Diagnosis of Meniere's disease

Physical examination for suspected Meniere's disease is performed depending on the associated pathology.

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Indications for consultation with other specialists

Given the complexity of differential diagnosis of this disease, it is necessary to conduct a comprehensive general clinical examination with the participation of a therapist, neurologist, ophthalmologist (with examination of the fundus and retinal vessels), endocrinologist, and, if indicated, a consultation with a traumatologist.

Laboratory research

It is necessary to conduct tests for glucose tolerance and thyroid function, as well as general clinical and biochemical blood tests using generally accepted methods.

Instrumental diagnostics of Meniere's disease

Since the changes in Meniere's disease are localized in the inner ear, the most important thing in diagnosing this disease is to evaluate the condition of the organ of hearing and balance. Otoscopy reveals unchanged eardrums. An otolaryngologist can conduct a primary examination of the hearing function. A tuning fork study determines the lateralization of sounds in the Weber test. When the hearing function changes, lateralization is determined already at the early stages by the type of sensorineural changes (towards the better hearing ear). The Rinne and Federici tests also reveal changes typical of sensorineural hearing loss - both tests are positive on the side of both the better and worse hearing ear,

Next, tonal threshold audiometry is performed to study the auditory function. At the initial stage, a typical audiometric picture is revealed, usually of an ascending or horizontal type with the greatest damage in the low-frequency region and the presence of a bone-air interval of 5-15 dB at frequencies of 125-1000 Hz. Hearing loss does not exceed stage I. Subsequently, a progressive increase in tonal hearing thresholds is observed according to the sensory type, up to stage IV in stage III of the disease. Hearing examination methods also include the use of suprathreshold audiometry, with all patients, as a rule, exhibiting a positive phenomenon of accelerated loudness increase.

To assess the state of the balance system, vestibulometric tests are carried out, such as cupulometry with threshold and suprathreshold stimuli, bithermal calorization, posturography, indirect selective otolithometry. The study of the vestibular analyzer during an attack is limited to recording spontaneous nystagmus as the most stable and objective sign of an attack of dizziness. In this case, the nystagmus is horizontal-rotatory and sharply expressed (III or II degree). In the irritation stage, the fast component of nystagmus is directed to the painful side, and in the interictal period - to the healthy side (a symptom of suppression or shutdown of the function). In the pointing test, the side of the slow component is also missed.

The study of the vestibular apparatus in the interictal period may yield completely normal data, but in a certain number of cases, decreased sensory sensitivity of the affected ear is detected (increased thresholds for rotation and calorization). As a rule, vestibular hyporeflexia on the affected side is detected in patients in the interictal period. With suprathreshold stimulation, vegetative reactions may increase. Very often, asymmetry is observed in the caloric reaction, namely, decreased reflex excitability of the affected ear in relation to the nystagmus reaction. Vestibular asymmetry increases with the development of the disease (from 30% and more). For the final stage of the disease, balance disorder is more characteristic than attacks of dizziness.

To verify the diagnosis of Meniere's disease, it is necessary to establish the presence of endolymphatic hydrops. Currently, two instrumental methods for diagnosing hydrops of the inner ear are most widely used in the clinic - dehydration tests and electrocochleography.

When performing dehydration, glycerol is used in a dose of 1.5-2.0 g/kg of the patient's weight with an equal volume of lemon juice to potentiate the effect. Hearing testing is performed immediately before taking the drug and then after 1, 2, 3, 24 and 48 hours. The need for testing after 48 hours is determined for each patient individually, depending on the rate of rehydration.

The results of dehydration are assessed according to several criteria. The test is considered "positive" if 2-3 hours after taking the drug, the thresholds of tonal hearing decrease by at least 5 dB in the entire range of frequencies studied or by 10 dB at three frequencies and speech intelligibility improves by at least 12%. The test is considered "negative" if the thresholds of tonal hearing increase after 2-3 hours and speech intelligibility worsens relative to the initial level. Intermediate options are considered "questionable".

