Thyrotoxicosis Flashcards
What is thyrotoxicosis?
Thyrotoxicosis refers to the clinical syndrome caused by excess circulating thyroid hormones, regardless of the cause.
What is hyperthyroidism?
Hyperthyroidism is a specific cause of thyrotoxicosis due to excessive thyroid hormone production by the thyroid gland.
What are the common symptoms of thyrotoxicosis?
Weight loss, heat intolerance, palpitations, tremor, increased appetite, sweating, anxiety, and diarrhoea.
What are the common signs of thyrotoxicosis on examination?
Tachycardia, goitre, tremor, warm moist skin, lid lag, and exophthalmos (in Graves’ disease).
What are the common causes of thyrotoxicosis?
Graves’ disease, toxic multinodular goitre, toxic adenoma, and thyroiditis.
What is the most common cause of hyperthyroidism?
Graves’ disease is the most common cause of hyperthyroidism.
What is the pathophysiology of Graves’ disease?
Graves’ disease is an autoimmune condition where thyroid-stimulating antibodies stimulate TSH receptors, leading to increased thyroid hormone production.
What is the pathophysiology of toxic multinodular goitre?
Autonomous hyperfunctioning nodules in the thyroid gland produce excessive thyroid hormones, independent of TSH regulation.
What is the typical age of onset for Graves’ disease?
Graves’ disease commonly affects women aged 20-40 years.
What are the risk factors for hyperthyroidism?
Female sex, family history of thyroid disorders, autoimmune diseases, and iodine excess.
What are the characteristic eye signs in Graves’ disease?
Exophthalmos, lid lag, lid retraction, and conjunctival injection.
What are the features of thyroid storm (thyrotoxic crisis)?
Fever, tachycardia, hypertension, agitation, confusion, and multi-organ dysfunction.
What investigations are used to diagnose thyrotoxicosis?
TFTs (low TSH, high free T4 and/or T3), thyroid antibodies, and imaging such as thyroid ultrasound or radioisotope scanning.
What is the role of thyroid-stimulating hormone receptor antibodies (TRAb)?
TRAb is a specific marker for Graves’ disease and helps differentiate it from other causes of thyrotoxicosis.
What are the typical TFT findings in primary hyperthyroidism?
Low TSH and high free T4 and/or free T3 levels.
What is the role of thyroid ultrasound in thyrotoxicosis?
It helps identify structural abnormalities like nodules and assess for increased vascularity seen in Graves’ disease.
What is the first-line treatment for Graves’ disease?
Anti-thyroid drugs, such as carbimazole or propylthiouracil, are typically used as the first-line treatment.
What are the treatment options for hyperthyroidism?
Treatment options include anti-thyroid drugs, radioactive iodine therapy, and thyroidectomy.
What is the mechanism of action of anti-thyroid drugs like carbimazole?
They inhibit thyroid hormone synthesis by blocking the enzyme thyroid peroxidase.
When is radioactive iodine therapy indicated in hyperthyroidism?
It is indicated in cases of recurrent Graves’ disease, toxic multinodular goitre, or toxic adenoma.
What are the complications of untreated hyperthyroidism?
Complications include atrial fibrillation, heart failure, osteoporosis, and thyroid storm.
How is thyroid storm managed?
Management includes high-dose beta-blockers, anti-thyroid drugs, glucocorticoids, and supportive care in an intensive care setting.
What are the side effects of carbimazole?
Side effects include rash, agranulocytosis, and hepatotoxicity.
What are the long-term risks of radioactive iodine therapy?
Long-term risks include hypothyroidism and, rarely, radiation-induced thyroiditis or cancer.
What is the role of thyroidectomy in hyperthyroidism?
Thyroidectomy is indicated for large goitres, suspicion of malignancy, or in patients unresponsive to other treatments.
