Disorders of the orbit & Nasolacrimal System

Question 1

Oribital cellulitis/ Abscess causes (5)

Answer 1

1) penetrating wound through mouth
2) foreign body
3) tooth root abscess
4) infection of zygomatic/ salivary gland
5) idiopathic

Question 2

Oribital cellulitis/ Abscess clinical signs (6)

Answer 2

1) Acute unilateral exophthalmos
2) pain upon globe retropulsion & opening of the mouth
3) protrusion of 3rd eyelid
5)conjunctival hyperemia, chemosis
6) periocular swelling, mucopurulent discharge

Question 3

How are Oribital cellulitis/ Abscess diagnosed and treated (4)

Answer 3

1) Ultrasound
2) CT scan
3) Drainage
4) systemic antibiotic

Question 4

Sialocele (2)

Answer 4

1) Acquired disorder
2) Cystic structures: grandular or epithelial tissue

Question 5

Sialocele causes (3)

Answer 5

1) trauma to the head
2) leakage of saliva from zygomatic gland/duct
3) ulceration of oral mucosa: obstruction of saliva outflow

Question 6

Masticatory Muscle Myositis signalment and causes (3)

Answer 6

1) dogs, young, large breeds
2) immune mediated inflammatory myopathy
3) temporalis, masseter & pterygoid muscle

Question 7

Masticatory Muscle Myositis acute phase clinical signs (5)

Answer 7

1) Exophthalmos with 3rd eyelid elevation
2) severe pain upon palpation
3) restricted jaw movements
4) anorexia
5) +/- blindness: optic neuritis

Question 8

Extraocular Muscle Myositis (2)

Answer 8

1) Immune mediated inflammatory myopathy to extraocular muscles
2) CD3 + lymphocytic infiltration

Question 9

Extraocular muscle Myositis clinical signs (3)

Answer 9

1) Bilateral exophthalmos without third eyelid elevation
2) not painful
3) retraction of the upper eyelid

Question 10

Orbital Neoplasia (2)

Answer 10

1) Primary: arise from orbital tissue
2) Secondary: invade the orbit from adjacent structures or metastasize from distant sites

Question 11

Orbital Neoplasia clinical signs (5)

Answer 11

1) Slowly progressive exophthalmos
2) not painful
3) typically unilateral
4) decrease globe retropulsion
5) 3rd eyelid elevation

Question 12

Proptosis (3)

Answer 12

1) Sudden forward displacement of the globe with entrapment of the eyelids
2) Brachycephalic breeds
3) cats require greater force (poor prognosis)

Question 13

Premature Evaporation of Tears causes (4)

Answer 13

1) Qualitative tear film deficiencies
2) marginal blephritis/meibomianitis
3) autoimmune diseases affecting mucocutaneous junctions
4) severe cicatrization/conjunctival scarring

Question 14

Keratoconjunctivitis Sicca (KCS) causes (7)

Answer 14

1) Quantitative Aqueous deficiency
2) Immune mediated (most common)
3) congenital (alacrima, lacromal gland hypoplasia)
4) Infectious (canine distemper)
5) Drug induced (sulfanamides, atropine, topical anesthesia)
6) Iatrogenic (third eyelid gland removal)
7) Neurogenic (parasympathetic denervation)

Question 15

Congenital anomalies of the orbit (6)

Answer 15

1) Anophthalmia
2) Microphthalmia
3)Synophthalmia
4) Cyclopia
5) Converging Strabismus
6) Diverging Strabismus

Question 16

Anophthalmia (3)

Answer 16

1) absence of the eye
2) severe developmental deficiency in the primative forebrain: nonviable fetus
3) close exam reveals primative ocular tissues

Question 17

Microphthalmia (2)

Answer 17

1) early deficiency in the size of the globe
2) associated w/ small palpebral fissure

Question 18

Causes of Microphthalmia (5)

Answer 18

1) hereditary
2) merle ocular dysgenesis (MOD)
3) Collie eye anomaly (CEA)
4) BVDV
5) Nutritional (hypovitaminosis A-pig)

Question 19

Synophthalmia (3)

Answer 19

1) 2 incompletely separated of fused fused globes
2) severe cranial malformations: nonviable fetus
3) ingestion of Veratrum californicum weed on day 14 of gestation

Question 20

Converging strabismus (3)

Answer 20

1) eyes meeting at a point- nose
2) bilateral convergent strabismus with exophthalmia (BCSE)
3) Inherited in Siamese cats

Question 21

Diverging strabismus (2)

Answer 21

1) Eyes going in different directions
2) considered normal in brachycephalic breeds

Question 22

Clinical manifestations of nasolacrimal system disorders (2)

Answer 22

1)Epiphora (most common): onstruction of tear flow through NLS or over production of tears
2) Mucopurulent puntal, conjunctival & nasal discharge

Question 23

What is the Jone’s test?

Answer 23

Fluorescein dye passage
- normograde (eye to nose)
- retrograde (nose to eye