Equine conjunctivitis by faslu muhammed

1. EQUINEEQUINE
CONJUNCTIVITISCONJUNCTIVITIS
OPTOM FASLU MUHAMMEDOPTOM FASLU MUHAMMED

2. OutlineOutline
 Anatomy/PhysiologyAnatomy/Physiology
 Clinical signsClinical signs
 Clinical and diagnosticClinical and diagnostic
examinationexamination

3. OutlineOutline
 EtiologiesEtiologies
 Diagnosis/treatment ofDiagnosis/treatment of
selected etiologiesselected etiologies

4. Conjunctival Anatomy/PhysiologyConjunctival Anatomy/Physiology
 Composed of nonkeratinized,Composed of nonkeratinized,
stratified squamous epithelium andstratified squamous epithelium and
underlying substantia propriaunderlying substantia propria
 Capable of rapid and dramaticCapable of rapid and dramatic
response to insultsresponse to insults
 Richly supplied by blood vesselsRichly supplied by blood vessels
 Loose arrangement of conjunctivalLoose arrangement of conjunctival
stromastroma
 Resident lymphoid tissueResident lymphoid tissue
 Specialized antigen-presenting cellsSpecialized antigen-presenting cells
(M-cells)(M-cells)

5. Conjunctival Anatomy/PhysiologyConjunctival Anatomy/Physiology
 Often secondarily involved in otherOften secondarily involved in other
intraocular, extraocular, andintraocular, extraocular, and
systemic diseasessystemic diseases
 Anatomical proximity and sharedAnatomical proximity and shared
blood supply with other ocularblood supply with other ocular
structuresstructures
 Extensive vascular/lymphoidExtensive vascular/lymphoid
tissuetissue
 Relatively accessible andRelatively accessible and
observableobservable

6. Conjunctivitis Clinical SignsConjunctivitis Clinical Signs
 Conjunctivitis associated withConjunctivitis associated with
some combination of thesome combination of the
following clinical signs:following clinical signs:
 Ocular discharge:Ocular discharge: epiphora,epiphora,
mucoid, or mucopurulentmucoid, or mucopurulent
 Chemosis:Chemosis: edema resultingedema resulting
from increased permeability offrom increased permeability of
conjunctival vessels with fluidconjunctival vessels with fluid
extravasationextravasation
 Hyperemia:Hyperemia: red discolorationred discoloration
from conjunctival vesselfrom conjunctival vessel
vasodilatationvasodilatation
 Ocular discomfort:Ocular discomfort:
blepharospasm, rubbingblepharospasm, rubbing

7. Conjunctivitis Clinical SignsConjunctivitis Clinical Signs
 Conjunctivitis associated withConjunctivitis associated with
some combination of thesome combination of the
following clinical signs:following clinical signs:
 Tissue proliferation:Tissue proliferation:
lymphatic, epitheliallymphatic, epithelial
hyperplasia, or keratinizationhyperplasia, or keratinization
 Ulceration:Ulceration: any severeany severe
conjunctivitis or thoseconjunctivitis or those
associated with particularassociated with particular
etiologies (viral, chemical,etiologies (viral, chemical,
trauma)trauma)
 PigmentationPigmentation oror
depigmentationdepigmentation

8. Conjunctivitis ExaminationConjunctivitis Examination
 Physical examinationPhysical examination
 To rule-out primary orTo rule-out primary or
concurrent systemicconcurrent systemic
diseasesdiseases

9. Conjunctivitis ExaminationConjunctivitis Examination
 Complete ophthalmicComplete ophthalmic
examination:examination:
 Focal light source andFocal light source and
magnificationmagnification
 Adnexa, extraocular, andAdnexa, extraocular, and
intraocular structuresintraocular structures
 Including Schirmer tearIncluding Schirmer tear
tests, fluorescein stain,tests, fluorescein stain,
tonometrytonometry
 Examine behind nictitansExamine behind nictitans
membranemembrane

