PGS.TS CAO PHI PHONG

Ca lâm sàng giảm thị lực đột ngột

Cập nhật 2017

Ca lâm sàng

BN nam, 38 tuổi, thợ hồ, TP. HCM

Nhập viện ngày: 28/12/2016

LDNV : nhìn mờ

Cách nhập viện 2,5 tháng , Bn nhìn mờ mắt T . Một tuần

sau thì nhìn mờ cả mắt P, nhìn mờ ngày càng tăng dần, bn

không thể chạy xe được , không đi làm được , bn đi khám

và điều trị nhiều nơi tình trạng không giảm BV CHỢ RẪY

. Trong quá trình bệnh không ghi nhận đau 2 mắt, không

đau đầu, không sốt.

Tiền căn: Nhồi máu cơ tim – suy thận mạn – tăng huyết áp (8/2016 : BV 115)

đang điều trị : Plavix 75 Mg, Aspirin 81 Mg, Rosuvastatin 10mg, Exfort

5/80mg, Furosemide 40 Mg, Isosortbid Mononitrat 60mg.

Thăm khám

+ M: 80 l/p, NT: 20 l/p, T 37°C, HA 120/70mmHg, CN 65 kg

+ Thăm khám tổng quát chưa ghi nhận bất thường

+ Khám thần kinh Thị lực 2 mắt bóng bàn tay 15cm .

Đáy mắt 2 bên: đĩa thị hơi bạc màu, động mạch, tĩnh mạch bình

thường, không xuất huyết

Tóm tắt bệnh án

Bn nam 38 tuổi , nhập viện vì nhìn mờ , bệnh 2,5 tháng

Tiền căn : NMCT – THA – Suy thận mạn 4 tháng

Bệnh khởi phát và diễn tiến từ từ, tăng dần, mạn tính

Nhìn mờ 2 mắt

Thăm khám giảm thị lực 2 mắt,

PXAS giảm trực tiếp và gián tiếp 2 mắt .

FO: gai thị bạc màu 2 bên

Kết quả MRI não

Tổn thương chất trắng cạnh não thất 2 bên và tăng tín hiệu dây

thần kinh thị 2 bên nghĩ bệnh lý viêm hủy myelin

MRI tủy

Thoái hóa cột sống cổ . Thoát vị đĩa đệm tầng C4/5 chèn ép

nhẹ trước tủy sống ,không ép rễ thần kinh .

Thoát vị đĩa đệm tầng C4/5 kèm gai xương , chèn ép nhẹ trước

tủy sống ,hẹp lỗ liên hợp 2 bên ,ép rễ C5 2 bên . . Thoát vị đĩa

đệm tầng C5/6 kèm gai xương, dạng trung tâm, hẹp lỗ liên hợp

2 bên, ép rễ C6 2 bên

Dịch não tủy

Trong , không màu

Tế bào : hc 5 , tb: 4 , hầu hết là lymphocyte

Sinh hóa :

Đường huyết : 189 mg/dl

Protein/DNT : 8,5

Glucose/DNT : 105

Clo/DNT : 125,5 mmol/l

Bilirubin tp/DNT : 0

Vi nấm soi tươi : không thấy

PCR lao : negative

Sinh hóa

Glucose : 175 mg/dl

Alt: 30 u/l, Ast:31 u/l

Bilirubin tp:0.8 mg/dl

Bilirubin tt : 0.39 mg/dl

Bilirubin gt : 0.42 mg/dl

B.u.n : 14 mg/dl

Creatinin : 1.33 mg/dl

eGFR(MDRD) : >=60 ml/min/1.73 m2

Na : 139 mmol/l, K : 2.8 mmol/l, Clo : 105 mmol/l

Công thức máu

RBC: 4,63 t/l , Hgb : 143 g/l , Hct : 42 %

WBC : 7,94g/l , Neu : 77%, Lym :14%

PLT : 188 g/l

PT : 10,1 s, INR : 0,9 , Fib : 4,6 g/l, aPTT : 38,6s

Giới thiệu

Mất thị lực cấp hay gặp trong cấp cứu thần kinh

Nhiều bn khám chuyên khoa mắt bình thường chuyển

cấp cứu hay phòng khám thần kinh

Mất thị lực một hay hai mắt nhiều nguyên nhân có thể

bộc lộ hay đi trước bệnh lý thần kinh

Nhanh chóng thăm khám lâm sàng, định khu tổn

thương, xác định có hay không khẩn cấp trong thần kinh

hay hội chẩn chuyên khoa mắt

Chiến lược chẩn đoán giảm thị lực đột ngột

Tổn thương thị giác có thể phân loại do mắt hay thần kinh:

+ optical,

+ macular,

+ neural,

+ chiasmal,

+ retrochiasmal visual pathway

.

(For each of these categories, there are specific guidelines to the tests

that will clarify the nature of the problem)

optic nerve hay retinal disorder?

Chẩn đoán phân biệt mất thị lực đột ngột

Phần lớn bn mất thị lực cấp phân 2 nhóm (1) optic nerve disease, thường nhất là viêm

thần kinh thị (ON) hay bệnh lý thiếu máu thần kinh thị (ischemic optic neuropathy)

(2) retinal disease, thường arterial occlusion.

Thăm khám thần kinh mắt trong cấp cứu

Đánh giá chức năng thị giác

Khám đồng tử và vận nhãn

Khám đáy mắt

Khám thường quy thần kinh

Dụng cụ thăm khám

1. a near visual acuity card

2. a bright red object,

3. a bright light for external and pupil examinations,

4. a direct ophthalmoscope.

Prestige Medical 3909

Snellen Pocket Eye Chart

Price: $4.57 & FREE

Shipping on orders over

$35.

Thăm khám cấp cứu

1. Visual Acuity

(If the vision loss is so profound that the patient cannot see anything on the

near card, vision is measured as “count fingers,” “hand motion,” “light

perception,” or “no light perception.”)

2. Color Vision

+ Altered color vision can be the only early sign of an optic neuropathy.

+ A simple way to test it at bedside in patients complaining of unilateral

vision loss is to present a bright red object to each eye and to ask the

patient to estimate the amount of “redness” in each eye .

+ Unilateral optic neuropathies will produce red desaturation (dimmer or

darker red) in the affected eye.

+ A more formal and quantitative way to test color vision is with Ishihara

+ For refractive errors, blurring of images and double or ghosting of contrasting

contours.(tật khúc xạ: nhìn mờ, hai hình hay mù mờ đường viền xung quanh)

+ The symptoms of macular disease are dominated by micropsia and

metamorphopsia, (thu nhỏ và loạn thị hình thề)

+ Optic neuropathies more commonly are described as having darker images with

poor color perception

Ishihara Test, color Blindness

3. Visual Fields

+ confrontation methods

+ As for visual acuity, visual fields are tested one eye at a time, with

special attention directed to the horizontal and vertical axes of the

visual field.

+ the Amsler grid is useful to test the central visual field at bedside

(mạng lưới các ô trên bản đồ Amsler trong test thị trường trung tâm)

The Amsler grid is a tool that eye doctors use to detect vision problems

resulting from damage to the macula (the central part of the retina) or

the optic nerve.

The damage may be caused by macular degeneration or other eye

diseases, so the Amsler grid is useful in detecting these problems.

An early diagnosis means early treatment, so it may help to limit or at

least slow the vision loss you experience

Mạng lưới các ô trên bản đồ Amsler

How To Do The Amsler Grid Test

Testing your eyes with an Amsler grid is easy and takes only a few minutes. Here

are the basic steps:

Test your eyes under normal room lighting used for reading.

Wear eyeglasses you normally wear for reading (even if you wear only store-bought

reading glasses).

Hold the Amsler grid approximately 14 to 16 inches from your eyes.

Test each eye separately: Cup your hand over one eye while testing the other eye.

Keep your eye focused on the dot in the center of the grid and answer these

questions:

• Do any of the lines in the grid appear wavy, blurred or distorted?

• Do all the boxes in the grid look square and the same size?

• Are there any "holes" (missing areas) or dark areas in the grid?

• Can you see all corners and sides of the grid (while keeping your eye on the

central dot)?

