Fainting and fainting are different. Let's understand the reasons

For many people, summer means warm, comfortable days that are ideal for eating al fresco or taking long walks during breaks in the air-conditioned office.

But for some of us, summertime means working outside in direct sunlight or repairing buildings without cooling systems.

Working in high temperature environments can pose a particular safety and health hazard because it interferes with the body's most important system, the thermoregulation system.

This article provides an overview of various heat stress-related illnesses and injuries and provides recommendations for recognizing and preventing them.

What is heat stress (overheating, hypothermia)?

Heat stress is a condition when the body cannot get rid of excess heat. When this happens, your body temperature rises and your heart rate increases.

As the body continues to accumulate heat, the person begins to lose concentration and has difficulty concentrating on any task, may become irritable or sick, and often loses the desire to drink. The next stage most often is fainting and even death if the person has not cooled down.

Factors that contribute to heat stress include high air temperature, radiant heat sources, high humidity, direct physical contact with hot objects, and strenuous exercise.

Types of fainting and their consequences

Spontaneous loss of consciousness can be short-term and persistent. As is correct, short-term fainting does not pose a threat to life and lasts no more than a few minutes.

Short-term fainting can occur with the following diseases:

• state of hypoglycemia (sharp decrease in blood glucose);
• epilepsy;
• ONMK;
• a sharp change in blood pressure;
• minor brain injuries (concussions, bruises).

Persistent loss of consciousness is accompanied by more dangerous consequences, and even if timely assistance is provided, a threat to the patient’s life remains. The development of persistent fainting is possible as a result of the following factors:

• extensive strokes and cerebral hemorrhages;
• cardiac arrest and arrhythmia;
• subarachnoid hemorrhages resulting from aortic ruptures;
• various states of shock;
• severe TBI;
• acute poisoning of the body;
• heavy bleeding due to damage to internal organs.

In addition, the pathological condition may be the result of asphyxia with prolonged oxygen starvation.

How the body reacts to high temperatures

Four environmental factors influence the level of stress a worker experiences in a hot work area: temperature, humidity, radiated heat (such as from the sun or furnace), and wind speed. People with high blood pressure or certain heart conditions and people who take diuretics (water tablets) may be more sensitive to the effects of heat. Measuring the climate in the workplace is the first step towards preventing heat stress-related illnesses.

The body protects itself from heat through three mechanisms: breathing, sweating, and changes in blood flow. The first reaction is blood circulation to the skin, which raises the skin temperature and allows the body to release some heat. During hard work, muscles need more blood flow, which reduces the amount of blood available to reach the skin and generate heat.

Sweating also helps the body cool down, but only when humidity levels are low enough to allow sweat to evaporate and if the water and salts lost through sweating are replaced.

Causes of convulsive fainting

As a rule, for the development of such a condition, there are predisposing factors that have a direct impact on the human body.

The most common factors that may be accompanied by seizures are:

• physical and mental trauma;
• pain attack, fear, prolonged stay in a stuffy room;
• sudden change in body position (from horizontal to vertical);
• drop or increase in blood pressure;
• heart attack, arrhythmia;
• in some cases, an attack occurs due to a malfunction of internal organs (cardiovascular diseases, diabetes, central nervous system disorder, vascular problems, etc.).

Quite often, loss of consciousness, accompanied by convulsive syndrome, occurs as a result of tumor-like neoplasms in the brain and epilepsy.

Tomogram of a malignant brain tumor that compresses blood vessels and nerve endings, leading to loss of consciousness

The etiology of a neuroepileptic attack is not fully understood, but, as a rule, this condition is accompanied by stroke, anoxia (hypoxia) of the meninges, which leads to loss of consciousness.

Heat stress and illness

When the body overheats, a state of heat stress occurs. Heat stress can lead to a number of problems, including heat exhaustion, heat stroke, seizures, fainting, or rashes. Many people confuse these disorders, but it is important to be able to recognize each and know what to do when it happens. Each of these heat stress disorders is described below.

