Hyperthyroidism

Question 1

Describe the thyroid hormone levels in primary vs secondary disease?

Answer 1

Primary:
overactive thyroid causes high T3 and T4 and low TSH

Secondary:
-TSHoma secretes TSH causing a high TSH and high T3 and T4

Question 2

What are the 3 causes of hyperthyroidism? symptoms?

Answer 2

Autoimmune: graves disease (60-80%)

Nodular thyroid (20-40%): multinodular goitre, toxic nodule (adenoma)

Thyroiditis: subacute, post-partum

(rare causes include iodine or medication)

Question 3

Describe the epidemiology and risk factors for graves disease. what is the natural history of disease?

Answer 3

• Lifetime risk 2% females, 1% males
• younger 20-50YO
• F>M 10:1
• genetic, FH
• high iodine intake
• smoking
• at 18mths 50% burn out and 50% relapse

Question 4

What tests are available for graves disease?

Answer 4

• high T3/T4, low TSH
• TSH receptor antibodies +ve
• smooth symmetrical goitre
• scintigraphy shows high uptake
• USS

Other antibodies:

• anti-TPO antibodies (70-80%)
• anti-thyroglobulin antibodies (30-50%)

Question 5

What signs are seen in graves disease?

Answer 5

lid retraction/lag
chemosis
proptosis
visual loss
diplopia
pre-tibial myxoedema

Question 6

What is the treatment for eye disease in graves disease?

Answer 6

• lubricants
• decompressive surgery
• radiotherapy
• corrective surgery
• stop smoking

Question 7

Nodular thyroid disease:

-what is the epidemiology?

Answer 7

older patient
more insidious onset
gland may feel nodular

Question 8

What tests are used for nodular thyroid disease?

Answer 8

• high T3/T4, low TSH
• TSH receptor antibodies negative
• Assymetrical goitre
• high uptake on scintigraphy

Question 9

What is subacute thyroiditis?

-epidemiology?

Answer 9

F>M, age 20-50, may be viral triggered, may be assoc. with sore throat/fever/viral symptoms
-usually self limiting over few mths

Question 10

What tests for subacute thyroiditis?

Answer 10

T4 - high in early stage, low in late, then normal
TSH - low in early stage, high in late, then normal
Scintigraphy scan = low uptake

Question 11

What are the:

• cardiac
• sympathetic
• CNS
• GI
• Visual
• Hair/skin
• periods
• muscles
• weight change
• thermogenesis
  assoc. symptoms in hyperthyroid

Answer 11

• cardiac: palpitation/AF/Cardiac failure
• sympathetic: tremor/sweating
• CNS: anxiety/nervousness/irritability/sleep
• GI: frequent loose bowel movement
• Visual: lid retraction, diplopia
• Hair/skin: brittle, thin, fast nail growth
• periods: lighter less frequent bleeding
• muscles: weakness esp. in thighs/upper arms
• weight change: inc. in appetite but wt loss
• thermogenesis: intolerance to heat

Question 12

What is the oral treatment for hyperthyroidism?

Answer 12

Carbimazole (if pregnant propylthiouracil)

• in graves start at high dose, reduce over 12-18mths, then stop (50% relapse)
• use B blocker for sympathomimetic sx

Question 13

What is the surgical treatment for hyperthyroidism?

Answer 13

Radio-iodine:

• high risk hypothyroidism
• avoid prolonged contact with children/pregnant women
• avoid pregnancy for 6mths

Question 14

What is a thyroid storm?

Answer 14

Severe thyrotoxicosis:

• resp. and cardiac collapse
• hyperthermia
• exaggerated reflexes
• may require ventilation
• may be assoc. with underlying infection

Tx:

• lugols iodine
• glucocorticoids
• PTU
• B blockers
• fluids
• monitoring