Thyroid Disorders Flashcards
What is the name of the dimple at the back of the tongue and what caused the formation of that structure?
Foramen Caecum
This is a remnant left by the descending thyroglossal duct
What is the weight and dimensions of a normal thyroid gland?
20 g
4 cm x 2.5 cm x 2.5 cm
Which lobe of the thyroid is the biggest?
RIGHT > left
What nerves run near the thyroid gland?
Recurrent laryngeal nerves
What are three problems that can occur with the development of the thyroid?
AGENESIS - complete absence of the thyroid
INCOMPLETE DESCENT
THYROGLOSSAL CYST - thyroglossal duct persists and cysts may form
What is cretinism?
Irreversible brain damage caused by a lack of thyroxine
State two features of cretinism.
Stunted growth
Low IQ
How are newborns tested for cretinism and what is the treatment?
Heel-prick test
TSH is measured and if it is ABNORMALLY HIGH then they are given THYROXINE
Is thyroid disease more common in males or females?
Females
Female: Male ratio = 4:1
Define myxoedema.
Primary Hypothyroidism - primary thyroid failure
What is the most common cause of primary thyroid failure?
Autoimmune damage to the thyroid
How do TSH levels change in primary thyroid failure?
TSH levels rise to try and stimulate and increase in thyroxine production
(eventually the TSH production will become exhausted and it will decline)
What exerts negative feedback on TSH and TRH release?
T3/T4 - direct and indirect negative feedback
State some features of primary hypothyroidism.
EVERYTHING SLOWS DOWN Deepening voice Depression and tiredness Bradycardia Cold intolerance Weight gain and reduced appetite Constipation
What is the treatment for hypothyroidism?
Give THYROXINE daily and monitor TSH
How does TSH change in hyperthyroidism?
TSH is low because the elevated Thyroxine exerts a powerful negative feedback effect on it
State some features of hyperthyroidism.
Raised metabolic rate Raised temperature Lose weight + burn up calories Tachycardia Clinical: diarrhoea, myopathy, mood swings, palpitations, feeling hot in all weather, goitre
What is a common cause of hyperthyroidism?
Graves’ Disease
What causes Graves’ disease?
The whole thyroid gland is SMOOTHLY ENLARGED and the whole gland is OVERACTIVE
Caused by the immune system producing an antibody that MIMICS TSH
Other than an increase in thyroxine production, state two other features of hyperthyroidism.
GOITRE - enlargement of the thyroid could form a goitre
EXOPHTHALMOS - other antibodies could bind to the eye muscles pushing the eye forwards
PRETIBIAL MYXOEDEMA - other antibodies could promote growth of soft tissue on the SHIN
