Thyroid eye disease (OP)

Question 1

Who does thyroid eye disease affect?

Answer 1

In the context of hyperthyroidism, Grave’s patients can get this disease:

• 25-50% of patients with Grave’s
• F>M

Question 2

Describe the pathophysiology of thyroid eye disease.

Answer 2

• autoimmune response against TSH receptor leads to retro-orbital inflammation (TSH receptors found in retro-orbital tissue)
• autoantibodies target extraocular muscles causing swelling behind the eye –> eye proptosis (AKA exophthalmos)
• inflammation –> glycosaminoglycan and collagen deposition in muscles –> orbital fat and tissue expansion

Question 3

What is the most important modifiable risk factor for thyroid eye disease?

Answer 3

Smoking

Question 4

What are the clinical features of thyroid eye disease? (8)

Answer 4

• patients may be eu/hypo/hyperthyroid
• exophthalmos
• lid lag (upper eyelid retraction) - upper eyelid is higher than normal with globe in downgaze
• conjunctival oedema AKA chemosis
• optic disc swelling
• ophthalmoplegia - paralysis of muscles surrounding eye
• inability to close eyelids –> sore dry eyes –> exposure keratopathy (damage to cornea)
• EOM involvement (late stage) –> double vision

Question 5

What does inability to close eyelids in thyroid eye disease lead to?

Answer 5

Sore and dry eyes –> exposure keratopathy (damage to cornea)

Question 6

What are some risk factors for thyroid eye disease? (3)

Answer 6

• Fx autoimmune thyroid disease
• female sex
• smoking / tobacco use

Question 7

How do we detect hyperthyroidism (thyroid eye disease)?

Answer 7

Low TSH, high T3/T4

Question 8

What is the specific and sensitive test for Grave’s disease (thyroid eye disease)?

Answer 8

High anti-TSH-R antibodies

Question 9

What might a CT/MRI of the orbit show in thyroid eye disease?

Answer 9

Muscle thickening

Question 10

What are some differential diagnoses for thyroid eye disease? (2)

Answer 10

• inflammatory eye conditions
• myasthenia gravis (typically unilateral and no thyroid dysfunction)

Question 11

What do we do if there are any changes to vision in thyroid eye disease?

Answer 11

Urgent review by ophthalmologist (immediate surgical intervention needed)

Question 12

What do patients with thyroid eye disease need to avoid?

Answer 12

Smoking - can worsen it

Question 13

How do we manage inflammation in thyroid eye disease?

Answer 13

• topical lubricant to prevent corneal inflammation caused by exposure
• high dose IV steroids (prednisolone)

Question 14

How do we treat hyperthyroidism if present in thyroid eye disease? (3)

Answer 14

• thionamides (anti-thyroid drugs e.g. carbimazole, propylthiouracil)
• radiotherapy
• surgery

Question 15

How do we sometimes manage thyroid eye disease in children?

Answer 15

‘Wait and see’ strategy may be appropriate if no changes in vision etc

Question 16

What is a complication of thyroid eye disease?

Answer 16

Sight-threatening orbitopathy - usually in first year after diagnosis of hyperthyroidism

These complications are rare and include corneal ulcers and optic neuropathy

Rx - protective measures, systemic corticosteroids and orbital decompression to relieve pressure on optic nerve

Rehabilitative surgery (to reduce proptosis and for correction of diplopia) and eyelid surgery may also be needed