Hyperthyroidism Flashcards
How are the causes of hyperthyroidism categorised
Primary
Secondary
Thyrotoxicosis without hyperthyroidism
What are the primary causes of hyperthyroidism
Graves disease (70-80%)
Toxic Multinodular Goitre (20%)
Toxic adenoma
What is the epidiiology of graves disease
Incidence 2-3 per 1000 per year
More common in females
Usually affects young adults (20-40 years)
What is the pathophysiology of graves disease
- Antibodies produced (anti-TSH antibodies) that bind mimic TSH and continually activate the thyroid gland.
- Increased release of TH switches off TSH release from anterior pituitary so [TSH]plasma very low and so is TRH release from hypothalamus
- Thyroid gland may be 2-3x normal size due to hyperplasia. Hyperactivity of cells also apparent.
- Patient has very high levels of T4
What are signs and symptoms of graves disease (x13)
Bulging eyes (Graves’ ophthalmopathy) 30%
Thick, red skin usually on the shins or tops of the feet (Graves’ dermopathy)
Anxiety and irritability
A fine tremor of the hands or fingers
Heat sensitivity and an increase in perspiration or warm, moist skin
Weight loss, despite normal eating habits
Enlargement of the thyroid gland (goiter)
Change in menstrual cycles
Erectile dysfunction or reduced libido
Frequent bowel movements
Fatigue
Rapid or irregular heartbeat (palpitations)
Sleep disturbance
What causes graves opthalmopathy
A build up of carbohydrates in the muscles and tissue behind the eyes
What is the Histopathology of a thyroid gland in graves disease
If its dissected then it looks meaty (pink dense appearance)
There is increased cell activity and increased cell number (larger, columnar cells with smaller follicles)
Hyperplasia of the acinar epithelium
Reduction of stored colloid
local accumulations of lymphocytes with lymphoid follicle formation
What is Toxic Multinodular Goitre
A goitre containing multiple autonomously functioning nodules, resulting in hyperthyroidism.
What triggers thyroid hormone release from the Toxic Multinodular Goitre
These nodules function independently of thyroid-stimulating hormone
When should you suspect if there are non-functioning thyroid nodules in the a Toxic Multinodular Goitre
Malignancy
What age group gets Toxic Multinodular Goitre
Over 50
What is thyrotoxicosis
Refers to an abnormal amount of thyroid hormone in the body
How common is Toxic Multinodular Goitre
Its the second most common cause of thyrotoxicosis
What condition sees an elevated level of thyroid hormone followed by a hypothyroid phase
Subacute (de Quervain’s) thyroiditis
What is Subacute (de Quervain’s) thyroiditis
Subacute thyroiditisis an acute inflammatory disease of thethyroidprobably caused by a virus.
What are symptoms of Subacute (de Quervain’s) thyroiditis
Symptoms include fever andthyroidtenderness.
What age group commonly get Subacute (de Quervain’s) thyroiditis
<50 years
What is treatment for Subacute (de Quervain’s) thyroiditis
Short term steroids and NSAIDS
What is thyroid storm
Thyroid storm is a rare presentation of hyperthyroidism. It is also known as “thyrotoxic crisis”
What are presenting symptoms of thyroid storm
It is a more severe presentation of hyperthyroidism with pyrexia, tachycardia and delirium
What are treatment options available for hyperthyroidism
Anti-thyroid drugs
Radioiodine
Surgery
Beta blockers
What is the first line anti-thyroid drug
Carbimazole
How long does it usually take for carbimazole to work?
4-8 weeks for normal thyroid function
Complete remission after 18 months
What is the Second line anti-thyroid drug
Propylthiouracil
Why is Carbimazole preferred over Propylthiouracil
Propylthiouracil has a small risk of severe hepatic reactions, including death,
How does Radioiodine treatment work
Involves drinking a single dose of radioactive iodine. This is taken up by the thyroid gland and the emitted radiation destroys a proportion of the thyroid cells.
What is a risk of radio iodine therapy
patients can be left hypothyroid afterwards and require levothyroxine replacement.
What are the 3 strict rules when using radioiodine therapy
Must not be pregnant and are not allowed to get pregnant within 6 months
Must avoid close contact with children and pregnant women for 3 weeks (depending on the dose)
Limit contact with anyone for several days after receiving the dose
Why are beta blockers used to treat hyperthyroidism
Beta blockers are used to block the adrenalin related symptoms of hyperthyroidism.
