349 Recurrent toxoplasmosis. Fig. 12.34 Acute grayish white chorioreti- nal focal lesion (arrow) and brownish white chorioretinal scars (arrow- head). Lesions usually recur at the margin of the original scar, the ”mother spot”. Posterior uveitis due to toxoplasmosis usu- ally heals without severe loss of visual acuity where the macula is not involved. However, it can recur at any time. There is no cure for the congenital form. Retinal disorders in AIDS involve either AIDS-associated microangiopathy or infection. Up to 80% of all AIDS patients have retinal disorders as a result of the disease. Other ocular involvement is rare. The pathogenesis of microangiopathy is still unclear. Oppor- tunistic infections are frequently caused by viruses. Microangiopathy is usually asymptomatic. Patients with infec- tious retinal disorders report loss of visual acuity and visual field defects. Ophthalmoscopic findings in AIDS-associated microangiopathy include hemorrhages, microaneurysms, telangiectasia, and cotton-wool spots. Direct involvement of vascular endothelial cells in HIV infection or immune-complex-mediated damage to endothelial cells and vascular structures is thought to play a role. 12.7 Retinal Inflammatory Disease 350 Cytomegalovirus retinitis occurs in 20 – 40% of older patients. Peripheral retinal necrosis and intraretinal bleeding (Fig. 12. 35) are frequently observed. Vascular occlusion is rare. Secondary rhegmatogenous retinal detachment may develop. These lesions heal to produce fine granular pigment epithelial scars. Less frequently, AIDS may involve retinal infection caused by herpes sim- plex and varicella-zoster viruses, Toxoplasma gondii, or Pneumocystis carinii . The diagnosis of a viral retinal infection in AIDS is confirmed by attempting to obtain positive serum cultures and by resistance testing. Inflammatory retinal changes due to other causes should be excluded by serologic studies. Microangiopathy does not require treatment. Viral retinitis is treated with ganciclovir or foscarnet. Herpes simplex and varicella-zoster viruses are treated with acyclovir. Ophthalmologic screening examinations are indicated in the presence of known viral infection. The prognosis for microangiopathy is very good. Infectious retinitis will lead to blindness if left untreated. Visual acuity can often be preserved if a prompt diagnosis is made. Cytomegalovirus retinitis. Fig. 12.35 Typical signs in- clude extensive white areas of retinal necrosis and hemor- rhages. 12 Retina Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 351 Retinal disorder caused by viral infection. Viral retinitis is a rare disorder Infection of the retina and retinal vasculature caused by cytomegalovirus, herpes simplex, varicella-zoster, or rubella viruses. Viral retinitis frequently occurs in immunocompromised patients. Patients report loss of visual acuity and visual field defects. Slit-lamp examination will reveal cells in the vit- reous body. Ophthalmoscopic findings will include retinal necrosis with intraretinal bleeding (see Fig. 12. 35). Necrosis can occur as acute lesions and spread over the entire retina like a grassfire within a few days. When the reti- nitis heals, it leaves behind wide-area scarring. During pregnancy, rubella virus can cause embryopathy in the child. Oph- thalmic examination will reveal typical fine granular pigment epithelial scars on the fundus that are often associated with a congenital cataract. The diag- nosis is confirmed by measuring the serum virus titer. The possibility of com- promised immunocompetence should be verified or excluded. Posterior uveitis and vasculitis should be excluded. These disorders may be distinguished from viral retinitis by the absence of necrosis. The disorder is treated with high doses of an antiviral agent (acy- clovir, ganciclovir, or foscarnet) according to the specific pathogen. Ophthalmologic screening examinations are indicated in immunocompromised persons with suspected viral infection. Viral retinitis can be arrested if diagnosed early. However, recurrences are frequent in immunocompromised patients. Blindness usually cannot be prevented in retinal necrosis syndrome. Inflammation of the retina usually caused by Borrelia burgdorferi. The incidence of this retinal disorder has increased in recent years. 