Ординатура / Офтальмология / Английские материалы / Oxford American Handbook of Ophthalmology_Tsai, Denniston, Murray_2011

356 CHAPTER 11 Uveitis

Clinical features

Ophthalmic

•External: madarosis, trichiasis, lagophthalmos (CN VII palsy), conjunctivitis, epi/scleritis, keratitis (neurotrophic, exposure, or secondary infection).

•Anterior: anterior uveitis is usually persistent; less commonly, acute anterior uveitis; “iris pearls” at the pupillary margin may enlarge and drop into the AC; iris atrophy; miosis.

Systemic

•Tuberculoid: thickened and tender nerves associated with hypopigmented anesthetic patches and muscle atrophy.

•Lepromatous: nerve changes are less marked but with widespread infiltration, including skin, ears, nose (saddle-nose), face (leonine appearance), and larynx (hoarse voice).

Investigation and treatment

This should include skin and nasal mucosa smears for noncultivable acidfast bacilli. Systemic treatment should be coordinated by a referral center with multidisciplinary support. Treatment of eye disease is usually with topical steroids.

SPIROCHETAL AND OTHER BACTERIAL UVEITIS 357

Spirochetal and other bacterial uveitis

Syphilis

The spirochete Treponema pallidum is usually transmitted by sexual contact or transplacentally. Acquired syphilis is divided into primary, secondary, and tertiary stages. Congenital syphilis may be divided into early (equivalent to acquired secondary stage) and late (equivalent to acquired third stage) (see Table 11.20).

Clinical features (Table 11.21)

Anterior uveitis

This is the most common ocular feature of both secondary and tertiary syphilis.

•Granulomatous or nongranulomatous; variable severity; ± roseolae (vascular fronds on the iris); ± iris atrophy; nodules on the iris or iridocorneal angle occur in tertiary disease only.

Posterior uveitis

This may be unior bilateral, unior multifocal, and choroiditis or chorioretinitis.

•Yellow plaque-like lesions with overlying vitritis ± serous retinal detachment. Resolution of the lesions results in a pigmentary retinopathy.

Investigation

•Nontreponemal serology (Table 11.22): venereal disease research laboratory (VDRL) tests disease activity; it may become negative in later-stage syphilis. Rapid plasma reagin (RPR) is a simple test used in screening; it has a high false-positive rate and also turns negative in many patients with tertiary and neurosyphilis.

•Treponemal serology (Table 11.22): fluorescent treponemal antibody absorption (FTA-ABS) and hemagglutination tests (TPHA) test previous or current infection. They do not distinguish from other treponematoses (e.g., yaws).

•Dark-ground microscopy of chancre or mucocutaneous lesion

•Lumbar puncture: consider if there is active ocular disease, suspected neurosyphilis, or HIV. Cerebrospinal fluid (CSF) typically shows raised protein, pleocytosis, and positive VDRL.

•HIV test; coinfection is increasingly observed.

Treatment

Management of syphilitic eye disease should be in conjunction with an infectious disease physician. Treatment requires high-dose intravenous procaine penicillin G with an extended regimen for late latent and tertiary syphilis. Spirochete death may transiently worsen inflammation (Jarish– Herxheimer reaction).

Consider topical steroids for interstitial keratitis and anterior uveitis. Systemic steroids must be used with caution but have a role in sightthreatening posterior uveitis or scleritis.

SPIROCHETAL AND OTHER BACTERIAL UVEITIS 359

Other bacteria

Other bacteria that may cause uveitis include the spirochetes Borrelia burdorferi (Lyme disease) and Leptospira interrogans (leptospirosis, including Weil’s disease), the gram-positive bacillus Tropheryma whippelii (Whipple’s disease), and the gram-negative bacilli Bartonella henselae (cat-scratch disease) and Brucella (brucellosis).

Lyme disease

Lyme disease is caused by the infectious organism Borrelia burgdorferi through a tick-borne transmission. The organism is found in rodents, deer, birds, cats, and dogs and is transmitted to humans by the ticks Ixodes dammini (east) or Ixodes pacificus (west). The first reported case of the disease was discovered in 1975 in Lyme, Connecticut.

While most patients do not recall exposure to ticks or tick bite, 80% of affected patients develop a classic skin lesion of erythema chronicum migrans. After several weeks, the organism may spread systemically and is associated with annular skin lesions, meningitis, cranial or peripheral neuritis, migratory musculoskeletal pain, and carditis. Months to years later, chronic arthritis or neurological symptoms may develop.

