hyperthyroidism W6

Question 1

commonest cause of primary hyperthyroidism? what occurs in this condition?

Answer 1

Graves Disease (75%)
autoimmune disease, antibodies attack thyroid to make it overactive. can be associated with eye disease.
smooth goitre with uniform increased uptake on scintigraphy

Question 2

what is scintigraphy?

Answer 2

gamma scan

Question 3

what accounts for 15% of primary hyperthyroidism? what occurs in this condition?

Answer 3

toxic multinodular goitre
multiple lumps (nodules) on enlarged thyroid (goitre)
often one or more lumps will be overactive
can get lid lag or lid retraction, but no other features of thyroid eye disease
isolated hot-spots between dark spots on scintigraphy

Question 4

what is lid lag or lid retraction a result of?

Answer 4

activation of the sympathetic nervous system

Question 5

links between age and thyroid gland?

Answer 5

as age increases glands become progressively more nodular. can cause compression of trachea. can get elevation of T3 and T4

Question 6

other causes of primary hyperthyroidism (other then Graves disease or toxic multinodular goitre)

Answer 6

toxic nodule (single lump)
thyroiditis (temp overactivity, can be followed by underactivity)

Question 7

what can trigger thyroiditis?

Answer 7

pregnancy, infection, drugs

Question 8

symptoms of hyperthyroidism?

Answer 8

weight loss (despite good appetite - often very hungry)
tiredness
tremor, palpitations, hot/sweaty (activation of symp system)
diarrhoea
light/absent menses (menstrual blood)
irritable/anxiety
eye problems
muscle weakness

Question 9

eye problems in hyperthyroidism?

Answer 9

change in appearance
red
gritty
painful
double vision

Question 10

muscle weakness is particularly prominent in which muscles in hyperthyroidism?

Answer 10

large proximal muscles of the thigh

Question 11

hyperthyroidism - points to focus on when taking a history?

Answer 11

PMH and meds - asthma, heart disease
FH - thyroid or other autoimmune disease
SH - smoking, job and family

Question 12

examination for hyperthyroidism?

Answer 12

agitated, talk fast
warm, sweaty
temor
increased heart rate, may be atrial fibrillation
smooth goitre (Graves) vs MNG vs single nodule vs no goitre (thyroiditis)
bruit heard over goitre almost diagnostic of graves
eyes

Question 13

bruit?

Answer 13

increased vascular supply causes rushing noise

Question 14

eye examination for graves disease?

Answer 14

non specific to graves - lid retraction and lag
specific to graves:
redness
gritty sensation
dry/watery eyes
pain on eye movement
swelling around eyes
proptosis
double vision
loss of colour vision

Question 15

proptosis?

Answer 15

pushed forward appearance of eyes

Question 16

pathogenesis of eye disease in graves disease?

Answer 16

beta cells produce TSH receptor antibodies which bind with receptors in retro orbital connective tissue. this affects adipocytes and fibroblasts. adipocytes produce new fat (adipogenesis). fibroblasts produce glycosaminoglycans retain more water. this oedema and increased fatty tissue contribute to swelling in muscles and tissues behind eyes, leading to symptoms.

Question 17

conjunctive redness categories?

Answer 17

mild - 25% of whites of eyes or less
moderate - up to 50%
severe - over 50%

Question 18

eyelid/periorbital swelling types?

Answer 18

fluid swelling
non-fluid swelling (caused by fatty tissue)

Question 19

eyelid/periorbital erythema
definition and types?

Answer 19

redness of eyelids
pretarsal - bit that closes over eye
preseptal - further out around eyelid

Question 20

swelling of the plica/caruncle?

Answer 20

areas in medial aspect of eye (corner of eye closest to nose)
caruncle - white structure
plica - red structure (fold)

Question 21

primary hyperthyroidism diagnosis?

Answer 21

TRAbs (TSH receptor antibodies) - significantly positive indicates Graves
TPO (thyroid peroxidase) - less specific

if TRAbs negative then do scintigraphy (often technetium rather than radio-iodine uptake)

Question 22

management of hyperthyroidism - drugs?

Answer 22

antithyroid drugs (ATDs) - carbimazole and propylthiouracil (PTU)
both block thyroid peroxidase activity.

Question 22

scintigraphy - why does technetium benefit over radio-iodine uptake?

Answer 22

less radiation

Question 23

when are carbimazole and propylthiouracil not used for hyperthyroidism? why?

Answer 23

not used for thyroiditis.
high T4 levels are due to release of hormone stores from damaged gland, but gland is not actually overactive.

Question 24

what betablocker is used for hyperthyroidism? what does this treat and when shouldn’t it be used?

Answer 24

propranolol.
treats sympathetic systems (tremor, increased heart rate)
contraindicated in asthma

Question 25

radioactive iodine treatment for hyperthyroidism limitations?

Answer 25

risk of long term hypothyroidism
avoid pregnancy for 6 months
restrict contact with children under 12 and pregnant women
limit close contact (don’t share bed w partner for 11 days)

Question 26

surgery for hyperthyroidism risks?

Answer 26

risk of hypothyroidism
risk of damage to recurrent laryngeal nerve and parathyroid glands

Question 27

what treatment to use when in hyperthyroidism?

Answer 27

Graves - ATDs first time around.
Radioactive iodine for recurrent Graves and TMNG or toxic nodule
consider surgery for patients with large goitre or eye disease

Question 28

risk of hypothyroidism after radioactive iodine in different conditions? why?

Answer 28

risk is lower with TMNG and toxic nodule than graves as isn’t taken up by whole gland

Question 29

which patients should avoid radioactive iodine and why

Answer 29

those with eye disease as there is a risk of thyroid eye disease flaring up after radioactive iodine.

Question 30

treatment of thyroid eye disease - active disease?

Answer 30

may respond to steroids or other immunosupression

Question 31

treatment of thyroid eye disease - inactive/burnt out disease?

Answer 31

will not respond to immunosuppression
may need surgical reconstruction

Question 32

management of thyroid eye disease?

Answer 32

achieve euthyroidism (normal thyroid function)
smoking cessation
topical lubricants
selenium 200mcg daily (antioxidant)
steroids

Question 33

management of thyroid eye disease if initial measures do not work?

Answer 33

consider additional immunosuppressant treatment (eg rituximab) as it is TRAbs that drive the eye disease
consider orbital radiotherapy
surgical decompression if evidence of optic neuropathy and raised intraocular pressure