12.7 Retinal Inflammatory Disease Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 352 The inflammation is caused by spirochetes usually transmitted by bites from infected ticks. Lyme disease can lead to many inflammatory ocu- lar changes with their respective symptoms. These include conjunctivitis, keratitis, and iridocyclitis. Retinal vasculitis, retinal artery occlusion, neu- roretinitis, optic neuritis, and choroiditis have also been described. Lyme disease should be excluded as a possible cause of posterior uveitis of uncertain etiology. The diagnosis is made by ophthalmoscopy and serologic studies to identify the pathogen. Inflammatory ocular changes due to other causes (such as toxoplasmosis or tuberculosis) should be excluded. Antibiotic treatment with tetracycline, penicillin G, or third- generation cephalosporins is indicated. Retinal changes due to Lyme disease tend to recur. Inflammation of the retina caused by infection with parasites such as Onchocerca volvulus (the pathogen that causes onchocerciasis), Toxocara canis or Toxocara cati (nematode larvae that are normally intestinal parasites of dogs and cats), Taenia solium, (pork tapeworm), and other parasites. Onchocerciasis, like trachoma and leprosy, is one of the most frequent causes of blindness worldwide. However, like the other parasitic dis- eases discussed here, it is rare in Europe and North America. Onchocerca volvulus is transmitted by the bite of black flies. This allows the larvae (microfilaria) to penetrate the skin, where they form fibrous subcutaneous nodules. There they reach maturity and produce other micro- filaria, which migrate into surrounding tissue. The danger of ocular infiltra- tion is particularly great where there are fibrous nodules close to the eye. Toxocara canis or Toxocara cati (eggs of nematodes infesting dogs and cats) are transmitted to humans by ingestion of substances contaminated with the feces of these animals. The eggs hatch in the gastrointestinal tract, where they gain access to the circulatory system and may be spread through- out the entire body. The choroid can become infested in this manner. 12 Retina Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 353 Taenia solium: The pork tapeworm infestation can occur from eating pork contaminated with larvae or other substances contaminated with tapeworm eggs. Mature tapeworms can also release eggs into the intestine. The larvae travel through the bloodstream to various organs and can also infest the eye. Diagnostic considerations and findings: Ophthalmoscopy will reveal intraocular inflammation. Onchocerciasis has been known to be associated with posterior uveitis as well as keratitis and iritis. Histologic examination will demonstrate microfilaria in the retina. Visceral larva migrans, Toxocara canis, or Toxocara cati can cause complications involving endophthalmitis and retinal detachment. Subretinal granulomas and larval inflammation of the retina have been known to occur. The larvae of different species of worms can produce diffuse unilateral subacute neuroretinitis with the typical clini- cal picture of grayish white intraretinal and subretinal focal lesions. Fly larvae can also invade the subretinal space in ophthalmomyiasis. Differential diagnosis: Other causes of retinal inflammation and subretinal granulomas should be excluded. Treatment: Laser photocoagulation or surgical removal of the worm larvae may be indicated. Clinical course and prognosis: It is not uncommon for these disorders to lead to blindness. 12.8 Retinal Tumors and Hamartomas 12.8.1 Retinoblastoma Definition A retinoblastoma is a malignant tumor of early childhood that develops from immature retinal cells. Epidemiology: Retinoblastoma is the most common malignant ocular tumor in children, occurring in approximately one of 20 000 births. In 30% of all cases, it is bilateral. Pathogenesis: A somatic mutation is detected in about 95% of all patients. In the other patients, it is inherited as an autosomal dominant trait. Changes on chromosome 13q have been observed in germ-cell mutations. Retinoblas- tomas may then occur at several locations in the retina or bilaterally. Where retinoblastoma is inherited as an autosomal dominant trait, the siblings of the affected child should be regularly examined by an oph- thalmologist. 12.8 Retinal Tumors and Hamartomas Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 354 Symptoms: Retinoblastoma manifests itself before the age of three in 90% of affected children. Parents observe leukocoria (a whitish yellow pupil; Fig. 12. 