Clinical features: systemic

Stage I

•Classic triad of nonspecific follicular conjunctivitis (10%), skin rash, and flu-like symptoms.

•Erythema chronicum migrans is a spreading target lesion skin rash often forgotten by the patient (60–80% of patients).

•Headache, stiff neck, malaise, myalgias, arthralgias, and fever.

Stage II

• 1–4 months after infection, further invasion brings neurological, musculoskeletal, and cardiac findings.

•Neurological (30–40%): Bell’s palsy, encephalitis, meningitis.

•Cardiac (8%): myocarditis, heart block.

•Musculoskeletal: arthritis, tendonitis, joint effusions.

Stage III

•After 5 months of infection.

•Chronic atrophic skin changes, keratitis, chronic arthritis, ataxia, chronic encephalomyelitis, acute respiratory distress syndrome (ARDS).

Clinical features: ophthalmic

•Follicular conjunctivitis early (11% of patients).

•Chronic iridocyclitis.

•Vitritis.

•Peripheral retinal vasculitis.

•Diffuse choroiditis.

•Panuveitis.

•Intermediate uveitis.

•Optic neuritis.

•Neuroretinitis.

•Orbital myositis.

•Cranial nerve palsies.

PROTOZOAN UVEITIS 361

Protozoan uveitis

Toxoplasmosis

The protozoan Toxoplasma gondii is an obligate intracellular parasite that is estimated to infect up to 50% of the world’s population. Lifetime risk of ocular toxoplasmosis is around 18/100,000 but up to 20 times this level in West Africa and South America.

The definitive host is the cat; livestock and humans are only intermediate hosts. Oocysts are excreted in cat feces, which are ingested by humans and livestock in which they may become encysted (bradyzoite) or actively proliferate (tachyzoite). Human infection arises from contact with cat feces or contaminated soil, ingestion of undercooked meat (bradyzoites), contaminated water, or transplacentally.

In the past, most toxoplasmosis was thought to be congenital, but acquired disease is increasingly recognized. Vertical transmission rate (transplacental) increases from 15% in the first trimester to 60% in the third trimester; disease severity is much greater if acquired in early pregnancy.

Clinical features

Ophthalmic

Affects both eyes in 40%, but if simultaneously active, suspect immunocompromise.

•Asymptomatic finding, floaters, dVA.

•Vitritis (may have “vitreous precipitates” akin to KPs on posterior surface of PVD), retinitis (white, fluffy area when active; becomes circumscribed and pigmented as it heals; atrophic scar with pigmented border when inactive; satellite lesions with old scars commonly seen); retinal vasculitis (periphlebitis); may have an anterior uveitis often with iIOP.

•Other presentations include scleritis, punctate outer retinitis (with quiet vitreous), large lesions (especially in the elderly),

endophthalmitis-like, neuroretinitis, serous retinal detachments, and pigmentary retinopathy.

•Complications include cataract, glaucoma, and CNV membrane.

Systemic

•Congenital: the impact of transplacental infection is greatest early in pregnancy; complications include hydrocephalus, cerebral calcification, hepatosplenomegaly, and retinochoroiditis (more commonly bilateral and affecting the macula).

•Acquired: if the patient is immunocompetent, the disease is usually asymptomatic, but the patient may have fever and lymphadenopathy. If immunocompromised, they may have life-threatening disease, including encephalitis, intracerebral cysts, hepatitis, and myocarditis.

Investigation

This is essentially a clinical diagnosis. Interpret positive serological tests with caution. Many of the adult population are positive for anti-toxoplasma IgG; however IgM antibodies do suggest acquired infection, and negative serology in undiluted serum makes the diagnosis unlikely. Matched early and convalescent samples are not required. PCR of intraocular samples may also be used.

362 CHAPTER 11 Uveitis

Figure 11.1 Active macular toxoplasmosis retinochoroiditis with overlying vitreous cells and associated optic disc edema. See insert for color version.

