Introduction
Uveitis is the inflammation of the vascular coat of the eye. It is a
common presenting sign in canine and feline ophthalmology. It is classified
into three categories: 1) Anterior (inflammation of iris and ciliary body);
2) Intermediate (ciliary body, pars plana); and, 3) Posterior (choroid)
uveitis. Early recognition and immediate control of inflammation are essential
to avoid irreversible complications such as glaucoma, cataract and blindness.
The cause of uveitis should next be identified if possible.
Clinical diagnosis
The diagnosis is based on clinical findings of active uveitis, recognition
of complications and elements of differential "red- eye" diagnosis.
Clinical signs
Redness (episcleral
reddening)
Ocular pain (watery
discharge, blepharospasm, photophobia, enophthalmos)
Corneal changes
(edema, deep vascularization)
Anterior chamber
changes (aqueous flare, keratic precipitates, hyphema, hypopion)
Iris changes (in
colour, swelling, granulomas)
Myosis
Low intra ocular
pressure
Lens anomalies (deposits,
cataract)
Vitreous flare
Fundus anomalies
Differential diagnosis
Differential diagnosis must include consideration of other acquired ocular
conditions (conjunctivitis, corneal diseases, KCS, glaucoma, tumors) and
of developmental conditions (aniridia, heterochromia, persistent pupillary
membrane, cysts).
Complications
Complications of anterior uveitis are: synechiae (adhesion of the iris
to contiguous structures), secondary glaucoma (hypertensive uveitis),
iris atrophy, corneal edema (secondary to endothelial damage), lens subluxation/luxation,
cataract (in cats), fundus changes, panophthalmitis, phtisis bulbi.
Aetiological diagnosis
Examination and History
After a complete ocular examination (both eyes) a thorough general examination
is not to be neglected. Precise questions should be asked in taking a
history (age, vaccination, environment, trauma, travels) combined with
epidemiological considerations.
Additional examinations
Imaging: Head radiographs
are indicated in cases of unilateral uveitis. Chest and abdominal radiographs
may reveal major organs abnormalities. Ocular Ultrasound is useful in
cases of media opacity.
Blood samples: A
conventional laboratory profile should include a blood count, protein
electrophoresis (hyperglobulinaemia in chronic "parasitic" diseases and
FIP, FIV), a biochemical profile and serological screening tests when
available.
Aqueous humor samples
are useful to demonstrate local antibody production, for cytology and
Polymerase Chain Reaction (PCR).
Conjunctival samples
are useful for cytology, cultures, direct parasite observation and PCR
Causes of Canine Anterior Uveitis
Unknown-Idiopathic
Trauma (accidental
and surgical)
Viral: Hepatitis,
Distemper
Bacterial: Corneal
wounds, Bacterial sepsis (e.g. pyometra, dental disease), Leptospirosis,
Borreliosis, Brucellosis, Tuberculosis
Protozoal: Leishmaniasis,
Neosporosis, Toxoplasmosis
Parasitic: Dirofilariasis,
Angiostrongyliasis, Toxocariasis
Rickettsial: RMSF,
Ehrlichiosis
Fungal/Algal: Blastomycosis,
Histoplasmosis, Coccidioidomycosis, Cryptococcosis, Protothecosis
Immune mediated:
Lens induced uveitis, uveodermatologic syndrome
Metabolic: Hyperlipidemia,
Diabetes Mellitus
Genetic: Uveitis
in Golden Retrievers associated with iridociliary cysts
Neoplasia
Causes of Feline Anterior Uveitis
Unknown-Idiopathic
Trauma
Viral: FIP, FeLV,
FIV, FHV-1
Protozoal: Toxoplasmosis,
Leishmaniasis?
Bacterial: Corneal
wounds, Tuberculosis, Bartonellosis, Borreliosis
Fungal: Cryptococcosis
Hypertension: hyphema
(+/- retinal detachment)
Neoplasia
Treatment
Mydriatic: Atropine
1% applied 4 times daily.
Corticosteroids
(SAIDS)
Topical: Prednisolone
or Dexamethasone can be used (contraindication: ulcerative or mycotic
keratitis) . Both of these products have a good penetration into the
eye.
Subconjunctival:
Triamcinolone acetonide or Methylprednisolone acetate (0,2 ml) provide
anti inflammatory activity for at least 2 weeks.
Systemic corticosteroids:
Prednisolone or Prednisone can be used (immunosuppressive dosage: 1mg-2
mg/kg per os BID). When inflammation is under control, the dosage is
reduced gradually.
Non Steroidal Drugs
(NSAIDS)
. Topical: Flurbiprofen,
Suprofen, Diclofenac, Indomethacin can be used.
. Systemic NSAIDS:
These are an excellent choice for treating intra ocular inflammation
at the same time avoiding the side effects of steroidal drugs. Flunixin
meglumine, Carprofen, Ketoprofen, Tolfenamic acid (Inject 4 mg/kg) are
all efficient products.
Immunosuppressive
drugs: Systemic Azathioprine (2,2 mg/kg), or Cyclosporine (10-5 mg/kg)
may be used in case of unresponsive uveitis. Patients need to be monitored
for their side effects. Topical cyclosporine is not efficient in the treatment
of intra ocular inflammation.
Specific treatment:
If the cause is found, specific medical therapy (antibiotics, antifungals,
antiparasiticides) are administered combined with the anti inflammatory
therapy. Surgery might be advised to eliminate focal infections.
Practical strategy: Always follow a strict protocol
1. Diagnosis of uveitis on clinical findings
2. Control inflammation immediately (strike
hard). Begin with topical atropine, topical and subconjunctival corticosteroids,
always combined with systemic NSAIDS or SAIDS.
3. Ascertain the cause (take a history, perform
an ophthalmic and general examination, perform complementary tests)
4. Add specific treatment in cases where the
cause is found
Conclusion
New laboratory techniques and new drugs such as NSAIDS can now help the
veterinarian to recognize and control uveitis more efficiently.
Maurice Roze, DVM DECVO
Ophthalmology, Clinique Vétérinaire
Marseille, France
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