Heat exhaustion

Although not the most serious health problem, heat exhaustion is the most common heat-related illness. Heat exhaustion occurs when temperature and relative humidity are not controlled and a worker sweats a lot and does not drink enough fluids or take in enough salt, or both. An easy way to determine this is to look at the worker: he will be wet, pale and weak.

Signs and symptoms:

• sweating,
• Weakness or fatigue, possible confusion,
• Nausea,
• Normal or slightly higher body temperature,
• Pale, clammy skin (sometimes red).

What to do:

• Let it rest in a cool place,
• Give the electrolyte solution to drink. Avoid caffeinated drinks such as cola, iced tea or coffee.
• In serious cases involving vomiting or loss of consciousness, call 911 and transport the worker to a medical center, as appropriate.

Heatstroke

Heat stroke is the most serious health problem for people who work in hot weather, but not very often. It is caused by the body's inability to regulate the temperature of its systems. Sweating stops and the body cannot get rid of excess heat. Victims will die if they do not receive proper treatment immediately. If a worker is exposed to high temperatures, measuring the intensity of thermal exposure can help prevent heat stroke.

Signs and symptoms

• Confusion, delirium, fainting, or seizures.
• Body temperature is 41.1ºC or higher.
• Hot, dry skin, usually red or bluish in color.

What to do:

• Call an ambulance immediately.
• Move the victim to a cool place.
• Cool the victim with cool water.
• Fan the victim vigorously to increase cooling.

Heat cramps

Heat cramps are painful muscle spasms. They occur when a worker drinks a lot of water but does not replace the salts lost from sweating. Tired muscles—those that are used to do work—are usually the most likely to cramp.

Signs and symptoms:

• Cramps or muscle spasms.
• This may happen during or after work.

What to do:

• Drink an electrolyte solution.
• If the cramps are severe or do not go away for a long time, seek medical attention at a health center.

Fainting (loss of consciousness)

Fainting usually happens to someone who is not used to working in a hot environment and is simply standing nearby. Moving, as opposed to staying still, usually reduces the likelihood of fainting.

Signs and symptoms

• Brief loss of consciousness.
• Sweaty skin, normal body temperature.
• There are no signs of heatstroke or heat exhaustion.

What to do:

• Lie down in a cool place.
• Seek medical attention if the victim does not recover after a short rest.

Heat rash

Heat rashes, also called heat urticaria, can occur in hot, humid environments where sweat does not evaporate easily. This usually occurs if the measurement of air speed is ignored, which prevents adequate measures from being taken. When the rash covers a large area or if it becomes infected, it can become very uncomfortable. Heat rash can be prevented by resting in a cool place and drying the skin.

Signs and symptoms:

• A rash with small pink or red bumps.
• Irritation or tingling sensation.
• Itching.

What to do:

• Keep skin clean and dry to prevent infection.
• Wear loose cotton clothing.
• Cool baths and air conditioning are very beneficial.
• Some over-the-counter lotions can help relieve pain and itching.

Convulsive syndrome in childhood

Any fainting in a child, especially if it happens for the first time, necessarily requires medical intervention. This may not be a simple loss of consciousness, but an epileptic attack, which is impossible to distinguish on your own. Disorders of consciousness and the development of seizures in children are most often associated with the immaturity of the nervous system, but “provocateurs” can be traumatic brain injuries, brain tumors, and epilepsy.

Bleeding from the ears or mouth is often observed, in which case immediate hospitalization in an ambulance is required. In children under 2 years of age, disturbances of consciousness are provoked by loud sounds and other external stimuli. It is characteristic that at this age such a disorder is often preceded by convulsions - loss of consciousness occurs after their completion. Such symptoms are often caused by hyperthermia, so there is no need to overly wrap the child, which is often the “sin” of young parents.

