Hyperthyroidism Flashcards
What is Hyperthyroidism?
Hyperthyroidism is where there is over-production of thyroid hormone by the thyroid gland. Thyrotoxicosis refers to an abnormal and excessive quantity of thyroid hormone in the body.
What are causes of hyperthyroidism?
Primary hyperthyroidism
Secondary hyperthyroidism
Grave’s Disease
Toxic Multinodular Goitre
What is primary hyperthyroidism?
Primary Hyperthyroidism is due to thyroid pathology. It is the thyroid itself that is behaving abnormally and producing excessive thyroid hormone.
What is secondary hyperthyroidism?
Secondary hyperthyroidism is the condition where the thyroid is producing excessive thyroid hormone as a result of overstimulation by thyroid stimulating hormone. The pathology is in the hypothalamus or pituitary.
What is Grave’s Disease?
Grave’s Disease is an autoimmune condition where TSH receptor antibodies cause a primary hyperthyroidism. These TSH receptor antibodies are abnormal antibodies produced by the immune system that mimic TSH and stimulate the TSH receptors on the thyroid. This is the most common cause of hyperthyroidism.
What antibodies are present in Grave’s Disease?
TSH receptor antibodies
What is a toxic multinodular goitre?
Toxic Multinodular Goitre is a condition where nodules develop on the thyroid gland that act independently of the normal feedback system and continuously produce excessive thyroid hormone.
What is exophthalmos and how does it occur?
Exopthalmos is the term used to describe bulging of eyeball out of the socket caused by Graves Disease. This is due to inflammation, swelling and hypertrophy of the tissue behind the eyeball that forces the eyeball forward. (caused by TSH antibodies)
What is pretibial myxoedema and how does it occur?
Pretibial Myxoedema is a dermatological condition where there are deposits of mucin under the skin on the anterior aspect of the leg (the pre-tibial area). This gives a discoloured, waxy, oedematous appearance to the skin over this area. It is specific to Grave’s disease and is a reaction to the TSH receptor antibodies.
What is the Universal Symptoms of Hyperthyroidism?
Anxiety and irritability Sweating and heat intolerance Tachycardia Weight loss Fatigue Frequent loose stools Sexual dysfunction
What are the symptoms that are specific to Grave’s Disease?
These features all relate to the presence of TSH receptor antibodies.
Diffuse Goitre (without nodules)
Graves Eye Disease
Bilateral Exopthalmos
Pretibial Myxoedema
What are the unique features of 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?
This is where a single abnormal thyroid nodule is acting alone to release thyroid hormone. The nodules are usually benign adenomas. They are treated with surgical removal of the nodule.
What is De Quervain’s Thyroiditis?
De Quervain’s Thyroiditis describes the presentation of a viral infection with fever, neck pain and tenderness, dysphagia and features of hyperthyroidism. There is a hyperthyroid phase followed by hypothyroid phase as the TSH level falls due to negative feedback. It is a self-limiting condition and supportive treatment with NSAIDs for pain and inflammation and beta blockers for symptomatic relief of hyperthyroidism is usually all that is necessary.
What is a thyroid storm?
Thyroid storm is a rare presentation of hyperthyroidism. It is also known as “thyrotoxic crisis”. It is a more severe presentation of hyperthyroidism with pyrexia, tachycardia and delirium. It requires admission for monitoring and is treated the same way as any other presentation of thyrotoxicosis, although they may need supportive care with fluid resuscitation, anti-arrhythmic medication and beta blockers.
