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.
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.
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.