10. Conjunctivitis ExaminationConjunctivitis Examination
Conjunctivitis diagnostics:Conjunctivitis diagnostics:
 Conjunctival cytologyConjunctival cytology
 Scrapings, swabs, aspiratesScrapings, swabs, aspirates
often helpful in diagnosisoften helpful in diagnosis
 Microbiologic diagnosticsMicrobiologic diagnostics
 Cultures, PCR, IFA, etc… asCultures, PCR, IFA, etc… as
indicated for select cases whereindicated for select cases where
infectious etiology suspectedinfectious etiology suspected
 Biopsy/histopathologyBiopsy/histopathology
 For conjunctivitis that isFor conjunctivitis that is
severe, chronic, unresponsivesevere, chronic, unresponsive
to treatment, or associated withto treatment, or associated with
mass formationmass formation

11. Conjunctivitis EtiologiesConjunctivitis Etiologies
 Inflammation of theInflammation of the
conjunctiva is a commonconjunctiva is a common
condition and may be a:condition and may be a:
 Primary or secondaryPrimary or secondary
disease processdisease process
 Result of ocular orResult of ocular or
systemic diseasesystemic disease

12. Conjunctivitis EtiologiesConjunctivitis Etiologies
 The conjunctiva hasThe conjunctiva has
limited mechanisms bylimited mechanisms by
which it can respond towhich it can respond to
insults, thus the etiologyinsults, thus the etiology
of conjunctivitis canof conjunctivitis can
usually not beusually not be
determined from clinicaldetermined from clinical
signs alonesigns alone

13. Conjunctivitis EtiologiesConjunctivitis Etiologies
 Secondary conjunctivitisSecondary conjunctivitis
more common than primarymore common than primary
in the horsein the horse
 Secondary conjunctivitisSecondary conjunctivitis
typically occurs as a result oftypically occurs as a result of
adjacent ocular inflammationadjacent ocular inflammation
or systemic disease:or systemic disease:
 Intraocular disease: uveitis,Intraocular disease: uveitis,
glaucomaglaucoma
 Extraocular disease: cornealExtraocular disease: corneal
ulcers or abscesses, blepharitisulcers or abscesses, blepharitis
 Systemic disease: infectious,Systemic disease: infectious,
neoplastic, immune-mediatedneoplastic, immune-mediated

14. Conjunctivitis EtiologiesConjunctivitis Etiologies
 The diagnosis and treatmentThe diagnosis and treatment
of secondary conjunctivitisof secondary conjunctivitis
should be directed towardshould be directed toward
the underlying ocular orthe underlying ocular or
systemic conditionsystemic condition

15. Secondary ConjunctivitisSecondary Conjunctivitis
Conjunctivits secondary toConjunctivits secondary to
a corneal ulcera corneal ulcer
Conjunctivits secondary toConjunctivits secondary to
anterior uveitisanterior uveitis

16. Primary Conjunctivitis EtiologiesPrimary Conjunctivitis Etiologies
 Idiopathic, immune-mediated:Idiopathic, immune-mediated:
eosinophilic, lymphocyticeosinophilic, lymphocytic
 AllergicAllergic
 InfectiousInfectious
 Bacterial:Bacterial: Streptococcus equiStreptococcus equi,,
Moraxella equiMoraxella equi,, ChlamydiaChlamydia, etc…, etc…
 Fungal:Fungal: AspergillusAspergillus,, RhinosporidiumRhinosporidium,,
Histoplasmosis, Blastomycosis,Histoplasmosis, Blastomycosis,
Cryptococcus, etc…Cryptococcus, etc…
 Viral: Equine herpesvirus 2 and 5Viral: Equine herpesvirus 2 and 5
 Parasitic: Onchocerciasis,Parasitic: Onchocerciasis,
Habronemiasis,Habronemiasis, Thelazia lacrimalisThelazia lacrimalis,,
TrypanosomiasisTrypanosomiasis
 Toxic/Chemical:Toxic/Chemical:
Stachybotryotoxicosis, alkali/acid burnStachybotryotoxicosis, alkali/acid burn

