radiation retinopathy
Introduction
Introduction to radiation-induced retinopathy Radioactive retinopathy has a large clinical variation, but the incidence is dose-related. The early clinical features of mild radioactive retinopathy can be seen in the small posterior nucleus of the eye, scattered small capillary occlusion lesions, irregular expansion of the capillaries around the lesion, severe radioactive retinopathy often occurs in remote radiotherapy without good When the eye is protected, there are extensive capillary atresia and retinal vascular abnormalities in the fundus, which can cause macular edema, exudation, and decreased vision. basic knowledge The proportion of sickness: 0.004% - 0.006% Susceptible people: no special people Mode of infection: non-infectious Complications: vitreous hemorrhage
Cause
Causes of radiation-induced retinopathy
Causes
Radiation factor (35%):
The key to the occurrence of radiation-induced retinopathy in teletherapy is to determine the amount of radiation entering the eye. In the short-term treatment of choroidal melanoma and retinoblastoma, local radioactive changes in the retina and choroid are common, and the severity of radiation-induced retinopathy remains. Related to radiation dose, close treatment of the posterior segment of the eye, as long as 5mm around the macular area, will cause macular lesions leading to decreased vision, the minimum dose of macular degeneration is still unclear.
Chemotherapy (40%):
Tumor patients who have received several chemotherapy are more likely to develop radiation-induced retinopathy. In addition, the retina of patients with diabetic retinopathy is prone to extensive ischemia and neovascularization after radiation therapy, and patients with systemic vascular disease, such as hypertension. Leukemia, etc. are also prone to radiation retinopathy, and radiation therapy and chemotherapy are prone to optic neuropathy.
Pathogenesis
Retinal vascular endothelial cells first suffer from radiation damage. Their dysfunction and cell death are the beginning of radiation-induced retinopathy. Most of the retinal endothelial cell populations undergoing mitosis die under radiation stimulation, and a few interphase cells absorb a sufficient amount of radiation. Immediate death occurs. The initial cell death wave triggers the division and migration of adjacent endothelial cells to establish the continuity of endothelial cells. However, when these mitotic cells receive a sufficient amount of radiation, they also die, affecting the metabolism of the cell cycle until Endothelial cells can no longer complete its integrity, which triggers the formation of blood clots, a form of compensatory repair.
Capillary atresia leads to the expansion of small collateral vessels, establishing a pathway between ischemic and dilated blood vessels, microaneurysms, and microvascular anomalies in the retina are reactions to hemodynamics and local metabolic changes, capillary atresia When the area is large, the optic disc and retinal neovascularization can be formed. Whether the radiation directly leads to the disc disease is not clear, the ciliary circulation of the optic disc has compensatory ability, the higher dose of radiation can lead to choroidal vascular atresia, and the retinal ganglion cells have radiation resistance. Force, axial flow block is a characteristic of radioactive optic disc disease, or ischemic changes secondary to the optic disc.
Retinal cells have relative radiation resistance, non-replicating nerve cells have high radiation resistance, and retinal vascular endothelial cells and pericytes have high radiosensitivity and are susceptible to radiation damage.
Prevention
Radioactive retinopathy prevention
1. Eat more foods containing vitamin A, such as liver, cod liver oil, milk and eggs, plant foods such as carrots, leeks, spinach, leeks, green peppers, red sweet potatoes, and oranges and apricots in fruits. Persimmon and so on.
2, fasting garlic, onions, onions, ginger, pepper and other irritating foods.
3, more participation in physical exercise, enhance physical resistance.
4. Pay attention to the protection during radiotherapy.
Complication
Radioactive retinopathy complications Complications, vitreous retinal detachment
Macular edema, retinal hemorrhage and cotton vellus, can produce vitreous hemorrhage, traction retinal detachment, iris red change and so on.
Symptom
Symptoms of radiation-induced retinopathy Common symptoms Congestive retinal edema
The early clinical features of mild radioactive retinopathy can be seen in the small posterior nucleus of the eye, scattered small capillary occlusion lesions, irregular expansion of the capillaries around the lesion, fluorescent angiography can determine the extent of capillary leakage, with the retina The development of lesions occurs in microaneurysms, dilated collateral circulation and loss of functional capillary network, which gradually develops into ischemic retinopathy, and can also be combined with exudation and superficial retinal hemorrhage, and the visual acuity changes slowly.
Severe radioactive retinopathy often occurs when remote radiotherapy does not perform good eye protection. There are extensive capillary atresia and retinal vascular abnormalities in the fundus, which can cause macular edema, exudation and decreased vision, acute ischemic retinopathy. Can occur after the use of large doses of radiation, extensive retinal necrosis and small arterial atresia, cotton hair spots, superficial retinal and deep hemorrhage, retinal and optic disc neovascularization, vitreous hemorrhage, traction Retinal detachment, iris reddening, and even eyeball atrophy.
Radioactive damage caused by the use of a radiation applicator mainly occurs in the choroid and pigment epithelial layer of the patch, occlusion of the choroidal vessels, pigmentation or depigmentation, and occasionally choroidal neovascularization.
Radioactive optic neuropathy can be caused by remote radiotherapy or by radiation applicator, often with radioactive retinopathy, acute optic disc congestion, edema, often accompanied by edema around the optic disc, hard oozing, hemorrhage and cotton hair spots, fluorescent blood vessels The angiography showed a large area of non-perfusion area around the optic disc. The optic disc edema can last for weeks or months, eventually resulting in optic atrophy, and the visual loss is severe.
Examine
Radioactive retinopathy examination
Blood routine white blood cell count examination is more valuable for patients with radiation therapy in other large areas of the body.
FFA and ICG can determine retinal ischemia and choroidal ischemic changes. Cortical visual evoked potential (VEP) can help determine radioactive optic neuropathy and prolong P-100 wave latency.
Histological changes showed that the damage of the inner layer of the retina was heavier than the outer layer of the retina, and the early vascular endothelial cells were lost, while the pericytes remained, mainly in the arterial side of the microaneurysm and capillary spindle expansion, cell-free and collapsed The appearance of capillary network and non-perfusion area is characteristic of ischemic retinopathy. When the amount of radiation exceeds 60Gy (6000Rad), photoreceptor cells, pigment epithelium and choroidal capillaries are widely lost, and inner retina and optic atrophy can occur.
Diagnosis
Diagnosis and diagnosis of radiation retinopathy
A diagnosis can be made based on the history of radiation therapy and the presence of ischemic retinopathy at the fundus.
Differential diagnosis should be differentiated from diabetic retinopathy, venous obstruction, foveal telangiectasia, ischemic optic disc disease, optic discitis and other vascular diseases and optic nerve diseases. The important identification point is the existence of radiotherapy history.
