Dizziness is a feeling of imaginary rotation and /or translational movements of the patient in various planes, less often — the illusion of displacement of a stationary environment in any plane. In clinical practice, the term “dizziness” is interpreted much more broadly, therefore it includes states and sensations caused by disturbances in the receipt of sensory information (visual, proprioceptive, vestibular, etc.), its processing. The main manifestation of dizziness is difficulty in orientation in space. Dizziness can have a variety of causes. The task of diagnosis is to identify the etiology of vertigo, which in the future allows you to determine the most effective tactics for its treatment.
Dizziness is a feeling of imaginary rotation and /or translational movements of the patient in various planes, less often — the illusion of displacement of a stationary environment in any plane. In clinical practice, the term “dizziness” is interpreted much more broadly, therefore it includes states and sensations caused by disturbances in the receipt of sensory information (visual, proprioceptive, vestibular, etc.), its processing. The main manifestation of dizziness is difficulty in orientation in space.
Etiology and pathogenesis
Ensuring balance is possible with the integration of the activities of the vestibular, proprioceptive, visual and tactile systems closely related to the cerebral cortex and subcortical formations. Histamine, acting on histamine receptors, plays an important role in the transmission of information from the receptors of semicircular channels. Cholinergic transmission has a modulating effect on histaminergic neurotransmission. Thanks to acetylcholine, it is possible to transfer information from the receptors to the lateral vestibular nuclei and the central parts of the vestibular analyzer. It is proved that vestibulovegetative reflexes function due to the interaction of choline and histaminergic systems, and histamine and glutamatergic pathways provide vestibular afferentation to the medial nucleus.
There are systemic (vestibular) and non-systemic dizziness. Non-systemic dizziness includes psychogenic dizziness, pre-fainting states, balance disorders. In some cases, the term “physiological dizziness” may be used. Physiological dizziness is caused by excessive irritation of the vestibular apparatus and occurs due to prolonged rotation, a sharp change in the speed of movement, observation of moving objects. It is part of motion sickness syndrome.
Systemic vertigo is pathogenetically associated with direct damage to the vestibular analyzer. Depending on the level of its lesion, central or peripheral systemic dizziness is isolated. The central one is caused by damage to the semicircular canals, vestibular ganglia and nerves, the peripheral one is caused by damage to the vestibular nuclei of the brainstem and cerebellum. Within the framework of systemic vertigo, there are: proprioceptive (the feeling of passive movement of one’s own body in space) and tactile or tactile (the feeling of swaying on the waves, lifting or sinking of the body, the unsteadiness of the soil, moving support under one’s feet).
Non-systemic dizziness is characterized by a feeling of instability, difficulties in maintaining a certain posture. It is based on the mismatch of the activity of vestibular, proprioceptive, visual sensitivity, occurring at various levels of the nervous system.
Symptoms of dizziness
Systemic dizziness is observed in 35-50% of patients with complaints of dizziness. The occurrence of systemic dizziness is often caused by damage to the peripheral part of the vestibular analyzer due to toxic, degenerative and traumatic processes, much less often – acute ischemia of these formations. Damage to the brain structures located above (subcortical structures, brain stem, cerebral cortex and white matter of the brain) most often occurs in connection with vascular pathology, degenerative and traumatic diseases. The most common causes of systemic vertigo are vestibular neuritis, Meniere’s disease, benign paroxysmal positional vertigo, neurinoma of the VIII pair of CN. To determine the nature of the disease already at the first examination of the patient, an adequate assessment of the anamnesis and the results of the clinical examination is necessary.
Benign paroxysmal positional vertigo (BPPV) is the most common cause of systemic vertigo. It is based on cupulolithiasis – the formation of calcium carbonate aggregates in the cavity of semicircular channels, which have an irritating effect on the receptors of the vestibular apparatus. BPPV is characterized by short-term (up to 1 minute) episodes of intense dizziness (when changing the position of the head), accompanied by nausea, bradycardia and other autonomic disorders. One of the distinguishing features of BPPV is the absence of tinnitus, focal neurological deficit during episodes of dizziness.
Vestibular neuritis is characterized by attacks of dizziness lasting from several hours to several days. It occurs acutely, often after a bacterial or viral infection. The patient experiences very intense dizziness, accompanied by pronounced autonomic disorders. There are no meningeal and focal neurological symptoms. Hearing is preserved.
Post-traumatic vertigo occurs immediately after a traumatic brain injury. At the same time, the presence of focal symptoms of brain damage is not necessary. Post-traumatic dizziness may also occur some time (4-5 days) after a head injury, which may be associated with the formation of a serous labyrinth.
Toxic lesion of the vestibular apparatus is progressive systemic dizziness in combination with impaired coordination of movement associated with the use of aminoglycosides, which can accumulate in the endo- and perilymph.
