms that may be masked by beta-adrenergic blockade, such as those of hyperthyroidism, include:

• Thyroid storm The label does not provide a comprehensive list of causes and symptoms of thyrotoxicosis, only the potential effects of beta-adrenergic blockade on the condition 2.

From the Research

Causes of Thyrotoxicosis

• Thyrotoxicosis has multiple etiologies, including Graves' disease, toxic multinodular goiter, and toxic adenoma 3
• The most common causes of an excessive production of thyroid hormones are Graves disease, toxic multinodular goiter, and toxic adenoma 4
• Other causes of thyrotoxicosis include painless (silent) thyroiditis, and an endogenous or exogenous extrathyroidal source of thyroid hormones 4

Symptoms of Thyrotoxicosis

• The symptoms of thyrotoxicosis are not explicitly stated in the provided studies, but the studies discuss the management and treatment of the condition 3, 5, 6, 7, 4

Treatment of Thyrotoxicosis

• Treatment options for thyrotoxicosis include antithyroid medications (methimazole and propylthiouracil), radioactive iodine ablation of the thyroid gland, or surgical thyroidectomy 3, 5, 6, 7, 4
• The choice of treatment depends on the underlying diagnosis, the presence of contraindications to a particular treatment modality, the severity of hyperthyroidism, and the patient's preference 4
• In children, treatment options include antithyroid drugs, radioactive iodine, and surgery, with the choice of treatment depending on the individual case and the family's preferences 5, 6