Thyroid

Question 1

Describe the classic features of Graves disease (epidemiology, risk factors, presentation)

Answer 1

F, middle aged, previous autoimmune diseases
Presents with:
-Symptoms of hyperthyroidism
-Goitre
-Eye signs: exophthalmos, proptosis, lid lag

Question 2

Describe the pathophysiology of Graves disease

Answer 2

Autoimmune disease w anti-TSHR antibodies produced

• Bind to TSH-R and activate, causing release of thyroxine
• Antibodies also act on shins (pretibial myxoedema), eyes (Graves ophthalmopathy)

Question 3

Describe what eye signs can be seen in Graves disease

Answer 3

• Exophthalmos
• Proptosis
• Lid lag
• Redness, tearing
• Diplopia

Question 4

Describe the symptoms of hyperthyroidism

Answer 4

• Feeling hot (heat intolerance), sweating
• Weight loss
• Loose stools
• Tremor
• Anxiety
• Amenorrhoea
• Palpitations

Question 5

Describe the investigations for hyperthyroidism (+Graves)

Answer 5

• After history and examination
• Bloods: FBC, CRP, TFTs, U+Es, antibodies (to Dx Graves- anti-TSHR, anti-thyroid peroxidase)
• ECG
• Imaging: not necessary to Dx Graves, but important to differentiate from other conditions. Thyroid USS, technetium uptake scan

Question 6

Describe the management of Graves disease

Answer 6

Conservative:
-Clothing, avoid caffeine, etc

Medical (mainstay):

1) Beta-blockers: propranolol for everyone
2) Thyroid blocking drugs: carbimazole, PTU
3) Radio-iodine

Surgical:
-Thyroidectomy (total)

Question 7

What is the Wolff-Chaikoff effect?

Answer 7

Auto-regulatory phenomenon

Ingestion of a large amount of iodine suppresses release of thyroid hormones

Question 8

Describe the signs and symptoms of thyroid storm

Answer 8

• Congestive HF
• Confusion
• N+V
• Extreme agitation

Question 9

Describe the management of thyroid storm

Answer 9

Emergency!

• Call for help
• Admission to ITU
• Supportive: cooling, correct fluid status, resp support
• IV ABx if septic
• High dose carbimazole
• Steroids
• Beta-blockers
• Lugol’s iodine (to suppress thyroxine release)

Question 10

Describe the pros and cons of different thyroid lowering therapies

Answer 10

Anti-thyroid drugs (carbimazole):

• Non-invasive, appropriate for all patients w mild-mod
• Daily meds, can be stopped if AI disease remits
• SE: rash more common, rarely agranulocytosis

Radio-iodine: (NICE recommends 1st line)

• Usually just 1 treatment
• Can’t be used in pregnancy/lactation or in 6 months before, risk to family (eg parents must be away from young children)
• Risk of hypothyroidism in future requiring replacement (about 50%)

Thyroidectomy:

• Curative, good if planning pregnancy soon
• Invasive: risk of hypoparathyroidism + recurrent laryngeal nerve palsy (1-2/100)

Question 11

Describe the differential diagnoses for hyperthyroidism

Answer 11

Graves' disease
Toxic multinodular goitre (Plummer's)
Viral thyroiditis (de Quervain's)
Cancer 
Pregnancy 
TSHoma

Question 12

Describe the uses of technetium uptake scan

Answer 12

Helps to differentiate causes of goitre/thyroid nodules

• Widespread uptake (Graves) vs hot-spots (nodules)
• Cold (cancer) vs hot nodules (TMNG)

Question 13

Describe the causes of an enlarged thyroid gland

Answer 13

Diffuse: Graves, thyroiditis, pregnancy/postnatal
Nodular: Plummer’s, thyroid adenoma, thyroid carcinoma, lymphoma

Question 14

Describe the investigations to identify a thyroid swelling

Answer 14

• History: symptoms of hyperthyroidism? PMH? FHx?
• Examination: nodular vs diffuse swelling
• Bloods: FBC, CRP, TFTs, antibodies
• Imaging: USS (+/- FNA), technetium uptake scan

Question 15

Describe the causes of hypothyroidism

Answer 15

Hashimoto’s thyroiditis
de Quervain’s thyroiditis
Post-partum

Iatrogenic:

1) Graves: anti-thyroid drugs, radioiodine, surgery
2) Drugs: lithium, amiodarone

Question 16

Describe the symptoms of hypothyroidism

Answer 16

• Cold intolerance
• Fatigue
• Weight gain and increased appetite
• Constipation
• Depression
• Memory difficulties
• Dry skin
• HMB
• Voice changes

Question 17

Describe the signs of hypothyroidism on examination

Answer 17

• Cold intolerance (inappropriately dressed)
• Low voice
• Bradycardia
• Dry skin
• Delayed relaxation of reflexes

Question 18

Describe the signs of hyperthyroidism on examination

Answer 18

• Heat intolerance, sweating
• Agitation
• Fine tremor
• Tachycardia +/- tachyarrhythmia
• Thyroid acropachy**
• Proptosis, exophthalmos, lid lag, diplopia**
• Goitre**
• Pretibial myxoedema**

Question 19

Describe the investigations for hypothyroidism

Answer 19

• After history and examination

- Bloods: FBC, CRP, U+Es, LFTs, TFTs, antibodies (anti-thyroid peroxidase), lipids

Question 20

Describe the management of hypothyroidism

Answer 20

Conservative:
-Diet, exercise

Medical (mainstay):
-Levothyroxine lifelong

Question 21

What is subclinical hypothyroidism? When should it be treated?

Answer 21

Abnormally raised TSH with normal T3/T4
Risk of progression to hypothyroidism
Treat if TSH >10 or if antibodies and TSH 6-10

Question 22

How is levothyroxine dose titrated?

Answer 22

According to TSH levels (normalise is the goal)

-Measure after 4-6 weeks of dose change

Question 23

Describe the risks of untreated hyper/hypothyroidism

Answer 23

Hyperthyroidism:

• AF/ tachyarrhythmia, HF
• Osteoporosis
• Thyroid storm
• Infertility

Hypothyroidism:

• CVD
• Obesity
• Infertility

Question 24

Describe the types of thyroid cancer

Answer 24

Papillary:

• Most common type, younger pts
• Lymphatic mets early (detected w lymphadenopathy) but good prognosis

Follicular:
-Mets early, good prognosis

Medullary:

• Assoc w MEN2
• Parafollicular C cells, produces calcitonin

Anaplastic:

• Poorly differentiated
• Poor prognosis

Question 25

Describe the management of thyroid cancer

Answer 25

Typically:

Surgical (total thyroidectomy) -> medical (radioiodine ablation + TSH suppression w levo)