Uveitis

Dr.suzan

Uveitis
Definition: it is an inflammation of the uveal tract (Iris, Ciliary body and choroid) and adjacent structures, most probably the retina.
Classification: - Anatomical.
- Clinical.
- Aetiological.

Anatomical Classification:

1- Anterior uveitis: which is subdivided into:
a- Iritis: in which inflammation predominantly affects the iris.
b- Iridocyclitis: in which both the iris and anterior part of the ciliary body (pars plicata) are equally involved.
If the number inflammatory cells was equal in both the aqueous and vitreous, it is iridocyclitis, while if the number was larger in aqueous, it is iritis.
2- Intermediate uveitis:
It is characterized by involvement predominantly of the posterior part of the ciliary body (pars plana), periphery of the retina and thevitreous.
3- Posterior uveitis:involve the fundus posterior to the vitreous base:
a.retinitis with primary focus in the retina
b.choroiditis with primary focus in the choroid
c.vasculitis which arteries and /or veins.
4- Panuveitis:
Involvement of the entire uveal tract.
Note:endophthalmitis mean inflammation often purulent involve all intra ocular tissues except sclera.


Clinical classification:
1- Acute uveitis: usually has a sudden, symptomatic onset and persists for up to 3 months. If the inflammation recurs following the initial attack it is referred as recurrent acute uveitis.
2- Chronic uveitis: the onset is frequently insidious and may be asymptomatic. It usually persists for longer than 3 months. Acute or subacute exacerbations on chronic may occur.
Aetiological classification:
1- Idiopathic: which forms more than 50% of cases of uveitis.
2- Associated with a systemic disease, e.g.:
a- Spondyloarthopathies: ankylosing spodylitis, Reiter's syndrome, psoriatic arthritis and chronic juvenile arthritis.
b- Inflammatory bowel disease: ulcerative colitis, Crohn's disease, Whipple's disease.
c- Nephritis.
d- Non-infectious multi-system disease: sarcoidosis, Behet's disease.
e- Infectious systemic disease: e.g. TB, syphilis
f- Diabetes.
3- Infections:
a- Bacterial: tuberculosis.
b- Fungal: Candidiasis.
c- Viral: Herpes Zoster.
4- Infestations:
a- Protozoa: Toxoplasmosis.
b- Nematodes: Toxocariasis.

Clinical Features:

Anterior uveitis
Symptoms:
1- Acute anterior uveitis: Photophobia, pain, redness, decreased visual acuity and lacrimation.
In acute anterior Uveitis, the pain is due to spasm of ciliary muscle, and decrease visual acuity is due to turbidity of aqueous by inflammatory cells, leakage of proteins which are present due to break down of blood-aqueous barrier. There may be normal or increased IOP (if the angle are closed by cells and proteins), but more commonly is decreased IOP or hypotony due to ciliary shutdown.
2- Chronic anterior uveitis: many patients asymptomatic until development of complications occasionally give rise to mild redness(during sever exacerbation) .so usually the eye white .
Signs:
1- Circumcorneal injection: acute anterior uveitis has a violaceous hue.
2- Keratic precipitates: cellular deposits on the on the corneal endothelium (deposition of inflammatory cells into corneal endothelium).
Their characteristics and distribution may indicate the probable cause of uveitis.
3- Cells: indicative of acute inflammation: it is graded from 1 to 4.
a- Aqueous cells.
b- Anterior vitreous cells.
4- Aqueous flare: is seen due to scattering of light by proteins that have leaked into aqueous humour by break down of blood-aqueous barrier. It is graded from 1 to 4 according to its haziness or obscuration to the details of iris.
5- Iris nodule: which is a feature of chronic granulomatous inflammation.


Complications of anterior uveitis:
1- Posterior synechiae: 360 (seclusio pupillae) causes iris bomb that leads to closure of the angle of anterior chamber and ends with secondary angle closure glaucoma.
2- Cataract.
3- Glaucoma: inflammatory or secondary angle closure glaucoma.
4- Cyclitic membrane formation which leads to traction and then detachment of the Ciliary body which causing phthisis bulbi.

Intermediate Uveitis

Symptoms:
Initially, floaters (inflammatory cells in anterior vitreous) and later, decreased visual acuity due to macular edema (due to associated vitritis).
Signs:
Cellular infiltration of vitreous (vitritis).
Complications:
1- Cystoid macular oedema.
2- Cyclitic membrane and phthisis bulbi.
3- Cataract.
4- Tractional retinal detachment.

