Peripheral vascular destructive labyrinthine syndrome

Peripheral vascular destructive labyrinthine syndrome (PVDS). This form of ear labyrinth disease was first described by P. Meniere in 1848 in a young woman who, while traveling in a stagecoach in winter, suddenly became deaf in both ears, and also developed dizziness and vomiting. These symptoms persisted for 4 days, and she died on the 5th day. At autopsy, hemorrhagic exudate was found in the ear labyrinth. This clinical case remains mysterious to this day; one can only assume that the deceased suffered from a severe form of bilateral influenza labyrinthitis.

Much time has passed since then, and in clinical practice there are many cases of so-called acute labyrinthine pathology, during which sudden hearing loss or deafness in one ear occurs, noise in it and pronounced signs of vestibular dysfunction (dizziness, spontaneous nystagmus, nausea, vomiting, etc.), indicating hypofunction or shutdown of the vestibular apparatus on the side of the affected ear.

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Causes of peripheral vascular destructive labyrinthine syndrome

The causes of peripheral vascular destructive labyrinthine syndrome are varied; its causes may be diabetes, blood diseases, vertebrobasilar vascular insufficiency, atherosclerosis, hypertensive or hypotensive arterial syndrome, and viral lesions of the ear labyrinth. In some cases, AUL occurs due to severe baroacoustic trauma or gas embolism of the branches of the labyrinthine artery in decompression sickness.

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Pathogenesis

The pathogenesis is determined by two possible immediate causes of peripheral vascular destructive labyrinthine syndrome - its ischemic or hemorrhagic forms.

Ischemic form. Of the three mechanisms of ischemia (angiospastic, obstructive, compression), the first two are characteristic of peripheral vascular destructive labyrinthine syndrome.

Angiospastic ischemia occurs as a result of irritation of the vasomotor centers, and the irritants causing angiospasm may be factors such as catecholamines (mental stress), chemicals (adrenaline, vasopressin, opium, ergotine), trauma (pain shock), microbial toxins, general and cerebral hypertension, etc. The listed factors can cause angiospasm of the labyrinthine arteries to varying degrees, but the leading risk factors in terms of pathogenetic significance for the development of the angiospastic form of peripheral vascular destructive labyrinthine syndrome are vertebrobasilar vascular insufficiency, hypertensive crises, and psychoemotional stress.

Obstructive ischemia occurs when the lumen of an artery is blocked by a thrombus or embolus, or may develop as a result of thickening of the arterial wall with narrowing of its lumen as a result of some pathological process (atherosclerosis, periarteritis nodosa, inflammatory process). For peripheral vascular destructive labyrinthine syndrome, the atherosclerotic process is most characteristic, and the most typical combination of pathogenetic factors is its combination with angiospasm developing in the labyrinthine arteries.

The pathogenesis of ischemia, so characteristic of many diseases of the ENT organs, is as follows: oxygen starvation of tissue, accompanied by a characteristic metabolic disorder; toxic under-oxidized metabolic products (catabolites) accumulate in tissues; the acid-base balance shifts towards acidosis; the phenomena of anaerobic tissue decay increase; the accumulation of acidic metabolic products leads to tissue swelling, secondary compression ischemia and increased permeability of vascular and cellular membranes (secondary hydrops of the labyrinth), irritation of receptor formations. The resulting metabolic disorders lead first to a dysfunction of the organ, tissue (reversible stage), and then to structural changes in the form of dystrophic, atrophic, necrobiotic processes, up to complete necrosis (irreversible stage).

The consequences of ischemia depend on both the degree of blood flow disturbance and the sensitivity of tissues to oxygen starvation. In the ear labyrinth, the most sensitive to hypoxia are the hair cells of the SpO, as they are phylogenetically younger than the vestibular receptors, so they die earlier in case of inner ear ischemia. With short-term ischemia and appropriate treatment, not only vestibular but also auditory function can be restored.

The hemorrhagic form of peripheral vascular destructive labyrinthine syndrome is characterized by hemorrhages in the cavity of the inner ear, which can be either limited (for example, only in the cochlea or in any semicircular canal) or generalized, affecting most of the ear labyrinth. One of the main causes of this form of peripheral vascular destructive labyrinthine syndrome is a hypertensive crisis that occurs against the background of increased permeability of the vascular wall. Various hemorrhagic diathesis (hemophilia, thrombocytopenia and thrombocytopathy, thrombohemorrhagic syndrome, hemorrhagic vasculitis, etc.), diabetes, hemorrhagic fevers in some acute infectious diseases (flu, shingles of the inner ear and other viral diseases) can act as the primary cause of peripheral vascular destructive labyrinthine syndrome.

The hemorrhagic form of peripheral vascular destructive labyrinthine syndrome is characterized by a sudden increase in intralabyrinthine pressure and the occurrence of hypoxia followed by complete degeneration of the inner ear receptors.

Bilateral AUL is extremely rare and usually results in complete deafness and persistent dysfunction of the vestibular apparatus.

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Symptoms of peripheral vascular destructive labyrinthine syndrome

Symptoms of peripheral vascular destructive labyrinthine syndrome are manifested by a sudden severe cochleovestibular crisis without any precursors, and the hemorrhagic form manifests itself most often during physical exertion, sharp emotional stress, and the ischemic form - during sleep in the early morning hours. Symptoms of the crisis are typical for an attack of Meniere's disease, and they often develop against the background of chronic hypertensive encephalopathy or are accompanied by signs of acute hypertensive encephalopathy. A distinctive feature of Meniere's disease in AUL is persistent hearing loss that never returns to the original level, as well as a sharp deterioration in sound perception both in air and bone conduction with breaks in the curves of the tonal threshold audiogram at high frequencies. The arising spontaneous nystagmus can be directed towards the affected ear only for a short time (minutes, hours), and only with a slow increase in ischemia. In all other cases, it immediately acquires the features of labyrinth shutdown and is directed towards the unaffected ear.

