Causes of eye fundus edema

The most common cause of these vascular lesions of the fundus
are hypertensive disease and atherosclerosis. In view of the considerable
prevalence of these diseases and annual increase
They have a tendency to increase the number of cases
vaso-occlusive diseases of the retina.

Retinal vein thrombosis is an occlusion of the central vein
retina or its branches. In most cases, there are thromboses
vascular arcades, according to V.V. Nikolskaya (1987), in 67.2% of cases.
The most frequently affected upper limb branch of the central vein of the retina
(82.4%). Occlusion of the central artery of the retina is one of the heaviest
forms of pathology of the eyes, leading to a sharp loss of vision. It is often associated with
systemic diseases requiring urgent therapy for
life indications. This is mainly a one-sided disease. AT
Most cases of patients aged 40 to 70 years. More often suffer
men.

The cause of venous occlusion may be hypertensive disease,
Atherosclerosis, blood diseases (polycythemia), changes in rheological
blood properties and disorders of the hemostasis system, diabetes mellitus, angiitis
retina, primary glaucoma, eye trauma.

In the mechanism of thrombosis, microcirculation disorders, vascular compression and arterial spasm are important.

Ophthalmoscopic symptoms are caused by the development of hypoxia and
retinal ischemia as a result of arterial spasm and disturbance
permeability of the vascular wall. This occurs due to damage
endothelium of veins and leads to the formation of transudate and edema of the retina.

Classification of venous thrombosis of the retina is based on the location of the thrombus and the stage of the process.

  • I. Thrombosis of the central vein of the retina.
  • II. Thrombosis of vascular arcades (upper, lower, upper, lower, nizhnenosovoy) with edema of the macula, without edema of the macula.
  • III. Postthrombotic retinopathy.

Thrombosis of the central vein of the retina begins suddenly and
accompanied by a sharp decline in vision. Retinal veins are significantly
expanded, strained and tortured, some of them immersed in the depth of edema
retina. Due to increased vascular wall permeability, edema
the retina appears early. The most characteristic picture of thrombosis
central veins of the retina create multiple flame
hemorrhages, located mainly in the layer of nerve fibers.
Sometimes massive preretinal hemorrhages develop.

In venous occlusion, edema of the macular zone often occurs - the main
cause of reduced central vision. Ischemia of the macula is caused
occlusion of periphovial capillaries. Depending on the area
occluded capillaries can distinguish 4 degrees of perfusion disorder
maculae (Figure 4-56).

I degree - occlusion of periphovial capillaries in an area less than 1 quadrant.

II-IV degree - distribution of an occlusive process, exciting
more than half of the periphovial capillary bed. The beginning and
progression of occlusion of capillaries is clearly defined when
fluorescence angiography, which is an important prognostic
sign.

Fluorescent angiograms of the fundus in central vein thrombosis
retina reflect retardation of retinal contrast, lengthening
venous perfusion, uneven contrasting of veins, granularity
blood flow. Experimental and clinical data show that
isolated thrombosis of retinal veins does not happen. In each case, in
or lesser extent, the blood flow in the corresponding
artery, so it's more correct to talk about thrombosis of the arteriovenous arcade.

Clinical manifestations of occlusion of arteriovenous arcade are similar
changes in the fundus of the eye when the central vein of the retina is damaged, but
confined to the affected branch. Prognostically significant
has edema of the macula, which is most often formed with occlusion
lower arcade, because it is through it
drainage of the macular zone (Figures 4-57, 4-58, 4-59, 4-60, 4-61, 4-62).

The late phase of retinal vein thrombosis is called postthrombotic
retinopathy. The peculiarity of the venous occlusion of the fundus is its
duration, depending on the evolution of the thrombus, its location and extent
occlusion of the vessel.

Adequate blood flow can recover or recanalize
thrombosed vessels, or with the development of collateral blood flow and
shunts. Usually, collaterals develop 3 months after the onset
a thrombus, connecting either the distal and proximal ends of the occluded
vessel, or the upper and lower vascular branches.

Shunts formed on the optic nerve disk are important for
rapid transport of blood from the retinal vascular system in
choroidal.

If the blood flow in the affected arcade is not restored or
partially restored and the development of collaterals is not sufficient for
ensuring the normal circulation of blood, then in the affected area
of the retina, ischemic zones are formed, which are initiators
neovascularization. Thus, the ophthalmoscopic picture
postthrombotic retinopathy shows collaterals, shunts,
dilated intra-retinal capillaries, micro- and macro-aneurysms, zones
ischemia and neovascularization. By this time either resorbed
diffuse edema of the central zone of the retina, or formed a cyst
macular degeneration; the deposition of solid exudate is also observed (Figure 4-63, 4-64, 4-65, 4-66, 4-67, 4-68, 4-69, 4-70,
4-71, 4-72, 4-73).

In the acute stage, locally, in the form of parabulbar injections,
direct anticoagulants (heparin), thrombolytics (recombinant
prourokinase, diaplasmin), corticosteroids. Intravenous drip is administered
reopoliglyukin, trental, dexazon, prescribe dehydration therapy.
When the macular area is swollen, barrier laser coagulation is indicated
retina. The main method of treatment of postthrombotic retinopathy
is the laser coagulation of the retina in order to close the ischemic zones and
destruction of neovascular complexes.

Complications of retinal vein thrombosis are similar to complications of diabetic retinopathy.


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