Switch to the other eye and repeat.

IMPORTANT

Report any irregularities to your eye doctor immediately. Mark areas of

the Amsler grid that you're not seeing properly (print two grids if you

notice problems in each eye), and bring the grid(s) with you when you

visit your eye doctor.

Check your eyes with the Amsler grid as frequently as your doctor

recommends, or whenever you notice a significant change in your

eyesight

Swinging Flashlight Test

Relative Afferent Pupillary Defect:

+ If the swinging flashlight test detects an abnormality, one can conclude that

there is a relative afferent pupillary defect (RAPD)..

+ Relative afferent pupillary defect (RAPD) is of great importance, particularly

when visual loss is unilateral or asymmetric

4. Khám đồng tử

(ngoại lệ duy nhất xuất huyết thủy tinh thể nhiều)

(Bệnh phía sau thể gối)

( chứng giảm sức nhìn)

5. Khám mắt và khám đáy mắt (Ocular Examination and

Funduscopic Examination

+ Examination of the ocular fundus is essential in all patients complaining of

visual loss.

+ Pharmacologic dilation of the pupils with short-acting drops, such as a

parasympathetic antagonist (tropicamide) and a sympathetic agonist

(phenylephrine), allows the best and easiest view of the optic nerve,

macula, and blood vessels.

+ Phenylephrine should be avoided in patients with severe systemic

hypertension or malignant hypertension

Tổn thương ở đâu?

+ Vision loss results from ocular disorders, and an ophthalmologist

should be consulted first in the emergency department when a

patient presents with acute visual changes.

Ocular redness, eye pain, or an abnormal fundus help localize the lesion

to the eye and often reveal ocular emergencies(mắt đỏ, đau hay bất

thường đáy mắt)

+ However, the ocular examination does not explain the visual loss and

an optic neuropathy or an intracranial process is suspected; sign

suggestive of a neurologic disorder :

optic nerve head edema, bitemporal or homonymous visual field

changes, an efferent pupillary disorder, or abnormal extraocular

movements (phù gai thị, bán manh thái dương 2 bên, bán manh đồng

danh, rối loạn đồng tử, vận nhãn)

+ A neurologic consultation should also be requested when the patient

is diagnosed with acute retinal ischemia (transient or permanent) or

retinal emboli, which may precede a cerebral infarction and warrant

urgent neurovascular evaluation.

Tham vấn thần kinh:

acute retinal ischemia (transient or permanent)

or retinal emboli,

Ocular Causes of Acute Vision Loss: BS thần kinh phải biết

Painful Red Eye with Vision Loss

+ Acute vision loss with eye pain, photophobia, tearing, and eye redness

suggests an ocular disease involving the anterior segment of the eye

+ These disorders are mostly unilateral.

+ Trauma, corneal infections, anterior uveitis, and acute angle-closure

glaucoma are classic causes of acute visual loss with pain, which should

always prompt an immediate examination by an ophthalmologist

+ Patients with corneal ulcerations or trauma are often unable to open their

eye because of reflex blepharospasm.

+ Angle-closure glaucoma is suspected when the vision loss is preceded by

severe eye pain and headaches and often associated with nausea. The eye

becomes red rapidly and patients typically complain of seeing halos around

lights in addition to blurry vision. The cornea is cloudy and the pupil is

dilated, not reactive to light. Palpation of both eyes allows the neurologist to

realize that the affected eye feels harder than the normal eye.

+ Uveitis can only be diagnosed with slit lamp examination: most

patients complain of photophobia, floaters, and mild pain, and the eye may

be moderately or very red.

Uveal tract: màng bồ đào

Uveitis : viềm màng mạch nho

Uvea: màng mạch nho

Retinopathy

1. Any damage to the retina of the eyes, which may cause

vision impairment

2. Retinopathy often refers to retinal vascular disease, or

damage to the retina caused by abnormal blood flow

3. Macular degeneration(age-related macular degeneration)

(AMD or ARMD), is a medical condition which may result in

blurred or no vision in the center of the visual field.

