Conjunctiva

Question 1

What are the differential diagnoses for Red eye?

Answer 1

• Conjunctival hyperemia
  
  • extensive branching
  • Extraocular disease
• Episcleral injection
  
  • Radial pattern from limbus
  • Dark red
  • Intraocular disease
• Subconjunctival hemorrhage
  
  • Diffuse red
  • Trauma/bleeding disorder

Question 2

What types of ocular Discharge are there

Answer 2

• Serous
• Mucoid
• Mucopurulent

Question 3

What diagnostic tests can be done for “Red Eye”

Answer 3

• Fluorescein stain
• Schirmer tear test
• Intraocular pressure
• +/- Conjunctival cytology
• +/- Aerobic culture and sensitivity

Question 4

What is Ophthalmia Neonatorum? treatment?

Answer 4

• Infection prior to separation
  
  • Puppies - bacterial
  • Kittens - viral (FHV-1) or Chlamydia
• Treatment:
  
  • Separate eyelids
  • Flush with sterile saline
  • Puppies - broad spectrum antibiotic ointment - BNP (Bacitracin/Neomycin/Polymyxin B)
  • Kittens - Tetracycline ointment (Terramycin®)
  • Treat 4 - 6 times daily

Question 5

What are possible sequelae of Ophthalmia Neonatorum?

Answer 5

• Symblepharon
  
  • bulbar and palpebral conjunctiva form an abnormal adhesion to one another
• Corneal perforation
• Corneal scar formation
• Blindness

Question 6

What is Canine Conjunctivitis?

Answer 6

• Rarely infectious
• Usually secondary to other abnormalities
  
  • Entropion, ectropion, trichiasis, eyelid tumors…..
  • Tear film abnormalities - keratoconjunctivitis sicca (KCS)
  • Irritants - chemicals, dust, smoke….
• Bacteria can frequently be cultured at low numbers from normal conjunctiva
  
  • Staphylococcus, Streptococcus, Cornyebacterium, Bacillus spp.

Question 7

What is the treatment for Canine Conjunctivitis?

Answer 7

• Treat underlying cause
• Broad spectrum topical antibiotics QID
• Topical corticosteroids (hydrocortisone)
  
  • must be fluorescein negative
• If no response - re-evaluate diagnosis

Question 8

What is Follicular Conjunctivitis

Answer 8

• Typically seen in young dogs
• Lymphoid follicles bulbar surface of the nictitans
• Etiology - immune mediated, allergic, chronic irritation….
• Treatment: topical steroids +/- topical antihistamines (olopatadine)

Question 9

What is Feline Conjunctivitis?

Answer 9

• Usually Infectious
  
  • Feline herpesvirus 1 (FHV-1)
  • Chlamydia
  • Mycoplasma
  • Calicivirus
• Eosinophilic conjunctivitis

Question 10

What is Feline Herpesvirus 1?

Answer 10

• Most common cause of feline conjunctivitis
  
  • Seroprevalance up to 97% of cats
  • >80% of cats that recover are carriers
    
    • ~½ shed under normal conditions
• Latency occurs in trigeminal ganglion
• Short-lived in the environment (<18hr)
  
  • Virus is inactivated by most disinfectants
  • Sneezing carries the virus ~14ft
• Severe cases can result in Corneal Ulcers/Keratitis

Question 11

How is FHV-1 treated

Answer 11

• Most recover in 10-21 days
  
  • treat ones with moderate to severe conjunctivitis or corneal disease
• Topical antiviral medications
  
  • Cidofovir 0.5% solution BID
  • Idoxuridine 0.1% solution 4-8x daily
  • Trifluridine 1% solution 4-8x daily
    
    • keep refrigerated
    • topically irritating
• Systemic antiviral medications
  
  • Famciclovir 30-40mg/kg B-TID PO
• Oral lysine
  
  • 250mg PO BID kittens
  • 500 mg PO BID cats
• Decrease stress

Question 12

How is FHV-1 diagnosed?

Answer 12

• Clinical signs
  
  • conjunctivitis, ocular discharge, nasal discharge, sneezing
• Conjunctival cytology
  
  • Intranuclear inclusions, PMNs (WBC)
• PCR - sensitive and specific
• IFA - insensitive
  
  • Fluorescein may cause false+
• Serology (serum neutralization titer) - insensitive
• Virus Isolation
  
  • definitive dx for acute infection
  • insensitive for chronic infections

Question 13

What are the common sequela to FHV-1

Answer 13

• Recurrence
• Corneal disease/ulceration/perforation
• Chronic epiphora
• Symblepharon

Question 14

What isChlamydia felis

Answer 14

• Gram negative, obligate intercellular bacterium
• Causes Upper Respiratory infection in young cats
  
  • Chemosis begins unilaterally then bilateral
  • Follicles develop w/ chronicity

Question 15

How is a Chlamydia felis infections diagnosed?

Answer 15

• Cytology
  
  • Intracytoplasmic inclusion bodies
  • Days 3-14
• PCR

Question 16

What is the treatment for Chlamydia felis

Answer 16

• Oral medications:
  
  • Doxycycline (kittens >4wks)
    
    • 5mg/kg PO BID or 10mg/kg SID
    • *Risk of Esophageal stricture
  • Azithromycin (5-10mg/kg SID)
  • Pradofloxacin (5-7.5 mg/kg SID)
• Topical medications QID
  
  • in addition to oral therapy
  • Tetracycline (Terramycin)
  • Erythromycin
• Treat for at least a month
  
  • ideally at least 2 weeks beyond resolution of clinical signs

Question 17

What mycoplasma spp affect the eyes in cats? what issues do they cause

Answer 17

• Mycoplasma felis & M. gatae
• Opportunistic infections
• Conjunctival pseudomembranes

Question 18

How are Mycoplasma ocular infections diagnosed?

Answer 18

• Cytology: small cytoplasmic basophilic inclusion bodies
• Culture in specific media
• PCR test for M. felis

Question 19

What is the treatment for ocular mycoplasma infections

Answer 19

• Topical medications QID
  
  • tetracycline
  • Fluoroquinolones
• Oral medications
  
  • Doxycycline (kittens >4wks)
    
    • 5 mg/kg BID or 10mg/kg SID
  • Pradofloxacine (5-7.5 mg/kg SID)
• Treat for at least 2 weeks

Question 20

What is calicivirus

Answer 20

• RNA virus
• Common cause of URI in cats
  
  • oral and nasal ulceration
  • polyarthritis
  • low pathogenicity for conjunctiva
• Topical antivirals are ineffective
  
  • supportive care

Question 21

What are the common conjunctival neoplasias?

Answer 21

• Mast cell tumor
• Papillomas
• Hemangioma
• Lymphoma
• Melanoma
• Squamous cell carcinoma

Question 22

What are some common geographic infectious conjunctival lesions?

Answer 22

• Oncocerca granuloma
  
  • parasitic worm
  • Africa
• Histoplasma capsulatum
  
  • Fungal infection
  • Eastern US