The main causes of a sudden fall (with and without loss of consciousness):
- Astatic epileptic seizure.
- Vasovagal syncope.
- Fainting when coughing, when swallowing, nocturic syncope at night.
- Carotid sinus hypersensitivity syndrome.
- Adams-Stokes syndrome (atrioventricular block).
- Drop attack.
- Cataplectic attack.
- Psychogenic seizure (pseudosyncope).
- Basilar migraine.
- Parkinsonism.
- Progressive supranuclear palsy.
- Shy-Drager syndrome.
- Normotensive hydrocephalus.
- Idiopathic senile dysbasia.
Falls are also promoted (risk factors): paresis (myopathy, polyneuropathy, some neuropathies, myelopathy), vestibular disorders, ataxia, dementia, depression, visual impairment, orthopedic diseases, severe somatic diseases, old age.
Astatic epileptic seizure
The age of debut of astatic epileptic seizures is early childhood (from 2 to 4 years). An individual attack lasts only a few seconds. The child falls vertically, does not lose consciousness and is able to immediately rise to his feet. The attacks are grouped in series, separated by light intervals lasting about an hour. Due to the large number of attacks, the child receives many bruises; some protect the head by wrapping it in a thick layer of cloth. There is mental retardation and various behavioral deviations are possible.
Diagnosis: pathological changes are always detected on the EEG in the form of irregular high-amplitude slow-wave activity with the presence of sharp waves.
Vasovagal syncope
Fainting usually first occurs during adolescence or young adulthood, but the condition can persist for many years after this age period. At the initial stage, situations that provoke fainting and are the cause of orthostatic hypotension with insufficiency of the sympathetic and predominant parasympathetic innervation of the cardiovascular system are identified quite easily. Fainting occurs, for example, after a jump with a hard landing on the heels or when forced to stand motionless in one place for a long time. Emotional stress predisposes to the development of fainting. Over time, even minimal stress becomes sufficient to provoke fainting, and psychological factors already come to the fore in provoking attacks.
Individual attacks gradually lose their characteristic features (darkening or haze before the eyes, dizziness, cold sweat, slow sliding to the ground). In case of severe fainting, the patient may fall suddenly, and at this moment there may be involuntary urination, bruises, tongue biting and loss of consciousness for quite a long time – up to one hour. In such situations, it can be difficult to clinically differentiate simple fainting and an epileptic seizure if the doctor did not have the opportunity to personally observe the attack and see pale rather than hyperemia of the face, closed rather than open eyes, narrow rather than wide pupils that do not respond to light. When fainting, short-term tonic stretching of the limbs is possible, even short-term clonic twitching of the limbs is possible, which is explained by the rapidly occurring transient hypoxia of the brain, leading to simultaneous discharges of large populations of neurons.
If it is possible to conduct an EEG study, then normal results can be seen. The EEG also remains normal after sleep deprivation and during long-term monitoring.
Cough syncope, syncope when swallowing, nocturic syncope
There are several specific situations that provoke fainting. These are coughing, swallowing and night urination; each of these actions predisposes to a rapid transition to a state in which the tone of the parasympathetic autonomic nervous system predominates. It is noteworthy that in a particular patient, fainting never occurs under circumstances other than the characteristic provoking situations for that particular patient. Psychogenic factors are almost never identified.
Carotid sinus hypersensitivity syndrome
In carotid sinus hypersensitivity syndrome, there is also a relative lack of sympathetic influences on the heart and blood vessels. The general implementing mechanism is the same as for fainting, namely hypoxia of the cortex and brain stem, leading to a drop in muscle tone, sometimes to fainting, and, rarely, to several short convulsive twitches. Attacks are provoked by turning the head to the side or throwing the head back (especially when wearing a collar that is too tight), or by applying pressure to the sinus area. Under these conditions, external mechanical pressure is exerted on the carotid sinus, which, with altered receptor sensitivity, provokes a drop in blood pressure and fainting. Attacks occur mainly in elderly people who show signs of atherosclerosis.
The diagnosis is confirmed by pressing on the carotid sinus while recording an electrocardiogram and electroecephalogram. The test should be carried out with extreme caution due to the risk of developing prolonged asystole. Moreover, using Doppler ultrasound, it is necessary to verify the patency of the carotid artery at the site of compression, otherwise there is a risk of embolus detachment from a local plaque or the risk of provoking acute occlusion of the carotid artery with its subtotal stenosis, which in 50% of cases is accompanied by thromboembolism of the middle cerebral artery.