17. Primary Conjunctivitis EtiologiesPrimary Conjunctivitis Etiologies
 Trauma: blunt or penetratingTrauma: blunt or penetrating
 Frictional irritants: entropion,Frictional irritants: entropion,
ectopic cilia, distichia, foreignectopic cilia, distichia, foreign
bodiesbodies
 Keratoconjunctivitis siccaKeratoconjunctivitis sicca
 Exposure: facial nerve dysfunction,Exposure: facial nerve dysfunction,
lagophthalmoslagophthalmos
 ActinicActinic
 NeoplasticNeoplastic

18. Eosinophilic ConjunctivitisEosinophilic Conjunctivitis
 Idiopathic infiltration ofIdiopathic infiltration of
conjunctiva with eosinophilsconjunctiva with eosinophils
 May be present with or withoutMay be present with or without
corneal lesionscorneal lesions
 Diagnosis: eosinophils on cytologyDiagnosis: eosinophils on cytology
or histopathology without parasitesor histopathology without parasites
presentpresent

19. Eosinophilic ConjunctivitisEosinophilic Conjunctivitis
 Treatment:Treatment:
Topical corticosteroids orTopical corticosteroids or
cyclosporine: tapered to leastcyclosporine: tapered to least
frequent effective dosefrequent effective dose
Topical mast cell stabilizersTopical mast cell stabilizers
(cromolyn, olopatadine,(cromolyn, olopatadine,
lodoxamide) may also be effectivelodoxamide) may also be effective
in some casesin some cases

20. Eosinophilic ConjunctivitisEosinophilic Conjunctivitis
Conjunctival biopsy from a horse with eosinophilicConjunctival biopsy from a horse with eosinophilic
keratoconjunctivitis displaying numerous eosinophilskeratoconjunctivitis displaying numerous eosinophils

21. Lymphocytic ConjuctivitisLymphocytic Conjuctivitis
 Lobulated or smooth, pinkLobulated or smooth, pink
conjunctival massesconjunctival masses
 Composed of lymphocytesComposed of lymphocytes
and macrophagesand macrophages
 Most common locations:Most common locations:
dorsal bulbar conjunctivadorsal bulbar conjunctiva
and third eyelidand third eyelid

22. Lymphocytic ConjuctivitisLymphocytic Conjuctivitis
 Diagnosis: lymphocyticDiagnosis: lymphocytic
aggregates onaggregates on
cytology/histopathologycytology/histopathology
 Treatment: topical orTreatment: topical or
intralesional corticosteroids,intralesional corticosteroids,
topical cyclosporine, ortopical cyclosporine, or
surgical excisionsurgical excision

23. Lymphocytic ConjuctivitisLymphocytic Conjuctivitis
Conjunctival biopsy from a horse with lymphocytic conjunctivitisConjunctival biopsy from a horse with lymphocytic conjunctivitis
displaying numerous lymphocytes and occasional plasma cellsdisplaying numerous lymphocytes and occasional plasma cells

24. Bacterial and Fungal ConjunctivitisBacterial and Fungal Conjunctivitis
 Bacterial and fungalBacterial and fungal
conjunctivitis usuallyconjunctivitis usually
secondary infectionssecondary infections
 Diagnosis based uponDiagnosis based upon
cytology and culturecytology and culture
findingsfindings
Fungal conjunctivitis secondaryFungal conjunctivitis secondary
to keratomycosisto keratomycosis

25. Bacterial and Fungal ConjunctivitisBacterial and Fungal Conjunctivitis
 Treatment: identify andTreatment: identify and
treat underlying causetreat underlying cause
along with thealong with the
opportunistic infectionopportunistic infection
Fungal conjunctivitis secondaryFungal conjunctivitis secondary
to keratomycosisto keratomycosis

26. Viral ConjunctivitisViral Conjunctivitis
 Equine herpesvirus 2 andEquine herpesvirus 2 and
5 may cause primary5 may cause primary
conjunctivitis in theconjunctivitis in the
horsehorse
 Diagnosis: virus isolation,Diagnosis: virus isolation,
PCR, IFAPCR, IFA
 Treatment: topicalTreatment: topical
idoxuridine, trifluridine,idoxuridine, trifluridine,
or interferonor interferon

