Ординатура / Офтальмология / Английские материалы / Pediatric Ophthalmology for Primary Care 3rd edition_Wright, Farzavandi_2008
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Figure 14 6.
Toxocara granuloma with traction on the optic disc.
(endophthalmitis) should be treated with systemic or periocular cortico steroids. If a worm has been identified within the retina, antihelminthics should be avoided. However, if antihelminthics are used, corticosteroids should also be prescribed because larval death will cause severe intraocular inflammation. The use of laser to kill the larvae has been advocated by some, but this also leads to severe intraocular inflammation.
Congenital Toxoplasmosis
See Chapter 6.
Lyme Disease
Lyme disease is caused by the spirochete, Borrelia burgdorferi. It is trans mitted to humans by the bite of a deer tick commonly found in New England, Middle Atlantic, and upper Midwest states. Three stages of Lyme disease have been described, and all 3 stages may affect the eye.
Early Localized Disease
The first stage occurs within 1 month after the tick bite and consists of headaches, stiff neck, malaise, fever, lymphadenopathy, and a migratory erythematous skin rash termed erythema migrans. Ocular involvement is usually a conjunctivitis.
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Early Disseminated Disease
The second stage occurs approximately 1 to 4 months after infection and results in secondary erythema migrans skin lesions and neurologic, muscu loskeletal, cardiac, and ocular disease. Neurologic disease occurs in approxi mately 40% of patients and can take the form of encephalitis, meningitis, or Bell palsy (facial nerve palsy). Almost 10% of patients will develop cardiac disease. Ocular manifestations of Lyme disease include keratitis, uveitis, and optic neuritis. Treatment includes intramuscular (IM) ceftriaxone, penicillin, or doxycycline for children younger than 8 years.
Late Disease
The final stage has its onset months after the initial infection. Complications consist of chronic neurologic disease and arthritis. Ocular findings include uveitis. Laboratory workup includes ELISA titers for the antibody to B burg dorferi; however, not all patients with Lyme disease will have elevated titers. Because of the similarity to syphilis, patients with Lyme disease may have
a false positive syphilis serology. Treatment consists of tetracycline, eryth romycin, or penicillin. Patients with encephalitis or meningitis should be treated with ceftriaxone IM, penicillin, or doxycycline for children younger than 8 years.
Episcleritis and Scleritis
Episcleritis is an inflammatory condition of the scleral surface. It occurs in adolescents and young adults as a unilateral or, more often, bilateral con junctivitis. Patients present with localized injection of the conjunctiva and deeper episcleral tissue, with the injection usually localized over the rectus muscle insertion. There is often pain on eye movement, distinguishing episcleritis from allergic or infectious conjunctivitis where there is no pain on eye movement. The area of inflammation is tender to palpation. Another distinguishing characteristic is the localized nature of the conjunctival injec tion (Figure 14 7). In contrast to allergic conjunctivitis, episcleritis is not associated with itching, but it is associated with some tearing, discomfort, and tenderness to touch. Although often recurrent, episcleritis is a self limiting disorder usually not associated with systemic disease. In contrast, true inflammation of the sclera (scleritis) is usually seen in adult patients and is often associated with rheumatoid arthritis. Patients with a localized
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Figure 14 7.
Episcleritis with conjunctival injection localized around the lateral rectus muscle. Note that the conjunctiva close to the cornea (perilimbal conjunctiva) is clear and the sclera is white. This localized pattern of inflammation is distinct from the generalized pattern of inflammation associated with an infectious conjunctivitis.
conjunctival inflammation and tenderness should be referred for a full ophthalmic evaluation. The treatment of episcleritis is usually topical, nonsteroidal, anti inflammatory agents or topical corticosteroids.
Systemic anti inflammatory agents such as ibuprofen and indomethacin may be required.