Treatment

Box 11.3 Indications for treatment

•Lesions involving optic disc, macula or papillomacular bundle

•Lesions threatening a major vessel

•Marked vitritis

•Any lesion in an immunocompromised patient

Systemic treatment is with 4 weeks of prednisone AND cotrimoxazole OR clindamycin/sulfadiazine OR pyrimethamine/sulfadiazine/folinic acid (weekly CBC required) OR atovaquone. Steroids must not be used without effective antitoxoplasmosis therapy and should not be given if the patient is immunosuppressed.

For maternal infection acquired during pregnancy, use spiramycin (named-patient basis) to reduce transplacental spread. Atovaquone may theoretically reduce recurrences, as it is active against bradyzoites as well as tachyzoites.

364 CHAPTER 11 Uveitis

Nematodal uveitis

Toxocariasis

The ascarid Toxocara canis is one of the most common of all nematode infections and is a significant cause of visual loss worldwide. The definitive hosts are puppies (or kittens for the less common T. catis).

Ova excreted in feces are inadvertently ingested by humans, where they develop into larvae. The larvae invade the gut wall and spread hematogenously throughout the body, notably to the liver, lung, brain, heart (visceral larva migrans), or eye (ocular toxocariasis). Larval death causes an intense inflammatory reaction.

Infection by Toxocara usually occurs <3 years of age, although some ocular disease may not present until adulthood.

Clinical features

Ophthalmic

Ocular toxocariasis is unilateral. Presentation may vary with age.

•Diffuse chronic endophthalmitis (age 2–9 years): dVA + floaters; white eye with chronic anterior uveitis, posterior synechiae, vitritis, snowbanking, macular edema, exudative retinal detachment; complications include tractional retinal detachment, cyclitic membrane, cataract, hypotony.

•Posterior pole granuloma (age 6–14 years): dVA; yellow-white granuloma 1–2 DD at the macula/papillomacular bundle with retinal traction and vitreous bands.

•Peripheral granuloma (age 6 years–adult): usually asymptomatic until significant traction; yellow-white granuloma anterior to the equator with vitreous bands. Traction may cause macula heterotopia or retinal detachment (tractional or rhegmatogenous).

•Less common presentations include isolated anterior uveitis, intermediate uveitis, optic papillitis, and vitreous abscess.

Systemic (visceral larva migrans)

Systemic features usually occur in patients <4 years of age.

•Fever, pneumonitis + bronchospasm, hepatosplenomegaly, fits, myocarditis, death (rare); eosinophilia.

Investigation

This is essentially a clinical diagnosis, although ELISA for serum antibodies may be supportive and B-scan ultrasound may help differentiate it from other diagnoses.

Treatment

For ocular toxocariasis use systemic or periocular steroids titrated according to disease severity; antihelminthics (e.g., thiabendazole) are of limited use. Consider vitrectomy to clear debris, relieve traction, and repair retinal detachments.

NEMATODAL UVEITIS 365

Diffuse unilateral subacute neuroretinitis (DUSN)

DUSN is an increasingly recognized cause of posterior uveitis in young people in which a solitary nematode persists in the subretinal space for years, causing progressive damage. Two unknown nematodes may cause the syndrome. They have different sizes (0.5 mm and 1–2 mm) and occur in different geographical distributions.

Signs include a unilateral vitritis, optic disc swelling (later atrophy), deep retinal gray-white lesions, and sometimes the worm itself. Treatment is difficult. If directly visualized, the worm may be killed by argon laser; if not, use antihelminthics (e.g., thiobendazole). Steroids suppress inflammation but do not alter outcome.

Onchocerciasis

Worldwide onchcocerciasis (river blindness) affects around 20 million people, causing visual impairment in 10%.

The filarial nematode Onchocerca volvulus is spread between humans (definitive host) by bites of the Simulium blackfly (vector). Having entered the subcutaneous tissue, the larvae mature into adult worms (up to 80 cm long) and mate to produce microfilariae within large subcutaneous nodules. The microfilariae then spread to nearby tissues, which may include the eye.

The Simulium breeds in areas of fast flowing water that also tend to be those regions that are most fertile and heavily farmed.

Ocular disease from the microfilariae includes sclerosing keratitis (with an opaque apron over the inferior cornea), chorioretinitis, sclerosis of the retinal vessels, optic neuritis, and optic atrophy. Microfilariae may best be seen in the AC after face-down posturing. Histology may be obtained from skin nodules.

Treatment was traditionally with diethylcarbamazine (which induces the severely itchy Mazzotti reaction), but has now been replaced with ivermectin.