Thyroid Disorders

Question 1

What is the name of the dimple at the back of the tongue and what caused the formation of that structure?

Answer 1

Foramen Caecum

This is a remnant left by the descending thyroglossal duct

Question 2

What is the weight and dimensions of a normal thyroid gland?

Answer 2

20 g

4 cm x 2.5 cm x 2.5 cm

Question 3

Which lobe of the thyroid is the biggest?

Answer 3

RIGHT > left

Question 4

What nerves run near the thyroid gland?

Answer 4

Recurrent laryngeal nerves

Question 5

What are three problems that can occur with the development of the thyroid?

Answer 5

AGENESIS - complete absence of the thyroid
INCOMPLETE DESCENT
THYROGLOSSAL CYST - thyroglossal duct persists and cysts may form

Question 6

What is cretinism?

Answer 6

Irreversible brain damage caused by a lack of thyroxine

Question 7

State two features of cretinism.

Answer 7

Stunted growth

Low IQ

Question 8

How are newborns tested for cretinism and what is the treatment?

Answer 8

Heel-prick test

TSH is measured and if it is ABNORMALLY HIGH then they are given THYROXINE

Question 9

Is thyroid disease more common in males or females?

Answer 9

Females

Female: Male ratio = 4:1

Question 10

Define myxoedema.

Answer 10

Primary Hypothyroidism - primary thyroid failure

Question 11

What is the most common cause of primary thyroid failure?

Answer 11

Autoimmune damage to the thyroid

Question 12

How do TSH levels change in primary thyroid failure?

Answer 12

TSH levels rise to try and stimulate and increase in thyroxine production
(eventually the TSH production will become exhausted and it will decline)

Question 13

What exerts negative feedback on TSH and TRH release?

Answer 13

T3/T4 - direct and indirect negative feedback

Question 14

State some features of primary hypothyroidism.

Answer 14

EVERYTHING SLOWS DOWN
Deepening voice
Depression and tiredness
Bradycardia
Cold intolerance 
Weight gain and reduced appetite 
Constipation

Question 15

What is the treatment for hypothyroidism?

Answer 15

Give THYROXINE daily and monitor TSH

Question 16

How does TSH change in hyperthyroidism?

Answer 16

TSH is low because the elevated Thyroxine exerts a powerful negative feedback effect on it

Question 17

State some features of hyperthyroidism.

Answer 17

Raised metabolic rate 
Raised temperature 
Lose weight + burn up calories
Tachycardia 
Clinical: diarrhoea, myopathy, mood swings, palpitations, feeling hot in all weather, goitre

Question 18

What is a common cause of hyperthyroidism?

Answer 18

Graves’ Disease

Question 19

What causes Graves’ disease?

Answer 19

The whole thyroid gland is SMOOTHLY ENLARGED and the whole gland is OVERACTIVE
Caused by the immune system producing an antibody that MIMICS TSH

Question 20

Other than an increase in thyroxine production, state two other features of hyperthyroidism.

Answer 20

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