“Uveitis” refers to the group of eye conditions defined by the presence of intraocular inflammation. The middle pigmented layers of the eye—the iris, ciliary body, and choroid—are collectively called the uvea, from the Latin word, uva (grape) for its round shape and dark color. The suffix, itis is of Greek origin, meaning “inflammation” ( Fig. 26.1 ).
In modern ophthalmology, uveitis is used as an umbrella term to encompass a diverse group of autoimmune and infectious diseases of the uvea, retina, retinal vessels, optic nerve head, sclera, and cornea. Inflammation of these structures can cause an abnormal accumulation of white blood cells in the anterior chamber (anterior uveitis), vitreous cavity (intermediate uveitis), or retina and choroid (posterior uveitis). Often multiple structures may be involved. When all three regions are involved, the condition is considered a panuveitis. Infiltration of the cornea or sclera can cause opacity, redness, or thinning ( Fig. 26.2 ). Depending on the location and type of inflammation, patients may experience eye redness, pain, light sensitivity, blurred vision, or floaters. Over time, untreated inflammation may lead to complications, such as tissue swelling, scarring, cataract, or glaucoma, which can result in permanent vision loss ( Fig. 26.3 ).
Uveitis accounts for between 5% and 20% of blindness in the United States and Europe, and up to 25% of blindness in the developing world. In Western countries, uveitis is found to affect between 15 and 100 per 100,000 people per year, and may be responsible for up to 30,000 new cases of legal blindness annually in the United States. Uveitis can affect patients at any age; many forms may have a female predominance. In about half of patients, the age of onset is in the third or fourth decade of life, making uveitis one of the ocular diseases with an important socioeconomic effect. In 25% to 50% of cases, there is an associated underlying systemic disease. The etiologic factor in more than 30% of uveitis cases is unknown.
Only with prompt identification and complete and proper treatment can the ophthalmic team mitigate damage and preserve vision. Even low levels of asymptomatic smoldering inflammation are capable of inflicting permanent vision loss over time. In addition, the treatments used in uveitis can cause significant ocular and systemic side effects, requiring ongoing monitoring. In no other subspecialty of ophthalmology are the patient’s medications, exposures, medical history, and current symptoms so critical to diagnosis and treatment. As the front line to the patient, the ophthalmic assistant has a key role to play in gathering patient information and initial examination data. This information not only will alert the physician to the possibility of a uveitic disease, but also help narrow the differential diagnosis, ask appropriate follow-up questions, and choose the most appropriate therapy.
Classification of uveitis
In 2005 a panel of experts formed the Standardization of Uveitis Nomenclature (SUN) Working Group to define a set of common terms to classify uveitis. Uveitic diseases are organized by primary site of inflammation: anterior, intermediate, posterior, and panuveitis. The SUN system also provides nomenclature to describe the character and severity of uveitis ( Table 26.1 ).
|Type||Primary site of inflammation a||Includes|
|Anterior uveitis||Anterior chamber||Iritis|
|Intermediate uveitis||Vitreous||Pars planitis|
|Posterior uveitis||Retina or choroid||Focal, multifocal, or diffuse choroiditis|
|Panuveitis||Anterior chamber, vitreous, and retina or choroid|
The character of the uveitis is ascertained by taking a thorough history of the present illness. The uveitis may occur suddenly or gradually (insidious onset). It may resolve relatively quickly or it may persist for months to years. A summation of these characteristics can help define what is called the “course” of uveitis: whether it is acute, recurrent, or chronic ( Table 26.2 ). Other descriptive categories frequently used include unilateral versus bilateral involvement, solitary retinal/choroidal lesions versus multifocal lesions, and others.
