What are the different types of uveitis and their clinical manifestations?

Types of Uveitis and Their Clinical Manifestations

Uveitis is anatomically classified into four distinct types—anterior, intermediate, posterior, and panuveitis—each with characteristic clinical presentations that guide diagnosis and management.

Anatomical Classification System

The classification of uveitis is based on the primary anatomical location of intraocular inflammation, which directly correlates with clinical presentation and underlying etiology 1, 2.

Anterior Uveitis (Iritis)

Clinical Manifestations:

• Classic triad: Eye pain, photophobia, and blurred vision with conjunctival injection 1, 3
• Cell and flare visible in the anterior chamber on slit-lamp examination 3
• Tearing and eye discomfort are common presenting features 1
• May be acute (sudden onset) or chronic/insidious in onset 4, 1
• Can be unilateral or bilateral; when associated with systemic inflammatory conditions like Crohn's disease, frequently bilateral 4, 1

Epidemiology:

• Most common form of uveitis, representing approximately 56% of cases 5
• Acute fibrinous unilateral anterior uveitis often associated with HLA-B27 haplotype 2
• Granulomatous anterior uveitis typically associated with sarcoidosis or herpes infections 2

Common Etiologies:

• Idiopathic (most common, 74% of anterior uveitis cases) 6
• Trauma 6
• HLA-B27-associated conditions 2
• Herpes simplex virus and varicella zoster virus (can cause uveitis as sequelae) 4
• Behçet's disease 3, 6

Intermediate Uveitis (Pars Planitis)

Clinical Manifestations:

• Primary inflammation focused in the vitreous and pars plana region 2
• Floaters and blurred vision are predominant symptoms 2
• Less pain and photophobia compared to anterior uveitis 2
• Represents approximately 7-16% of uveitis cases 6, 5

Common Etiologies:

• Usually idiopathic in nature 2
• Multiple sclerosis association 2
• Sarcoidosis 2
• Critical pitfall: Vitreoretinal lymphoma must be considered as a masquerade syndrome in patients over 45 years 2

Posterior Uveitis

Clinical Manifestations:

• Blurred vision and visual disturbances are primary symptoms 1
• Less pain than anterior uveitis but photophobia may be present 1
• Includes retinitis, choroiditis, and retinal vasculitis 2
• Represents approximately 13-32% of uveitis cases 6, 5

Common Etiologies:

• Idiopathic (most common, 51% of posterior uveitis) 6
• Retinitis: Often infectious—Toxoplasma gondii (most common infectious cause of retinitis), cytomegalovirus, HSV, VZV 4, 2, 7
• Choroiditis: Frequently idiopathic, but tuberculosis and other infections must be considered 2
• Retinal vasculitis including Eales' disease (28% of posterior uveitis) 6
• Toxoplasmosis (11% of posterior uveitis) 6, 7
• Sarcoidosis 7
• Birdshot chorioretinopathy 7

Panuveitis

Clinical Manifestations:

• Inflammation involves all anatomical compartments of the eye 2
• Combination of symptoms from anterior and posterior involvement: pain, photophobia, blurred vision, and floaters 1, 2
• Most severe form with highest risk of vision loss 8
• Represents approximately 18-24% of uveitis cases 6, 5

Common Etiologies:

• Idiopathic (48% of panuveitis cases) 6
• Behçet's disease (25% of panuveitis cases) 6, 7
• Sarcoidosis 7
• Vogt-Koyanagi-Harada disease 2
• Sympathetic ophthalmia 2

Critical Distinguishing Features from Other Ocular Conditions

Differentiation from Episcleritis:

• Episcleritis: Relatively painless, hyperemic sclera with itching/burning, NO visual changes, NO photophobia 4, 1, 9
• Uveitis: Moderate to severe pain, photophobia, blurred vision, and potential for vision loss 1, 9

Differentiation from Scleritis:

• Scleritis: Severe, boring, deep ocular pain with deep vessel injection 9
• Both scleritis and uveitis require urgent ophthalmologic referral, unlike episcleritis 4, 9

Red Flags Requiring Urgent Ophthalmologic Referral

Any patient presenting with the following requires immediate referral to an ophthalmologist with expertise in ocular inflammatory disease:

• Visual disturbance or blurred vision 1, 3
• Moderate to severe eye pain 4, 1
• Photophobia 4, 1
• Inability to differentiate from sight-threatening conditions (scleritis, uveitis) 4, 9

Critical pitfall: Progression to permanent vision loss can occur if treatment is delayed 4, 1, 3. Uveitis causes approximately 10% of blindness cases 8.

Key Clinical Pearls

• Uveitis related to systemic inflammatory conditions (Crohn's disease, Behçet's disease) can be independent of bowel symptoms and may precede gastrointestinal manifestations 4, 3
• Episcleritis tends to parallel IBD activity, while uveitis follows an independent course 4
• The most common overall etiology across all uveitis types is idiopathic (43-74% depending on anatomical location) 6, 5
• Infectious causes represent approximately 19% of all uveitis cases, with Toxoplasma gondii being the most common infectious agent 4, 5
• Pain intensity is the most reliable clinical differentiator: minimal in conjunctivitis, mild or absent in episcleritis, moderate to severe in uveitis and scleritis 9