Causes and pathogenesis of hyperventilation syndrome

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

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

In the overwhelming majority of cases, the main causes that determine the occurrence of the 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 the 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 a change in the nature of nutrition, etc., which leads to an imbalance of respiratory enzyme systems manifested by hyperventilation;
3. Hyperventilation syndrome is the result of the habit of improperly breathing, which is associated with many factors, including cultural factors.

Apparently, all three factors are involved in the pathogenesis of the hyperventilation syndrome. Undoubtedly, the psychogenic factor plays a leading role in this. This is confirmed by our research. So, examination of patients with hyperventilation syndrome revealed the overwhelming majority of them having psychotraumas - actual and childish. The peculiarities of children's psychogenies consisted in the fact that breathing function was included in their structure. This - the observation of asthma attacks in close people, dyspnea, suffocation of sinking patients, etc. In addition, in the anamnesis, many patients often sing out sports, most often swimming, which indicates a certain hyperfunction in the past of the respiratory system. This may have played a role in symptom formation.

It was shown [Moldovanova IV, 1991] that in addition to the known physiological changes accompanying hyperventilation (hypocapnia, alkalosis, mineral imbalance, etc.), the violation of the pattern, respiration, the main characteristics of which are violations of the ratio of inspiratory and expiratory phases of the respiratory cycle and high instability of respiratory regulation.

The pathogenesis of the hyperventilation syndrome from the position of a neurologist appears multidimensional and multilevel. Apparently, the psychogenic factors largely disorganize the normal and optimal for each patient respiratory pattern, resulting in increased pulmonary ventilation and there are stable biochemical shifts. Biochemical disorders, which are the most important factors of symptom formation, further violate the cerebral-respiratory pattern, which supports mental disorders by the feedback mechanism. Thus, a "vicious circle" is formed where the dysfunction of the stem mechanisms (increased respiratory center excitability and the violation of its adequate sensitivity to gas stimuli) and the violation of the supra-segmental integrating mechanisms (respiratory regulation, activation-behavioral and vegetative processes) are combined with biochemical disorders as a result increased ventilation. As we see, neurogenic mechanisms are most important in the pathogenesis of the hyperventilation syndrome. Therefore, it seems to us the most adequate to designate the hyperventilation syndrome as a syndrome of neurogenic hyperventilation, or simply neurogenic hyperventilation.

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

1. The presence of complaints on the respiratory, vegetative, muscular-tonic, algic disorders, altered consciousness, mental disorders.
2. Absence of organic disease of the nervous system and somatic disease, including lung disease.
3. Presence of a psychogenic anamnesis.
4. Positive hyperventilation test: deep and frequent breathing reproduces most of the patient's symptoms within 3-5 minutes.
5. Disappearance of a spontaneous or hyperventilation-induced crisis with inhalation of a mixture of gases containing 5% CO2, or when breathing into a cellophane bag. Breathing in the bag contributes to the accumulation of its 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): symptoms of the Khvostek, a positive Trusso-Bonsdorff test, a positive EMG test for latent tetany.
7. Reducing the concentration of CO2 in the alveolar air, changing the pH (shift towards alkalosis) of the blood.

Differential diagnosis in hyperventilation syndrome, as a rule, depends on its leading manifestation. In the presence of hyperventilation paroxysms, it becomes necessary to differentiate it from bronchial and cardiac asthma.

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