Video

Authors):

Roberto A. Santilli Med.Vet., PhD, DECVIM-CA (Cardiology)
Organization(s):
Clinica veterinaria Malpensa-Samarate-Varese-Italy Ospedale Veterinario I Portoni Rossi – Zola Predosa – Bologna – Italy Cornell University- cardiology department_New York – USA
Magazine:
No. 3 - 2017
IVCS MATERIALS
translation from English by Maria Nazarova

Introduction

Transient loss of consciousness (TLOC) is a brief loss of consciousness with sudden onset, short duration, and spontaneous and rapid recovery. The main forms of TLOC are: traumatic loss of consciousness, or concussion, and non-traumatic loss of consciousness, which in turn is divided into: syncope, epileptic seizure and various groups of rare disorders such as catalepsy.

Syncope is loss of consciousness due to global cerebral hypoperfusion due to a drop in systemic blood pressure due to a sharp decrease in vascular resistance or a drop in heart rate.

The typical syncope is short. Complete loss of consciousness in cases of reflex syncope lasts no more than 20 seconds. However, fainting rarely lasts longer, up to several minutes. In such cases, differentiating the diagnosis between syncope and other causes of loss of consciousness may be difficult. Recovery from syncope is usually accompanied by an immediate return to normal behavior and orientation. Fatigue may sometimes be noticeable during the recovery period. Presyncope is a term used to identify the precursor to fainting, but this stage is not accompanied by loss of consciousness. A sudden cessation of blood flow to the brain for a short period of just 6–8 seconds is enough to cause complete loss of consciousness. Systemic blood pressure is determined by cardiac output and total peripheral vascular resistance, and a fall in either of these parameters causes syncope, but a combination of a fall in both may also occur, with varying degrees of severity for each component.

Low or inadequate peripheral vascular resistance may result from an inadequate reflex response, which leads to vasodilation and bradycardia and is referred to as vasodepressor, mixed, or cardioinhibitory reflex syncope. Other causes of inadequate peripheral vascular resistance are functional and structural damage to the autonomic nervous system, such as dysautonomia (due to, for example, drug therapy). In the case of disturbances in the functioning of the autonomic nervous system, the sympathetic vasomotor pathways are unable to provide an increase in total peripheral vascular resistance (TPVR) in response to a change in body position (from lying to standing). Gravitational stress, in combination with vasomotor insufficiency, leads to the deposition of blood in the veins of the abdominal cavity and pelvic extremities, causing a sharp decrease in preload (venous return) and, as a consequence, cardiac output. The causes of a transient decrease in cardiac output are: reflex bradycardia, known as the cardioinhibitory type of reflex syncope, cardiovascular diseases (arrhythmias, structural diseases, pulmonary embolism and pulmonary hypertension), inadequate venous return due to emptying of the veins or deposition of blood in the veins. According to the underlying mechanism, fainting is divided into: reflex, orthostatic and cardiogenic.

Reflex fainting

Reflex syncope traditionally refers to a heterogeneous group of conditions in which cardiovascular reflexes that normally control circulation become intermittently inappropriate in response and act as triggers, causing vasodilation and/or bradycardia, thereby leading to a drop in blood pressure and global cerebral hypoperfusion . Reflex syncope is usually classified based on the efferent pathways most involved, i.e., sympathetic or parasympathetic. The term "vasodepressor" type usually means that hypotension predominates due to loss of vasoconstrictor tone during standing. The “cardioinhibitory” type is used when bradycardia or asystole predominate, the “mixed” type is used when both mechanisms (*vasodepressor and cardioinhibitory) are present. Vasovagal syncope is caused by pain, emotional or orthostatic stress. There are usually previous symptoms of activation of the autonomic nervous system (pallor, nausea). Situational fainting traditionally refers to reflexive, associated with certain circumstances (coughing, urination, defecation, vomiting, pain, physical activity). Syncope due to carotid sinus stimulation is a rare, sudden disorder caused by mechanical manipulation of the carotid sinus.

