Benign paroxysmal vertigo: diagnosis

In benign paroxysmal positional dizziness, anamnesis does not provide exhaustive information for establishing a diagnosis. It is more important to conduct a survey of a patient with a neurologist or an otoneurologist using a standard protocol. Specific tests for establishing benign paroxysmal positional dizziness are positional tests of Dix-Hallpike, Brandt-Daroff, and others.

The Dix-Holggike positional test is performed as follows: the patient sits on the couch and turns his head to 45 degrees. Right or left. Then the doctor, fixing the patient's head with his hands, quickly moves it to the position lying on the back, while the patient's head hangs over the edge of the couch and is in a relaxed state, held by the doctor's hands. The doctor observes the movements of the patient's eyes and asks about the occurrence of dizziness. It is necessary to warn the patient in advance about the possibility of appearance of a typical dizziness and convince in reversibility and safety of this condition. The nystagmus typical for benign paroxysmal positional vertigo is necessarily latent, which is associated with some delay in the movement of the clot in the plane of the canal or deviation of the cupula when the head is tilted. Since the particles have a certain mass and move under the action of gravity in a fluid with a certain viscosity, there is a short period of set the settling rate.

A typical positional nystagmus for benign paroxysmal positional vertigo is rotational and directed toward the ground (geotropic). This is typical only for the pathology of the posterior semicircular canal. The rotational direction of the nystagmus is due to the organization of the weight of the tibulo-ocular reflex from the posterior semicircular canal, in which the end link is the ocular muscles, including the oblique muscles, with the contraction of which the rotational movement of the eyes arises. When you take your eyes in the opposite direction from the ground, you can observe vertical movements. Nystagmus, characteristic of the pathology of the horizontal canal, has a horizontal direction, for the anterior one it is torsion, but directed from the ground (aeotropically).

The latent period (the time from the nucleon to the appearance of the nystagmus) for the pathology of the posterior and anterior semicircular canals does not exceed 3-4 seconds, for the horizontal one, 1-2 seconds. The duration of the positional nystagmus for canalolithiasis of the posterior and anterior channels does not exceed 30-40 seconds, horizontal 1-2 min. Kupulolithiasis is characterized by a longer positional nystagmus. Always the typical positional nystagmus of benign paroxysmal positional vertigo is accompanied by a dizziness that occurs along with the nystagmus, decreases and disappears also harmoniously. When returning a patient with benign paroxysmal positional dizziness to the initial sitting position, one can often observe reverse nystagmus and dizziness directed to the opposite side and, as a rule, less bright than when tilted. When the test is repeated, nystagmus and dizziness are repeated with harmoniously reduced characteristics.

When examining a horizontal semicircular canal to determine benign paroxysmal positional vertigo, the head and body of the patient lying on the back should be rotated, respectively, to the right and left, with the head fixed in certain positions. For benign paroxysmal positional dizziness of the horizontal canal, positional nystagmus is also specific and is accompanied by positional vertigo.

The greatest disequilibrium in patients with benign paroxysmal positional vertigo is experienced in a standing position with a head thrown back or turned in the plane of the affected canal, which was shown in studies using statokinetic samples and objective electronic systems for recording the deviation of the center of gravity.

Laboratory research

Laboratory studies have no specific manifestations in benign paroxysmal positional vertigo, but in a small group of patients with macroglobulinemia may contribute to identifying the etiology of the disease.

Instrumental research

It should be borne in mind that benign paroxysmal positional vertigo is accompanied by peripheral vestibular nystagmus, which is suppressed by fixation of the eye, therefore, when visual examination of the patient is not always possible to register it. It is recommended to use devices that enhance visual observation of the nystagmus and eliminate fixation of the gaze. The simplest devices are the Blessing or Frenzel glasses with astigmatic or dioptric (+20) lenses. Electrooculography in its traditional design does not allow recording torsion (rotational) movements of the eyes, but it gives an opportunity to obtain information about the horizontal and vertical components of the nystagmine cycle. Modern diagnostic systems of video oculography, consisting of opaque glasses with built-in infrared tracking cameras and mathematical processing of eye movements, allow objectively and with great accuracy to register nystagmus. As a rule, in such diagnostic systems, not only nystagmus is registered, but also the position of the patient at the time of the study and comments on his feelings.

Differential diagnosis of benign paroxysmal dizziness

Benign paroxysmal positional vertigo is accompanied by positional vertigo caused by the pathology of the inner ear. However, positional vertigo may also have central causes. First of all, these are diseases of the posterior cranial fossa, including tumors, which are characterized by the presence of neurologic symptoms, marked balance disorder and central positional nystagmus.

The central positional nystagmus is characterized, first of all, by a special direction (vertical or diagonal); fixation of the eye does not affect him or even strengthens him, he is not always accompanied by dizziness and is not depleted (lasts for as long as the patient is in the position at which he appeared).

Positional nystagmus and dizziness may accompany the development of multiple sclerosis and vertebral-basilar insufficiency, but neurological symptoms characteristic for both diseases will be recorded.

Indications for consultation of other specialists

The most important specialists for the diagnosis of benign paroxysmal positional vertigo are the neurologist and otorhinolaryngologist (otoneurologist or surdologist). Since this disease has specific manifestations (positional nystagmus and positional vertigo), consultations of other specialists and additional research methods, except for vestibulometric ones, will not be necessary to establish a diagnosis.

[1], [2], [3], [4], [5]