27. Viral ConjunctivitisViral Conjunctivitis
Equine viral arteritis, equineEquine viral arteritis, equine
adenovirus, equineadenovirus, equine
infectious anemia, equineinfectious anemia, equine
influenza, and Africaninfluenza, and African
horse sickness often causehorse sickness often cause
mild conjunctivitismild conjunctivitis
associated with systemicassociated with systemic
diseasedisease

28. Parasitic ConjunctivitisParasitic Conjunctivitis
 Parasitic conjunctivitis mostParasitic conjunctivitis most
commonly occurs withcommonly occurs with
Onchocerca cervicalisOnchocerca cervicalis::
 Insect vectors:Insect vectors: CulicoidesCulicoides spp.spp.
 Larvae migration incitesLarvae migration incites
inflammationinflammation
 Lesions: temporolimbalLesions: temporolimbal
conjunctival thickening,conjunctival thickening,
nodules, and depigmentationnodules, and depigmentation
+/- keratitis+/- keratitis

29. Parasitic ConjunctivitisParasitic Conjunctivitis
 Diagnosis: conjunctivalDiagnosis: conjunctival
biopsy or cytologybiopsy or cytology
(microfilaria, eosinophils,(microfilaria, eosinophils,
lymphocytes)lymphocytes)
 Treatment: systemicTreatment: systemic
ivermectin and topicalivermectin and topical
corticosteroidscorticosteroids

30. Parasitic ConjunctivitisParasitic Conjunctivitis
OnchocercaOnchocerca limbal conjunctival noduleslimbal conjunctival nodules
in a horsein a horse
Cytology of conjunctivalCytology of conjunctival
nodules with eosinophilsnodules with eosinophils
andand OnchocercaOnchocerca microfilaramicrofilara

31. Parasitic ConjunctivitisParasitic Conjunctivitis
 Habronemiasis may also causeHabronemiasis may also cause
conjunctivitisconjunctivitis
 HabronemaHabronema andand DraschiaDraschia spp.spp.
(equine gastric worms)(equine gastric worms)
 Larvae deposited onLarvae deposited on
conjunctiva by flies, migrationconjunctiva by flies, migration
incites intense granulomatousincites intense granulomatous
or eosinophilc inflammationor eosinophilc inflammation
 Lesions: proliferative nodules,Lesions: proliferative nodules,
granulation tissue appearance,granulation tissue appearance,
may be ulcerative, may havemay be ulcerative, may have
yellow-white exudates (“sulfuryellow-white exudates (“sulfur
granules”)granules”)
 Occur on conjunctiva,Occur on conjunctiva,
nictitans, and periocular skin;nictitans, and periocular skin;
most commonly adjacent tomost commonly adjacent to
medial canthus (where fliesmedial canthus (where flies
feed)feed)

32. Parasitic ConjunctivitisParasitic Conjunctivitis
 Diagnosis: seasonal, clinicalDiagnosis: seasonal, clinical
appearance, cytology/histopathappearance, cytology/histopath
 Treatment: systemic ivermectin,Treatment: systemic ivermectin,
topical/intralesional/systemictopical/intralesional/systemic
corticosteroids, surgical debulkingcorticosteroids, surgical debulking
for large massesfor large masses

33. Parasitic ConjunctivitisParasitic Conjunctivitis
Habronemiasis “sulfur granules”Habronemiasis “sulfur granules”
at medial canthus in a horseat medial canthus in a horse
HabronemaHabronema conjunctival noduleconjunctival nodule
and blepharitis in a horseand blepharitis in a horse

34. Parasitic ConjunctivitisParasitic Conjunctivitis
 Thelazia lacrimalisThelazia lacrimalis
 Nematode inhabiting conjunctivalNematode inhabiting conjunctival
fornices and nasolacrimal ductfornices and nasolacrimal duct
 Diagnosis: identification ofDiagnosis: identification of
parasites during clinicalparasites during clinical
examinationexamination

