Ординатура / Офтальмология / Английские материалы / Handbook of Pediatric Retinal Disease_Wright, Spiegel, Thompson_2006

whitening of the peripheral retina and vitreous inflammation may be present initially or may develop over days to weeks. Arterial sheathing is common. The white areas may coalesce and spread posteriorly (Fig. 11-6B). The active phase of retinitis lasts 4 to 6 weeks. When lesions clear, they leave atrophic scars with RPE stippling. Three-fourths of these patients develop retinal detachment in the involved eye within 1 to 2 months, often complicated by large breaks and tractional components. Visual loss secondary to optic nerve involvement may also occur.

Herpesvirus particles have been identified within necrotic retina from eyes with ARN. Varicella zoster virus (VZV) and herpes simplex type 1 and 2, demonstrated by polymerase chain reaction (PCR) and antibody testing, have been shown to be the most common causes.9,23,53,55

The treatment of ARN is difficult, and no randomized clinical trials have been performed. However, the retinitis responds to acyclovir. Retinal tears often occur despite treatment, commonly leading to retinal detachment. Prophylactic laser at the edge of the involved retina and i.v. acyclovir therapy may improve the prognosis.19 Poor visualization may preclude laser therapy, and early vitrectomy may be required in patients with ARN and hazy vitreous. The role of corticosteroids in this disorder is controversial.

RUBELLA

Expectant mothers who are infected with the rubella (German measles) virus during pregnancy may give birth to infants with a variety of congenital anomalies affecting the eyes, ears, heart, and other organs. Depending on the stage of gestation at the time of infection, a wide variety of clinical features may be seen. The most common ocular findings of the congenital rubella syndrome are nuclear cataract (often eccentric), microphthalmos, and a salt-and-pepper retinopathy. Other findings include congenital glaucoma, strabismus, and iris hypoplasia. Nonocular findings include sensorineural hearing loss and congenital heart disease.

Rubella retinopathy is classically described as a “salt and pepper” mottling of the retinal pigment epithelium (RPE) (Fig. 11-7A,B) that is often most prominent in the posterior fundus. Eighty percent of cases are bilateral. The abnormal fundus

FIGURE 11-7A,B. Fundus photograph (A) and angiogram (B) from two different patients with congenital rubella show the characteristic “salt- and-pepper” retinopathy.

appearance may be seen alone or may be accompanied by other ocular abnormalities such as cataract and microphthalmos. When seen alone, the abnormal fundus appearance does not usually result in a decrease in visual acuity. Visual fields, color vision, electroretinography, and electro-oculography are usually normal. Fundus changes may progress throughout childhood, and

choroidal neovascularization has been described. The fundus picture is not specific for rubella. A similar appearance may occur in patients with congenital syphilis as well as toxic or inherited diseases of the RPE and the carrier state of X-linked ocular albinism.16 Positive serum titers of antibody against the rubella virus are indicative of prior infection and may aid in making the diagnosis. However, negative antibody titers do not rule out the diagnosis of congenital rubella because antibodies may disappear with time. Treatment for the choroidal neovascularization can be performed with conventional laser photocoagulation or photodynamic therapy.

SYPHILIS

Syphilis is a sexually transmitted disease caused by the spirochete Treponema pallidum. Syphilitic eye disease may be congenital or acquired. Congenital syphilis is associated with a pigmentary retinopathy that is classically described as a “salt- and-pepper” mottling of the fundus (Fig. 11-8A). The retinal pigment epithelial clumping may mimic retinitis pigmentosa. Optic atrophy is also commonly seen. Infants with congenital syphilis acquire the disease transplacentally. Affected infants may have failure to thrive, hepatosplenomegaly, and anemia. Classic nonocular physical signs include saddle nose, sabre shins, and Hutchinson’s teeth. Some cases are asymptomatic and are recognized later in life (e.g., after an episode of interstitial keratitis). Acquired syphilis commonly produces a patchy neuroretinitis that may result in profound visual field loss. Uveitis (Fig. 11-8B) or optic disc edema may also occur with or without chorioretinitis.

