Vertigo

VERTIGO (Latin vertigo), cannot be considered an independent disease form, but is observed as a symptom in various diseases. V. is a peculiar state of consciousness accompanying a disturbance of the equilibrium of the body. It can be characterized as confusion of the sense of static equilibrium, a false assessment of the spatial relations of our body to the surrounding environment. In the statics and locomotion of our body, the main controlling factors are those processes in the cerebral cortex, which can be designated collectively as the consciousness of the surrounding space and the position in this space of our body and its parts. This concept includes all moments of awareness of those sensory-motor phenomena in our body, which act as innate and acquired automatisms for maintaining equilibrium and producing life-advantageous movements. The complex reflex apparatus governing equilibrium enters its central part (coordination center) into the composition of the midbrain (Vasaliev bridge, cerebellum, quadrigeminal body); signals- tactile, kinesthetic, visual, auditory, and special static (originating from the ear labyrinth) are conducted here through the system of centripetal nerve fibers, which are transformed here into motor reactions aimed at preserving static and kinetic equilibrium. Tactile and, above all, kinesthetic sensations determine the correctness and accuracy of muscle contractions; visual and auditory sensations are like additional factors in the regulation of movements, but they acquire primary significance in the insufficiency or loss of one or another category of sensations. Thus, vision compensates for the lack of kinesthetic sensations in ataxics, the blind regulate their movements through auditory perceptions. But the starting point of sensations, from which the spatial sense in our consciousness is composed, are the semicircular canals of the ear labyrinth, which are in connection with the nuclei of the eye muscles, the cerebellum, the large brain, and the spinal cord through the vestibular nerve and the system of Deiters-Bekhterev nuclei. The hydrostatic relations in the semicircular canals (located in the three main planes of space) are the source of signals changing in connection with the position of the head and the whole body, with their shifts or movements; through such centripetal impulses the labyrinth reflexively changes the tone of the muscles of the eyes, neck, trunk, and limbs. The labyrinth has the nearest effect on the position of the head and thereby transmits a directing influence on the tone of the limb musculature to the tone of the neck musculature (the automatic adaptability of the musculature of the neck and limbs has been proven experimentally by Magnus and Klein). The existence of such a regulating apparatus makes it possible for our body to automatically adapt to changing conditions of its statics, to restore equilibrium through the so-called compensatory or reactive movements: thus, balancing movements of the trunk and limbs arise to preserve equilibrium, movements of the eyeballs arise in the form of rotation of them around the line of vision in the direction opposite to the rotation of the head, which allows preserving the ordinary projection of the external world on the retina. The harmonious activity of the complex static apparatus as a whole ensures two possibilities: automatic preservation of the equilibrium of the body and orientation of consciousness in the relations of our body to the surrounding environment both in a state of rest and when changing place, as well as orientation in the spatial-geometric relations of external objects. If in the general stream of signals of all categories a contradiction arises between the state of excitation of one of the receiving apparatuses and the actual position of the body, then the perceptions coming through other conductors will turn out to be false and will be perceived by our consciousness as a violation of the stability of the body, expressing itself as a vertigo symptom-complex, consisting of subjective phenomena: sensations of imaginary rotational movements of the patient's own body or surrounding objects and of objectively observed compensatory movements of the trunk, limbs, and nystagmus. In severe cases, painful phenomena of nausea and vomiting join in. From a practical point of view, one should distinguish physiological and pathological V. V. of the first category can be observed: when transferring the gaze from a moving object to a stationary one, when fixing the gaze on a swaying object, when looking through a prismatic glass, when rotating the body around the longitudinal axis - "rotatory V." (see Vestibular methods of investigation), when passing a galvanic current through the head - "galvanic V." (see Voltaic reaction), when pouring cold or hot water into the external ear - "caloric V." (see Barany method of investigation). Great interest represents pathological V. One distinguishes systemic V., observed in diseases of one or another department of the complex apparatus of equilibrium, and non-systemic V., which is a diffuse disturbance of the representation of space. Systemic V. is caused by diseases: 1) of the labyrinth: their etiology: hemorrhages (Meniere's disease in the narrow sense), syphilis, infection from the middle ear, tumors and brain abscesses, defects of development of the labyrinth (primary labyrinth, Voltaolini disease); 2) of the vestibular nerve or nuclei; their etiology: hemorrhage on the basis of the brain and in the bridge, tumors, gummatous processes; 3) of the cerebellum; etiology: tumors, abscesses, hemorrhages; 4) of the conductors of deep sensitivity (in tabes dorsalis); 5) of the muscles of the eye (vertigo as a companion of diplopia). To the category of non-systemic ones belong V. in various neuropathies and disturbances of cerebral circulation: neurasthenic states in neuroses, epilepsy (V. as an aura and V. as an equivalent), migraine (especially with scintillating scotoma V. is often observed); acute and chronic infections (among the latter syphilitic lesions of the brain in the initial stage often manifest only as vertigo); acute anemia, especially in children; toxic (nicotine, caffeine, alcohol) and auto-intoxic forms (diabetes, gout, uremia); reflex moments: diseases of the nose, stomach (vertigo e stomacho laeso), dysmenorrhea, irritation of the mucous membrane of the rectum, urethra (recto-, urethroscopy, bougienage), pressure on the testicle (cryptorchism). For differential diagnosis it is necessary: otological investigation, labyrinthine tests (caloric, galvanic, rotatory) and a careful account of all phenomena of irritation or loss. In lesions of the labyrinth, the position of the head influences both the appearance of attacks of V. and the direction of rotational imaginary movements (V. can arise at night, when the patient in bed changes the position of the body). Such dependence is not observed in foci of lesion in the cerebellum. Treatment of V. is strictly causal.