尖峰眼科分享之Wills——急性视网膜坏死

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急性视网膜坏死是眼部常见的急症之一，是否及时有效的处理，将直接关系到视力预后程度。

第八节 急性视网膜坏死

【症状】

视物模糊，眼前漂浮物，明显的眼痛，畏光。大部分患者身体健康，免疫功能正常。

【体征】

见图12.8. 1

【主要体征】

周边部视网膜可见局灶性的、边界清楚的视网膜白变区(坏死灶)，向四周迅速扩散;阻塞性血管炎:玻璃体和前房可见严重的炎症反应;后极部不受累。

【其他体征】

前房反应;结膜充血;巩膜炎;眼压升高;视网膜小动脉鞘，有时有小静脉鞘，特别是在周边部视网膜;视网膜出血(少见);视盘水肿;大约70%的患者在病变晚期出现孔源性视网膜脱离，继发于后部的不规则的巨大裂洞;有时会出现视神经病变，表现为视盘水肿或苍白。

【病因学】

急性视网膜坏死(ARN)是一种临床综合征，老年患者由水痘-带状疱疹病毒引起，单纯疱疹病毒侵犯年轻患者。偶尔的，由巨细胞病毒感染造成。

【鉴别诊断】

参见本章第三节后葡萄膜炎。

1.疱疹病毒感染 水痘-带状病毒或单纯疱疹病毒。

2.巨细胞病毒性视网膜炎。

3.进展性外层视网膜坏死(PORN) 迅速进展的视网膜炎，特征为玻璃体清晰，玻璃体片状浑浊深达貌似正常的视网膜血管，有时有自发性玻璃体出血。进展性外层视网膜坏死通常由于感染本身或继发性视网膜脱离导致迅速出现双眼失明，应尽快明确诊断并给以治疗。

4.梅毒。

5.弓形体病。

6.Behcet病。

7.真菌性或细菌性眼内炎。

8.巨细胞淋巴瘤 老年患者，单侧玻璃体炎，无眼痛，出血性玻璃体炎。

【检查】

非特异性的葡萄膜炎相关的检查参见本章第三节后葡萄膜炎。

1.病史 有无导致艾滋病的危险因素?是否免疫抑制?如果有，鉴别诊断应包括巨细胞病毒性视网膜炎。

2.全面的眼科检查 观察前房和玻璃体有无细胞，测眼压，间接检眼镜联合巩膜压迫散瞳查眼底。

3.全血细胞计数及分类，螺旋体抗体吸附荧光测定(FTA-ABS)，快速血浆反应素

(RPR)，血沉，弓形体滴度，PPD+无变应性反应板，胸部X线用以排除其他致病原因。

4.检测艾滋病病毒(HIV)。

5.前房穿刺液行多聚酶链反应(PCR)，检测单纯疱疹病毒和水痘-带状疱疹病毒参见附录13，前房穿刺。

6.眼底荧光血管造影。

7.如果怀疑视神经病变，做眼眶CT或B超检查观察视神经是否增粗。

8.如果怀疑巨细胞淋巴瘤、三期梅毒或脑炎时，行颅脑CT或磁共振(MRI)和腰穿

检查。

【治疗】

注：所有急性视网膜坏死患者必须经由对该病诊治经验丰富的专家诊治。

1.住院治疗 目的是降低对侧眼的发病率，治疗并不能降低发病眼的视网膜脱离率。

2.抗病毒治疗 阿昔洛韦，每日1500mg/m2体表面积，分3次静脉滴注，连用10-14天后，肾功能不全的患者应调整剂量。口服伐昔洛韦1g，日3次，或阿昔洛韦，400-600mg，日5次，从发病开始共治疗6周，因为对侧眼受累通常发生于患眼发病后6周之内。在治疗开始后的48h之内视网膜炎仍有可能进展，但通常在4日内稳定和出现早期的消退。泛昔洛韦500mg，口服，日3次，中枢神经系统的穿透性很好，可用作静脉治疗的替代治疗。

3.有眼前节炎症时局部滴用睫状肌麻痹剂 如1%阿托品，日3次;类固醇滴眼液，

如1%醋酸泼尼松龙，日4-12次。

4.抗血小板治疗 给予阿司匹林，125-650mg,，日1次

5.全身类固醇治疗 尚有争议。一些医生采用类固醇治疗，确诊后态度更为积极

特别是在考虑视神经受累时，如甲基泼尼松龙，250mg，静脉滴注，日4次，连用3天后，改为口服泼尼松，60mg，日2次，连用1-2周。有些医生的类固醇延续治疗为1周或数周，直至视网膜炎开始消退。经典的口服皮质类固醇药物(首剂量或延续治疗采用)为泼尼松，60-80mg/d，连用1-2周，以后减量维持2-6周。全身应用类固醇之前，相关的检查参见药物手册中“泼尼松”部分。

6.治疗眼压升高 参见第九章第七节炎症性开角型青光眼。

7.预防性激光光凝屏蔽或预防继发性视网膜脱离 激光光凝斑置于活动性视网膜炎之后。

8.经平坦部玻璃体切除术、玻璃体内长效气体或硅油填充 是治疗并发的复杂性孔源性视网膜脱离的最有效的方法。增殖性玻璃体视网膜病变很常见。

【随访】

1.住院患者每日复查，随后数周或数月检查1次，直至1年。

2.每次复查时都要进行巩膜压迫，详细检查眼底，以排除可造成视网膜脱离的视网膜裂孔。如果视网膜炎越过先前激光治疗的边界，则需要补充激光光凝治疗。

3.检查瞳孔反应，如果视网膜病变不能解释视力丧失的全部原因，应考虑视神经病变。

12.8 Acute Retinal Necrosis (ARN)

Symptoms

Blurred vision, floaters, ocular pain, photophobia. Most patients are healthy and not immunocompromised.

