Thyroid

Question 1

Why do you ask the patient to swallow?

Answer 1

the thyroid is attached to the pre-tracheal fascia, and the fascia moves upwards during swallowing

Question 2

Why do you ask the patient to stick out the tongue?

How is a thyroglossal cyst linked to pt sticking out their tongue?

Answer 2

thyroid starts in the base of the tongue embryologically, and descends downward towards the thoracic cavity, and the thryoglossal duct should obliterate after the descend is completed

if the thyroglossal duct is not obliterated, then it forms a throglossal duct cyst, that is still attached to the base of the tongue, which would move upwards when tongue is protruded

Question 3

What if you detect a pulse while palpating the lump?

Answer 3

Could be a carotid body tumor

Question 4

What feature is virtually diagnostic of Graves?

Answer 4

Bruit in the neck

Question 5

What lumps are in the midline of the neck?

Answer 5

goitre

thyroglossal cyst

Question 6

What is the anterior triangle? What lumps are in the anterior triangle?

Answer 6

midline of neck, inf border of mandible, anterior border of SCM

branchial cyst
carotid body tumor
lymph nodes

also: sebaceous cyst; lipoma

Question 7

What is the posterior triangle? What lumps are in the posterior triangle?

Answer 7

posterior border of the SCM, anterior border of trapezius, mid 1/3 of clavicle

cystic hygroma (above clavicle)
lymph node

also: sebaceous cyst; lipoma

Question 8

DDx for goitre?

Answer 8

multinodular goitre
Graves disease
solitary nodule (adenoma/ca)
Hashimoto's thyroiditis
Subacute thyroiditis

Question 9

Causes for hypothyroidism?

Answer 9

autoimmune

• primary atrophic thyroiditis (no goitre)
• Hashimoto’s initially

acquired

• iodine deficiency (no.1 cause worldwide)
• subacute thyroiditis
• iatrogenic: surgery; radioiodine; carbimazole; lithium; amiodarone

secondary
- panhypopituitarism (v rare)

Question 10

Features of Grave’s disease?

Answer 10

Goitre
thyrotoxicosis
eye disease in 50%: exophthalmos; ophthalmoplegia
pretibial myxedema
thyroid acropachy

Question 11

How to differentiate Graves from MNG?

Answer 11

Graves: smooth goitre, Grave’s features, TSH-receptor antibodies

Question 12

Indication for surgery for Grave’s disease?

Answer 12

cosmetic
local compression effect
failed medical Rx
intolerant of medication

Question 13

What causes lid lag and lid retraction?

Answer 13

ANY cause of hyperthyroidism

specific to Graves: exophthalmos & ophthalmoplegia

Question 14

What causes hyperthyroidism?

Answer 14

Graves
Toxic MNG
Toxic nodule (usually adenoma)
–> these 3 are 90%

thyroiditis in initial phase
- Hashimotos
- post-partum
- subacute
secondary (rare)
- TSHoma
- hydatidiform mole
- choriocarcinoma

Question 15

How do you Rx hyperthyroidism

Answer 15

medical

• symptom control: beta-blocker
• anti-thyroid therapy: carbimazole

radioiodine

surgical

• cosmetic, compression, malignancy
• procedures: total thyroidectomy; subtotal thyroidectomy

Question 16

Radioiodine CI?

Answer 16

pregnancy/breast feeding
young children @ home
incontinence - radioiodine is eiminated via urine

Question 17

Thyroidectomy complications?

early - late

Answer 17

early

• anaesthetic
• hemorrhage
• infection
• damage to surrounding structures - recurrent laryngeal nerve, external laryngeal nerve, trachea, esophagus, neck musculature
• transient hypoparathyroidism

late

• hypoparathyroidism
• recurrent hyperthyroidism
• hypothyroidism

Question 18

Causes for bilateral parotid swelling?

Answer 18

viral/bac parotitis
TB
alcohol
pleomorphic adenoma
Sjogrens
sarcoidosis

Question 19

Causes for unilateral parotid swelling?

Answer 19

duct blockage

unilateral pleomorhpic adenoma

Question 20

arterial supply of the thyroid?

Answer 20

superior thyroid artery - branch of external carotid
inferior thyroid a - thyrocervical trunk from 1st subclavian a
thyroideal ima a - arch of aorta

Question 21

venous drainage of thyroid?

Answer 21

superior thyroid v - drains into int jugular
mid thyroid v - drains into int jugular
inf thyroid v - drains into L brachiocephalic

Question 22

nerve supply of thyroid? what arteries do they run with?

Answer 22

ext laryngeal n - near sup thyroid A

recurrent laryngeal n - near inf thyroid A

Question 23

lymphatics of thyroid?

Answer 23

prelaryngeal
paratracheal
pretracheal

Question 24

position of thyroid and the isthmus?

tracheal rings/vertebral level

Answer 24

midline
thyroid cartilage - 6th tracheal ring (C5-T1)
isthmus location - tracheal rings 2, 3, 4
vertebral level - hyoid bone (C3), thyroid cartilage (C4), cricoid cartilage (C6)

Question 25

How do you investigate a lump in the neck?

Answer 25

Ultrasound

radioiodine uptake scan