2.2 Thyroid Eye Disease II

Question 1

What are some differentials of TED?

Answer 1

• Orbital injury (eg blow out fracture)
• Orbital inflammation
• Space occupying lesion (orbital tumour)
• Iatrogenic
• CPEO (chronic progressive external ophthalmoloplegia)
• MG (myasthenia gravis)
• Ocular myositis

Question 2

What are the effects of TED on each of IR, MR, SR?

Answer 2

• Typically IR fibrosis causes a hypo deviation. Maximum in elevation +/- small degree of excyclotorsion. CHP – chin elevation for comfort.
• MR fibrosis leads to an eso deviation due to abduction deficit.
• SR fibrosis leads to a depression deficit, usually maximum in abduction and adduction.
• It is common to see an eso and a hypo deviation together.
• These deviations can be manifest or latent – patients can have extended fusional reserves due to the gradual onset.

Question 3

What are orbital examinations that can be performed on TED?

Answer 3

• Lid lag (von Graefe’s sign) – delay in moving the eyelid as the eye moves downwards.
• Measure the PF.
• Look at the levator function (distance lids travel while frontalis muscle is held inactive at the brow).
• Marginal fold distance (from upper eyelid margin to fold of skin)
• Abnormalities of tear production
• Lower eyelid laxity or scleral show
• Lagophthalmos (difficulty in complete closure of the eyelid over the eyeball).
• Eyelid retraction

Question 4

What enhanced orthoptic assessments are appropriate for TED?

Answer 4

• IOP – iCare - (normal range 10-21mmHg)
• Proptosis – Hertel exophthalmometer (normal range 12-21mm)
• Colour vision – Ishihara – indication of optic nerve compression.

Question 5

What are the visual aims in TED patients?

Answer 5

• Watch for stabilisation of OM
• Centralise and enlarge the field of binocular single vision where possible
  o Prisms
  o CHP
  o Bangerter foil
  o Patch

Question 6

How can TED be prevented?

Answer 6

• Stabilise thyroid function – regular blood tests required
• Selenium – can be taken as a supplement (2/3 brazil nuts per day)
• Probiotics
• Smoking cessation - smoking and vaping increases the risk of TED in Graves’ disease by 7x. The number of cigarettes smoked per day influences the incidence of proptosis and diplopia.

Question 7

How is TED investigated?

Answer 7

• Blood tests – TSH receptor antibodies, TSH, FT3, FT4
• CT scans and MRI imaging – shows large muscles within the orbit. It is important to scan in cases of unilateral proptosis to exclude an orbital tumour.

Question 8

What are the treatments of TED?

Answer 8

• Radioactive iodine – can increase the risk of new or worsened TED symptoms
• Thyroidectomy – reduces the risk of TED
• Teprotumumab – can significantly reduce proptosis
• Conservative medical management – topical therapy – to aid with sore and red eyes caused by conjunctival injection and chemosis. – Artificial tears, tape eyes closed at night and clingfilm to create a ‘greenhouse’ over the eyes at night.

Question 9

What are the aims of medical management in TED?

Answer 9

• Aim of treatment – suppress orbital inflammation and reduce tissue changes in the EOM, orbital fat and periocular soft tissues.
• Preservation of sight is the priority
• Initially high-dose steroids – reduce inflammation and thereby reduce pressure on the optic nerve.
• Radiotherapy treatment – avoid in cases of TED, if cannot avoid give steroid cover. Can increase the risk of TED.
• Immunosuppressive therapy – improve congestive changes. Main treatment for active moderate to severe TED.

Question 10

What are the surgical management steps?

Answer 10

1. 1st - Decompression surgery – proptosis, cosmetic improvement or VA risk
2. 2nd – Strabismus surgery – recession MR/IR, improve OM caused by mechanical restriction, correction cosmetic defect.
3. 3rd – Lid surgery