Causes and pathogenesis of hyperventilation syndrome

Hyperventilation syndrome or prolonged persistent hyperventilation can be caused by numerous reasons. It is advisable to distinguish three classes of such reasons (factors):

1. organic diseases of the nervous system;
2. psychogenic diseases;
3. somatic factors and diseases, endocrine-metabolic disorders, exogenous and endogenous intoxications.

In the vast majority of cases, the main causes that determine the occurrence of hyperventilation syndrome are psychogenic. Therefore, in most publications, the term hyperventilation syndrome implies a psychogenic basis. However, not all researchers agree with this assessment.

Three concepts of the genesis of hyperventilation syndrome can be distinguished:

1. Hyperventilation syndrome is a manifestation of anxiety, fear and hysterical disorders;
2. Hyperventilation syndrome is the result of complex biochemical changes in the system of mineral (mainly calcium and magnesium) homeostasis, caused by changes in the nature of nutrition, etc., which leads to an imbalance in the respiratory enzyme systems, manifested by hyperventilation;
3. Hyperventilation syndrome is the result of a habit of breathing incorrectly, which is associated with many factors, including cultural ones.

Apparently, all three factors participate in the pathogenesis of hyperventilation syndrome. Undoubtedly, the psychogenic factor plays a leading role. This is confirmed by our studies. Thus, examination of patients with hyperventilation syndrome revealed the presence of psychological traumas in the overwhelming majority of them - current and childhood. The peculiarities of childhood psychogenies consisted in the fact that their structure included the respiratory function. This is the observation of asthma attacks in close people, dyspnea, suffocation of drowning patients before our eyes, etc. In addition, in the anamnesis of many patients, sports activities are often singled out, most often swimming, which indicates a certain hyperfunction of the respiratory system in the past. This may have played a certain role in the formation of symptoms.

It has been shown [Moldovanu I. V., 1991] that, in addition to the known physiological changes accompanying hyperventilation (hypocapnia, alkalosis, mineral imbalance, etc.), of great importance is the disruption of the breathing pattern, the main characteristics of which are disruptions in the ratio of the inspiratory and expiratory phases of the respiratory cycle and high instability of respiratory regulation.

The pathogenesis of hyperventilation syndrome from the neurologist's point of view appears to be multidimensional and multilevel. Apparently, psychogenic factors largely disorganize the normal and optimal respiratory pattern for each patient, resulting in increased pulmonary ventilation and stable biochemical shifts. Biochemical disorders, which are the most important factors in the formation of symptoms, further disrupt the cerebro-respiratory pattern, which maintains mental disorders through a feedback mechanism. Thus, a "vicious circle" is formed, where dysfunction of stem mechanisms (increased excitability of the respiratory center and disruption of its adequate sensitivity to gas stimuli) and disruption of suprasegmental integrating mechanisms (responsible for the regulation of respiration, activation-behavioral and vegetative processes) are combined with biochemical disorders as a result of increased ventilation. As we can see, neurogenic mechanisms are most important in the pathogenesis of hyperventilation syndrome. Therefore, it seems to us most appropriate to designate hyperventilation syndrome as neurogenic hyperventilation syndrome, or simply neurogenic hyperventilation.

The diagnosis of neurogenic hyperventilation is based on the following criteria:

1. The presence of complaints about respiratory, vegetative, muscular-tonic, algic disorders, changes in consciousness, mental disorders.
2. Absence of organic disease of the nervous system and somatic disease, including lung disease.
3. Presence of psychogenic history.
4. Positive hyperventilation test: deep and frequent breathing for 3-5 minutes reproduces most of the patient's symptoms.
5. Disappearance of spontaneous or hyperventilation test-induced crisis by inhalation of a gas mixture containing 5% CO2 or by breathing into a cellophane bag. Breathing into a bag promotes accumulation of one's own CO2, which compensates for the lack of CO2 in the alveolar air and improves the patient's condition.
6. The presence of symptoms of increased neuromuscular excitability (tetany): Chvostek symptoms, positive Trousseau-Bonsdorf test, positive EMG test for latent tetany.
7. A decrease in the concentration of CO2 in the alveolar air, a change in pH (shift towards alkalosis) of the blood.

Differential diagnosis of hyperventilation syndrome usually depends on its leading manifestation. In the presence of hyperventilation paroxysms, it is necessary to differentiate it from bronchial and cardiac asthma.

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