|Duration||Limited||≤3 months’ duration|
|Persistent||>3 months’ duration|
|Course||Acute||Episode characterized by sudden onset and limited duration|
|Recurrent||Repeated episodes separated by periods of inactivity without treatment ≥3 months in duration|
|Chronic||Persistent uveitis with relapse in <3 months after discontinuing treatment|
The inflammatory activity of uveitis is defined by the degree of circulating white blood cells seen on physical examination. A high-magnification, bright, obliquely aimed 1 × 1 mm slit-lamp beam is focused on the space between the cornea and the iris. The number of individual white blood cells floating in this anterior chamber space is counted to grade the degree of anterior chamber cell on a 1 to 4 scale. The phenomenon of white blood cells floating in the anterior chamber is said to look like specks of dust floating in a sunbeam. Typically, the anterior chamber should look completely black, or optically empty. If this space is cloudy, it represents protein extravasation from a damaged blood–aqueous barrier. This physical examination finding, called flare, can be a marker of disease severity or chronicity. The appearance of flare is often likened to that of headlights in the fog ( Fig. 26.4 ). Grading systems for vitreous inflammation are more complex, often focusing on the degree of obscuration of fundus details. The degree of vitreous cell and haze is also graded on a 1 to 4 scale. Scleritis is categorized as either anterior (e.g., diffuse, sectorial, nodular, or necrotizing) or posterior.
Causes of uveitis
Ocular inflammatory diseases may be limited to the eye, or have systemic manifestations. They may be caused by infectious or noninfectious etiology. Certain uveitic diseases have a predilection for the young or for the old, for a particular anatomic section of the eye, or for unilateral or bilateral disease. Entering the patient encounter with basic knowledge of some of the causes of uveitis can give new importance to patient responses to health and symptom questions when uveitis is suspected.
Infectious diseases that can enter the eye to cause uveitis include viruses, such as the herpesviruses that cause cold sores and shingles; bacteria, such as syphilis, tuberculosis, or Lyme disease; fungi, such as Candida (usually from contamination in the setting of indwelling intravenous [IV] lines in hospitalized patients, or IV drug users); and parasites, such as the tiny intracellular toxoplasmosis organism transmitted from undercooked meat or exposure to cat feces.
Inflammatory causes can be linked to systemic autoimmune diseases, such as juvenile idiopathic arthritis, multiple sclerosis, ankylosing spondylitis, and sarcoidosis, or they can be isolated to the eye, as is the case with sympathetic ophthalmia and birdshot chorioretinitis. Blunt trauma, occult penetrating trauma, or a retained intraocular foreign body can cause chronic intraocular inflammation. In rare cases, uveitis can be caused by an inflammatory reaction to certain systemic medications. Finally, some cancers, such as lymphoma can mimic or “masquerade” as uveitis, with deposition of abnormal white blood cells in various structures of the eye. See Table 26.3 for a more complete list of uveitis causes.
|With systemic disease||Viral|
|Systemic lupus erythematosus||Herpetic (HSV, VZV, CMV, EBV)|
|Sarcoidosis||Fuchs heterochromic iridocyclitis (rubella)|
|Systemic vasculitis||Measles virus|
|Juvenile or rheumatoid arthritis||West Nile virus|
|Inflammatory bowel disease (Crohn/ulcerative colitis)||Syphilis|
|Ankylosing spondylitis, psoriatic arthritis, HLA-B27 diseases||Tuberculosis|
|Without systemic disease||Cat scratch disease (Bartonella henselae)|
|Vogt–Koyanagi–Harada (VKH) syndrome||Lyme disease (Borrelia burgdorferi)|
|Inflammatory chorioretinopathies (white dot syndromes)||Rickettsial diseases (e.g., Rocky Mountain spotted fever)|
|Osteoporosis drugs (bisphosphonates)||Histoplasmosis|
|Select antibiotics: sulfonamides, fluoroquinolones||Parasitic|
|Select topical drops: brimonidine, prostaglandin analogs||Toxoplasmosis|
|Blunt trauma||Diffuse unilateral subacute neuroretinitis (DUSN)|
|Occult foreign body or ruptured globe||Onchocerciasis (river blindness)|
|Primary intraocular lymphoma|
|Metastasis to eye from extraocular cancer site|