Orthostatic syncope

In contrast to reflex syncope, in dysautonomia, sympathetic efferent activity is impaired and there is a deficit in vasoconstriction. When standing, the pressure drops and fainting or near-syncope occurs. Orthostatic hypotension is defined as an abnormal decrease in systolic blood pressure when the body changes position to standing. Orthostatic intolerance can cause fainting, but also dizziness, lightheadedness, weakness, fatigue and lethargy.

Classically, orthostatic hypotension is characterized by a decrease in systolic pressure by more than 20 mmHg. Art. and diastolic - more than 10 mm Hg. Art. within 3 minutes after taking a standing position.

Orthostatic hypotension may be caused by structural damage to the autonomic nervous system, medications that cause autonomic failure, and inadequate venous return due to decreased blood volume or pooling of blood in the veins.

Cardiogenic syncope

Structural diseases of the cardiovascular system (valvular disease, ischemia, hypertrophic cardiomyopathy, cardiac neoplasms, pericardial disease and tamponade), pulmonary embolism or pulmonary hypertension can cause syncope, and they are associated with the fact that the body's needs cannot be met by the impaired ability of the heart increase your emissions. The basis for syncope is inadequate blood flow resulting from mechanical obstruction.

However, in some cases, syncope not only results from decreased cardiac output, but may also be caused in part by an inappropriate reflex response or orthostatic hypotension.

Arrhythmias are the most common cause of cardiogenic syncope. They cause hemodynamic disturbances, which lead to a critical decrease in cardiac output and blood flow in the brain. Fainting often depends on a number of associated factors, which include heart rate, type of arrhythmia (supraventricular or ventricular), left ventricular function, body position, and adequacy of vascular compensation. The latter factor includes the reflex response from the baroreceptors, as well as the response to orthostatic hypotension due to arrhythmia.

Sick sinus syndrome, atrial inactivity, and severe degrees of atrioventricular block (high-grade 2nd degree AV block or 3rd degree AV block) are most often associated with syncope.

Arrhythmogenic syncope

Arrhythmias are the most common cardiogenic causes of syncope. They lead to hemodynamic disturbances that can cause a critical decrease in cardiac output and blood flow to the brain. However, syncope often requires a combination of factors, such as heart rate, type of arrhythmia (supraventricular or ventricular), left ventricular function, body position, and adequacy of the vascular response. The latter involves reflexes controlled by baroreceptors and the response to orthostatic hypertension caused by arrhythmia.

Sick sinus syndrome, atrial inactivity and the most severe forms of AV block (high grade 2 or grade 3) are most often associated with the occurrence of syncope.

The hemodynamic contribution of arrhythmias depends on various factors, including: changes in atrial and ventricular rates, duration of rhythm changes, ventricular functional status, concomitant drug therapy, peripheral vasomotor function, and concomitant systemic diseases.

Changes in the frequency of ventricular contractions are one of the factors of hemodynamic disturbances in dogs with arrhythmias. Marked increases in ventricular rate (185–230 beats/min) during atrial stimulation lead to a fall in cardiac output, while changes in systemic blood pressure and coronary blood flow occur with high frequency. Inadequate ventricular diastolic filling is a likely cause of decreased cardiac output. The reduction in ventricular rate causes a fall in cardiac output and a subsequent fall in systemic blood pressure, despite an increase in stroke volume in response to increased preload. In such cases, systolic blood pressure is usually preserved, but prolonged diastolic pauses are associated with low diastolic blood pressure.

The long course of tachycardia of both supraventricular and ventricular origin leads to hemodynamic changes, the result of which most often is heart failure, weakness or cardiogenic shock. Fainting is less common in the absence of concomitant dysautonomia or systolic dysfunction. Continuous tachycardia provokes the development of cardiomyopathy, which is called arrhythmia-induced cardiomyopathy, and occurs as a result of increased myocardial oxygen demand, increased myocyte-capillary distance, decreased AMPc production, and abnormal concentrations of sarcoplasmic and myofibrillar calcium ATPase.

