Table of contents

Uveitis

A good way to approach uveitis is to treat it as a sign of underlying disease. Look for features that suggest inflammation of the uveal tract and then look for key features that point towards a particular diagnosis. You would've already covered many of these uveitic conditions elsewhere in medical school!

In practice, most cases of uveitis are idiopathic and causes are found.

Uveitis Overview

The term uveitis describes the inflammation of the uveal tract, involving or not involving its neighbouring ocular structures such as the retina and vitreous. A wide array of diseases are known to cause inflammation of the uveal tract including infections, system inflammatory conditions and neoplastic syndromes. The disease course can vary significantly, acute or chronic, mild or severe, persistent or one-off. It largely depends on the underlying cause of inflammation.

Classification

A patient with anterior uveitis. By Jonathan Trobe, M.D, CC BY 3.0.

Anatomically, uveitis is categorised in 4 ways:

Anterior uveitis - Iritis + AC inflammation
Intermediate uveitis - Pars planitis + vitritis
Posterior uveitis - Chorioretinitis
Pan uveitis - iritis + pars planitis + chorioretinitis (+ inflammation of associated structures)

Anterior Uveitis

Keratic precipitates in a patient with Vogt-Koyanagi-Harada disease. By Imran kabirhossain, CC BY-SA 4.0.

Overview

Anterior uveitis is the inflammation of the iris (including pars plicata)
Most commonly idiopathic, but can be HLA-B27 associated, infectious or systemic
Anterior uveitis can predispose to posterior synechiae and angle-closure
White blood cells can accumulate in the corneal endothelium and are known as keratic precipitates (KPs). The nature of these can be further classified based on appearance:
- Mutton fat KPs indicate granulomatous inflammation
- Stellate KPs indicate non-granulomatous inflammation

Presentation

Inflammation of the iris and anterior ciliary body leads to AC flare.
Inflammation of the iris sphincter can lead to irregular meiosis.
Typically presents with a painful red-eye, AC flare, photophobia and blurred vision

Intermediate Uveitis

Overview

Intermediate uveitis is the inflammation of the posterior ciliary body (pars planitis) and can also involve the vitreous
Inflammatory accumulations in the vitreous are described as snowballs
Characteristic white inflammatory exudation on the pars plana and ora Serrata is described as snow-banking (can be seen on indirect ophthalmoscopy with scleral depression)

Presentation

Painless blurry vision and floaters, without red-eye
Pars planitis and vitritis leads to floaters and blurring of vision.

Infective Uveitis

	Description	Diagnostics	Management
Onchocerciasis (Onchocerca volvulus)	Endemic to Africa and also known as African river blindness Second commonest infective cause of blindness worldwide (to trachoma) The vector is the simulium black fly	Presentation Maculopapular rash followed by the ocular features Bilateral panuveitis, keratitis and optic neuritis Investigation Diagnosis is made on visualisation of the nematode on slit lamp with retroillumination	Ivermectin
Toxocariasis (Toxocara cani)	Toxocariasis is an important cause of childhood leukocoria. Dogs are the definitive hosts	Presentation Unilateral endophthalmitis in children Investigation ELISA for Toxocara excretory secretory (TES) antigen	Steroids
Toxoplasmosis (Toxoplasma gondii)	Infection by this parasite can be acquired or congenital Cats are the vector Commonest cause of posterior uveitis in children	Presentation Congenital toxoplasmosis presents with a triad of: Hydrocephalus, intraretinal calcification and chorioretinitis. Acquired toxoplasmosis is typically seen in AIDS patients where CD4<200. It causes an anterior uveitis and a characteristic white lesion of the retina with a pigmented scar.	Pyrimethamine + sulfadiazine + steroids
Histoplasmosis (Histoplasma capsulatum)	A dimorphic fungus Characteristically found around the Mississippi and Ohio river valleys	Presentation vision loss and examination findings show multiple white chorioretinal scars and peripapillary atrophy More common in AIDS patients
Cytomegalovirus Retinitis	CMV is a week opportunistic infection that only tends to manifest in AIDS patients with CD4<50.	Patients typically present with rapid vision loss.	IV ganciclovir

Toxocariasis is an important cause of childhood leukocoria. The absence of calcification on CT scan differentiates it from retinoblastoma

Multisystem Uveitis

This section summarises some of the commonly examined causes of uveitis. It is important to be aware of these conditions for the exam.

