Syncope

SYNCOPE, fainting, syncope, is a state, for the most part, of a brief, complete loss of consciousness accompanied by a drop in heart activity and weakened breathing movements. Syncope usually occurs suddenly, but sometimes it follows a state of dizziness, i.e., a temporary general weakening of strength with a general disturbance of well-being; this is accompanied by a feeling of emptiness in the head and dizziness, flickering and dimming of the eyes, ringing in the ears, a pause in the heart, a state of anguish, nausea, and sometimes vomiting. The duration of syncope is mostly about 1–5 minutes, but sometimes it drags on for 10–15–30 minutes and even for several hours, during which it may pass into death without a clearing of consciousness.- Symptoms of syncope: unconscious state, complete immobility, deathly pallor, cold sweat; pulse is small, sometimes barely palpable; breathing is superficial, sometimes barely noticeable; pupils are constricted; cooling of the extremities, skin sensitivity is weakened. Upon waking, the patient cannot account for what happened to him, starting from the moment preceding the syncope. After syncope, the patient feels a fairly long-lasting general weakness. Pathogenesis. Syncope apparently occurs due to a suddenly occurring anemia of the brain, and may also be of the spinal cord, in which the function of the psychic sphere of the brain ceases and the function of the motor and vegetative centers, including the centers of circulation and breathing, sharply decreases; consequently, the weakening of heart activity and the act of breathing represent secondary phenomena. The primary phenomenon in most cases of syncope is a strong decrease in the tone of the vasomotor centers, which leads to paralysis of the vascular musculature, a drop in blood pressure, and an accumulation of a larger amount of blood in the peripheral part of the circulatory system, mainly in the vascular sphere innervated by the splanchnic nerves. As a result, the blood supply to organs, measured by the amount of blood flowing to them in a unit of time, sharply falls, which leads to a decrease in their functions; in this process, as the most sensitive to all disturbances of blood supply, the central nervous system reacts first, and in particular the psychic sphere. The paralysis of the vasomotor center, which lies at the basis of syncope, is caused, for the most part, by reflex-psychic influences, for example, strong mental experiences, most often—fear. In other cases, a sharp change in body position, in particular the transition from a horizontal to a vertical position, and strong overexertion cause acute paralysis of the vasomotor centers. These influences have an effect primarily under conditions that lower the stability of the vegetative centers in general and the vasomotor centers in particular. There are people with a congenital lability of the tone of the vasomotor centers; a predisposition to syncope is young age, women are more prone to syncope than men. All pathological states accompanied by a decrease in arterial pressure, in general, also predispose to syncope. Among the conditions favoring syncope, one should especially note all anemic states, the state of hunger, all exhausting diseases (frequent syncope during the recovery period from prolonged infectious diseases), etc. Another mechanism of the pathogenesis of syncope, or, more precisely, of that disturbance of blood supply to the brain centers which leads to syncope, should be accepted for those syncope which are observed in heart diseases. It is necessary, however, to emphasize that the widespread notion that syncope is a manifestation of heart weakness is absolutely incorrect. If we observe syncope as a manifestation of a decline in the activity of the cardiovascular system, then the cause of syncope is primarily a decline in vasomotor tone. There is, however, a definite group of heart diseases, relatively rare, where syncope belongs to the characteristic manifestations of the disease. These are the disturbances of the heart rhythm which cause a longer or shorter absence of heart contractions, more precisely of the ventricles; first of all, this is atrioventricular dissociation, i.e., heart block, and bradycardia of another origin, for example, sinus bradycardia, of vagal origin, when the pulse frequency falls below 40–30 beats per minute. Syncope is observed significantly less often as a result of long compensatory pauses after extrasystoles, especially in elderly people with arteriosclerosis of the cerebral vessels, where the blood supply to the brain is already difficult. Syncope is observed even less often as a result of several extrasystoles (groups of extrasystoles) following one another quickly or of transient ventricular fibrillation. Among local disturbances of blood supply to the higher nervous centers, as a cause of syncope, some authors recognize the spasm of the small arteries of the brain. For example, this is how the pathogenesis of syncope during strong mental agitation is represented. Undoubtedly, as already mentioned, sclerosis of the cerebral arteries must be considered as a factor favoring syncope, since it leads to a less uniform flow of blood in the capillaries of the brain. Finally, the cause of anemia of the higher nervous centers can be strong blood loss; syncope during external and internal severe hemorrhages is a common phenomenon. Differential diagnosis. Shock is a state having many common features with the state of dizziness passing into syncope, representing a deep fall of the general vital tone, including the tone of the heart and vessels, due to the damage of the higher vegetative centers, which is caused by strong irritations from the periphery (traumatic shock), or biochemical changes in the blood under the influence of intoxication (toxic shock).- Lethargic sleep, in external signs, has great similarity with syncope, since it is accompanied by complete motor paralysis with an extreme weakening of heart and breathing activity, to the extent that the patient gives the impression of being dead. The difference is that in this case sensitivity and consciousness may be preserved, although the patient does not react to external irritation. Syncope (see) differs from collapse only quantitatively. In collapse we are dealing with a more severe state, i.e., with a more acute and widespread inhibition of all vital functions of the organism. Correspondingly, the basis of collapse usually lies in more severe pathological states. In comatose states, in contrast to syncope, we are dealing not with the result of a disturbance of blood supply to the nervous centers, but with their poisoning. Correspondingly, the clinical picture of coma (see) differs from syncope and collapse. Therapeutic measures in syncope. The first thing to do for a fainting person is to free him from any constriction by clothing: unbutton the collar, buttons, and ties on the clothes. Then actions vary depending on the basic cause of the syncope. If it occurred due to psychic trauma, they try to bring the fainting person to consciousness. For this, they call him loudly by name; they spray his face with cold water; they hold pungent-smelling substances, such as ammonia, to his nose; they rub the extremities with something hard (a brush), they pat the soft parts with the palm; they place a hot compress or a hot water bottle on the head. If the patient does not come to, they lay him without a pillow or even raise the foot of the bed so that the head is lower; they warm the extremities with hot water bottles; they perform artificial respiration, they inject excitatory agents, such as caffeine, camphor, and adrenaline, under the skin. If syncope is due to a disturbance of heart activity, then appropriate therapy is applied—see Heart block. If, on the other hand, the cause of syncope is general acute anemia, they perform a subcutaneous injection of a physiological solution, blood transfusion, bandage the extremities, etc. (see Hemorrhage).