Also, chronic bradycardia associated with high-grade AV block or sick sinus syndrome can cause syncope, fatigue, weakness, and heart failure. Reflex syncope can be caused by a vasovagal or situational reflex, which was accompanied by cardiac inhibition, which, in turn, is characterized by the presence of sinus node arrest, blockade of the impulse exit from the sinus node, 2nd degree high grade AV block or 3rd degree AV block.

The hemodynamic effects of arrhythmias are potentiated by the presence of systolic dysfunction. In such cases, the contribution of the atria is decisive for cardiac output, and very often a high ventricular rate, particularly in ventricular tachycardia, can lead to symptoms of syncope or cardiogenic shock. The consequences of ventricular activation are also important, especially when systolic function is impaired, because in the presence of a healthy heart, ventricular depolarizations themselves lead to minor changes in cardiac output.

Anxiety, loss of peripheral vasomotor function, concomitant drug therapy, circulating catecholamine levels, increased blood viscosity or redistribution, neurogenic reflexes, and systemic disease may also contribute to hemodynamics in dogs with arrhythmias that would otherwise remain stable if the arrhythmia were present alone.

Diagnosis of arrhythmias and reflex fainting

Holter monitoring and event monitors are important diagnostic tools for determining the cause of transient loss of consciousness caused by arrhythmia or neurogenic bradycardia. Currently available in practice are ECG monitoring (Holter) for 24–48 hours, or event monitors that allow recording for 7 days. However, because most patients do not become symptomatic during the monitoring period, the true value of Holter in identifying the causes of syncope may be small. Holter monitoring may be more informative if symptoms are very frequent. If one or more episodes of transient loss of consciousness occur per day, this increases the likelihood of obtaining information and correlating symptoms with ECG changes. Among dogs, almost ¼ of cases of syncope occurred during 24-hour ECG recording, which was associated with diagnosis in 42% of cases. Arrhythmia as the cause of fainting was found in 30% of them, and in 20% these were tachyarrhythmias and in 10% bradyarrhythmias. In 38% of patients, as a result of Holter monitoring, treatment tactics changed. Event monitors, designed for 7 days of study, are also external recording devices in which the recording loop is designed in such a way that the previous ECG tape is constantly recorded and deleted. When the device is activated by the owner, usually during a fainting episode, the ECG is stored and can be sent for analysis. Such an event monitor (R-test) has great diagnostic value in cats and dogs (a diagnosis can be made in 84.4% of cases), and according to this monitoring, on average, arrhythmia or reflex syncope was detected in 34.7% of patients. These event monitors are typically smaller and lighter than the Holter, making them more suitable for diagnostic purposes in small dogs and cats. Implantable loop recorders (ILRs) are placed subcutaneously under local anesthesia and have a battery life of 36 months. Such devices have long-term memory that stores ECG data retrospectively, and storage occurs when the device is activated by the owner when fainting is detected, or automatically if parameters have been set that characterize the arrhythmia that needs to be recognized. Such devices are successfully used in the diagnosis of fainting (informative in 56.5–66% of cases). Disadvantages include the need for a minor surgical procedure, the fact that it is sometimes impossible to differentiate between supraventricular and ventricular arrhythmias, the presence of errors due to differences in the algorithms for diagnosing arrhythmias in humans and animals, and the cost of the device.

Treatment options

All true bradyarrhythmias can be treated by implantation of a permanent pacemaker.

Reflex syncope with a significant cardiac inhibitory component can be partially controlled with a pacemaker, but because the accompanying vasodepressor component cannot be fully appreciated, complete resolution of symptoms is rarely achieved.

Ventricular and supraventricular arrhythmias can be controlled with antiarrhythmic drugs, monitored by Holter monitoring, or treated with catheter ablation.
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Differences between epilepsy and convulsive syncope

When diagnosing, it is necessary to differentiate epilepsy from convulsive syncope, since both of these conditions are accompanied by changes in blood pressure and pupil dilation. As a rule, after loss of consciousness has occurred, the patient cannot remember what preceded such a state.