35. Parasitic ConjunctivitisParasitic Conjunctivitis
 Treatment:Treatment:
 Manual removal of parasites withManual removal of parasites with
lavage, swabs, or forcepslavage, swabs, or forceps
 Systemic ivermectin or topicalSystemic ivermectin or topical
levamisolelevamisole

36. Traumatic ConjunctivitisTraumatic Conjunctivitis
 May occur from blunt orMay occur from blunt or
penetrating injuriespenetrating injuries
 Often dramatic chemosis initiallyOften dramatic chemosis initially
 May be associated withMay be associated with
subconjunctival hemorrhagessubconjunctival hemorrhages
or emphysemaor emphysema
 Diagnostics: exclude other ocularDiagnostics: exclude other ocular
injuries and foreign bodiesinjuries and foreign bodies
 May be difficult on initialMay be difficult on initial
presentationpresentation

37. Traumatic ConjunctivitisTraumatic Conjunctivitis
 TreatmentTreatment
 Most lacerations/punctures doMost lacerations/punctures do
not require sutures as thenot require sutures as the
conjunctiva healsconjunctiva heals
spontaneously and rapidlyspontaneously and rapidly
 Cold compresses acutely mayCold compresses acutely may
decrease clinical signsdecrease clinical signs
 Topical antibiotics untilTopical antibiotics until
resolvedresolved
 Systemic antibiotics ifSystemic antibiotics if
penetrating or full-thicknesspenetrating or full-thickness
woundswounds
 Consider systemic nonsteroidalConsider systemic nonsteroidal
anti-inflammatoriesanti-inflammatories

38. Traumatic ConjunctivitisTraumatic Conjunctivitis
Traumatic conjunctivitis withTraumatic conjunctivitis with
subconjunctival hemorrahgesubconjunctival hemorrahge
Traumatic conjunctivitis withTraumatic conjunctivitis with
conjunctival emphysemaconjunctival emphysema

39. Actinic ConjunctivitisActinic Conjunctivitis
 Occurs following chronicOccurs following chronic
UV-light exoposureUV-light exoposure
 Diagnosis: ulcerativeDiagnosis: ulcerative
conjunctivitis adjacent toconjunctivitis adjacent to
lid margins, develops inlid margins, develops in
areas of conjunctiva thatareas of conjunctiva that
are not pigmentedare not pigmented

40. Actinic ConjunctivitisActinic Conjunctivitis
 Precursor to squamous cellPrecursor to squamous cell
carcinomacarcinoma
 Treatment: shade (flyTreatment: shade (fly
mask, stabling), monitormask, stabling), monitor
for neoplasiafor neoplasia
developmentdevelopment

41. Conjunctival NeoplasiaConjunctival Neoplasia
 Conjunctival neoplasia mayConjunctival neoplasia may
masquerade as conjunctivitismasquerade as conjunctivitis
initiallyinitially
 Most common types:Most common types:
squamous cell carcinoma,squamous cell carcinoma,
lymphoma, hemangioma,lymphoma, hemangioma,
hemangiosarcoma, papilloma,hemangiosarcoma, papilloma,
and melanomaand melanoma
 Diagnosis based uponDiagnosis based upon
excisional/incisional biopsy,excisional/incisional biopsy,
scrapings, or aspiratesscrapings, or aspirates

42. Conjunctival NeoplasiaConjunctival Neoplasia
 Treatment:Treatment:
 Surgical excision (alwaysSurgical excision (always
treatment of choice whentreatment of choice when
complete excision possible)complete excision possible)
 Ancillary therapies oftenAncillary therapies often
indicated based upon tumorindicated based upon tumor
type, location, extent:type, location, extent:
 Diode laser ablation,Diode laser ablation,
cryotherapy, radiation,cryotherapy, radiation,
chemotherapychemotherapy

43. Conjunctival NeoplasiaConjunctival Neoplasia
Conjunctival squamous cell carcinoma Conjunctival lymphoma

44. Questions????Questions????