36) in 60% of these children, strabismus in 20%, and a reddened eye in 10%. Every child presenting with strabismus should undergo examination of the fundus with the pupil dilated to exclude a retinoblastoma. Findings and diagnostic considerations: A grayish white, vascularized reti- nal tumor will be observed on ophthalmoscopy. In its advanced stages, this tumor was formerly referred to as an amaurotic cat's eye. Infiltration of the vitreous body, anterior chamber (pseudohypopyon), and orbit may occur. A retinoblastoma that also involves the fellow eye and pineal body is referred to as a trilateral retinoblastoma. A trilateral retinoblastoma is defined as additional manifestation of the tumor in the pineal body. Calcifications frequently occur in these tumors. Radiographs or CT images that show calcifications can therefore help to confirm the diagnosis in uncer- tain cases. Differential diagnosis: Several other disorders should be excluded by oph- thalmoscopy. These include: ❖ Cataract (with leukocoria). ❖ Primary strabismus (with strabismus). ❖ Infection (with a reddened eye). Leukocoria in the left eye due to a retinoblastoma. Fig. 12.36 The whitish gleam of the pupil of the left eye is a typical finding in retino- blastoma. 12 Retina Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 355 Retinal detachment, persistent hyperplastic primary vitreous (PHPV), and Coats’ disease should also b e excluded. Treatment: Tumors less than four pupil diameters may be managed with radiation therapy delivered by plaques of radioactive ruthenium or iodine (brachytherapy) and cryotherapy. Larger tumors require enucleation of the eye. Prophylaxis: Following the diagnosis, the fellow eye should be examined with the pupil dilated every three months for five years. After that, follow-up examinations may be performed at greater intervals. Clinical course and prognosis: Left untreated, a retinoblastoma will eventu- ally metastasize to the brain and cause death. Patients frequently develop a second malignant tumor such as an osteosarcoma. 12.8.2 Astrocytoma Definition An astrocytoma or astrocytic hamartoma is a benign tumor that develops from the astrocytes of the neuroglial tissue. Epidemiology: Astrocytomas are rare. Etiology: Astrocytomas belong to the phakomatoses and are presumably congenital disorders that develop from the layer of optic nerve fibers. They may manifest themselves as purely ocular disorders or in association with tuberous sclerosis (Bourneville’s disease). Symptoms: Patients usually have no ocular symptoms. Calcifying astrocytic hamartomas in the region of the basal ganglia or ventricles can cause epilepsy and mental deficiency. An astrocytoma in Bourneville’s disease will be associated typically with an adenoma sebaceum in the facial skin. Findings and diagnostic considerations: Astrocytomas are either incidental findings in ophthalmic examinations performed for other reasons, or they are diagnosed in patients presenting with reduced visual acuity. Ophthalmos- copy will reveal single or multiple “mulberry” tumors one to two pupil diame- ters in size. These will appear white and are often calcified. The tumors are inherently fluorescent when observed in blue light in fluorescein angiogra- phy with a blue filter. Differential diagnosis: A retinoblastoma should be excluded in children. That is usually larger than an astrocytoma on ophthalmoscopy. A possible Toxocara canis granuloma should be confirmed or excluded by serologic studies. 12.8 Retinal Tumors and Hamartomas Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 356 Treatment: No ophthalmologic treatment is required. The patient should be referred to a neurologist to exclude cerebral involvement. Clinical course and prognosis: These tumors rarely increase in size. 12.8.3 Hemangiomas Definition Capillary hemangiomas or hemangioblastomas occur in angiomatosis retinae (von Hippel-Lindau disease). 12 Retina Von Hippel-Lindau disease. Fig. 12.37 a A hemangio- blastoma (arrow) in von Hippel-Lin- dau disease with enlarged retinal arteries and veins and retinal detachment with hard exudate (ar- rowhead). b Corresponding fluorescein angio- gram. Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 357 12.8 Retinal Tumors and Hamartomas Epidemiology: Hemangiomas are rare. Etiology: These are benign congenital changes. There may be an autosomal dominant inheritance. Symptoms: Loss of visual acuity will result where exudative retinal detach- ment develops. Findings and diagnostic considerations: Retinal hemangiomas are charac- terized by thickened tortuous arteries and veins (Figs. 12. 37 a and b). Bilateral changes are present in 50% of all patients. Differential diagnosis: Coats’ disease, branching retinal hemangiomas in Wyburn-Mason syndrome, and cavernous hemangiomas should be con- sidered. Cerebral hemangiomas, renal cysts, hypernephromas, and pheochro- mocytomas should also be excluded. Treatment: Retinal hemangiomas may be treated by laser or cryocautery therapy. However, exudative retinal detachment will develop as the treat- ment increases this risk. Clinical course and prognosis: The disorder is gradually progressive. The prognosis for visual acuity is poor in the disorder where retinal detachment develops. Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. [...]