Endophthalmitis
Endophthalmitis is an intraocular infection that may be caused by a bacteria or fungus. This is a devastating ocular condition with an extremely poor prognosis, even when treated with high dose antibiotics and vitrectomy to remove the infection. Damage to intraocular structures occurs not only from the toxins released by the microorganism, but also from the inflammatory response produced by the host. The retina and anterior segment structures may be directly injured. Scarring, secondary to inflammation, can cause a secondary retinal detachment.
Endophthalmitis can be divided into 2 types based on the cause.
1.Exogenous endophthalmitis is caused by direct penetration of a microor ganism into the eye, such as in the case of traumatic endophthalmitis.
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Features include
•Bacterial corneal ulcer that penetrates the anterior chamber
•Ruptured globe with contamination of the intraocular structures
•Postoperative endophthalmitis after intraocular surgery
2.Endogenous endophthalmitis is caused by hematogenous spread of an infectious agent into the eye. This disease is
•Rare
•Associated with an indwelling catheter and colonization by the infecting organism
Characteristics of endophthalmitis include pain, decreased vision, and a severely inflamed eye with conjunctival injection. There are usually an associated hypopyon (white cells layered out in the anterior chamber) and white cells in the vitreous cavity, producing a dull red reflex (Figure 14 8).
Traumatic endophthalmitis occurs in approximately 3% to 8% of patients with penetrating ocular injuries. Bacillus cereus accounts for almost one fourth of traumatic endophthalmitis cases and is commonly found in soil. Therefore, soil contaminated penetrating ocular injuries are usually associ ated with bacillus endophthalmitis. Fungal endophthalmitis (eg, Candida albicans) should be suspected if plant or organic intraocular debris is
Figure 14 8.
Endogenous endophthalmitis with diffuse injection of the conjunctiva, a hypopyon (which is the white layered material in the anterior chamber), and vitreous cells evidenced by the whitish appearance in the pupil.
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present. Streptococcus epidermidis and Staphylococcus aureus are also com mon causes of traumatic bacterial endophthalmitis.
Endogenous endophthalmitis occurs from infections arising at sites dis tant from the eye and is spread by hematologic dissemination. Patients who are immunosuppressed, are chronically ill, or have indwelling catheters are predisposed to developing endogenous endophthalmitis. Common organ isms responsible for endogenous endophthalmitis include Staphylococcus species (associated with endocarditis), S aureus (associated with a cutaneous infection), and B cereus (associated with intravenous drug use). Neisseria meningitidis and Haemophilus influenzae, Escherichia coli, and Klebsiella species can also cause endophthalmitis. Endogenous fungal endophthal mitis is most commonly caused by candidal and aspergillus fungi. Fungal endophthalmitis typically presents with a quiet eye and focal, or multifocal, chorioretinal lesions. Candida infections are usually seen in patients who are immunosuppressed, on hyperalimentation, or who have chronic indwell ing catheters.
The treatment of endophthalmitis consists of intravenous systemic anti microbials along with topical, subconjunctival, and intraocular antimicrobi als. Topical and intraocular corticosteroids are often administered to limit the host mediated intraocular inflammation, thus reducing intraocular tis sue damage.
The prognosis of patients with endophthalmitis depends on the causative organism; however, the prognosis is generally poor, and the majority of the patients end up legally blind in the involved eye. Traumatic endophthalmitis caused by B cereus has an especially poor prognosis.
Acute Retinal Necrosis Syndrome
Acute retinal necrosis (ARN) syndrome is caused by a viral infection of the retina. Herpes simplex virus, herpes zoster virus, and cytomegalovirus (CMV) have been implicated as infectious causes. Patients present with symptoms of photophobia, pain, and decreased vision. Acute retinal necrosis syndrome can occur in either sex and in any age group, but most
commonly occurs in the third and fifth decade of life. Acute retinal necrosis syndrome presenting in children may indicate an immunocompromised host. Retinal inflammation causes a severe uveitis with retinal necrosis
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(Figure 14 9). Over time, the areas of necrotic retina form chorioretinal scars (Figure 14 10).
