Thyroid Disorders Flash Cards
What are the four main types of thyroid disorders?
Hypothyroidism, hyperthyroidism, structural abnormalities (e.g., goiter), and thyroid tumors (benign or malignant).
What is the most common cause of hyperthyroidism?
Graves’ disease, an autoimmune disorder causing excessive thyroid hormone production.
Which thyroid disorder is associated with exophthalmos and pretibial myxedema?
Graves’ disease.
What is the most common cause of hypothyroidism worldwide?
Iodine deficiency.
What is the most common cause of hypothyroidism in iodine-sufficient areas?
Hashimoto’s thyroiditis, an autoimmune disorder.
Which thyroid hormone is more biologically active: T3 or T4?
Triiodothyronine (T3) is more biologically active than thyroxine (T4).
What is the function of thyroid hormones in metabolism?
They regulate basal metabolic rate, carbohydrate, fat, and protein metabolism.
Which structure connects the two lobes of the thyroid gland?
The isthmus.
What is the normal weight of the thyroid gland in adults?
15-25 grams.
What is a simple goiter?
A benign, non-toxic enlargement of the thyroid gland not caused by inflammation or neoplasm.
What is the most common cause of goiter worldwide?
Iodine deficiency.
What are common dietary goitrogens?
Cabbage, cassava, and certain drugs like lithium and amiodarone.
What are the two types of goiter based on iodine status?
Endemic goiter (iodine deficiency) and sporadic goiter (in iodine-sufficient populations).
What is the first-line investigation for thyroid function?
Thyroid function tests (TSH, Free T3, and Free T4).
Which thyroid disorder has a female predominance with an F:M ratio of 5:1?
Thyroid disorders in general, including hypothyroidism and hyperthyroidism.
What is the triad of Graves’ disease?
Exophthalmos, pretibial myxedema, and acropachy.
Which antibodies are commonly found in Graves’ disease?
TSH receptor antibodies (TRAb), thyroid peroxidase (TPO), and thyroglobulin (TG) antibodies.
What is the pathogenesis of Graves’ disease?
Autoantibodies stimulate the TSH receptor, leading to excess thyroid hormone production and gland enlargement.
What are the clinical signs of hyperthyroidism?
Weight loss, heat intolerance, palpitations, tremors, exophthalmos, and hyperreflexia.
What are the first-line treatment options for hyperthyroidism?
Thionamides (carbimazole, propylthiouracil), radioactive iodine, and thyroidectomy.
Which beta-blocker is commonly used for symptomatic relief in hyperthyroidism?
Propranolol.
Which medication is used to block thyroid hormone synthesis in hyperthyroidism?
Carbimazole or propylthiouracil (PTU).
What is a thyroid storm?
A life-threatening exacerbation of hyperthyroidism presenting with fever, tachycardia, hypertension, and delirium.
What is the most common cause of hypothyroidism?
Hashimoto’s thyroiditis.
What are the common symptoms of hypothyroidism?
Fatigue, weight gain, cold intolerance, bradycardia, and constipation.
What are the common signs of hypothyroidism?
Dry skin, puffy face, hoarseness, slow speech, bradycardia, and delayed deep tendon reflexes.
Which hormone is typically elevated in primary hypothyroidism?
TSH (thyroid-stimulating hormone).
What is the preferred treatment for hypothyroidism?
Levothyroxine (T4) replacement therapy.
Which laboratory test helps differentiate primary from secondary hypothyroidism?
TSH (elevated in primary hypothyroidism, low or normal in secondary hypothyroidism).
What is myxedema coma?
A severe form of hypothyroidism characterized by hypothermia, bradycardia, and altered mental status.
What is the first-line treatment for myxedema coma?
Intravenous levothyroxine and supportive care.
What is postpartum thyroiditis?
A transient thyroid disorder occurring within a year after childbirth, often presenting with hyperthyroidism followed by hypothyroidism.
What is De Quervain’s thyroiditis?
Subacute granulomatous thyroiditis, often post-viral, causing painful thyroid swelling and transient hyperthyroidism.
Which thyroiditis is commonly associated with a viral infection?
Subacute granulomatous (De Quervain’s) thyroiditis.
What is the most common type of thyroid cancer?
Papillary thyroid carcinoma.
Which thyroid cancer is associated with calcitonin secretion?
Medullary thyroid carcinoma.
Which thyroid cancer has the worst prognosis?
Anaplastic thyroid carcinoma.
What is the commonest presentation of thyroid cancer?
A painless thyroid nodule.
What is the best initial investigation for a thyroid nodule?
Fine-needle aspiration cytology (FNAC).
What is the most common cause of a solitary toxic thyroid nodule?
Toxic adenoma.
What is the mainstay treatment for thyroid cancer?
Surgery (thyroidectomy) followed by radioactive iodine therapy if needed.
Which thyroid disorder is associated with MEN 2 syndrome?
Medullary thyroid carcinoma.
What is the role of radioactive iodine in thyroid disorders?
Used to treat hyperthyroidism and ablate residual thyroid tissue in thyroid cancer.
Which thyroid hormone disorder can cause infertility?
Both hypothyroidism and hyperthyroidism.
What is the recommended daily iodine intake for adults?
150 μg per day.
What is the primary treatment for toxic multinodular goiter?
Radioactive iodine therapy or surgery.
What is the commonest thyroid disorder in pregnancy?
Hypothyroidism, often due to Hashimoto’s thyroiditis.
Which drugs can induce hypothyroidism?
Amiodarone, lithium, and interferon-alpha.
What is the most common cause of secondary hypothyroidism?
Pituitary disease leading to low TSH production.
What is the purpose of TSH suppression therapy after thyroid cancer treatment?
To prevent recurrence by suppressing residual thyroid tissue growth.
