Thyroid eye disease

Question 1

What is thyroid eye disease?

Answer 1

Autoimmune response against TSH receptor leads to retro-orbital inflammation. Inflammation results in glycosaminoglycan and collagen deposition in the muscles.
- Auto-antibodies target the extraocular muscles, causing swelling behind the eye which results in proptosis of the eyeballs

Question 2

Describe the epidemiology of thyroid eye disease

Answer 2

• Affects 25-50% of patients with Graves’ Disease
• F>M

Question 3

What are the risk factors for thyroid eye disease?

Answer 3

Smoking → most important modifiable risk factor for development of thyroid eye disease.

Question 4

What are the presenting signs/ symptoms of thyroid eye disease?

Answer 4

• Patients may be eu/hypo/hyperthyroid
• Conjunctival Oedema
• Optic Disc Swelling
• Ophthalmoplegia (paralysis of muscles surrounding eye)
• Lid Lag → upper eyelid is higher than normal with the globe in downgaze
• upper eye lid retraction
• Exophthalmos
• Inability to close eyelids → leads to sore, dry eyes. If untreated patients at risk of exposure keratopathy

Question 5

What investigations are used to diagnose/ monitor thyroid eye disease?

Answer 5

• ↓ TSH and ↑ free T3/T4 → hyperthyroidism
• ↑ TSH Receptor Antibodies → specific and sensitive for graves disease
• Any Changes in Vision - urgent review by ophthalmologist

Question 6

How is thyroid eye disease managed?

Answer 6

1. Avoid Smoking → worsens thyroid eye disease
2. Eye Protection
3. Topical Lubricants → prevent corneal inflammation caused by exposure
4. High Dose IV Steroids → prednisolone
5. Thionamides + Radiotherapy + Surgery → treat hyperthyroidism if present
   (Radioactive iodine ablation therapy worsens thyroid eye disease; contraindicated)

Question 7

What complications may arise from thyroid eye disease?

Answer 7

Exposure keratopathy – where corneal damage and infection occur as the patient is unable to close their eyes

Compressive optic neuropathy – occurs when the retro-orbital swelling begins to compress on the optic nerve

suspect this when signs of optic nerve involvement occur – reduced visual fields, reduced colour vision, reduced visual acuity, relative afferent pupillary defect
Diplopia – due to fibrosis of the extraocular muscles limiting gaze in various directions