Ischemic Optic Neuropathy이연희

(1)

Ischemic Optic Neuropathy

이연희

충남대학교 의과대학 안과학교실

Ischemic optic neuropathy

충남대 안과학교실 이연희

Introduction

• 단일 질환이 아닌 여러 질환의 Spectrum

• 급성, 무통성, 비가역적, 시신경의 Ischemic event

• 시력저하, 실명의 주요 원인

Classification

• 위치에 따라

– Anterior : optic nerve head에 이환 -> disc edema

– Posterior: disc edema(-)

• 원인에 따라

– Arteritic : giant cell arteritis – non-arteritic: most often idiopathic

• 기타 ION

Anterior ION(AION)

• Majority of ION

• Always Optic disc edema

• Unilateral

• RAPD

(2)

NAION(Non-arteritic AION)

• 대부분의 AION

• Epidemiology

– Incidence

• 50세 이상에서 가장 흔한 시신경병증 (2.3-10/100000) – Age

• Typically occurs after 50 yrs

• Average age : 57 ~ 65 yrs

• Older 혹은 younger에서도 발생 – 남/녀: 차이(-)

Clinical presentation

• Vision loss : 다양, 1.0 to 광각(-)

• Course

– Abrupt and static

– Progressive : 22-37%, stepwise or steady decline

• Pain

– About 10%

– Minor ocular discomfort, pain with eye movement(-)

Clinical presentation

• Laterality – 대개 편측성

– 반대안 발생 확률 : 5년 내에 15%

• Disc edema – Classic : segmental – Diffuse :75%

– May be massive or mild – 흔히 flame-shaped hemorrhages – Hard exudate :7%

Clinical presentation

• RAPD:

양측성이 아니라면 거의 항상 존재

• 색각 감소:

시력이 떨어진 만큼

• 시야결손 – Altitudinal defects

• 가장 흔하고 전형적 (55-80%)

• 아래쪽에 더 흔하다.

• Disc edema의 반대 방향 – 기타 다양한 형태가 모두 가능

• Central scotoma, arcuate, quadrantic, generalized constriction, combination of these

Pathogenesis

Short posterior ciliary arteries 의 paroptic branch에 insufficiency

-> Infarction of the optic nerve head

Nature of the insufficiency

• Embolic phenomenon – Only occasional – Massive damage

• Transient non-perfusion or hypoperfusion – Common cause

– Evidence

• FA show slow filling

• Less severe damage than AAION

• Unrelated to carotid disease, atrial fibrillation

• Cases of slow progression & edema prior to visual loss

(3)

Risk factors

• Proven

– Small cup (crowded disc, disc at risk)

• 반대안에서 흔히 발견 – DM

• Unproven

– Nocturnal hypotension – Sleep apnea

– 여러가지 Vasculopathy or Coagulapathy – Hypertension

– Other vascular risk factors : smoking, high TG hypercholesterolemia – drugs: sildenafil, INF-α

– 거의 무관: Other vascular event (stroke, MI)

Course

• Generally stable

• Progression

– Progressive form에서도 1-2개월 후 더 진 행하지 않는다

– 2개월 후에 더 진행하면 다른 질환을 고려

• 회복: 43%에서 2줄 이상의 시력 회복

• Atrophy – 4-6주 이내

– 이후에도 edema 지속되면 다른 질환 고려

Differential diagnosis

AION Optic neuritis

나이

Old, typically >50 Almost never in <40

Young, 대부분 <50

통증

Rare(10%, 눈움직임과 무관) Yes(92%), 눈움직임에 악화

시야결손 Altitudinal defect가 흔하다 다양, Central scotoma가 classical

Disc Always swell

전형적: Segmental swelling 출혈

Normal in 2/3~1/3 Swelling:generalized

색각 시력 감소만큼 시력보다 심한 감소

시력회복

Irreversible, 40%에서 약간 Recover in most

MRI

Unremarkable 대개 이상 소견

FA Disc filling delay 정상 filling

Further evaluation

• Typical presentation: 노인에서, 통증 없는, 갑작스런, 시각소실 과 disc edema

– HT, DM, Hyperlipidemia 확인 – ESR, CRP

– Neuroimaging은 필요 없다

– Vasculopathic and prothrombotic risk factor: unclear value – Carotid study: not routine

• < age 50, personal or familial thrombosis, sign of GCA – Further evaluation

Treatment

• No proven effective Tx

• Unsuccessful medication

– Standard dose systemic corticosteroids – Anticoagulants, hyperbaric oxygen

• Surgical optic nerve decompression

– Ischemic Optic Neuropathy Decompression Trial (IONDT) –> Not beneficial, potentially harmful

• Propylaxis

– Aspirin: no consistent positive effect

Arteritic AION

• Due to GCA

• 5.7% of AION in western study

• Common in Caucasians, unusual in African & Hispanic

• 국내 보고: Only 1 case

• 치료 안하면

– 반대안 이환

– Life threatening

(4)

Clinical manifestation

• GCA의 전신증상

– Headache, jaw claudication, temporal a. tenderness, malaise, anorexia, weight loss, fever

• Local sign

– Induration of temporal region, absent temporal a.

pulse

Clinical manifestation

• NAION에 비하여 – 더 심한 시력감소, 회복(-) – 더 많은 나이: 60 이하는 드물다.

– More commonly simultaneous bilateral – 반대안 이환: 54-95%

– Pallid(chalky white) disc edema – Normal fellow disc

– Excavation of disc after optic atrophy

Diagnosis

• Tentative Dx

– Old age + typical sx, + elevated ESR

• ESR

– 대부분의 GCA: 심한 상승 (평균 70mm/hr, often >100 ) – 심하게 상승하지 않으면 해석이 어렵다

• 정상치가 모호(male:9, female:20)

• 나이에 따라 증가

• 비특이적: Active inflammatory process의 존재를 의미할 뿐

Diagnosis

• Additional blood abnormality – CRP

• Not rise with age

• Recommended conjunction with ESR : ESR >47mm & CRP>2.45 -> 97% Specificity – Fibrinogen

– Thrombocytosis

Diagnosis

• Temporal artery Bx

– 확진 검사

– Recommended in any case of suspected AAION – Support for long-term steroid Tx.

– Negative Bx: dose not rule out GCA

• Skip lesion -> minimum 3-6cm

• Unilateral involvement -> bilateral Bx

• Improper handling

• Inexperienced pathologist

Therapy

• 확진을 기다리지 말고 의심되면 즉시 치료시작 – Further visual loss in the affected eye

– Fellow eye involvement – Systemic Cx

• High dose methyl-PD 1g/D x 3 -5day

• After initial Tx : Oral pd 1mg/kg/D

– Taper slowly for at least 4-6 Month

– Monitoring systemic Sx, ESR, CRP

(5)

Posterior ION

• Ischemia of retrobular portion

• Clinical presentation

: 급성 시력소실 + 정상 안저 + 나중에 시신경위축

• Rare

• Related anatomy

– Separate arterial supply

: pial plexus from ophthalmic artery, anterior cerebral a.

Common setting

• Vasculitis와 연관: 대개 GCA, 간혹 다른 vasculitis(Lupus, PAN)

• Non arteritic PION : NAION과 유사

• Related hemodynamic compromise

– Surgery :Coronary artery bypass, spine surgery – Bleeding: GI, uterine bleeding

DDx

• 모든 구후 시신경병증 – Inflammatory

– Infiltrative: carcinomatous meningitis, infection – Compressive: Pituitary apoplexy, ophthalmic a. aneurysm