Coats disease

Coats disease is clinically evident within the first decade of li fe and is more common in

boys. The lesion is typically characterized by unilateral ret inal telangiectasia associated

with intraretinal yellow exudation without a distinct mass (Fig 19-10). The progressive

leakage of fluid may lead to an extensive retinal detachment and neovascular glaucoma.

Ultrasonography documents the absence of a retinal tumor and shows the convection of

cholesterol in the subretinal fluid . Fluorescein angiography shows classic telangiectatic

vessels. Laser photocoagulation or cryoablation of the vascular anomalies eliminates the

exudat ive component of the disease and may restore visual function. Subretinal fluid may

be drained to facilitate these procedures. Serial evaluat ion and follow-up is critical for

these patients.

EPIDEMIOLOGY

Also known as exudative retinitis, retinal

telangiectasis, or Leber multiple military

aneurysm disease

Inheritance pattern unknown

Very rare; occurs predominately in young

males (male:female 3:1)

Adolescent form (<16 years-old); “Adult”

form (>16 years-old)

80% unilateral

Characterized by abnormal retinal blood

vessel development

Can cause poor prognosis in advanced stages

Retinal detchment at advanced stages

Congenital retinaltelangiectasis (Coats' disease)Congenital retinal telangiectasis (Coats' disease) is anidiopathic retinal vascular disorder that usually affectsyoung male patients unilaterally in their first orsecond decade of life.Congenital retinaltelangiectasis, however, can affect patients of eithergender and become manifest at any age. Up to onethird of patients are older than 30 years of age at thetime of presentation.There is no defined familialinheritance. Patients may present with decreasedvision, as well as strabismus or leukocoria in children.The hallmark feature of congenital retinaltelangiectasis is localized fusiform aneurysmaldilations of the retinal vessels reminiscent of tiny light bulbs

Coats disease (Primary/Congenital retinal telangiectasis)25,26

The condition is also known as Lebers miliary aneurysm. (see chapter on retinoblastoma).

It is an exudative retinal vasculopathy that can be seen on any part of the retina but

peripheral lesions are more. The temporal retina is most commonly involved. Both the

arteries and veins are involved. The condition is non hereditary, boys are affected more

than girls in a ratio of 80 : 20. In 80% of cases the condition is unilateral. However the other

eye should always be examined for evidence of peripheral lesion because such lesions may be

managed better than the original eye, which may be in advanced stage of disease and difficult

to treat.

Though most of the children with Coat’s disease seek help only after 8 to 10 years of age.

The condition has been divided into two forms - (1) Juvenile, (2) Adult. The adult cases are in

fact the juvenile cases that have been asymptomatic. Juvenile form has been detected even

before one year of age. As far as progression is concerned earlier the lesion develops faster is

the growth and poorer is the prognosis. Some peripheral lesion may become stationary.

Coats divided the condition in three groups:

1. No vascular changes, only massive retinal or sub retinal exudation, no haemorrhage.2. Multiple vascular changes, retinal and sub retinal haemorrhage, massive retinal and

sub retinal exudates

3. Prominent retinal vascular changes, in the form of arterio venous communication and late exudation. This stage was later considered as separate entity not related to Coat’s disease and named as angiomatosis retinae.

To these three groups a separate clinical feature of miliary aneurysm was added and he condition was also known as Leber’s miliary aneurysm. However the condition was proved to be a milder and early form of Coat’s disease.

Clinical features

Clinical features depend upon stage of the disease at which the child is brought.

1. It may be quiescent

(a) Discovered on routine fundus examination

(b) The child is brought with unilateral squint, diminished vision.

In the above stages the eye is non-congested without any signs in the anterior segment.

2. Stage of white reflex—This is commonest stage when a child either is brought by

parents or referred by pediatrician who is justified to think it as retinoblastoma.

3. Stage of complication

(a) Congested eye

(b) Raised tension

(c) Complicated cataract

(d) Retinal detachment

4. Stage of blindness due to above conditions and total retinal detachment.

Signs in a well established case:

1. There may be a retro lental white reflex in the pupil on oblique illumination.

2. On retinoscopy the reflex is grey instead of usual pink.

3. Fundus examination—Initially the media are clear. The changes are in the

(a) Vessels

(b) Retina

Retinal vessels

The changes are seen both in the artery as well as veins. The changes are - Bunches of

beading, kinking, and loop formation.

The calibre of the vessels are irregular, the vessels are tortuous, may show aneu-

rysm formation. There may be establishment of communication between the artery and the

veins. Neovascularisation may also take place.

Changes in the retina

In type I of original classification of Coat’s, the changes are predominantly in the retina

or sub retinal space with almost normal vessels that become involved later leading the eye to

the category of type II.

The retinal changes consist of ophthalmoscopically visible areas of greenish white or

yellowish white areas of exudates with shinning spots. The shinning spots are cholesterol

crystals, which are also seen in sub-retinal space. The exudation in the sub retinal space may

elevate the retina and form a mass. The retinal detachment is exudative in nature. If not

treated the retinal detachment extends leading to total detachment and the retina may be

pushed as far as the posterior pole of the lens or very near to it. By this time a white reflex is

visible that must be differentiated from retinoblastoma. There may be some haemorrhages

in the vitreous as the disease progresses, the eye goes into secondary glaucoma, uveitis,

complicated cataract and blindness. It may become painful and require enucleation.

Investigation

Most important investigation in presence of clear media is fluorescein angiography. The

findings are variable according to stage of the disease and type of the disease. Common

fluorescein angiographic findings in established cases of Coat’s disease are:

1. Vascular changes in the form of tortuosity, beading, loop formation, neovasculari-

sation, multiple-aneurysms which were not visible with ophthalmoscope but stand

out prominently on FFA.