AUL, along with cochlear and vestibular syndromes (loud noise in the ear, rapidly increasing hearing loss, up to complete deafness, sudden systemic dizziness, spontaneous nystagmus, falling towards the affected ear, nausea and vomiting), is usually accompanied by headache and a number of vegetative symptoms related to the cardiovascular, respiratory and vegetative systems. In some cases, the patient experiences a collapse state and loss of consciousness. These are the symptoms that are most characteristic of apoplexy of the vestibular part of the ear labyrinth, but if hemodynamic and hemorrhagic disorders occur only in the cochlea, then vestibular symptoms may be weakly expressed or even not noticed during sleep, and the patient, waking up, suddenly notices severe hearing loss or even deafness in one ear.

Having arisen suddenly, cochleovestibular crisis lasts for several days, and then gradually its severity decreases, and the auditory function either remains at a low level, or is switched off, or is somewhat restored (after a short-term ischemic crisis), and the symptoms of vestibular crisis pass, but chronic vestibular insufficiency persists, lasting many months. Patients who have suffered from AUL remain incapacitated for a month or more and need a long rehabilitation period. They are contraindicated to work at height, professional driving of vehicles, service in the Armed Forces as conscripts.

Forms

Peripheral tympanogenic labyrinthine syndrome. This syndrome can sometimes be observed in chronic or acute purulent diseases of the middle ear (induced labyrinthine disease). It occurs due to irritation of the tympanic plexus, penetration of toxins through the labyrinth windows in the inner ear or through the microcirculatory blood and lymphatic pathways. Peripheral tympanogenic labyrinthine syndrome manifests itself in attacks of mild dizziness, noise in the ear, which quickly pass with effective treatment of the inflammatory process in the middle ear. This syndrome should be differentiated from the initial stage of serous labyrinthitis, which arose as a complication of acute or exacerbation of chronic purulent otitis media.

Another form of peripheral tympanogenic labyrinthine syndrome is a process interpreted as cicatricial labyrinthosis, which occurs as a consequence of limited labyrinthitis in the area of the labyrinth windows and the penetration of scar tissue into the peri- and endolymphatic space. This form of peripheral tympanogenic labyrinthine syndrome is characterized by progressive hearing loss, tinnitus, latent vestibular dysfunction, revealed only by a bithermal caloric test in the form of mixed interlabyrinthine asymmetry (by side and direction).

Acute catarrhal tubootitis can also provoke mild labyrinthine dysfunctions caused by retraction of the eardrum and corresponding depression of the base of the stapes into the vestibule of the labyrinth. Signs of peripheral tympanogenic labyrinthine syndrome (noise in the ear, mild dizziness, slight increase in vestibular excitability on the side of the diseased ear) disappear when the patency of the auditory tube is restored and catarrhal inflammation in it and in the middle ear is eliminated.

Chronic catarrhal tubootitis, obliteration of the auditory tube rarely manifest vestibular symptoms; these diseases are characterized by progressive hearing loss, starting with conductive, continuing mixed and ending with preceptive without much hope for successful non-surgical treatment.

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Diagnostics of peripheral vascular destructive labyrinthine syndrome

The diagnosis is based on a characteristic clinical picture - the sudden appearance of a "destructive" labyrinthine syndrome: dizziness and spontaneous nystagmus towards the healthy ear, noise and sudden hearing loss (deafness) in the affected ear, equal hearing loss in both air and bone conduction, no history of similar attacks.

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Differential diagnosis

Differential diagnostics are carried out with Meniere's disease, brainstem and supratectorial apoplectic syndromes. Differential diagnostics with acoustic-vestibular neuritis is more difficult, especially with syphilitic meningoneuritis of the vestibulocochlear nerve and meninges of the MMU.

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Treatment of peripheral vascular destructive labyrinthine syndrome

Treatment depends on the form of peripheral vascular destructive labyrinthine syndrome.

In the vasospastic form, vasodilators (xanthinol nicotinate, nicotinoyl-GABA, cinnarizine), alpha-adrenergic blockers (dihydroergotoxin), angioprotectors and microcirculation correctors (betahistine) are prescribed. At the same time, cerebral circulation correctors (vinpocetine, nicotinic acid, pentoxifylline) are indicated. The drugs of choice are vasodilators such as bendazole, hydralazine, minoxidil, sodium nitroprusside.

In the case of the obstructive form of peripheral vascular destructive labyrinthine syndrome, the above-mentioned agents are individually selected in combination with hypolipidemic and antisclerotic drugs, as well as with antiplatelet agents (acetylsalicylic acid, dipyridamole, indobufen, clopidogrel).

In the hemorrhagic form of peripheral vascular destructive labyrinthine syndrome, angioprotectors and microcirculation correctors, antihypoxants and antioxidants (dimephosphone, vinpocetine) are used. However, the use of these agents is aimed not so much at restoring the function of the ear labyrinth, which is irreversibly lost in hemorrhagic apoplexy, as at preventing more severe vascular disorders of the brain, and in particular in the vertebrobasilar basin. Patients with suspected AUL must be examined by a neurologist to exclude acute vascular insufficiency of the brain.

Forecast

The prognosis for auditory function is unfavorable, for vestibular function it is cautious, and otherwise it is determined by the disease that caused the development of peripheral vascular destructive labyrinthine syndrome.

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