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Module 4 Orbit, Globe, Eyelids, TEL > The Orbit > Flashcards

The Orbit Flashcards

1
Q

What does the extraconal space consist of?

A 
Zygomatic salivary gland
Base of the third eyelid
Orbital fat
Maxillary artery
Palatine nerve
Infraorbital nerve
Maxillary branch of CN V
Parasympathetic pterygopalatine nerve and ganglion
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2
Q

What does the intraconal space consist of?

A

4 rectus muscles
2 oblique muscles
Retractor bulbi extraocular muscles
Periorbital fascial sheath

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3
Q

What are the clinical signs of extraconal orbital disease?

A

Non axial exophthalmos (strabismus)
Protrusion of the third eyelid
Extraocular muscle motility abnormalities

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4
Q

What are the signs of intraconal orbital disease?

A

Axial exophthalmos (no strabismus)
Minimal protrusion of the third eyelid
Extraocular muscle motility abnormalities

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5
Q

What is CT good for imaging in the orbit?

A

Bony structures
Dental/ sinus/ nasal cavity
Nasolacrimal disease
Metallic foreign body

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6
Q

What is MRI useful for in imaging the orbit?

A 
Soft tissues
Extraocular muscles
Orbital fat
Zygomatic salivary gland
Brain
Cranial nerves
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7
Q

Treatment for exposure keratopathy?

A

Lubricants

Medial/ lateral canthoplasty

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8
Q

What is an orbital arteriovenous fistula?

What is the clinical sign?

A

Rare congenital abnormal communication between the orbital arteries and veins

Pulsatile exophthalmos

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9
Q

What is the clinical sign of an orbital varice?

What is the treatment?

A

Intermittent exophthalmos, often worsens during exercise and can become permanent.

Coil embolization or exenteration

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10
Q

What is craniomandibular osteopathy?

A

Bilateral irregular nonneoplastic osseous proliferative disease of the cranium

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11
Q 
What breeds are affected by craniomandibular osteopathy?
What age?
Clinical signs?
Diagnosis 
Treatment?
A

WHWT
Scottish terrier
Cairn terrier
(Airedale)

Pain opening mouth
Not wanting head touched
Mandibular swelling/asymmetry of bony orbits

CT

Young dogs
None

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12
Q

What is the difference between exophthalmos and proptosis?

A

Proptosis has eyelid entrapment posterior to the equator of the globe, exophthalmos doesn’t.

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13
Q

Which extraocular muscle is the shortest and therefore the first to avulse in proptosis?

A

Medial rectus muscle

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14
Q

What is a good prognostic indicator for proptosis?

A

PLR and menace

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15
Q

If the sinuses are involved in a facial fracture (‘open fracture’) what medication should be given to the patient?

A

Broad spectrum ABs

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16
Q

What is the maximum time you should leave a facial fracture (due to fibrosis)?

A

5-7days

17
Q

Which imaging modality is best for looking for organic foreign bodies?

A

MRI

18
Q

Where in the orbit would you find a zygomatic mucocoele (sialocoele) on u/s?

What is the best imaging to perform for these?

A

Centrally

MRI

19
Q

What are the treatment options for a zygomatic mucocoele (sialocoele)?

A

Resected with the gland

Drainage of the pterygopalatine fossa

20
Q

What can orbital cellulitis and abscessation lead do?

A

Meningoencephalitis

21
Q

Where is the pterygopalatine fossa?

A

Behind the last maxillary molar

22
Q

What is masticatory muscle myositis?

A

An immune mediated disorder affecting muscles innervated by the mandibular branch of CN V and containing type 2M myofibres

23
Q

Which muscles are affected my MMM?

A

Temporal
Masseter
Ptyerygoid

24
Q

What ocular signs are seen with MMM?
Acute?
Chronic

A

Acute; Exophthalmos, TEL protrusion

Chronic; Enophthalmos (due to fibrosis)

25
Q

How is MMM diagnosed (2 ways)?

A

Serum antibodies to type 2M myofibrils

Biopsy of the temporalis muscle (muscle fibre degeneration + inflammation)

26
Q

What is the treatment for MMM?

A

Immunosuppressive doses of preds until resolution of CS then slow tapering
+/- other immunosuppressants

Lubricants
Physio

27
Q

What is extraocular polymyositis?

A

An immune mediated inflammatory myopathy affecting extraocular muscles in dogs.

28
Q

What size of dogs are most commonly affected by MMM?

A

Large breed

29
Q

What age/ sex is most commonly affected by extraocular polymyositis?
What breed?

A

Young entire females ~1yo

Golden retriever

30
Q

What are the clinical signs of extraocular polymyositis?

How do you diagnose?

A

Bilateral symmetrical exophthalmos with NO TEL protrusion (360’ scleral show)
No pain, clinically well

Clinical signs
Thickening and hyperechoicity oh the EOMs

31
Q

What is the treatment of extraocular polymyositis?

A

Immunosuppressive doses of preds/ other immunosuppressants

May need long term

32
Q

What clinical signs does fibrosing extraocular muscle myosotis with restrictive strabismus cause?

What animals/ breed/ sex are affected?

A

Uni/bilateral ventral/ventromedial strabismus (esotropia)
Enophthalmos

Young dogs
Shar Pei
Irish Wolfhound
Akita

33
Q

How do you diagnose fibrosing extraocular muscle myosotis?

How is it treated?

A

Biopsy- fibrosis and lymphocytic plasmacytic mononuclear cellular infiltration

Resecting the fibrotic muscle

34
Q

What percentage of orbital tumours in dogs are malignant?

Cats?

A

Dogs- 75%

Cats- 88%

35
Q

Are primary or secondary orbital tumours more common in dogs?
Cats?

A

Dogs- primary

Cats- secondary

36
Q

What are the clinical signs of Feline restrictive orbital myofibroblastic sarcoma (FROMS)?
Age/ breed/ sex?

A

Insidious unilateral exophthalmos
Restriction of the globe and eyelid motility (lagophthalmos)
Thickening of the eyelids
Then other eye +/- orbital tissue affected

Middle to older age, no sex/ breed

37
Q

How do you diagnose Feline restrictive orbital myofibroblastic sarcoma (FROMS)?
Treatment?

A

Biopsy (send off eye if remove)

No treatment - often PTS

38
Q

What are dacryops?

What is the cause?

A

Cysts of lacrimal gland tissue

Trauma or developmental

Module 4 Orbit, Globe, Eyelids, TEL (4 decks)

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