	Description	Key features
Sarcoidosis	A multisystem inflammatory granulomatous disorder characterised by noncaseating granulomata	Presentation Bilateral: hilar lymphadenopathy, CN7 palsy and parotid enlargement More common in black women Can cause any type of uveitis. Pre-retinal granuloma (Lander sign) Investigation Associated bloods: high ACE and hypercalcemia
Tuberculosis	Multisystem Infective granulomatous disease caused by Mycobacterium tuberculosis	Presentation Can cause any type of uveitis More common in Indians Night sweats, weight-loss, hemoptysis and dacryoadenitis Investigation Mantoux and antigen tests
Reactive arthritis	HLA-B27 associated reaction caused by non-gonococcal infections, most typically chlamydia.	Presentation A triad of: conjunctivitis, urethritis and arthritis Keratoderma blennorrhagica
Behcet's Disease	HLA-B51 associated multisystem vasculitis.	Presentation Anterior uveitis with a characteristic mobile hypopyon Investigation Positive skin pathergy test (lots of skin lesions erupt in response to minor traumatic insult) Pulmonary artery aneurysm is pathognomonic
Kawasaki Disease	A medium vessel vasculitis of childhood	Presentation Bilateral anterior uveitis and conjunctivitis Characteristic >5day fever which does not respond to antipyretics Red palms and soles and a strawberry tongue Investigation All patients require an echocardiogram to rule out coronary artery aneurysm
Vogt-Koyanagi-Harada disease	Multisystem granulomatous inflammation due to melanocyte Tcell hypersensitivity (commoner people with darker skin)	Presentation Bilateral panuveitis Prodrome of fever, meningism and tinnitus followed by vision loss and vitiligo. Can effect the auditory, neurological, and dermatological systems
Tubulointerstitial nephritis and uveitis	Non-granulomatous inflammation of the kidneys and the eye	Presentation Bilateral chronic anterior uveitis Female adolescent with renal symptoms followed by ocular symptoms Investigations Elevated urinary beta-2 microglobinuria
Juvenile Idiopathic Arthritis	The most common cause of anterior uveitis in children. Also the most common rheumatological disease in children Non-granulomatous inflammation	Presentation Chronic anterior uveitis Arthritis, fevers and rashes Associated with cataracts and band keratopathy

Reactive arthritis was formerly known as Reiter's syndrome (redacted because Reiter was an SS officer who was found guilty of war crimes at the Nuremberg trials).

IVIg and high dose aspirin are used in the management of Kawasaki disease. Note that aspirin is otherwise contraindicated in children because it has been linked to Reye’s syndrome

Limited Ocular Uveitis

This section will summarise the important causes of uveitis which are limited to the eye without systemic involvement.

	Description	Diagnostics
Sympathetic Ophthalmia	T-cell mediated autoimmune granulomatous inflammation following traumatic insult.	Bilateral panuveitis History of ocular trauma in one eye, followed by uveitis in the fellow eye. 0.1% risk in penetrating trauma, rarer after surgery Highest associated risk in is vitreoretinal surgery
Birdshot Chorioretinopathy	HLA-A29 associated uveitis with characteristic multifocal cream coloured oval lesions of the fundus	Chronic bilateral posterior uveitis with characteristic hypo-pigmented fundus lesions More common in middle-aged women Typical presentation involves gradual bilateral central vision loss with floaters and nyctalopia
Fuchs Heterochromic Uveitis	Idiopathic anterior uveitis which also leads to cataracts and open-angle glaucoma Also known as Fuchs heterochromic cyclitis.	Chronic non-granulomatous anterior uveitis but with a no red eye Affected iris is typically hypochromic, hence the patient is heterochromic (irises of different colours)

Description

Diagnostics

Sympathetic Ophthalmia

T-cell mediated autoimmune granulomatous inflammation following traumatic insult.

Bilateral panuveitis
History of ocular trauma in one eye, followed by uveitis in the fellow eye.
0.1% risk in penetrating trauma, rarer after surgery
Highest associated risk in is vitreoretinal surgery

Birdshot Chorioretinopathy

HLA-A29 associated uveitis with characteristic multifocal cream coloured oval lesions of the fundus

Chronic bilateral posterior uveitis with characteristic hypo-pigmented fundus lesions
More common in middle-aged women
Typical presentation involves gradual bilateral central vision loss with floaters and nyctalopia

Fuchs Heterochromic Uveitis

Idiopathic anterior uveitis which also leads to cataracts and open-angle glaucoma

Also known as Fuchs heterochromic cyclitis.

Chronic non-granulomatous anterior uveitis but with a no red eye
Affected iris is typically hypochromic, hence the patient is heterochromic (irises of different colours)

HLA Associations

Many different types of HLA alterations have been associated with various ophthalmic diseases. Some of the more commonly examined associations are summarised in this section.

Disease	HLA Types
Acute anterior uveitis + reactive arthritis	HLA-B27
Birdshot chorioretinopathy	HLA-A29
Bechet’s diseases	HLA-B51
VKH + sympathetic ophthalmia	HLA-DR4
Multiple sclerosis	HLA-B7, DR2
Sarcoidosis	HLA-BA, B13