S11 Thyroid Disorders Flashcards
What is the importance of the pre-tracheal fascia?
Means the thyroid moves on swallowing, so if want to know if something is someone’s thyroid, ask them to swallow
What do thyroid hormones control?
Metabolic rate
What systems are affected in the body by thyroid hormone?
- energy
- weight
- temperature
- heart rate
- nervous system
- GI system
- musculoskeletal
- skin
In primary hypothyroidism, what do you measure in an investigation? What will the levels be?
Free T4 and TSH
T4 will be low, TSH will be high
In primary hyperthyroidism, what do you measure in an investigation? What will the levels be?
Free T4 and TSH
T4 low, TSH high
When can you feel the thyroid?
Only when it’s enlarged
How can you use imaging to see the thyroid?
- ultrasound
- radioisotope scan
- CT can
- plain x-ray scan
When do you know of someone has hyperthyroidism looking at radioisotope scans?
There will be a hot nodule
Toxic multinodular goitre - causing thyrotoxicosis
Lingual thyroid (hot nodule in neck/tongue)
What are symptoms of hypothyroidism?
- tiredness
- weight gain
- cold intolerance
- change in appearance
- depression
- psychosis
- joint/muscle ache
- dry hair and skin
- constipation
- puffy eyes
What are signs of hypothyroidism?
- peri-orbital oedema
- ‘peaches and cream’ skin colour
- loss of eyebrows
- dry, thin hair
- bradycardia
- slow-relaxing reflexes
- carpal tunnel syndrome - oedema, etc causes median nerve compression
- cold peripheries
What can cause hypothyroidism?
- autoimmune strophic
- autoimmune (results in goitre) Hashimoto’s thyroiditis
- post-partum thyroiditis
- dyshormonogenesis - babies with underactive thyroid, can’t make thyroxine
- medication e.g. amiadarone
- iodine deficiency
If a mother has iodine deficiency, how does it affect her unborn children?
They are born with cretinism - hypothyroidism
How do you treat hypothyroidism? What are the aims of treatment?
- thyroxine replacement therapy - levothyroxine (synthetic T4) for life. Varying doses based on age and heart diseases etc
Resolution of symptoms, normalisation of blood tests (in 6-8 weeks)
How do you measure if you’re taking too much/too little thyroxine replacement therapy?
If you have high TSH, it’s under-replacement, need to take more
If you have low TSH, it’s over-replacement, need to take less
What is myxoedema coma?
Severe hypothyroidism usually seen in elderly (rare)
Occurring due to hypothermia and fluid overload in the heart (pericardial effusion)
What is borderline or subclinical hypothyroidism?
When a patient has fT4 and high TSH (very common)
It’s more common than having severe hypothyroidism
It can be monitored until symptoms need treatment
What are the symptoms of hyperthyroidism?
- weight loss
- irritability
- restlessness
- insomnia
- malaise
- itching
- sweating
- palpitations
- tremor
- muscle ache
- diarrhoea
What are the signs of hyperthyroidism?
- tremor
- hyperkinesis
- tachycardia
- atrial fibrillation
- warm peripheries
- hypertension
- proximal myopathy
- lid lag
What are causes of hyperthyroidism?
- Graves’ disease - autoimmune (most common)
- nodular thyroid disease (nodules secrete hormone continuously)
- thyroiditis
What happens in Graves’ disease?
Auto-antibodies bind to TSH receptor on thyroid cells and stimulate hormone synthesis
What are some signs of Graves’ disease?
- Graves’ opthalmopathy - optic nerve stretched
- Pretibial myoedema (Graves’ dermopathy) - stretching of skin/swelling of legs
- thyroid acropachy- thickening of extremities, looks like clubbing
What types of nodular hyperthyroidism can you have?
- a single toxic nodule - removed with surgery
* toxic multi-nodular goitre
What is thyroiditis? What could cause it? Why does the thyroid start off overactive and end up underactive?
Inflammation of thyroid
* release of thyroxine into circulation
Could be due to viral infection (de quervain’s thyroiditis), after childbirth (post-partum), medication (amiodarone)
Increase due to sudden release of hormone (thyrotoxicosis), but decreases as the thyroid is damaged and then it can normalise
How do you treat hyperthyroidism?
- medication - carbimazole (beware of agranulocytosis - risk of infections), beta-blockers for symptom control
- surgery - happens if side effects of medication - risk of damage to voice box (laryngeal nerve palsy) and hypocalcaemia due to parathyroid glands in close proximity
- radioactive iodine - not used if pregnant, radiation restrictions after treatment
What is thyroid crisis/‘thyroid storm’?
A rare condition with a 10% mortality
Presents as hyperpyrexia, tachycardia, cardiac failure, liver dysfunction
Urgent treatment on high dependency unit
What do you need to be aware of if someone has hyperthyroidism and is pregnant?
In Graves’ disease, antibodies can cross the placenta so the baby can be born with hyperthyroidism
Need to closely monitor pregnancy
What is goitre? Who is it more common in?
Thyroid swelling
Women
What are 4 types of goitre?
- diffuse goitre - simple, autoimmune thyroid disease, thyroiditis
- nodular goitre - multinodular goitre, a solitary nodule is a red flag symptom
- fibrotic goitre - Riedel’s thyroiditis (rare) or viral thyroiditis?
- iodine deficiency - common worldwide but rare in the UK
What are the red flag symptoms of thyroid cancer?
History
- very young or old
- rapid enlargement of lump in neck
- hoarse once and dysphagia
- family history of thyroid cancer
Examination
- hard irregular thyroid mass
- fixed to surrounding structures (doesn’t move when patient swallows)
- cervical lymph nodes palpable
How do you do investigations into suspected thyroid cancer?
- ultrasound guidance
- fine needle aspiration
- CT scan thorax and mediastinum
If cytology suggests cancer, remove with surgery