Adams-Stokes syndrome
With Adams-Stokes syndrome, syncope develops as a result of paroxysmal asystole lasting more than 10 seconds or, in very rare cases, with paroxysmal tachycardia with a heart rate of more than 180-200 beats per minute. With extreme severity of tachycardia, cardiac output decreases so much that cerebral hypoxia develops. The diagnosis is made by a cardiologist. A general practitioner or neurologist should suspect the cardiac nature of syncope in the absence of abnormalities on the EEG. It is important to study the pulse during an attack, which often determines the diagnosis.
Drop attack
Some authors describe a drop attack as one of the symptoms of vertebrobasilar insufficiency. Others believe that there is still no satisfactory understanding of the pathophysiological mechanisms of the drop attack, and they are probably right. Drop attacks are observed mainly in middle-aged women and reflect an acute lack of postural regulation at the level of the brain stem.
A patient who generally considers himself healthy suddenly falls to the floor, landing on his knees. There is no situational conditioning (for example, the presentation of an unusually high load on the cardiovascular system). Patients, as a rule, do not lose consciousness and are able to get up immediately. They do not experience lightheadedness (lightheadedness) or changes in heart rate. Patients describe the attack as follows: “…as if my legs suddenly gave way.” Injuries to the knees and sometimes to the face are common.
Doppler ultrasound of the vertebral arteries rarely reveals significant abnormalities such as subclavian steal syndrome or stenosis of both vertebral arteries. All other additional studies do not reveal any pathology. Drop attacks should be considered as a variant of transient ischemic attacks in the vertebrobasilar vascular system.
The differential diagnosis of drop attacks is carried out primarily with an epileptic seizure and cardiogenic syncope.
Ischemia in the region of the anterior cerebral artery can also lead to a similar syndrome with the patient falling. Drop attacks have also been described in tumors of the third ventricle and posterior cranial fossa (and other space-occupying processes) and Arnold-Chiari malformation.
Cataplectic attack
Cataplectic seizures are one of the rarest causes of sudden falls. They are characteristic of narcolepsy and, therefore, are observed against the background of a detailed or incomplete picture of narcolepsy.
Psychogenic seizure (pseudosyncope)
It should always be remembered that with certain personality traits, when there is a tendency to express oneself in the form of “conversion symptoms,” a predisposition to fainting in the past can become a good basis for psychogenic seizures, because a sudden fall outwardly gives the impression of a very serious symptom. The fall itself looks like an arbitrary “throw” to the floor; the patient “lands” on his hands. When trying to open the patient’s eyes, the doctor feels active resistance from the patient’s eyelids. To make a diagnosis for some of these patients (not only young people), no less important than the help of a cardiologist is the help of a qualified psychiatrist.
Basilar migraine
With migraine, in particular with basilar migraine, a sudden fall is one of the very rare symptoms; Moreover, such falls do not occur in every migraine attack. As a rule, the patient turns pale, falls and loses consciousness for a few seconds. If these manifestations occur only in connection with migraine, there is nothing threatening about them.
Parkinsonism
Spontaneous falls in parkinsonism are caused by postural disturbances and axial apraxia. These falls are not accompanied by loss of consciousness. Often a fall occurs at the start of an unprepared movement. In idiopathic parkinsonism, severe postural disturbances and falls are not the first symptom of the disease and appear at subsequent stages of its course, which facilitates the search for possible causes of falls. A similar mechanism of falls is characteristic of progressive supranuclear palsy, Shy-Drager syndrome and normal pressure hydrocephalus (axial apraxia).
Certain postural changes are also characteristic of physiological aging (slow, uncertain gait of the elderly). Minimal provoking factors (uneven ground, sudden turns of the body, etc.) can easily provoke a fall (idiopathic senile dysbasia).
Such rare variants of dysbasia as idiopathic apraxia of gait and primary progressive walking with “freezing” (“freezing”) can also cause spontaneous falls while walking.
“Cryptogenic falls in middle-aged women” (over 40 years old) have also been described, in which the above causes of falls are absent, and the neurological status does not reveal any pathology.