General Thyroid Disorders Flashcards
What is the thyroid shaped like?
Shield
Where is the thyroid?
Neck
What does the thyroid produce?
Thyroxine
From where does the thyroid originate
Back of tongue
How much does an adult thyroid gland weigh?
20g
Name the 4 lobes of the thyroid
Right
Left
Isthmus
Pyramidal
Which lobe of the thyroid is largest?
Right
What is embedded in the thyroid?
Parathyroid glands
What do parathyroid glands do?
Control calcium metabolism
What nerve runs very close to thyroid gland?
Left recurrent laryngeal nerve
Name 3 problems with thyroid development
Agenesis
Incomplete descent
Thyroglossal cyst
What is a cretin?
Individual with irreversible brain damage caused by lack of thyroxine
How is cretinism prevented?
All babies have heel prick test measuring TSH
If TSH is high, given thyroxine immediately
What occurs in thyroid follicular cells?
Thyroxine synthesis
What is thyroglobulin?
Protein that holds and stores Thyroxine
In thyroid gland
Not in circulation
Where is thyroxine binding globulin?
Circulation
How much thyroxine is bound to thyroxine binding globulin?
75%
How much free thyroxine is in the circulation?
1%
Which gender is thyroid disease more common in?
Females
What is primary hypothyroidism also known as?
Primary thyroid failure and Myxoedema
What happens to hormone levels in primary hypothyroidism?
Thyroxine levels decline
TSH levels increase
What causes primary hypothyroidism?
Autoimmune damage to the thyroid
or operation removing the thyroid
What are 7 features of primary hypothyroidism?
Deepening voice Depression & tiredness Cold intolerance Weight gain with reduced appetite Constipation Bradycardia Eventually myxoedema coma
Why is treatment of hypothyroidism essential?
They will perform poorly
Cholesterol increases-> Heart attacks & strokes
Patients will die
What will be high if there is insufficient T4?
TSH
What is overactive thyroid also known as?
Thyrotoxicosis
Hyperthyroidism
What occurs in hyperthyroidism?
Thyroid makes too much thyroxine
What are TSH levels in hyperthyroidism?
0 or very low
What causes the thyroid to make more thyroxine?
Immune system makes antibody that stimulates receptor in Thyroid to make more thyroxine
What happens when there is too much thyroxine?
Every cell in body speeds up
Raised BMR
Raised temperature
Increased HR
What are 10 features of hyperthyroidism?
Myopathy- weakness Mood swings Feeling hot in all weather Diarrhoea Weight loss but increased appetite Tremor of hands Tiredness Palpitations Sore eyes Goitre
What causes hyperthyroidism?
Graves’ disease
What causes Graves’ disease?
Autoimmune
Antibodies bind to and stimulate TSH receptor in the thyroid
Causes goitre (Smooth)
What are the other actions of antibodies in graves disease?
Bind to muscles behind eye –> Exophthalmos
Stimulate growth of shins -> Pretibial myxoedema
Pretibial myxoedema
Swelling that occurs on shins of patients with Graves’ disease
