Vertebrobasilar insufficiency: diagnosis

Physical examination

On the basis of diagnostics of peripheral cochleovestibular syndromes of vascular genesis, there are features of cochleovestibular disorders. The majority of the examined patients had bilateral spontaneous nystagmus and only single cases - one-sided. One-sided nystagmus is usually combined with a harmonious deviation of the arms and torso towards the slow component of the nystagmus, which is characteristic of the peripheral cochlear-vestibular syndrome in the acute period of the disease. The presence of bilateral nystagmus indicates a simultaneous ischemic injury of peripheral and central vestibular structures. Analysis of the symptoms of combined damage to the inner ear and brain structures (medulla oblongata, variolium bridge, middle brain, cerebellum, large hemispheres) showed that in 80% of cases peripheral cochleovestibular syndrome was formed against the background of symptoms of lesions of the variolium bridge. This is due to a single source of blood supply to the peripheral vestibular structures and central vestibular pathways and nuclei from the branches of the anterior cerebral artery and the penetrating arteries of the brainstem.

Laboratory research

Experimental vestibular tests in most patients reveal bilateral hyperreflexia (acute period), less often bilateral hyporeflexion, which corresponds to the period of remission of the disease. Also for this group of patients asymmetry in the labyrinth is characteristic; bilateral vestibular hyperreflexion is combined with a one-sided hearing loss, which is the clinical basis of the combined (peripheral and central) ischemic injury of the inner ear and brain structures. Asymmetry of nystagmus in the direction (a sign of central lesion) is usually detected in a single): patients and testifies in favor of simultaneous ischemia of the anterolateral sections of the variolium bridge and peripheral cochleovestibular structures. Evaluation of all components of the vestibular reaction (nystagmus, vegetative and sensory manifestations) was characterized by their harmonious correspondence. Violations of optokinetic nystagmus in patients with peripheral cochleovestibular syndromes have not been revealed.

Instrumental research

The basis of diagnosis of vestibular disorders of vascular genesis is otoneurological examination with the inclusion of a number of special, objective methods for determining the functional state of auditory and vestibular analyzers (computer-assisted electroremography, audiometry, auditory evoked potentials). Oto-neurological examination is complemented by impedance tachooscillography, in which it is possible to record blood pressure before and after experimental vestibular loads, determine the main parameters of central hemodynamics (impact and minute volume of circulating blood). Ultrasonic dopplerography and neuroimaging techniques are also used. The obtained results allow to accurately determine the level of lesion of auditory and vestibular analyzers and to reveal the peculiarities of hemodynamic disorders underlying their formation.

In all patients with peripheral cochleovestibular syndromes, auditory function impairments are detected with the help of audiography. The peculiarity of auditory disorders is the presence of neurosensory hearing loss, and in most patients it is bilateral. Conductive hearing loss is detected in patients with concomitant defeat of the middle ear scarring-adhesive nature. In support of the confirmation of conductive hearing loss tests of lateralization of sound in the Weber experiment (in the direction of the hearing ear worse), as well as otoscopy data (cicatrical process of the tympanic membrane) and tympanometry are used. Some patients experience unilateral deafness as a result of acute ischemia of the inner ear.

Acute ischemia of the labyrinth develops usually against a background of various hemodynamic situations, such as asymmetry of the diameters of the vertebral arteries, their hypoplasia combined with increased arterial pressure, their atherosclerotic stenosis, and anomalies of their departure from the arch of the aorta. Heart rhythm disturbances (paroxysmal tachycardia), venous outflow and increased platelet aggregation and blood viscosity also lead to acute labyrinth ischemia.

The development of peripheral cochleovestibular syndromes occurs against the background of organic changes in the brain, of which the widening of the subarachnoid space is most often observed. Focal changes in the hemispheres most often correspond to changes around the ventricles of the brain, characteristic of patients with arterial hypertension. The detected foci of small size of the trunk and cerebellum confirm the otoneurological diagnosis of simultaneous ischemia in various vessels of the vertebral-basilar basin.

Structural changes in the main arteries of the head and hemodynamic indices of blood flow along the vertebral and internal carotid arteries are examined using ultrasound Doppler and duplex scanning, in some cases transcranial dopplerography, angiography and veosinography. Structural changes in the brain and the state of the cerebrospinal fluid are assessed by CT and MRI of the brain.

Differential diagnosis of vertebral-basilar insufficiency

Vestibular dysfunction of vascular genesis is differentiated from Meniere's diseases, neurinoma, multiple sclerosis. With Meniere's disease, attacks of dizziness develop in patients who do not have vascular diseases in anamnesis, vestibular disorders are quickly compensated, a labyrinth hydrops is revealed. In the presence of neurinoma of the VIII cranial nerve, symptomatology from the side of the bridge-cerebellar angle (violation of the function of V, VII and XIII cranial nerves) is revealed in addition to cochleovestibular syndrome. With multiple sclerosis, dizziness in the patient is prolonged, not accompanied by simultaneous auditory disorders, neurological symptoms and central changes in the study of auditory and visual evoked potentials are revealed; when MRI is detected, foci of demyelination are detected.

A patient with vestibular dysfunction needs consultation of an obituary, a neurologist (the state of the vessels of the fundus), specialists in ultrasound diagnostics and neuroimaging.

Screening

Screening of this category of patients consists in the performance of an extended otoneurological examination including classical otoneurological examination, audiometry and SVP, ultrasound methods of examination of the main arteries of the head and methods of neuroimaging. To diagnose the level of the lesion of the vestibular analyzer, the spontaneous and experimental vestibular reactions, auditory function and SVP are investigated, the functional state of the other cranial nerves (olfactory, trigeminal, facial, glossopharyngeal and vagal) is determined. Peripheral cochleovestibular syndrome is characterized by the absence of focal otoneurological symptoms, the presence of unilateral spontaneous nystagmus, the asymmetry of vestibular excitability in the labyrinth, the preserved optokinetic nystagmus in combination with the peripheral lesion of the auditory analyzer. For peripheral vestibular syndrome is characterized by the presence of pathological changes from the main arteries in the form of assimetry diameters and hypoplasia of one of the vertebral arteries, as well as the absence of foci of brain ischemia in CT and MRI.

Central vestibular syndrome is characterized by the presence of focal otoneurological symptoms, bilateral or multiple spontaneous nystagmus, hyperreflexia and subtentorial nature of vestibular experimental samples, violation of optokinetic nystagmus, in combination with central hearing impairments. Central vestibular syndrome develops on the background of more pronounced changes in the main arteries of the head - stenosis and occlusion of the vertebral artery and internal carotid arteries, leading to a greater deficit of blood flow in the vessels of the brain, which is accompanied by the presence of foci of ischemia in various parts of the brain.