Endocrinology - hyperthyroidism Flashcards
What is Grave’s disease?
An autoimmune hyperthyroidism
TSH receptor antibodies cause a primary hyperthyroidism (mimic TSH)
Most common cause of hyperthyroidism
What is toxic multinodular goitre?
Nodules develop on thyroid that act independently of negative feedback and continuously produce T3 and T4
Causes of hyperthyroidism
Grave’s disease
Toxic multinodular goitre
Solitary toxic thyroid nodule
Thyroiditis (e.g. De Quervain’s, Hashimoto’s, postpartum and drug-induced thyroiditis)
Features of hyperthyroidism
Anxiety and irritability
Sweating and heat intolerance
Tachycardia
Weight loss
Fatigue
Frequent loose stools
Sexual dysfunction
Additional features seen in Grave’s disease
Diffuse goitre (without nodules)
Graves eye disease
Bilateral exophthalmos
Pretibial myxoedema
What is exophthalmos?
Bulging of eyeball forward
Due to inflammation and hypertrophy of tissue behind the eye
What is pretibial myxoedema?
Dermatological condition specific to Grave’s disease
Mucin deposits under the skin in the pre-tibial area (shin)
This gives a discoloured, waxy and oedematous appearance to the skin over this area
Additional features seen in Toxic multinodular goitre
Goitre with firm nodules
Most patients are aged over 50
Second most common cause of thyrotoxicosis (after Grave’s)
What is a solitary toxic thyroid nodule? Treatment?
Where a single abnormal thyroid nodule is acting alone to release thyroid hormone.
Usually benign adenomas.
Treated with surgical removal of the nodule.
What is De Quervain’s thyroiditis?
Presentation of a viral infection with fever, neck pain and tenderness, dysphagia and features of hyperthyroidism.
Usually is a self-limiting condition
Supportive treatment with NSAIDs and beta-blockers for hyperthyroid symptom relief
There is a hyperthyroid phase followed by a hypothyroid phase as the TSH level falls due to negative feedback
What is a complication of hyperthyroidism?
Thyrotoxic crisis
It is a more severe presentation of hyperthyroidism with pyrexia, tachycardia and delirium.
Need admission for monitoring and is treated the same way as any other presentation of hyperthyroidism
Although they may need supportive care with fluid resuscitation, anti-arrhythmic medication and beta-blockers.
Management of hyperthyroidism
Medical management:
- Carbimazole (first line)
- Propylthiouracil (second line)
Radioactive iodine
Beta-blockers e.g. propranolol can be used (particularly in thyrotoxic crisis) - for symptom control only, doesn’t treat underlying cause
Surgery - a definitive option
Carbimazole
First line anti-thyroid drug
Normalises thyroid function in 1-2 months
Risk of PTU
Small risk of severe hepatic reactions including death
Why carbimazole is preferred
Radioactive iodine - process
Drinking radioactive iodine
This is taken up by the thyroid gland and destroys thyroid tissue
