Hemianopsia - causes, symptoms, diagnosis and treatment
Hemianopsia - Polietiologic is a disease that manifests itself or homonymous visual field loss Geteronimnaja. Characteristic symptoms: inability to see certain halves of the eye, visual hallucinations are possible, the phenomenon agnosia, prosopagnosia and "mental paralysis of view." For diagnosis it is necessary to hold the perimeter and computer campimetry. Set etiology hemianopsia possible by means of ultrasonography, computed tomography, magnetic resonance imaging and computed tomographic angiography (CTA). Causal treatment is based on the elimination of organic pathology, caused hemianopsia clinic.
Hemianopsia
meningitis preferentially localized in the basal parts of the brain there is a mechanical compression of anatomical sites responsible for the transmission of nerve impulses in the cortex. The compression mechanism of hemianopsia occurs when intracranial localizations of malignant and benign tumors, brain abscesses.
Violation of cerebral circulation due to embolism or aneurysm of cerebral vessels leads not only to ischemia, but also increases the risk of increase of intracranial hypertension, and bleeding that is accompanied by a worsening of the clinical picture of stroke. Large amount of blood, as well as increased pressure adversely affect the operation of the visual pathways, up to their complete atrophy. Hemianopsia can be caused by severe skull injuries or be iatrogenic origin, caused by improper tactics neurosurgeons during surgery on the brain.
The development of an ischemic infarct in the posterior cerebral artery (PCA) hits striatornuyu cortex, visual radiance and lateral geniculate body that provokes homonymous hemianopsia on the opposite side. If ischemic necrosis develops in the lower zone of the cortex striatornoy calcarine grooves or in the lower optic radiation on the boundary of the temporal and occipital areas, verifying the upper-quadrant hemianopsia if the brain is affected the above structures on the border with the parietal area - lower-quadrant. Specific features of cerebral blood flow does not exclude the likelihood that middle cerebral artery (MCA) can provide regional blood flow optic radiation. Therefore infarction in MCA is one of the etiological factors of hemianopsia. At the same time damage calcarine furrows can manifest clinical get one side of the field of view of its part.
Congenital hemianopsia is one of the manifestations of severe malformations (hydrocephalus, encephalocele, microcephaly, cerebral cystic dysplasia).
arachnoiditis syndrome and "empty sella."
The clinical course of hemianopsia may be accompanied by the development of visual hallucinations and agnosia (violation of the processes of recognition of familiar objects when a saved partial vision). Most patients diagnosed with prosopagnosia, which manifests the inability to recognize familiar faces. Patients with hemianopsia tend to deny their disease while maintaining orientation, reflecting the positive symptoms of Anton-Babinski. There the ability to capture view only on a particular subject, it does not see the surrounding, which is the basis of "mental paralysis sight." Decorated (familiar images) or unregistered (fire, geometric images) visual hallucinations occur suddenly after a stroke.
Patients with acquired hemianopsia complain of poor ability to perform daily activities, t. To. Separate subjects drop out of sight. First of all they faced problems at the household level: do not see the whole portions of food for a long time can not find the things that are in the usual places, disoriented in space, much slower read and not even always notice oncoming traffic. Congenital form of the disease is often accompanied by organic abnormalities of the thalamus, and parietal lobes of the brain stem, so the visual symptoms are complemented by paresthesias, disorders of pain and temperature sensitivity.
perimetry and computer campimetry. To elucidate the etiology and lesion volume used Doppler ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and computed tomographic angiography (CT angiography). Patients are recommended to consult an ophthalmologist and a neurologist.
perimetry method makes it possible to identify pathological changes in visual fields. When homonymous defeat symmetrical drops in one eye temporal, but on the opposite - the nasal half of the visual field. When bitemporal form of the disease impaired temporal perception halves, both the left and the right eye. For binazalnaya blindness is characterized by loss of the medial. In total violation of it comes complete hemianopsia. Partial (quadrant), the form set by the visualization of the defect, since the point of view of fixing. Explore the pathology of the visual field can be also automated by a computer campimetry. The method allows to determine with precision color vision disorders and svetovospriyatiya in different parts of the retina, and indicates failure occurred at what level.
CT and MRI of the brain performed to establish the etiology of the disease and the choice of further treatment strategy. Using these techniques can be visualized three-dimensional formation (abscesses, cysts, tumors), the zone of ischemic or hemorrhagic stroke, as well as the amount of traumatic injuries. The method of CT angiography can get an image of the blood vessels of the brain and to evaluate the nature of the blood flow. The most frequently observed damage in ZMA, less AGR. Doppler ultrasound is a noninvasive technique that reveals blood flow in cerebral arteries and eye, as well as the place of occlusion.
Carrying visometry and ophthalmoscopy is recommended only as a screening. Hemianopsia not affect visual acuity. ophthalmoscopy method possible to verify the damage of the optic nerve only in the later stages of the disease.
traumatic brain injury often require immediate neurosurgical intervention. An effective way to eliminate hospital ischemic stroke is thrombolysis in the first 6 hours of further conservative therapy, which aims to reduce the viscosity of blood, taking nootropics. The treatment of oncological diseases of the brain depends on the stage of the tumor process and most often requires surgery, radiation or chemotherapy. Difficult to treat only a portion of the acquired disease caused by hemianopsia. Specific measures to eliminate congenital factors in the development of this disease has not been developed.
In the event that it is impossible to eliminate the clinical symptoms, the patient is recommended for rehabilitation, which aims to facilitate its interaction with the environment. First Rehabilitation should teach the patient to make a series of small eye movements toward the fallen sight. Moving in space requires a constant rotation of the eyes in the affected side, as well as reusable fixation of view on different distances - this is achieved only by means of training. The reading process is easier if you keep the book at an angle of 90 degrees and a vertical read lines.
Partially offset hemianopsia manages with special prisms and mirrors glasses. By moving the view in the direction of the affected side Special tools let you see the drop-down areas. This method requires an active movement of the eyes, but with no permanent head turns. Visual function can be improved by using computer techniques. Special courses are aimed at facilitating the orientation in space and perform household work.
ophthalmology not developed specific prevention measures. Patients are advised to undergo annual planned inspection by an ophthalmologist. The appearance of non-specific complaints (weight loss, malaise, headache) requires consultation of the neurologist or oncologist to exclude pathological brain tumors.