Posterior uveitis

Symptoms:
1- Floaters (due to cells and flare in the vitreous).
2- Impairment of visual acuity (due to macular oedema).
Signs:
1- Cells, flare, opacities and posterior vitreous detachment (inflammatory process of vitreous (vitritis) leads to its shrinkage and then separation of posterior vitreous face from the retina).
2- Retinitis: ill-defined, focal, white, cloudy appearance of retina with obscuration of retinal vessels.
3- Vsculitis: acute vasculitis, which is characterized by a fluffy white haziness surrounding the blood column.
4.chorioditis:appear as yellow round nodule.
Complications:
1- Cystoid macular oedema.
2- Macular ischaemia.
3- Epiretinal membrane formation.
4- Vascular occlusion.
5- Retinal detachment (tractional).
6- Consecutive optic neuropathy (due to ischaemia that affects the ganglion cells layer, nerve fiber layer and the optic disc itself).


Special investigations for patients with uveitis:
1- X-Ray:
- Sacroiliac joint (for ankylosing spondylitis).
- Chest x-ray (for TB and sarcoidosis).
- Skull calcification: toxoplasmosis.
2- Skin test: histoplasmosis, Mantoux and kveim (for sarcoidosis).pathergy test for Behcet syndrome.
3- Serum tests: ANA (Anti-Nuclear Antibodies) as in chronic juvenile arthritis, VDRL, toxoplasmosis test (IFAT) and ELISA.
4- HLA-typing: HLA-B27 for ankylosing spondylitis and B5, B51 for Behet's disease.

Treatment:

1- Mydriatics:
Short acting: Tropicamide 0.5% (for <1y) & 1% (for > 1y), the duration of action is 6 hours.
Cyclopentolate 0.5% (for <1y) & 1% (for > 1y), the duration of is 24hours.
* Both of previous drugs have mydriatic and cycloplegic effects by inhibiting the sphincter muscles of the iris and inhibition of Ciliary body muscles.
Phenylnephrine (sympathetic agonist) 2.5% (up to 16y) & 10% (adult), the duration of action is 3 hours, but has no cycloplegic effect. It causes dilatation of the pupil by stimulation of radial muscles of the iris. We have to be very cautious when using this drug, as it elevates blood pressure and causes tachycardia.
Long acting: Atropine 0.5% (for <1y) & 1% (for > 1y), it is the most powerful cycloplegic and mydriatic, its duration of action is 2 weeks.
Homatropin 2%:had duration up to 2days
Indications for these mydriatic and cycloplegic drugs:
a- To promote comfort through muscles paralysis (except phenynephrine).
b- To prevent formation of posterior synechiae through continuous movement of the pupil.
c- To break down recently formed synechiae.


2- Steroids:
-Topical steroids: only for anterior uveitis, because they do not reach therapeutic levels behind the lens.
Potent steroids are: prednisolone acetate, Dexamethasone and betamethasone.

Side effects of topical steroids (especially after prolonged use):

a- Glaucoma.
b- Cataract.
c- Corneal complications: they are rare, e.g. bacterial and fungal keratitis and recurrence of herpes simplex keratitis.
d- Systemic side effects.

-Periocular injection of steroids:

Indications:
a- Severe acute anterior uveitis.
b- As an adjunct to topical or systemic steroid in resistant cases.
c- Intermediate uveitis.
d- Poor patient compliance with topical or systemic steroids.

-Intravitreal injection of steroids:

Injection of triamcinolone acetonide (2mg in 0.05ml) in resistant uveitic chronic cystoid macular oedema.

-Systemic steroids:

Either orally: prednisolone tablets
Or as injections: intravenous infusion of methylpredinsolon 1gm /day repeated for 2to 3 days in sever cases.
Indications:
a- Intractable anterior uveitis resistant to topical and periocular steroids.
b- Intermediate uveitis unresponsive to preiocular injection.
c- Posterior ueveitis or panuveitis, particularly with severe bilateral involvement.


3- Immunosuppressive agents:
Either Antimetabolites (cytotoxic) as Azathioprine and Methotrexate, Or T-cell inhibitors as ciclosporin.
Indications:
a- Sight (vision)-threatening uveitis:
Which is usually bilateral, non-infectious and has failed to response to adequate steroid therapy.
b- in patients with intolerable side effect from systemic steroids.
1, 2 and 3 are used to treat cases with undetected etiology (idiopathic).
But if we find a cause, so the treatment is by 1, 2 in addition to:
4- Treatment of underling cause.
e.g. TB, syphilis, toxoplasmosis, toxocariasis, ect.








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