2. Retinal changes consist of leak, area of non perfusion and capillary drop out.

One of the characteristic appearance of fluorescein angiography is light bulb

appearance of dilated aneurysm.

The next important investigation especially in hazy media is CT of the eye, orbit and

skull and ultrasonography of the globe.

CT not only delineates the position of the retina, it shows the sub-retinal mass, there is

no intraocular calcification which is common in retinoblastoma. CT of the brain excludes

possibility of intracranial angiomatosis which is common in von Hippel Lindau’s disease, a

condition that may otherwise be confused with Coat’s disease.

Differential diagnosis

The conditions that come in differential diagnosis are long. It is headed by retinoblastoma

which is not only sight threatening but the life of the child is also jeopardised. The main points

in favour of Coat’s disease are - Unilaterality, more common in boys; late age of onset, slow

progressive. It never invades choroid or sclera hence it never becomes extraocular, being benign,

no metastasis is seen on x-ray and CT. Intraocular calcification is absent in Coat’s disease. The

most important similarity between the two conditions is white reflex in pupillary area. Other

conditions that should be excluded are:

• Persistent hyper plastic primary vitreous

• Congenital cataract

• Traumatic cataract

• Intra ocular toxocariasis

• Retinal angioma

• Familial exudative vitreo retinopathy

• Total retinal detachment

Management28,29

There is neither prophylaxis nor specific treatment for the condition. The aim is to clinch the

correct diagnosis. The treatment is directed towards vascular changes mostly on the peripheral telengectasis.

This is achieved by

1. Photo coagulation—This is a preferred treatment. The leaking vessels are treated

directly by laser. This may initially increase exudation, which can be reduced by

using lesser energy and smaller spots. The preferred laser is argon laser. It takes

about six weeks for any improvement to be visible and takes months or years for the

exudation to clear.

2. Cryo therapy—The cryo is applied through trans conjunctival route on the periphery

and reaction monitored under indirect ophthalmoscope.

3. If retina is elevated, a scleral buckle may be required.

Recurrence after adequate treatment are known.

http://www.eyerounds.org/cases/100-Coats-Disease.htm

Gambaran klinis tergantung pada tahap penyakit di mana anak dibawa.

1. Mungkin tidak terlihat

Ditemukan pada pemeriksaan fundus rutin

Anak itu dibawa dengan juling pada satu mata, visus berkurang.

Pada tahap di atas mata tidak terjadi kongesti tanpa ada tanda-tanda di segmen anterior.

2. Tahap reflex putih, tahap ini yang paling umum ketika seorang anak baik dibawa oleh

orang tua atau dirujuk oleh dokter anak yang dibenarkan untuk berpikir sebagai

retinoblastoma.

3. Tahap komplikasi

mata yang terkongesti

tekanan yang meningkat

komplikasi katarak

ablasio retina

4. Tahap kebutaan dari kondisi diatas dan ablasi retina total

Gejala dari penyakit ini adalah

1. Mungkin ada refleks putih retro lental di pupil pada pencahayaan miring.

2. Pada retinoscopy refleks abu-abu, bukan merah muda biasa.

3. Pemeriksaan fundus- Awalnya media yang jelas. Perubahan tersebut di

a. Pembuluh darah

b. Retina

Pembuluh darah retina

Perubahan terlihat baik di arteri maupun vena. Perubahan tersebut adalah

berbentuk Bunches of beading, keriting, dan berbentuk lekungan. Pembuluh darah yang

tidak teratur, pembuluh darah yang berliku-liku, mungkin menunjukkan Aneurysm

formasi. Mungkin terdapat hubungan antara arteri dan vena. Neovascularisation juga

mungkin terjadi.

Perubahan pada retina

Pada tipe I klasifikasi awal dari coats disease, perubahan tersebut terutama di

retina atau sub-retina dengan pembuluh darah yang normal yang ikut terlibat nantinya

menuju kekategori tipe II.

Perubahan retina terdiri dari ophthalmoscopically daerah terlihat putih kehijauan

atau putih kekuningan bidang eksudat dengan bintik-bintik Shinning. Bintik-bintik

Shinning adalah kolesterol kristal, yang juga terlihat di subretina. Eksudasi pada sub-

retina dapat

terjadi elevasi retina dan membentuk gumpalan. Jika tidak

dilakukan pengobatan ablasi retina akan meluas menyebabkan ablasio total dan retina

mungkin terdorong sejauh kutub posterior lensa atau sangat dekat dari itu.

Pada saat reflex putih terlihat harus dibedakan dari retinoblastoma. Mungkin ada

beberapa pendarahan pada vitreous sebagai suatu penyakit yang progresive, mata akan

menjadi glaucoma sekunder, uveitis,

komplikasi katarak dan kebutaan. Ini mungkin sangat menyakitkan dan memerlukan

enukleasi.

Menurut Gomez Morates coats disease dapat di dklasifikasikan ke dalam lima

tahap berdasarkan pada tingkat keparahan kelainan yang dihasilkan dari perubahan

vaskular

Stage 1 : hanya adanya eksudat

Stage 2 : eksudat intraretinal yang massif

Stage 3 : ablasio retina eksudatif sebagian

Stage 4 : ablasio retina total

Stage 5 : complikasi sekunder menuju ablasio retina kronik atau neovaskular

glaucoma.

Gambar 3. Coats disease. eksudat subretinal luas dan

ablasio retina eksudatif