(Early on there are often no symptoms. Over time, however, some

people experience a gradual worsening of vision that may affect one or

both eyes. Genetic factors and smoking also play a role)

Mất thị lực do bất thường võng mạc

+ A few neurologic emergencies may present with acute visual loss and

retinal changes.

+ Intravitreal and preretinal hemorrhages cause acute visual loss without

pain.(xuất huyết trong thủy tinh thể hay trước võng mạc)

+ The anterior segment of the eye looks normal,

+ There is no RAPD,

+ The view of the fundus is difficult; when looking at the eye with an

ophthalmoscope a few inches away, the examiner sees a dull or dark reflex

in the center of the cornea indicating the absence of the normal red reflex.

+ Vitreous hemorrhage is common in diabetic patients, and it may also

occur in patients with acute intracranial hypertension, particularly

resulting from subarachnoid hemorrhage (socalled Terson syndrome)

Terson syndrome in the right eye of a patient with subarachnoid hemorrhage. There

is a large preretinal hemorrhage as well as two small peripapillary hemorrhages

(a) The right fundus showing scattered superficial and deep retinal haemorrhages in the

posterior pole. (b) The left fundus showing a dome-shaped sub-ILM haemorrhage (white

asterix) and a subhyaloid haemorrhage located anterior and inferotemporal to the sub-

ILM hemorrhage (orange asterix). Note the 'double ring' sign with the 'inner ring' caused

by the sub-ILM bleed (blue arrows) and the 'outer ring' by the subhyaloid bleed (black

arrows). (c) At 1 week postlaser photograph showing drainage of the sub-ILM blood into

the vitreous (black arrows). Note the hazy view caused by the vitreous haemorrhage. (d)

At 2 weeks postlaser photograph showing almost complete resolution of the sub-ILM

haemorrhage. Note the subhyaloid pocket of blood remains unchanged (black arrow).

+ Retinal diseases such as central retinal artery occlusion (CRAO) and

large retinal detachments, can produce acute painless monocular visual

loss with an RAPD

+ CRAO produces acute, painless, severe, and permanent monocular visual

loss resulting from acute inner retinal ischemia

+ Funduscopic examination shows marked attenuation of the retinal arteries,

sometimes occluded by emboli, and whitening of the ischemic inner

retina with sparing of the outer retina in the foveal region supplied by the

intact choroidal circulation, creating the classic “cherry-red spot” -màu đỏ

anh đào

+ Acute CRAO is an emergency, should be considered a cerebral infarction of

the anterior circulation, and should be evaluated similarly.

+ In patients older than 50 years, giant cell arteritis must also be ruled out

+ Acute treatments for CRAO are limited, but there are studies evaluating

intravenous or intra-arterial thrombolysis in acute CRAO

Acute central retinal vein occlusion in the left eye. There are numerous flame

retinal hemorrhages, the veins are dilated ( arrows ), and there are cotton wool

spots ( arrow heads ) and optic nerve head edema

Acute central retinal artery occlusion in the right eye (shown on the left ). Note the

attenuated central retinal artery with segmental narrowing in the right eye ( arrows )

compared with the left eye. The ischemic retina is edematous and appears whitish

compared to the left eye and there is a cherry-red spot (*) (oculus dexter and oculus sinister,; mắt phải và mắt trái. oculus uterque: hai mắt)

+ Numerous other retinal disorders involving the macula may produce

central visual loss, but are usually not associated with an RAPD.

+ Central retinal vein occlusion is also a cause of painless monocular

vision loss, usually not associated with neurologic disorders.

+ Age-related macular degeneration is a common cause of acute

central visual loss in the elderly; these patients often also have a history of

progressive monocular or binocular visual loss with metamorphopsia

(biến thái)

+ Acute worsening of vision in one eye is usually related to bleeding

of a macular neovascular membrane.

+ Central serous retinopathy is a cause of acute painless unilateral

central vision loss with no RAPD and a normal-appearing optic nerve,

most often occurring in young men. Careful examination of the macula

shows a “blister” in the macular region.(phồng lên)

Optic Neuropathies

Optic neuropathies typically manifest:

+ decreased visual acuity,

+ altered color vision,

+ abnormal visual fields.

