8 Thyroid Disorders Flashcards Preview

Y1 LCRS Endocrinology > 8 Thyroid Disorders > Flashcards

Flashcards in 8 Thyroid Disorders Deck (30)
Loading flashcards...
1
Q

Q: What shape is the thyroid gland? Texture? from outside? How many parts are there to it? Name them.

A

A: shield shaped

soft and covered by cartilage

can feel thyroid cartilage= palpable

4

  • pyramidal lobe
  • left lobe
  • right lobe
  • isthmus
2
Q

Q: What can occur during thyroid operations? why? What else can be damaged? result?

A

A: bleeding, it’s close to lots of blood vessels

left recurrent larynheal nerve

voice change

3
Q

Q: What is visible from a side view of the thyroid? (3)

A

A: -superior parathyroid gland

  • inferior parathyroid gland
  • recurrent (inferior) laryngeal nerve running behind it = one of many important nerves that run along side thyroid
4
Q

Q: Draw a thyroid gland outline and label. (3) Which lobe is largest?

A

A: REFER

pyramidal lobe
isthmus
parathyroid glands

RIGHT

5
Q

Q: What is the foramen caccum? (2)

A

A: dimple at back of tongue (dissappearing thyroglossal duct)

6
Q

Q: What’s the weight of an adult thyroid?

A

A: 20g

7
Q

Q: When does the thyroid start developing? From? How? (3) Wrong?

A

A: 7 weeks in utero (once it has reached the correct place)

from base of tongue= midline outpouching of floor of pharynx

  • > outpouching forms a duct that elongates down= thyroglossal duct
  • > migrates down into neck until in correct place to grow (7 weeks = in correct position)
  • > divides into 2 lobes

if grows in wrong place= get lump

8
Q

Q: What can happen if parathyroid glands grow in the wrong place?

A

A: can cause calcium problems

9
Q

Q: What is the thyroglossal duct? function?

A

A: cord connecting thyroid to back of tongue

no function

10
Q

Q: What are the 3 possible problems with thyroid development?

A

A: Agenesis (complete absence)

Incomplete descent (ie base of tongue to trachea)= incorrect place

thyroglossal cyst (Segment of duct persists and presents as a lump years later)

11
Q

Q: What is a lingual thyroid? Treatment? Downside?

A

A: where it didn’t move at all and has grown at the back of the tongue

remove
-would need to be on thyroid hormone replacement for life

12
Q

Q: What is thyroxine essential for? Proof? Where does it occur?

A

A: normal brain development

neonates with thyroxine deficiency in utero have irreversible brain damage = cretin

countries with high iodine deficiency

13
Q

Q: What is a cretin? Feature? What happens when baby cretin is given thyroxine?

A

A: An individual with irreversible brain damage caused by lack of thyroxine

short

  • tongue back in mouth
  • more alert
14
Q

Q: How can cretinism be prevented? When?

A

A: Given thyroxine immediately if the TSH is found to be high

All babies have a heel prick for a blood test for thyroid function (measuring TSH) at the same time as the Guthrie test (for phenylketonuria) at 5-10 days of age

15
Q

Q: What is the site of thyroxine synthesis? Summarise. (3) Diagram. Active forms and inactive form?

A

A: thyroid follicular cell

  1. pituitary gland makes TSH
  2. stimulates iodine uptake from said cells ^
  3. events occur to produce thyroid hormone-> T3 and T4

REFER- 6 arrows

T3 and 4 are in the active form while thyroxine is inactive

16
Q

Q: Describe thyroid gland thyroxine storage.

A

A: have enough stored in colloid to last a month -> released as you need it (TSH controls)

17
Q

Q: Give an example of a thyroid hormone. Role. (2)

A

A: T4 goes into circulation and controls things like basal metabolic rate and body temperature

18
Q

Q: Compare thyroglobulin and thyroxine binding globulin. Which can be measured?

A

A: Thyroglobulin is not thyroxine binding globulin

Thyroxine binding globulin bonds 75% of thyroxine in the circulation whereas thyroglobulin is INSIDE the thyroid gland only

TBG

19
Q

Q: Which cells have a receptor for thyroid hormones? What are the overarching roles of thyroid hormones? (3)

A

A: all

regulate growth, development, metabolic rate

20
Q

Q: What percentage of the population is affected by thyroid disease? Male:female? Overacitve:underactive?

A

A: 5%

1: 4 (more common in females)
1: 1

21
Q

Q: What is primary hypothyroidism also called? What type of disease is it? Cause? (2) Result? (2) How do you clinically diagnose?

A

A: myxoedema

Primary thyroid failure

Autoimmune damage to the thyroid (or operation)

  • Thyroxine levels decline (causes below)
  • TSH levels climb

Measure TSH

22
Q

Q: Draw the HPT axis.

A

A: hypothalamo-pituitary-thyroid axis

REFER

H produces TRH (thyrotrophin RH)

thyrotrophs in pituitary produce thyrotrophin/TSH (thyroid stimulated hormone)

cause T3 and T4 release from the thyroid

negative feedback to the pituitary and hypothalamus

23
Q

Q: What are the features of primary hypothyroidism? (8)

A

A: -Deepening voice

  • Depression
  • tiredness
  • Cold intolerance
  • Weight gain with reduced appetite
  • Constipation
  • Bradycardia
  • Eventual myxoedema coma
24
Q

Q: Why is treatment of primary hypothyroidism essential? (3)

A

A: -Otherwise patients will die

  • They will perform poorly
  • Cholesterol goes up - causing death from heart attacks and strokes
25
Q

Q: What is the treatment of primary hypothyroidism? (2)

A

A: Simply replace thyroxine - usually one tablet (100 micrograms on average) daily

Monitor the TSH and adjust dose until TSH is normal

26
Q

Q: What’s the quantitative result of an overactive thyroid? (2) Name? (2)

A

A: Make too much thyroxine

TSH levels fall to zero

(thyrotoxicosis or hyperthyroidism)

27
Q

Q: What are the metabolic effects of an overactive thyroid? (5)

A

A: Raised basal metabolic rate

Raised temperature

Burn up calories and lose weight

Increased heart rate= dangerous

Every cell in the body speeds up

28
Q

Q: What are the sympomatic features of hyperthyroidism? (9)

A

A: Myopathy

Mood swings

Feeling hot in all weather

Diarrhoea

Increased appetite but weight loss

Tremor of hands= adrenaline making them over anxious

Palpitations

Sore eyes

goitre=swelling of the neck resulting from enlargement of the thyroid gland

29
Q

Q: What are the causes of hyperthyroidism? (1)

A

A: Graves’ disease, where the whole gland is smoothly enlarged and the whole gland is overactive

30
Q

Q: What is Graves disease? What does it involve? What does it cause? (4) Don’t confuse?

A

A: Autoimmune

Antibodies bind to and stimulate the TSH receptor in the thyroid

  • goitre (smooth)
  • hyperthyroidism
  • Other antibodies bind to muscles behind the eye and cause exophthalmos
  • Other antibodies stimulate growth/swelling of the shins and cause PRETIBIAL MYXOEDEMA (hypertrophy in front of tibia)

Not to be confused with myxoedema= hypothyroidism