Meniere’s disease is repeated attacks of intense systemic dizziness, accompanied by noise and ringing in the ears, fluctuating hearing loss and pronounced autonomic disorders. It is based on hydrops – an increase in the volume of endolymph, which causes stretching of the walls of the labyrinth channels. The duration of dizziness attacks is from several minutes to 24 hours, the frequency is from several times a day to 1 time a year. The attack is accompanied by pronounced balance disorders and vegetative disorders, which may persist after the end of the attack for several days. As the disease progresses, hearing decreases (usually unilaterally), but complete hearing loss does not occur.
Temporal lobe epilepsy is repeated unprovoked episodes of systemic dizziness, accompanied by pronounced autonomic disorders (nausea, pain in the epigastric region, bradycardia, hyperhidrosis, a feeling of heat). In addition, visual disorders and other perceptual disorders may also be present in the clinical picture.
The imbalance may be caused by dysfunction of the vestibular analyzer of various genesis. One of the most important distinguishing signs is the deterioration of the patient’s condition with loss of vision control (closed eyes). Other causes of imbalance may be damage to the cerebellum, subcortical nuclei, brain stem, multisensory deficiency, as well as the use of certain medications (phenothiazine derivatives, benzodiazepines). In such cases, dizziness is accompanied by impaired concentration, increased drowsiness (hypersomnia). The severity of these manifestations decreases with a decrease in the dose of the drug.
Pre-fainting states — a feeling of dizziness, ringing in the ears, “darkening in the eyes”, nausea, loss of balance. Psychogenic dizziness is one of the most frequent symptoms of panic attacks and is among the most frequent complaints made by patients suffering from psychogenic disorders (hysteria, hypochondriac syndrome, neurasthenia, depressive states). It is characterized by resistance and pronounced emotional coloring.
To diagnose dizziness, a neurologist must first confirm the fact of vertigo itself, since patients often put a different meaning into the concept of “dizziness” (headache, visual impairment, etc.). To do this, in the process of differential diagnosis between dizziness and complaints of a different nature, one should not suggest this or that term to the patient or offer them a choice. It is much more correct to hear from him a detailed description of the existing complaints and feelings.
Much attention should be paid to the neurological examination of the patient (the state of CN, detection of nystagmus, coordination tests, detection of neurological deficiency). However, even a full-fledged examination does not always allow you to determine the diagnosis, for this, monitoring the patient in dynamics. In such cases, information about previous intoxications, autoimmune and inflammatory diseases may be useful. A patient with vertigo may need a consultation with an otoneurologist, vestibulologist and examination of the cervical spine: radiography, CT, MRI of the spine.
With the help of CT and MRI of the brain, it is necessary to exclude neoplasms, the demyelinating process and other structural changes of an innate and acquired nature. The determination of antibodies to suspected pathogens, as well as a full-fledged study of the cellular composition of blood, can confirm or deny the presence of infectious diseases. In favor of the diagnosis of “Meyer’s disease” indicates an improvement in the perception of low frequencies when recording an audiogram. It should also be remembered about the EEG of the brain, which makes it possible to exclude epileptic and paroxysmal activity in the temporal leads. A study of the vestibular analyzer is also carried out: vestibulometry, stabilography, rotational tests, etc.
The choice of tactics for the treatment of vertigo is based on the cause of the disease and the mechanisms of its development. In any case, therapy should be aimed at ridding the patient of unpleasant sensations and concomitant neurological disorders. Therapy of disorders of cerebral circulation involves blood pressure control, the appointment of antiplatelet agents, nootropics, venotonics, vasodilators and, if necessary, antiepileptic drugs. Treatment of Meniere’s disease involves the appointment of diuretics, limiting the intake of table salt, and in the absence of proper effect and continuing attacks of dizziness, the issue of surgical intervention is decided. In the treatment of vestibular neuritis, the use of antiviral drugs may be required. Since the use of drugs that inhibit the activity of the vestibular analyzer is considered inappropriate in BPPV, the main method of treating benign paroxysmal positional vertigo is the repositioning of irritating vestibular analyzer aggregates according to J.M. Epley.
Vestibulolytics (betahistine) are used as symptomatic treatment of dizziness. The effectiveness of antihistamines (promethazine, meclozin) in the case of a predominant lesion of the vestibular analyzer has been proven. Of great importance in the treatment of non-systemic dizziness is non-drug therapy. With its help, it is possible to restore coordination of movements and improve gait. Therapy of psychogenic vertigo is advisable to be carried out together with a psychotherapist (psychiatrist), since in some cases it may be necessary to prescribe anxiolytics, antidepressants and anticonvulsants.
Prognosis for dizziness
It is known that an attack of dizziness is often accompanied by a feeling of fear, but dizziness, as a condition, is not life-threatening. Therefore, in the case of timely diagnosis of the disease that caused dizziness, as well as its adequate therapy, in most cases the prognosis is favorable.