+ RAPD is always present when the optic neuropathy is unilateral or

asymmetric.

+ Acutely, the optic nerve may be normal (posterior optic neuropathy), or

may be swollen (anterior optic neuropathy).

+ The optic nerve becomes pale 4–6 weeks later regardless of the

mechanism.

+ Optic neuropathies with acute or subacute vision loss are often

evaluated in the emergency department

+ optic neuropathies are best classified by mechanism and

the clinical characteristics often allow a diagnosis.

+ optic nerve imaging is often helpful, particularly to demonstrate

optic nerve inflammation, infiltration, or compression

+ it is important to emphasize that most brain scans (CT or MRI) do

not allow proper evaluation of the optic nerves

+ MRI of the orbits with contrast and fat suppression is the most

sensitive test to image the optic nerves in the orbits, at the level of

the orbital apex and intracranially

+ particularly important when an optic nerve sheath meningioma

or an orbital apex syndrome is suspected

Most common causes of acute optic neuropathies

Inflammatory Optic Neuropathy (Optic Neuritis)

1. Isolated optic neuritis is often the first manifestation

of multiple sclerosis (MS) and is one of the classic

clinically isolated syndromes.

2. However, inflammation of the optic nerve may also

occur in association with numerous infectious and

noninfectious inflammatory disorders.

3. Patients with optic neuritis present with acute or

subacute painful monocular visual loss.

4. Central vision typically deteriorates over hours or days.

5. In mild optic neuritis, color vision change can be the

first or the only visual complaint.

6. Pain on eye movement is a frequent early complaint

with the visual loss

Thăm khám :

+ decreased visual acuity,

+ decreased color vision,

+ visual field loss centrally.

+ RAPD will be present if the optic neuritis is unilateral or asymmetric.

(isolated optic neuritis associated with demyelinating disease, two-thirds

of patients have a normal optic nerve acutely and one-third of patients

have moderate optic nerve head swelling (so-called “anterior” optic

neuritis or papillitis)

+ Optic neuritis with normal-appearing optic nerve acutely is called

“retrobulbar” or “posterior” optic neuritis.(viêm thần kinh hậu nhãn cầu)

+ In all cases, optic nerve head pallor develops 4–6 weeks later (nhợt

màu sau 4-6 tuần).

+ MRI não trên bn viêm thần kinh thị đơn độc tìm kiếm bệnh mất myelin

+ xét nghiệm máu tùy biểu hiện lâm sàng (Syphilis, cat scratch disease,

and sarcoidosis are common alternate causes of optic neuritis)

+ chọc dò dịch não tủy

(in most cases, optic neuritis remains idiopathic or is associated with

multiple sclerosis.).

In patients with typical isolated optic neuritis, the risk of

multiple sclerosis is best predicted by a brain MRI:

+ Patients with a normal brain MRI

- risk of multiple sclerosis estimated at 25% at 15 years,

+ with at least one typical demyelinating lesion on the MRI

- risk close to 70% at 15 years

Nguy cơ MS

Patients with no lesions on the MRI, any of the following

features is associated with virtually no risk of multiple sclerosis:

1. male gender,

2. absence of pain,

3. severe optic nerve edema,

4. peripapillary hemorrhages,

5. macular changes suggesting neuroretinitis.

(This emphasizes the importance of a funduscopic examination by an

ophthalmologist in all cases with presumed optic neuritis).

Dự hậu thị lực trong ON đơn độc

1. The visual prognosis of isolated optic neuritis is

usually good even without treatment

2. High-dose intravenous methylprednisolone (1 g/ day

for 3 days followed by oral prednisone 1 mg/ kg/day

for 11 days) only accelerates visual recovery

3. but does not alter long-term visual outcome or the

long-term risk of subsequent MS

. The Optic Neuritis Treatment Trial

+ 1 mg/kg/ day of oral prednisone did not improve visual outcome and

doubled the risk of recurrent optic neuritis.