Signs

(See Figure 12.8.1.)

Critical. Focal, well-demarcated areas of retinal whitening (necrosis) located in the peripheral retina；rapid, circumferential progression of necrosis; occlusive vasculitis and prominent inflammatory reaction in the vitreous and anterior chamber. The posterior pole is typically spared.

Other. Anterior chamber reaction; conjunctival injection; scleritis; increased IOP; sheathed retinal arterioles and sometimes venules, especially in the periphery; retinal hemorrhages (minor finding); optic disc edema; delayed RRD occurs in approximately 70% of patients secondary to large irregular posterior breaks. An optic neuropathy with disc edema or pallor sometimes develops.

Etiology

Acute retinal necrosis (ARN) is a clinical syndrome caused by varicella-zoster virus (older patients), herpes simplex virus (younger patients), or, rarely, CMV.

Differential Diagnosis

See 12.3, Posterior Uveitis.

Herpes virus family (varicella-zoster or herpes simplex).

CMV retinitis (Table 12.8.1).

PORN: Rapidly progressive retinitis characterized by clear vitreous and sheet-like opacification deep to normal-looking retinal vessels, and occasional spontaneous vitreous hemorrhage. PORN frequently quickly leads to bilateral blindness due either to the infection itself or to secondary retinal detachment, making prompt diagnosis and treatment essential.

Syphilis.

Toxoplasmosis.

Beh?et disease.

Fungal or bacterial endophthalmitis.

Large cell lymphoma: Elderly patient with unilateral vitritis, absence of pain, homogenous-appearing vitritis.

Cytomegalovirus Acute Retinal Necrosis Toxoplasmosis

Retinal hemorrhages: Significant Uncommon Absent

Vitritis: Minimal Significant Significant

Pain: Absent Significant Moderate

Immune status: Immunocompromised Usually healthy Either

Appearance: “Brushfire” border with leading edge of active retinitis and necrotic retina and mottled retinal pigment epithelium in its wake Sharply demarcated lesions with nearly homogeneous appearance and same age “Headlight in fog” with dense vitritis and smooth edges

Work-Up

See 12.3, Posterior Uveitis, for a nonspecific uveitis work-up.

History: Risk factors for AIDS? Immunocompromised? If yes, the differential diagnosis includes CMV retinitis.

Complete ocular examination: Evaluate the anterior chamber and vitreous for cells, measure the IOP, and perform a dilated retinal examination using indirect ophthalmoscopy and scleral depression.

Consider a CBC with differential, FTA-ABS and RPR, ESR, toxoplasmosis titers, PPD, and chest radiograph to rule out other etiologies.

Consider HIV testing.

Consider anterior chamber paracentesis for herpes simplex and varicella-zoster virus PCR. See Appendix 13, Anterior Chamber Paracentesis.

Consider IVFA.

An orbital CT scan or B-scan US to look for an enlarged optic nerve in cases of suspected optic nerve dysfunction.

CT scan or MRI of the brain and lumbar puncture if large cell lymphoma, tertiary syphilis, or encephalitis is suspected.

Treatment

Note All patients with ARN should be referred to a specialist.

Prompt inpatient or outpatient treatment. The goal is to decrease the incidence of the disease in the fellow eye. Treatment does not reduce the rate of retinal detachment in the first eye.

Acyclovir, 1,500 mg/m2 of body surface area/day i.v., in three divided doses for 10 to 14 days (requires dose adjustment for renal insufficiency). Consider oral valacyclovir 1 gram t.i.d. or acyclovir (400 to 600 mg five times per day), for up to 6 weeks from the onset of infection since involvement of the second eye typically starts within 6 weeks of initial infection. Stabilization and early regression of retinitis is usually seen within 4 days. The lesions may progress during the first 48 hours of treatment. Famciclovir 500 mg p.o., t.i.d. has good CNS penetration and has been used as an alternative to intravenous therapy.

Topical cycloplegic (e.g., atropine 1% t.i.d.) and topical steroid (e.g., prednisolone acetate 1% q2–6h) in the presence of anterior segment inflammation.

Consider antiplatelet therapy (e.g., aspirin 125 to 650 mg daily).

Systemic steroids (controversial): Some physicians administer steroids aggressively at the time of diagnosis (e.g., methylprednisolone 250 mg i.v., q.i.d. for 3 days followed by prednisone 60 mg p.o., b.i.d. for 1 to 2 weeks), particularly when the optic nerve is thought to be involved. Others delay steroid therapy for 1 or more weeks until the retinitis begins to clear. A typical oral corticosteroid regimen (initial or delayed therapy) is prednisone 60 to 80 mg/day for 1 to 2 weeks followed by a taper over 2 to 6 weeks. See “Prednisone” in Pharmacopoeia for work-up before starting systemic steroids.

See 9.7, Inflammatory Open-Angle Glaucoma, for increased IOP.

Consider prophylactic barrier laser photocoagulation posterior to active retinitis to wall off or prevent subsequent RRD.

Pars plana vitrectomy, with long-acting gas or silicone oil, is the best way to repair the associated complex RRD. Proliferative vitreoretinopathy is common.

Follow-Up

Patients are seen daily and are examined every few weeks to months for the following year.

A careful fundus evaluation with scleral depression is performed at each visit to rule out retinal holes that may lead to a detachment. If the retinitis crosses the margin laser demarcation, consider applying additional laser therapy.

Pupillary evaluation should be performed, and optic neuropathy should be considered if the retinopathy does not explain the amount of visual loss.