Acute retinal necrosis syndrome is diagnosed by the appearance of the retinal lesions. Antibody titers to herpes simplex or herpes zoster virus may support the diagnosis, but these titers may not be elevated with
Figure 14 9.
Fundus photograph of a patient with acute retinal necrosis. Note the white retinal lesions representing areas of retinal necrosis. Also note that fundus details are not well seen because of vitreous cells and flare that produce an opacity.
Figure 14 10.
Fundus photograph of end-stage scars in a patient with acute retinal necrosis. Note the hyperpigmented and hypopigmented areas in the macular area and surrounding the optic nerve.
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isolated ocular involvement. Intravenous acyclovir is the treatment of choice to diminish the retinitis. Because acyclovir does not affect the uveitis, corticosteroids are often prescribed 2 days after initiation of acyclo vir. Visual prognosis is relatively poor, with 75% of patients developing a retinal detachment.
Ophthalmic Manifestations of Acquired
Immunodeficiency Syndrome
Children with AIDS rarely have eye involvement. Retinitis secondary to opportunistic infections from CMV, herpes zoster, and toxoplasmosis have been reported (Esposito et al; Gona et al). Of these infections, CMV retinitis is the most vision threatening. Cytomegalovirus retinal lesions are charac terized by areas of intraretinal hemorrhages and are located along vascular arcades in conjunction with white, edematous retina (Figure 14 11).
The treatment of CMV retinitis in patients with AIDS consists of antiviral agents (ganciclovir or foscarnet) or the use of colony stimulating factors. In addition, CMV retinitis can be treated with an intravitreal ganciclovir implant. This is a polymer implant that slowly releases ganciclovir into the vitreous cav ity. Relapses of CMV retinitis are common in patients with AIDS, and patients must be followed closely for recurrence.
Figure 14 11.
Fundus photograph of cytomegalovirus retinitis. Note the areas of intraretinal hemorrhage associated with white areas of edematous retina. The retinitis follows retinal vessels and produces severe retinal necrosis.
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Bibliography
1.Esposito S, Porta A, Bojanin J, et al. Effect of highly active antiretroviral therapy (HAART) on the natural history of ocular manifestations in HIV infected children. Eye. 2006;20:595–597
2.Gona P, Van Dyke RB, Williams PL, et al. Incidence of opportunistic and other infections in HIV infected children in the HAART era. JAMA. 2006;296:292–300
Chapter 15
Corneal
Abnormalities
Abnormal Corneal Size
Microcornea
Microcornea is defined as a corneal diameter of less than 10 mm. Isolated presence of microcornea, without other ocular problems, is consistent with normal visual acuity. Isolated microcornea can be unilateral or bilateral and sporadic, inherited as an autosomal dominant or recessive trait. Micro cornea can be associated with other ocular abnormalities, most commonly coloboma of the optic nerve or choroid and congenital cataracts, including persistent hyperplastic primary vitreous. Systemic syndromes associated with microcornea include Ehlers Danlos syndrome, Weill Marchesani syndrome, Rieger anomaly, fetal alcohol syndrome, congenital rubella syn drome, and trisomy 13 15 syndrome. Microcornea should be distinguished from nanophthalmos. Nanophthalmos is an otherwise normal eye that is small, including the cornea. A small eye is termed microphthalmia.
Megalocornea
Megalocornea is defined as a cornea larger than 13 mm in diameter. Isolated or primary megalocornea is consistent with excellent visual acuity and an otherwise normal eye. Primary megalocornea is usually bilateral and is most commonly seen as an X linked recessive trait in males. It is important to rule out congenital glaucoma in any child with a large cornea because increased pressure in children younger than 2 to 3 years can result in corneal enlarge ment. Megalocornea is also associated with systemic syndromes such as Down syndrome, Marfan syndrome, and Apert syndrome.
Cloudy Cornea
A cloudy cornea is distinct from leukocoria, which is a white pupil and is discussed in Chapter 22. With a cloudy cornea, structures within the eye cannot be seen clearly. Note that with leukocoria, the iris and pupil are