+ Therefore, low-dose oral prednisone is currently not recommended

for patients with isolated optic neuritis and intravenous steroids should

be discussed on a case-by-case basis

NMO

+ A subgroup of patients with severe optic neuritis and poor recovery,

or with bilateral or recurrent optic neuritis, are found to have positive

neuromyelitis optica (NMO) antibodies, even in the absence of

transverse myelitis

Viêm thần kinh võng mạc

+ Neuroretinitis characterizes patients with an anterior optic neuritis

associated with retinal exudates, usually in the shape of a star at the

macula.

+ In most cases, neuroretinitis is due to an infection such as cat scratch

disease or syphilis, or to a noninfectious infl ammatory disorder, such as

sarcoidosis.

+ Neuroretinitis is not associated with a risk of MS.

+ Treatment of neuroretinitis or infectious optic neuritis depends on the

underlying disease.

Anterior optic neuritis in the

left eye. ( a ) Fundus

photograph of both eyes

showing mild optic nerve

head edema in the left eye

(OS) compared with the

right eye(OD).

( b ) Axial T1-weighted

MRI of the orbits with

contrast and fat

suppression demonstrating

enhancement of the left

optic nerve ( arrow ).

( c ) Axial FLAIR MRI

of the brain showing two

periventricular ovoid lesions

suggestive of demyelinating

disease

Ischemic Optic Neuropathy (mach máu)

Phân loại Ischemic optic neuropathies

+ anterior ischemic optic neuropathy (AION), ( always optic nerve head swelling acutely)

+ posterior ischemic optic neuropathy (PION), ( posterior part of the optic nerve is ischemic with normal-appearing optic

disk acutely)

+ AION is much more common than PION,

+ Ischemic optic neuropathies are also classified:

“nonarteritic” and “arteritic”

(most often associated with giant cell arteritis).

+ Ischemic optic neuropathies present with painless,

acute or subacute visual loss with visual field defects

and an RAPD; 4–6 weeks later, the optic nerve

becomes pale.

Nonarteritic AION (NAION)

+ The most common form of ischemic optic neuropathy, affecting

between 2 and 10 individuals per 100,000.

+ The main risk factor is a small crowed optic disk with no cup (so-called

disk at risk), but other disk anomalies such as optic nerve head drusen

and papilledema can also predispose to NAION

+ Most patients with NAION are at least 50 years of age and have at

least one cardiovascular risk factor.

+ NAION is a small vessel disease involving the short posterior ciliary

arteries

.

+ It is not embolic and there is no increased risk of cerebrovascular

disease in patients with NAION.

+ The pathophysiology involves local arteriolosclerosis involving small

vessels, in addition to the “disk at risk.”

+ Atheromatous vascular risk factors should be identified and aggressively

treated, search for a carotid or cardiac source of emboli is usually not

necessary in patients with isolated NAION.

+ There is currently no proven treatment for ischemic optic neuropathies,

and the only emergency in evaluating a patient with AION or PION is to

rule out giant cell arteritis .

+ Giant cell arteritis should always be considered in all patients older

than 50 years with AION or PION, and blood tests looking for a

biologic inflammatory syndrome need to be obtained emergently.

+ High-dose steroids are initiated only in patients in whom there is

high clinical suspicion of giant cell arteritis, and a temporal artery

biopsy should be subsequently obtained in these patients

.

+ Administration of high doses of intravenous steroids at the

beginning of treatment for giant cell arteritis may decrease the

duration of treatment and the total dose of steroids used.

+ However, the treatment remains mostly empirical with very

few clinical trials available.

Anterior ischemic optic neuropathy in the right eye. There is an optic nerve head

edema, worse superiorly, and a small peripapillary hemorrhage superiorly. The

patient had an inferior altitudinal visual field defect

Ca lâm sàng:

1. Viêm thị thần kinh: bn giảm thị lực mắt(Bn nhìn mờ mắt T, một tuần

sau thì nhìn mờ cả mắt P, nhìn mờ ngày càng tăng dần gai thị, gai

thị bạc màu, Tổn thương chất trắng cạnh não thất 2 bên và MRI

tăng tín hiệu dây thần kinh thị 2 bên nghĩ bệnh lý viêm hủy myelin

2. BN có yếu tố nguy cơ mạch máu nên cần theo dõi chẩn đoán loại

trừ Nonarteritic AION (NAION)