Clinical Thyroid Disease Flashcards
What is the name given to the part of the thyroid gland which connects the right and left lobe?
Isthmus
Explain how thyroid function is controlled.
Hypothalamus produces TRH.
TRH acts on anterior pituitary.
Stimulates production of TSH.
Thyroid produces T3, the active component.
There is a negative feedback system so if there’s too much of anything, it can loop back and turn the production of the cycle off.
If the source of an endocrine condition is at the thyroid gland, what is this called?
Primary hypothyroidism
If the source of an endocrine condition is at the pituitary gland, what is this called?
Secondary hypothyroidism
List some of the symptoms of hypothyroidism.
Fatigue/lethargy
Cold intolerance
Weight gain
Non-specific weakness
Constipation
Depression
Dry skin
Thyroid pain
List some of the signs of hypothyroidism.
Coarse, dry hair
Skin and hair loss
Oedema
Vocal changes
Goitre
Bradycardia and diastolic hypertension
Delayed reflexes
Paraesthesia
What tests would you do if you suspected hypothyroidism?
Check TFT (thyroid function tests)
Possibly FBC and glucose too
What does TFT’s check for?
TSH
Free T4
In those with hyperthyroid disease, what are T3/4 levels like?
Increased
In those with hyperthyroid disease, what are TSH levels like?
Decreased
->too much TH so not releasing anymore
In those with hypothyroid disease, what are T3/4 levels like?
Decreased
In those with hypothyroid disease, what are TSH levels like?
Increased
->to try and release more TH
Which medication can be used to help in the treatment of hypothyroidism?
Levothyroxine
In adults <65 with hypothyroidism, how much levothyroxine should be given?
1.6 mcg per kg
In adults >65 or with pre-existing cardiac disease and hypothyroidism, how much levothyroxine should be given?
More cautious levels- 25-50mcg
->more cautious as medication can rapidly increase HR
At what point in the day should levothyroxine be taken?
First thing in the morning on an empty stomach
->if unable, late evening, at least two hours after meal
List the signs/symptoms of hypothyroidism.
Weight gain
Lethargy
Feeling cold
Constipation
Heavy periods
Dry skin/hair
Bradycardia
Slow reflexes
Goitre
List the signs/symptoms of hyperthyroidism.
Weight loss
Anxiety/irritability
Heat intolerance
Bowel frequency
Light periods
Sweaty palms
Palpitations
Hyperreflexia
Goitre
Thyroid eye symptoms
What is the most common endocrine condition?
Diabetes
-> hypothyroidism is the second most common
What is the most common cause of primary hypothyroidism?
Congenital- either developmental or dyshormonogenesis (hormones not getting produced or released)
If hypothyroidism isn’t diagnosed and treated quickly, it can lead to physical and mental retardation. How is this prevented?
Every baby screened in UK
What are some of the causes of acquired hypothyroidism?
Autoimmune thyroid disease
Iatrogenic cause
Chronic iodine deficiency
Post-subacute thyroiditis
Give an example of an autoimmune thyroid disease which can cause acquired hypothyroidism?
Hashimotos
List some causes of secondary/tertiary hypothyroidism.
Pituitary tumour
Post pituitary surgery/ radiotherapy
Suppressed TSH has an increased risk of what?
Atrial fibrillation
Osteopenia
Fracture
What is subclinical hypothyroidism?
Elevated TSH to ensure that FT3/4 levels are normal
->therefore, the pituitary gland is working a lot harder
What are some of the causes of primary hyperthyroidism?
Grave’s disease
Toxic Multinodular Goitre
Toxic adenoma
What is another term for hyperthyroidism?
Thyrotoxicosis
What is usually the cause of secondary hyperthyroidism?
Pituitary adenoma secreting TSH
What is meant by thyrotoxicosis without hyperthyroidism?
Thyroid gland itself is not producing excess TH, it is due to destructive thyroiditis
What causes the majority of cases of hyperthyroidism?
70-80%