Opthalmology posting: Diabetic retinopathy

Assalamualaikum semua!

Today's date is 18/11/2012. As you all can see in newspaper and internet there are a lots of news about ours brothers and sisters suffering a lots at Gaza because of the cruelty Israeli. Lets pray for them to be save and Allah help them to be a brave heroes to save their land and our religion, Islam. Allahuakhbar!

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my next topic is a about diabetic retinopathy  since now i'm at 3rd weeks of ophthalmology posting at HUKM. (posting mata)

DEFINITION

 

Diabetic retinopathy is a complication of diabetes and a leading cause of blindness. It occurs when diabetes damages the tiny blood vessels inside the retina in the back of the eye. Its altered vascular permeability (loss of pericytes, breakdown of blood retinal membrane and thickening of basement membrane.

CLASSIFICATION

1) Nonproliferative diabetic retinopathy (NPDR)

•  Most patients (95%) have NPDR.
•  This is the earliest stage of retinopathy and it progresses slowly. 
•  The earliest signs of retinal damage arise from capillary wall breakdown, seen on the fundus exam as vessel microaneurysms. 
• Injured capillaries can leak fluid into the retina and the aneurysms themselves can burst, forming “dot-and-blot hemorrhages.”

2) Advanced/Severely Nonproliferative diabetic retinopathy

• non proliferative findings + 

* venous beading (in 2 or 4 retinal quadrants)
*intraretinal microvascular anomalies (IRMA) in 1 or 4 retinal quadrants
                       -IRMA: dilated, leaky vessels within the retina
*cotton wool spots (nerve fiber layer infarct)

3) Proliferative Retinopathy   

  

• With ongoing injury to the retinal vasculature, there eventually comes a time when the vessels occlude entirely, shutting down all blood supply to areas of the retina. 
• In response, the ischemic retina sends out chemicals that stimulate growth of new vessels. 
• This new vessel growth is called neovascularization, and is the defining characteristic of proliferative retinopathy. 
• Far fewer patients have proliferative retinopathy, which is fortunate as this stage can advance rapidly with half of these patients going blind within five years if left untreated.

PATHOGENESIS 

other things you should know:

• What are the retinal signs of diabetic retinopathy. How do they compare to, say, hypertensive retinopathy.

-With diabetic retinopathy you typically see a lot of dot-blot hemorrhages, cotton-wool spots, and hard exudates. 
-Hypertension usually has more flame hemorrhages and vascular changes such as arterial-venous nicking and copper/silver wiring. 

• How are angiogenic molecules involved with diabetic retinas?

VEGF production by areas of ischemic retina leads to neovascularization. These new vessels are bad as they can cause traction, bleeding, detachments, etc.. 

•  What are some mechanisms in diabetic retinopathy that might lead to decreased vision? What causes the majority of vision loss in diabetic patients?

-There are several mechanisms for potential vision loss in these patients, including: 

*Macular edema (probably the leading cause of vision loss) 
*Vitreous hemorrhage 
*Retinal detachment

• How do we treat advanced diabetic retinopathy?

Proliferative diabetic retinopathy is treated with PRP (pan retinal photocoagulation). By ablating the peripheral ischemic retina with a laser, we decrease VEGF production and thus decrease neovascularization.

• A 35 year old man with bad type-1 diabetes presents with a pressure of 65. His anterior chamber is deep but you find neovascularization everywhere - in the retina and on the iris. What do you think is causing the pressure rise, and how do you treat it?

-The pressure is up because of neovascularization of the iris angle with blood vessels clogging up the trabecular drain. 
-You treat neovascularization by PRP lasering the peripheral retina to decrease VEGF production.
 - NVA (neovascularization of the angle) is hard to manage and this patient will probably require a surgical drainage procedure in the near future.

• Describe the three types of retinal detachment?

These include rhegmatogenous detachments, tractional detachments, and exudative detachments. 

• What are the symptoms of a retinal tear or detachment?

Flashes and floaters are the classic signs. With a large detachment your patient may also notice an area of “dark curtain” or “blurry spot” in their peripheral vision.

• What is a PVD?

This is a posterior vitreous detachment - with aging the vitreous jelly liquefies and contracts. A sudden contraction can cause new floaters. This event is usually harmless, but you should search carefully for retinal tears. 

• An elderly patient presents with a brief episode of flashing and now has a single floater that moves with eye movement. A thorough retina exam reveals no detachment or tear, but you observe a small vitreous opacity floating over the optic disk. What has happened?

This again sounds like a PVD. The floater is a Weis ring, a piece of optic disk debris that has pulled off with the detachment. PVDs are common and usually harmless, though patients should have a thorough exam for retinal tears and be taught about the symptoms of retinal detachment to look out for. 

• What kind of surgeries can we perform to relieve retinal detachments?

You can perform a vitrectomy to clean out the inside of the eye and relieve retinal traction. While in there you can also reappose the retina. You can also perform a scleral buckle or a pneumatic retinopexy.

• What is Schafer’s Sign?

This is when you see retinal pigment particles floating in the anterior vitreous chamber behind the lens. This slit-lamp sign increases your suspicion for a tear or detachment. 

•  What kind of travel restrictions would you tell a patient who has a pneumatic retinopexy?

Well, you don’t want these patients to fly. A decrease in ambient pressure causes gases to expand. If this happens in the eye it could explode! Your patients should also avoid SCUBA diving for similar reasons, as the change in gas volume over the changing atmospheric pressure will cause extreme pain and possible damage. 

• What’s the difference between dry and wet age-related macular degeneration?

-Dry ARMD is when you have drusen and macular RPE atrophy. 
-Wet ARMD implies choroidal neovascularization that has grown up through Bruch’s membrane.

MeREpek story from CIk BELLA:

 

 

 

pesanan penaja: Jaga lah mata anda kerna mata adalah satu anugerah yang tak ternilai harganya. Bila da hilang fungsinya baru lah anda sedar betapa nikmatnya dapat melihat. Bagi mereka yang mempunyai masalah kencing manis sila lah control pemakanan anda supaya ianya tidak menimbulkan masalah pada mata pula. Amalkan gaya sihat dan banyak makan carrot untuk kesihatan mata.

Sekian.

terima kasih.

Aligato and semoga mendapat ilmu yang bermanfaat.