... orbital or intracranial mass or hydrocephalus – Traumatic, such as avulsion, compression of the optic nerve in a fracture, or hematoma in the optic nerve sheath – Inflammatory, such as retrobulbar optic neuritis, arachnoiditis of the optic chiasm, or syphilis O Toxic: – Chronic abuse of low-grade tobacco and alcohol in tobacco and alcohol amblyopia – Lead, arsenic, or thallium – Methyl alcohol – Medications,... hemorrhage Therefore, papilledema is a conditional, unspecific sign of increased intracranial pressure that does not provide conclusive evidence of the cause or location of a process In approximately 60% of all cases, the increased intracranial pressure with papilledema is caused by an intracranial tumor; 40% of all cases are due to other causes, such as hydrocephalus, meningitis, brain abscess, encephalitis,... optic nerve passes through the optic canal, the short intracranial portion begins and extends as far as the optic chiasm Like the brain, the intraorbital and intracranial portions of the optic nerve are surrounded by sheaths of dura mater, pia, and arachnoid (see Fig 13.3) The nerve receives its blood supply through the vascular pia sheath Lang, Ophthalmology © 2000 Thieme All rights reserved Usage subject... Central scotoma in papillitis: A central scotoma is a typical functional finding in retrobulbar optic neuritis but on that may also be observed in papillitis In this case, a relative scotoma is present (indicated by single hatching), i.e., the patient is only unable to discern markers I/1 and weaker in central area whereas larger markers are visible (see also Fig 13.10) The blind spot is also located... scalp in the region of the temporal arteries, tenderness to palpation in the region of the temporal arteries, pain while chewing (a characteristic sign), weight loss, reduced general health and exercise tolerance Patients may have a history of amaurosis fugax or polymyalgia rheumatica Diagnostic considerations: The ophthalmoscopic findings are the same as in arteriosclerotic AION (see Fig 13.12 a) ... papilledema in as many as 60% of patients with brain tumors Since then, advances in neuroradiology have significantly reduced the incidence of papilledema The diagnostic importance of the disorder has decreased accordingly Etiology: An adequate theory to fully explain the pathogenesis of papilledema is lacking Current thinking centers around a mechanical model in which increased intracranial pressure and... impeded axonal plasma flow through the narrowed lamina cribrosa cause nerve fiber edema However, there is no definite correlation between intracranial pressure and prominence of the papilledema Nor is there a definite correlation between the times at which the two processes occur However, severe papilledema can occur within a few hours of increased intracranial pressure, such as in acute intracranial hemorrhage... vasculitis that primarily affects the medium-sized and small arteries Common sites include the temporal arteries, ophthalmic artery, short posterior ciliary arteries, central retinal artery, and the proximal portion of the vertebral arteries, which may be affected in varying combinations Symptoms: Patients report sudden unilateral blindness or severe visual impairment Other symptoms include headaches, painful... bundles of all the optic nerve fibers as they exit through the scleral canal The rim has a characteristic configuration: The narrowest portion is in the temporal horizontal region followed by the nasal horizontal area; the widest areas are the vertical inferior and superior areas Optic cup: This is the slightly eccentric cavitation of the optic nerve that has a slightly flattened oval shape corresponding... intracranial pressure has been normalized, the papilledema will resolve within a few weeks Usually complex atrophy of the optic nerve will remain The severity will vary according to the duration of the papilledema Lang, Ophthalmology © 2000 Thieme All rights reserved Usage subject to terms and conditions of license 370 13 Optic Nerve Papilledema Fig 13.10 a Early phase of papilledema: The nasal margin . microfilaria in the retina. Visceral larva migrans, Toxocara canis, or Toxocara cati can cause complications involving endophthalmitis and retinal detachment. Subretinal granulomas and larval inflammation. onchocerciasis), Toxocara canis or Toxocara cati (nematode larvae that are normally intestinal parasites of dogs and cats), Taenia solium, (pork tapeworm), and other parasites. Onchocerciasis, like trachoma. hemangiomas or hemangioblastomas occur in angiomatosis retinae (von Hippel-Lindau disease). 12 Retina Von Hippel-Lindau disease. Fig. 12. 37 a A hemangio- blastoma (arrow) in von Hippel-Lin- dau disease