Hyperthyroidism Flashcards
What causes Graves disease
- Autoimmune
- Antibodies bind to and stimulate the TSH receptors in the thyroid
symptoms of Graves disease (4)
- Cause goitre (large thyroid) (smooth) and hyperthyroidism
- (Hyperthyroidism causes lid lag)
- Other antibodies (which are also made in Graves’ disease) bind to muscles behind the eyes and cause exophthalmos
- Other antibodies cause pretibial myxoedema (hypertrophy)
What is pretibial myxoedema
The (non-pitting) swelling that occurs on the shins of patients with Graves’ disease growth of soft tissue
What diseases are often the cause of hyperthyroidism
Graves’ disease
PLUMMER’S DISEASE:
What do we use to look at a thyroid gland, why does this work?
Radioactive iodine scan Iodine is what thyroid hormones are produced from, so the radioactive iodine ends up collecting in the thyroid gland
What do we see in a radioactive iodine scan of a Graves’ patient
We see the whole gland enlarge (smooth goitre)
What is the cause of Plummers disease
- Benign adenoma that is overactive at making thyroxine
Difference in symptoms of Graves’ and Plummers? (3)
- NO pretibial myxoedema This is usually an autoimmune feature
- NO exophthalmos This is usually an autoimmune feature
- Toxic nodular goitre
EFFECTS OF THYROXINE ON THE SNS?
- Sensitises beta adrenoceptors to ambient levels of adrenaline and noradrenaline
- Thus there is apparent sympathetic activation
Consequences of EFFECTS OF THYROXINE ON THE SNS? (4)
TACHYCARDIA, PALPITATIONS, TREMOR OF THE HANDS, LID LAG
Features of hyperthyroidism? (7)
- Weight loss with increased appetite
- Breathlessness
- Palpitations, tachycardia
- Sweating
- Heat intolerance
- Diarrhoea
- Lid lag
Features of thyroid storm?
- Hyperpyrexia (>41 degrees C)
- Accelerated tachycardia/arrhythmia
- Cardiac failure
- Delirium/frank psychosis
- Hepatocellular dysfunction; jaundice
HYPERTHYROIDISM TREATMENT OPTIONS (3)
- Surgery (thyroidectomy)
- Radioiodine
- Drugs
What types of drugs are used to treat hyperthyroidism? (4)
- THIONAMIDES (thiourylenes; anti-thyroid drugs)
- Propylthiouracil (PTU)
- Carbimazole (CBZ) - POTASSIUM IODIDE
- RADIOIODINE
- BETA-BLOCKERS
Purpose of beta blocker use in hyperthyroidism?
aid symptoms
Examples of thionamides?
- Propylthiouracil (PTU)
- Carbimazole (CBZ)
Frequency of Admin for thionamides?
daily
3 uses of thionamides?
- Daily treatment of hyperthyroid conditions
- Treatment prior to surgery - neoadjuvant
- Reduction of symptoms while waiting for radioiodine to act
how do thionamides work
INHIBITING THYROPEROXIDASE
What must happen before thionamides start working
NOT an immediate effect as you’ve already got thyroid hormone stored in the colloid so this must be used up
What does thyroperoxidase do
Converts iodide to iodine to be used to make T3 and T4
What is given short term to ease side effects of hyperthyroidism till the Thionamides kicks in
Beta blockers - propranolol
UNWANTED ACTIONS of Thionamides? (2)
- AGRANULOCYTOSIS (reduction in WBC count- usually neutrophils)- rare and reversible on withdrawal of drug
- Rashes (relatively common)
RoA of Thionamides?
Oral
- Carbimazole is an example of …
a Thionamides
Propylthiouracil is an example of a ….
Thionamides
What beta blocker is usually used in hyperthyroidism
PROPRANOLOL
how does potassium iodide help with hyperthyroidism
A huge dose of iodide can be used to turn the thyroid gland off
You’d do this when you want to take effect quickly e.g. when a patient is about to go in for an operation and you want to get them under control before administration of general anaesthetic
what is the wolf-Chaikoff effect
the temporary reduction in thyroid hormones following ingestion of large amounts of iodine
Benefit of using KI as a neoadjuvant?
super quick compared to other thyroid drugs
What would you give during a thyrotoxic crisis (thyroid storm)
KI and propranolol
How does radioiodine work in hyperpituitarism
- Attempts to stop all thyroid function Needs to be supplemented with thyroxine
- Emits beta radiation, which destroys thyroid follicle cells
VIRAL (DE QUERVAIN’S) THYROIDITIS is caused by?
Virus attacks thyroid gland
Symptoms of VIRAL (DE QUERVAIN’S) THYROIDITIS
- Painful dysphagia
- Hyperthyroidism
- Pyrexia
- Raised ESR
history of VIRAL (DE QUERVAIN’S) THYROIDITIS
- Virus attacks thyroid causing pain and tenderness
- Thyroid stops making thyroxine and makes viruses instead
- Therefore, there is NO IODINE UPTAKE in radioiodine scans
How long after initial viral arrack do you see hypothyroid symptoms of viral thyroiditis and why
4 weeks after
body will have run out of thyroid hormone
Result of an iodine scan of a patient with viral thyroiditis?
No iodine uptake
