Ocular Myositis

Question 1

Describe ocular myositis?

Answer 1

• Inflammatory swelling of one or more of EOM
  o More likely 1 muscle – likely MR
• Pseudo tumour
  o These pxs must be scanned
• Px presents with painful diplopia
  o Acute glaucoma type pain
  o Pain – myositis - muscle
• Unilateral proptosis – must think there is a mass and need to be scanned
• Incomitant strabismus do not tend to have pain
• 3rd, 4th, 6th nerve palsy will not come with pain (unless have aneurysm and the pain is in the headache from this)
• Graves’ comes with discomfort not pain
• BO# - comes with pain from the injury

Question 2

What are the signs and symptoms of ocular myositis?

Answer 2

• Acute pain
  o Comes from the swollen tendon
  o If scan px with Graves’ they have swollen muscles but the tendon is spared – so they do not have acute pain
• Proptosis
• Diplopia
  o Increases as look in direction of infected muscle
• Oedema – periorbital/chemosis
  o Everything swollen around it
• Underlying inflammatory disease/autoimmune disorder/sinusitis/cellulitis
  o Sinus infection – can easily get in to orbit as sinuses are so close to eye
  o Orbital cellulitis – see this lot more from e.g. covid and other viruses and not being given antibiotics as easily  can end up with meningitis, encephalitis – v dangerous
  o Could be arthritis, MS, other autoimmune disorders – px needs full work up when seen

Question 3

What is the diagnosis of ocular myositis?

Answer 3

• Acute onset but can be chronic
  o Px may wake one morning – feeling weird – cant look over to one side – v sore looking to that side
• CT scan will show marked inflammation/swelling of one or more muscles, including tendon
• Ensure this is not Rhabdomyosarcoma, a highly malignant tumour that presents in childhood
  o Usually associated with acute proptosis & strabismus
  o Anyone with any form of muscle swelling, any sign of proptosis (look from above) – have to think there is a swelling & so MUST be scanned – could easily be benign but better safe than sorry

Question 4

Compare Graves’ with Ocular Myositis?

Answer 4

Graves’:
Lid retraction/lid lag
Dull pain
Bilateral/asymmetrical
Gradual onset
Abnormal TFT (thyroid function test)
Swelling of more than one EOM on CT, with tendon sparing

Ocular Myositis:
None
Severe pain
Unilateral typically
Acute onset
Normal TFT (thyroid function test)
Swelling of one muscle plus tendon

Question 5

What is the treatment of ocular myositis?

Answer 5

• Corticosteroids are highly effective
• Prisms are required
  o Fresnel – as they will be changing rapidly – they are seen weekly in hospital
• Botox if other treatments aren’t working