The diagnosis of syphilitic eye disease is made with a combination of clinical and laboratory examinations. In congenital cases, the serum VDRL and FTA-ABS tests may be negative early in the course of the disease. However, in cases of congenital syphilis that present late, as well as in cases of acquired syphilis, these tests are usually useful. Because the serum VDRL may be falsely negative in some patients, the FTA-ABS is a more reliable test. However, false-positive results occur with both tests. VDRL testing of the CSF should be performed in patients with suspected secondary or tertiary syphilis.

Treating affected mothers is the best preventative treatment for congenital syphilis. Infants with congenital syphilis should

FIGURE 11-8A,B. (A) Fundus photograph from patient with congenital syphilis. Note the pigmentary abnormalities and pale optic disc. (B) Anterior or posterior uveitis may be seen in patients with secondary syphilis. This patient presented with posterior uveitis and a chorioretinal inflammatory mass.

be treated similarly regardless of CSF serologies.17 Treatment of acquired cases depends on CSF serologies. The latest recommendations from the Centers for Disease Control should be consulted before starting therapy. Ocular syphilis should be treated

as if it were neurosyphilis. Cycloplegics and topical or periocular steroids may be helpful adjuncts in patients with uveitis.

AIDS AND OPPORTUNISTIC

OCULAR INFECTIONS

Acquired immunodeficiency syndrome (AIDS) is caused by infection with HIV-1, a retrovirus. Infection with the virus may occur in any age group and most commonly occurs through sexual intercourse or shared intravenous needles. Infants can acquire the disease in utero from an infected mother (vertical transmission) or from breast milk. Patients who are infected with the virus develop a profound depression in cell-mediated immunity. The disease may manifest itself many years after the initial infection with the virus. Patients are prone to develop opportunistic infections such as Pneumocystis carinii pneumonia and unusual neoplasms such as Kaposi’s sarcoma.

Ocular involvement is quite common in affected patients and ranges from scattered cotton wool spots to potentially blinding cytomegalovirus (CMV) retinitis.2 Cotton wool spots are commonly seen in affected patients. Clinically, these nerve fiber layer infarcts appear as whitish fluffy lesions of the inner retina (Fig. 11-9A) that may be up to 0.5 disc diameters in size. They do not enlarge with time (as do the lesions of CMV retinitis) and rarely cause any visual disturbance. Cytomegalovirus is a herpesvirus that can cause a severe retinitis. The disease occurs almost exclusively in immunocompromised hosts (e.g., organ and bone marrow transplant patients, cancer patients, patients with AIDS). Approximately 1.6% to 6% of children with AIDS develop CMV retinitis, which is significantly less frequent than in adults.2,12 CMV retinitis may appear as fluffy whitish retinal lesions with hemorrhage that enlarge over time (Fig. 11-9B). Alternatively, the lesions may be granular centrally with hemorrhage and retinal whitening at the periphery. The edges of the lesions are areas of active viral infection whereas the central areas represent necrotic retina. Lesions often start peripherally, and visual acuity may be normal until the macula or optic nerve are involved.

The diagnosis of CMV retinitis in children may be delayed because of their inability to report visual loss. Therefore, screening examinations on a more frequent schedule than in adults may be desirable. Retinal examinations should also be

FIGURE 11-9A,B. (A) Cotton wool spots are commonly seen in patients with the acquired immunodeficiency syndrome (AIDS) but do not seem to be predictive of other ocular complications. (B) Cytomegalovirus retinitis encroaching upon the optic disc in patient with AIDS.

