Hyperthyroidism Flashcards
What is hyperthyroidism?
Hyperthyroidism is the over-production of thyroid hormones (T3 and T4) by the thyroid gland.
What is thyrotoxicosis?
Thyrotoxicosis refers to the effects of an abnormal and excessive quantity of thyroid hormones in the body.
What is primary hyperthyroidism?
Primary hyperthyroidism is due to thyroid pathology, where the thyroid gland produces excessive thyroid hormone.
What is secondary hyperthyroidism?
Secondary hyperthyroidism is caused by pathology in the hypothalamus or pituitary, where the pituitary gland produces too much TSH, stimulating the thyroid to overproduce thyroid hormones.
What is subclinical hyperthyroidism?
Subclinical hyperthyroidism occurs when T3 and T4 levels are normal, but TSH is suppressed (low), often with mild or no symptoms.
What is Graves’ disease?
Graves’ disease is an autoimmune condition where TSH receptor antibodies cause primary hyperthyroidism by stimulating the TSH receptors on the thyroid.
What is toxic multinodular goitre?
Toxic multinodular goitre (Plummer’s disease) is a condition where nodules on the thyroid gland autonomously produce excessive thyroid hormones, often in individuals over 50 years old.
What is exophthalmos?
Exophthalmos (proptosis) is the bulging of the eyes, commonly associated with Graves’ disease, due to swelling and hypertrophy of tissue behind the eyeballs.
What is pretibial myxoedema?
Pretibial myxoedema is a skin condition caused by glycosaminoglycan deposits under the skin on the anterior aspect of the leg. It is specific to Graves’ disease.
What is goitre?
Goitre refers to a neck lump caused by the swelling of the thyroid gland.
What are the causes of hyperthyroidism?
The causes of hyperthyroidism can be remembered by the ‘GIST’ mnemonic:
* G: Graves’ disease
* I: Inflammation (thyroiditis)
* S: Solitary toxic thyroid nodule
* T: Toxic multinodular goitre
What is thyroiditis?
Thyroiditis is inflammation of the thyroid, which often causes an initial period of hyperthyroidism followed by hypothyroidism. Causes include:
* De Quervain’s thyroiditis
* Hashimoto’s thyroiditis
* Postpartum thyroiditis
* Drug-induced thyroiditis
What are the universal features of hyperthyroidism?
Universal features include:
* Anxiety and irritability
* Sweating and heat intolerance
* Tachycardia
* Weight loss
* Fatigue
* Insomnia
* Frequent loose stools
* Sexual dysfunction
* Brisk reflexes
What are the specific features of Graves’ disease?
Specific features include:
* Diffuse goitre (without nodules)
* Exophthalmos
* Pretibial myxoedema
* Thyroid acropachy (hand swelling and finger clubbing)
What is a solitary toxic thyroid nodule?
A solitary toxic thyroid nodule is a single abnormal thyroid nodule that releases excessive thyroid hormone. It is usually a benign adenoma and treated with surgical removal.
What is De Quervain’s thyroiditis?
De Quervain’s thyroiditis (subacute thyroiditis) causes temporary inflammation of the thyroid. It has three phases:
* Thyrotoxicosis
* Hypothyroidism
* Return to normal
What are the symptoms of De Quervain’s thyroiditis in the thyrotoxic phase?
Symptoms include:
* Excessive thyroid hormones
* Thyroid swelling and tenderness
* Flu-like illness (fever, aches, fatigue)
* Raised inflammatory markers (CRP and ESR)
What is thyroid storm?
Thyroid storm (thyrotoxic crisis) is a rare, severe presentation of hyperthyroidism with fever, tachycardia, and delirium. It can be life-threatening and requires urgent treatment.
How is hyperthyroidism treated?
Treatment options include:
* Carbimazole (first-line anti-thyroid drug)
* Propylthiouracil (second-line anti-thyroid drug)
* Radioactive iodine treatment
* Beta blockers (for symptom control)
* Surgery (thyroidectomy)
What is carbimazole, and what are the potential risks?
Carbimazole is the first-line anti-thyroid drug used to treat hyperthyroidism. Risks include acute pancreatitis and agranulocytosis (low white blood cell count).
What is propylthiouracil, and why is it used?
Propylthiouracil is a second-line anti-thyroid drug. It is used when carbimazole is not effective or appropriate, but carries a risk of severe liver reactions.
What is radioactive iodine treatment?
Radioactive iodine treatment involves drinking a single dose of radioactive iodine, which is absorbed by the thyroid. The radiation destroys thyroid cells, reducing hormone production. It may require long-term levothyroxine replacement after treatment.
How do beta blockers help in hyperthyroidism?
Beta blockers, such as propranolol, block adrenergic symptoms like tachycardia and tremors in hyperthyroidism. They do not treat the underlying thyroid issue but control symptoms while other treatments take effect.
What is thyroidectomy, and what is the result?
Thyroidectomy involves the removal of the thyroid gland or toxic nodules. It is a definitive treatment but will result in hypothyroidism, requiring lifelong levothyroxine replacement.
