Hyperthyroidism

• Hyperthyroidism, a common endocrine disorder, is a form of thyrotoxicosis resulting from an excessive synthesis and secretion of endogenous or exogenous thyroid hormones by the thyroid
• The most common causes are Graves disease, toxic multinodular goiter, and toxic adenoma.
• Other causes include thyroiditis (inflammation of the thyroid gland) and excessive ingestion of thyroid hormone.
• Graves disease is an autoimmune disorder that results from an excessive output of thyroid hormones caused by abnormal stimulation of the thyroid gland by circulating immunoglobulins.
• Myocardial hypertrophy and heart failure may occur if the hyperthyroidism is severe and untreated.
• Treatment of hyperthyroidism is directed toward reducing thyroid hyperactivity to relieve symptoms and preventing complications.
• Radioactive iodine has been used to treat toxic adenomas, toxic multinodular goiter, and most varieties of thyrotoxicosis and is considered the treatment of choice because a single dose is effective in treating 80% to 90% of cases
• thyroid storm , a life-threatening condition manifested by cardiac arrhythmias, fever, and neurologic impairment.
• Thyroid storm (thyrotoxic crisis) is a form of severe hyperthyroidism, usually of abrupt onset.
• Propylthiouracil: Blocks synthesis of hormones (conversion of T4 to T3 ) Monitor cardiac parameters. Observe for conversion to hypothyroidism. Must be given by mouth. Watch for rash, nausea, vomiting, agranulocytosis, SLE.
• Methimazole: Inhibits synthesis of thyroid hormone More toxic than propylthiouracil. Watch for rash and other symptoms as for propylthiouracil.
• Sodium iodide: Suppresses release of thyroid hormone Given 1 h after propylthiouracil or methimazole. Watch for edema, hemorrhage, gastrointestinal upset.
• Potassium iodide: Suppresses release of thyroid hormone Discontinue for rash. Watch for signs of toxic iodinism.
• Beta-blocker (e.g., propranolol) Beta-adrenergic blocking agent Monitor cardiac status. Hold for bradycardia or decreased cardiac output. Use with caution in patients with heart failure.
• Saturated solution of potassium iodide (SSKI): Suppresses release of thyroid hormone Mix with juice or milk. Given by straw to prevent staining of teeth.
• The most common type of goiter that occurs when iodine intake is deficient is the simple or colloid goiter.
• Some thyroid glands are nodular because of areas of hyperplasia
• Lesions that are single, hard, and fixed on palpation or associated with cervical lymphadenopathy suggest malignancy.