performed when systemic CMV infections are detected. Du et al.12 found that children with HIV and a CD4 lymphocyte count less than 20 were at greater risk for retinitis whereas those with higher counts did not develop retinitis. Optimal treatment of CMV retinitis in children has not yet been established. Treatment with intravenous foscarnet or ganciclovir often results in

a clinical response.51,56 These drugs are virostatic, and maintenance therapy is required. If ganciclovir alone fails to control the retinitis, the addition of foscarnet may control the disease.51 The use of ganciclovir and foscarnet together decreases the incidence of reactivation. For severe infections or for patients who cannot tolerate systemic medication, intravitreal ganciclovir (1 mg in 0.1 ml) or placement of sustained-release ganciclovir implants may be tried in conjunction with oral valganciclovir.10,28 Other opportunistic infections may occur in AIDS patients and may be difficult to differentiate from CMV retinitis. Both herpes simplex and herpes zoster may produce a retinitis in immunocompromised patients.36 If the patient has AIDS, HAART (highly active anti-retroviral therapy) may help cause resolution of the CMV retinitis, but a secondary iridocyclitis may develop (immune reconstitution uveitis). This iridocyclitis is responsive to topical corticosteroids.

OPHTHALMOMYIASIS AND DIFFUSE UNILATERAL SUBACUTE NEURORETINITIS

The term ophthalmomyiasis applies to cases of ocular infestation with the larval forms of flies. The larval forms may be transmitted by adult flies through bites or by touching the ocular area with hands contaminated with larvae.57

Characteristically, ocular findings consist of subretinal tracks with or without an encysted or moving organism within the subretinal space (Fig. 11-10A). The amount of inflammatory response is variable. Patients may complain of photopsias. Loss of vision may occur if the macula or optic nerve is involved.

Treatment of affected patients depends on the amount of inflammation present and whether the organism can be localized. Severe inflammatory reactions should be treated with periocular or oral corticosteroids. If the organism can be localized, photocoagulation of the organism has been recommended.44 Organisms may also be removed with vitrectomy.

Diffuse unilateral subacute neuroretinitis (DUSN) is caused by ocular infestation with nematode larvae other than Toxocara canis.15 These larvae are not found within granulomatous masses, as are T. canis organisms, but may be seen moving through the subretinal space. Patients typically present with scotomata and/or visual blurring. Diffuse patchy pigment epithelial atrophy and/or deep gray-white retinal lesions may be

seen. Optic nerve swelling is common, and visual field loss may be severe. In the late stages, optic atrophy, pigmentary retinal changes, and narrowing of the retinal vessels may be seen (Fig. 11-10B). Motile organisms may be seen at any stage of the disease. Toxocara ELISA titers are typically low. Electroretinogram (ERG) abnormalities are present in all stages of the disease, with the b-wave being affected more than the a-wave. Many entities are in the differential diagnosis of DUSN, depending on the stage of the disease. Early in the course, DUSN may mimic various “white-dot” syndromes or presumed ocular histoplasmosis syndrome (POHS) whereas late in the course it may mimic retinitis pigmentosa. It should be remembered that DUSN occurs most often in children and young adults who are otherwise healthy. This condition is almost always unilateral. A case of living nematodes in both eyes was referred to as diffuse bilateral subacute neuroretinitis.11

Treatment is similar to that for ophthalmomyiasis. Laser photocoagulation of the organism is the definitive treatment.

PRESUMED OCULAR

HISTOPLASMOSIS SYNDROME

The presumed ocular histoplasmosis syndrome (POHS) is characterized by peripheral “punched-out” chorioretinal scars, pe ripapillary scarring, disciform macular scarring, and a lack of inflammation (Fig. 11-11A). The disease is thought to be related to infection with Histoplasma capsulatum, a fungus that is a common soil contaminant in the Mississippi and Ohio river valleys of the United States. Initial infection with the organism occurs by respiratory contact and may result in a mild upper respiratory syndrome but is more commonly asymptomatic. An active choroiditis may occur at this early stage. In immunocompetent individuals, the syndrome (including ocular lesions) resolves spontaneously, resulting in multifocal areas of chorioretinal scarring. The disease is most commonly recognized in adults but may be seen in older children. Many patients are asymptomatic and the syndrome is recognized by noting the multifocal chorioretinal scars during routine ophthalmoscopy. However, choroidal neovascular membranes may occur adjacent to these scars, and these may cause hemorrhage and serous detachment of the retina (Fig. 11-11B,C). If this occurs in the macular area, visual acuity can be seriously affected. If left