Thyroid Disorders 7 Flashcards
What is the origin of the thyroid?
Back of the tongue. It migrates down and is in position by week 7.
Where is the foramen caecum?
Dimple at the back of the tongue (left by the disappearing thyroglossal duct)
What is an adults thyroid parameters?
- 20g
- 4x2.5x2.5cm each lobe
Describe lobe size
- two lobes
- right lobe is larger
What glands are embedded to the thyroid?
Parathyroid glands
What important nerve runs close to thyroid and what does it supply?
Left Recurrent Laryngeal Nerve
This supplies the Larynx and allows speech
3 Developmental Thryoid problems?
- Agenesis (complete absence)
- Incomplete Descent
- Thyroglossal Cyst (after duct persists)
Cretin Definition
An individual with irreversible brain damage due to a lack of thyroxine. typically due to a lack of iodine in the diet. the IQ is much lower and there is stunted growth
How is cretinism prevented?
All babies have a heel-prick test carried out at the same time at the Guthrie test for phenylketonuria. This is done at 5-10 days. Thryoxine if given if TSH is abnormally high
Two uses for Thryoglobulin
- iodised to form DIT and MIT
- binds to thyroxine to keep it in the thyroid`
Alternative Name for Primary hypothyroidism
Myxoedema
Causes of Myxoedema?
- autoimmune damage
- thyroidectomy
These cause TSH levels to initially rise and then eventually fall
Features for Primary hypothyroidism
Everything slows down
- deepening of voice
- Depression/tiredness
- cold intolerance
- weight gain with reduced appetite
- bradycardia
- constipation
- Eventual myxoedema coma
- amenorrhea late in disease
- heart enlargement
Treatment for Primary Hypothyroidism
- otherwise death
- Give thyroxine daily and monitor TSH levels
Describe cause of Hyperthyroidism
Thyroid produces too much Thyroxine and TSH levels fall to 0 as no stimulus needed.
Describe features of Hyperthyroidism
- myopathy
- mood swings
- feeling hot in all weather
- Increased appetite but weight loss
- tremor in hands
- diarrhea
- palpitations
- sore eyes
- goitre
Hyperthyroidism Causes
Graves Disease = the whole gland is smoothly enlarged and overactive. This is a feature as the immune system produces an antibody that pretends to be TSH. This leads to overactiveness and enlargement of the gland which can cause goitre. Other antibodies bind to muscles behind the eye causing exophthalmos. others bind to muscle in the shin causing pretibial myxoedema (hypertrophy)