The use of OAE as an objective non-invasive method for assessing the state of the sensory structures of the inner ear during dehydration is considered to be quite informative, which increases the sensitivity of the technique to 74%. With a positive dehydration test, the amplitude of the otoacoustic response increases by at least 3 dB. The use of OAE at the frequency of the distortion product is most informative. In addition, for monitoring the state of the balance function, it is advisable to use dynamic posturography when conducting dehydration tests to detect hydrops of the vestibular part of the inner ear.

The electrocochleography technique, also used to detect hydrops of the labyrinthine, allows recording the electrical activity of the cochlea and auditory nerve that occurs in the interval of 1-10 ms after the stimulus is presented. This activity consists of presynaptic activity, represented by the microphonic and summation potentials generated at the level of the inner ear, as well as postsynaptic activity, which includes the action potential of the auditory nerve generated by the peripheral part of this nerve. In the presence of hydrops in the inner ear, the following signs are detected:

• negative wave of the summation potential preceding the action potential. An increase in the amplitude of the summation potential is observed as the intensity increases, with a corresponding increase in the ratio of the amplitudes of the summation potential and the action potential to more than 0.4.
• shift in the latent period of the action potential during stimulation with clicks of alternating polarity by more than 0.2 ms.
• change in the amplitude of the summation potential during the study with tonal impulses.

In addition, a number of researchers confirm the effectiveness of using the low-frequency masking method in detecting hydrops of the inner ear. Normally, when a low-frequency tone is presented, the basal membrane of the inner ear moves synchronously along its entire length. In this case, the sensitivity of the organ of Corti for tones changes with a certain periodicity.

The perception of tone bursts of different frequencies, presented against the background of a low-frequency masker, by a person with normal hearing changes significantly depending on the phase of the signal. At the end of the 20th century, studies were conducted with the modeling of experimental hydrops of the inner ear, which allowed us to assume that masking of tone bursts by presentation of a low-frequency tone does not depend on the phase of tone presentation in endolymphatic hydrops of the inner ear, unlike the norm. In clinical practice, a masking tone and a short tone burst are fed into the auditory canal of the subject using a tightly fixed earmold. A tone with a frequency of 30 Hz and an intensity of up to 115 dB can be used as a masking tone. A frequency of 2 kHz is used as a tone burst. The test signal is presented in phase from 0 to 360 degrees relative to the masker, in a step of 30 degrees. In the presence of hydrops, there are practically no fluctuations in the perception of the test signal with a frequency of 2 kHz against the background of the masker, depending on the presentation phase. The method has a number of limitations in application.

During a comprehensive examination, an X-ray examination of the chest organs, temporal bones in the Stenvers, Schuller and Mayer projections is performed; CT and MRI of the head are the most informative. To study cerebral hemodynamics, extracranial and transcranial ultrasound Dopplerography of the main vessels of the head or duplex scanning of the vessels of the brain are performed. All patients need an audiological, vestibulometric and comprehensive stabilometric study to assess the condition of the organ of hearing and balance.

Differential diagnosis of Meniere's disease

Meniere's disease is characterized by a well-known triad of symptoms caused by the formation of hydrops in the inner ear. If hydrops is not detected during specific tests, a comprehensive examination is necessary to determine other causes that can cause attacks of systemic dizziness and hearing changes.

Differential diagnostics are carried out with pathological conditions that also cause systemic dizziness. Among them:

• acute cerebrovascular accident in vertebrobasilar insufficiency;
• benign paroxysmal positional vertigo;
• tumors in the cerebellopontine angle region;
• dizziness due to head injury;
• labyrinthine fistula;
• vestibular neuronitis;
• multiple sclerosis.

In addition, it is necessary to remember that dizziness can also be observed when taking certain groups of medications; with damage to the central nervous system; as a complication of acute middle or chronic otitis media; with otosclerosis; as a consequence of hyperventilation, as well as with psychogenic disorders.

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