test 2: lecture 22 orbit

Question 1

The bony cavity that encloses the eyeball with its associated muscles,
blood vessels and nerves.

Answer 1

orbit

Question 2

compare orbit between dog and horse

Answer 2

dog has incomplete orbital rim

horse have complete bony rim

Question 3

what nerves come from optic foramen

Answer 3

optic nerve (CN2)

Question 4

what nerves come from orbital fissure

Answer 4

occulomotor (3)
trochlear (4)
ophthamlic (5)
abducens (6)

Question 5

what are the 7 extraocular muscles and what do they control

Answer 5

Question 6

Answer 6

orbital ligament

Question 7

The orbital ligament completes the dorsolateral portion of the orbit in the dog and cat and covers the —

Answer 7

lacrimal gland

Question 8

what is red and pink?

Answer 8

medial pterygoid muscle
nasal cavity

Question 9

what is orange and blue

Answer 9

zygomatic salivary gland
frontal sinus

Question 10

Answer 10

endorbita (periorbita)

“cone” around the muscles and glands of the eye, blood vessels and optic nerve

Question 11

4 major clinical signs of orbital disease

Answer 11

Exophthalmos- eye buldging
Globe deviation
Lack of retropulsion - can’t get globe to move
Fundus lesion of globe indentation (retrobulbar mass)

Question 12

protrusion of the globe out of the orbit caused by an increase in orbital content).

Answer 12

exophthalmos

(buldging eye)

Question 13

most frequent types of orbital disease

Answer 13

tumor
trauma
abscesses
inflammation/cellulitis

Question 14

two uncommon causes of orbital disease

Answer 14

zygomatic cyst and mucocele
myositis

Question 15

— are rare causes of orbital disease

Answer 15

vascular abnormalities (AV fistula, varices)

Question 16

diagnostic approach to determine orbital disease

Answer 16

history
examine both eyes at a distance
palpate periorbital area
perform complete eye exam
examine oral cavity

extra testing can be FNA, imaging (CT/MRI, ultrasound, xray)

Question 17

orbital fracture due to trauma is most frequent in —

Answer 17

horses
dorsal orbital rim and zygomatic arch

Question 18

trauma to orbit in dogs is most common by

Answer 18

penetrating foreign body

through eye or through soft palate

Question 19

Proptosis following blunt trauma is frequent in what type of dogs

Answer 19

brachycephalic

hit by car or dog fight

Question 20

what to do in ophthalmic emergency due to trauma

Answer 20

Keep cornea lubricated!
Reposition eye as soon as patient is stabilized
Lateral canthotomy
Partial or complete tarsorrhaphy (stents)
Leave room medially for topical drugs.

stabilize and then wait and see

Question 21

clinical signs of orbital abscess or inflammation

Answer 21

Orbital signs (Exophthalmos * Globe deviation * Lack of retropulsion* Fundus lesion of globe indentation)

Acute
Unilateral
Pyrexia (fever)
Submandibular adenomegaly
Pain on palpation
Pain on jaw manipulation

Question 22

how to diagnose orbital abscess or inflammation

Answer 22

CBC
Imaging – ultrasound, CT, MRI

Skull radiographs not that useful

FNA (or drainage) + cytology + Anaerobic, aerobic, fungal culture

Question 23

what can cause orbital abscess or inflammation

Answer 23

Foreign body
Wound

2ary to sinusitis (maxillary, frontal)
2ary to tooth root abscess
2ary to infection of zygomatic or lacrimal gl.

Question 24

how to treat orbital abscess or inflammation

Answer 24

Systemic antibiotics for 14-21 days

Use AB directed against anaerobes (eg. amoxycilin + clavulanic acid)

Topical antibiotic/lubrication if cornea exposure and lagophthalmos

Systemic NSAIDs (NO STEROIDS)

Systemic opioids

Question 25

clinical signs of orbital tumor

Answer 25

**Slow progression** in older animals Unilateral **Initially no pain** Exophthalmos (frequent) Enophthalmos (if tumor located rostral to globe) Variable **deviation of the globe** Limited to no retropulsion **Globe indentation (fundus)** Vision often retained (except if optic nerve or meningioma involvement)

Question 26

Most orbital tumors are ---

Answer 26

primary and malignant

Question 27

how to treat orbital tumor

Answer 27

**Orbitotomy**: open orbit and take out tumor (**if benign and visual)**. **Exenteration**: clean everything out- leaving only bone (**if malignant**) ± chemotherapy ± radiotherapy.

Question 28

clinical signs of zygomatic mucocele/cyst

Answer 28

Orbital swelling Exophthalmos 3rd eyelid protrusion Protrusion oral mucosa behind last molar **Painless**

Question 29

how to diagnose zygomatic mucocele/cyst

Answer 29

Imaging : U/S, CT, MRI FNA: **Honeylike liquid**

Question 30

how to treat zygomatic mucocle/cyst

Answer 30

Surgical excision by one of these 3 approaches: * transconjunctival * oral, * lateral orbitotomy

Question 31

extraocular polymyositis

Answer 31

inflammation of the 7 muscles that control movement of the eye

Question 32

clinical signs of extraocular polymyositis

Answer 32

inflammation of muscles that move the eyeball immune-mediated? acute **bilateral** fever **anorexia** opening mouth is **painful/limited** at later stage muscle fibrosis causes mild enophthalmos (eye shrunken in) and strabismus(eye in wrong direction)

Question 33

what types of dogs get extraocular pilymyositis

Answer 33

golden retriever

Question 34

what kind of dogs get eosinophilic myositis of the masticatory muscules

Answer 34

german shepherd, wimaraner (golden retriever and lab)

Question 35

clinical signs of eosinophilic myositis of the masticatory muscules

Answer 35

Inflammation involves temporal, pterygoid, masseter muscles. immune-mediated? acute **bilateral** fever **anorexia** jaw opening **painful** and limited at later stage muscle fibrosis causes muscle atrophy and enophthalmos(eye shrunken in)

Question 36

how to treat myositis

Answer 36

Immunosuppresive doses of **corticosteroids** systemically for 3-4 weeks or **Azathioprine** 1-2 mg/kg for 10-14 days then tapered off ## Footnote used to treat extraocular polymyositis and eosinophilic myositis of the masticatory muscles

Question 37

how to diagnose extraocular polymyositis vs eosinophilic myositis of the masticatory muscles

Answer 37

**extraocular polymyositis**: CT/MRI **eosinophilic myositis of the masticatory muscles**: muscle biopsy, elevated CPK

Question 38

remove the globe

Answer 38

enucleation

Question 39

remove globe and soft tissue

Answer 39

exenteration

Question 40

surgery to open orbit

Answer 40

orbitotomy