However, there are differences between an epileptic seizure and a convulsive seizure:

You can also read: First aid for seizures in children

• loss of consciousness may be accompanied by warning signs such as dizziness, ringing in the ears, headache and weakness. However, this condition never occurs during sleep, unlike epilepsy, the attack of which occurs completely unexpectedly. It can occur during movement, even at night when a person is sleeping;
• if the patient loses consciousness as a result of psychological and physical influences, he is able to subsequently talk about them, in contrast to an epileptic attack, the cause of which patients cannot explain. An epileptic attack is always accompanied by involuntary urination, in contrast to ordinary fainting;
• convulsive manifestations vary in form: with the development of fainting, convulsions can be clonic. Muscle contraction and relaxation occurs very quickly. Epileptic fainting is characterized by the development of generalized tonic-clonic forms, in which the muscle group is constrained by a spasm for 3-5 minutes, followed by a transition to the clonic phase.

Most often, fainting is short-lived. In this case, the patient’s consciousness returns within a few seconds, but retardation remains.

Characteristic symptoms of an epileptic attack

Prevention

If certain preventive measures are followed, the frequency of fainting can be significantly reduced.

Prevention includes:

• prevention of stressful situations, feelings of hunger and increased fatigue;
• dosed physical activity to avoid overwork;
• hardening procedures;
• normalization of rest and work schedules;
• mandatory night sleep of at least 8 hours;
• You should not suddenly change your body position from horizontal to vertical to prevent orthostatic collapse (loss of consciousness);
• it is important to maintain normal blood vessels and control blood pressure; a sudden change in blood pressure can cause fainting;
• Particular attention to one’s own health must be paid to patients with heart diseases that are accompanied by arrhythmia, since in this case fainting can result in the death of the patient.

It should be noted that in case of a single case of loss of consciousness with convulsions, it is not necessary to go to a medical institution, although you can do this for your own peace of mind. However, if this situation recurs and especially systematic fainting, seeking medical advice is mandatory, as this may indicate signs of serious diseases in the body that require diagnosis.

It is impossible to say with certainty whether fainting conditions are dangerous or not. To do this, you need to find out the nature of the development of this condition. A detailed medical history and consultation with a highly qualified specialist, including a psychotherapist, are of great importance, since quite often the provoking cause of the pathological condition is psychogenic factors.

Diagnostics

Convulsive attacks that impair motor activity and cause severe pain, accompanied by loss of consciousness and/or breathing difficulties, require immediate medical attention.

To determine the causes of seizures, a general and biochemical blood test is performed to determine the electrolyte imbalance. An MRI of the brain shows the presence of hemorrhages or tumors that may cause seizures. EEG is the main method for diagnosing epilepsy, which also causes seizures.

Types of seizures in epilepsy

Depending on the cause of occurrence, the following types of epileptic seizures are distinguished:

• Idiopathic – occurring in the presence of epilepsy in close relatives;
• Symptomatic – occur after a traumatic brain injury, infectious or tumor lesion of the brain substance;
• Cryptogenic – the causes of occurrence cannot be determined.

The external manifestations of a convulsive syndrome are determined by its type. If the pathological focus is localized in one hemisphere of the brain, simple or complex seizures occur.

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Simple partial seizures

Against the background of simple convulsions, the patient does not always lose consciousness. Clinical symptoms depend on the location of the pathological focus in the cerebral cortex. The average duration of simple partial seizures is two minutes.

Neurologists identify the following main signs of the disease:

• Emotional lability;
• Hallucinations of various types;
• Twitching in various parts of the body;
• Cardiopalmus;
• Feeling of nausea;
• Frequent feelings of deja vu;
• Difficulty understanding and reproducing words.

Complex partial seizures

The duration of complex partial seizures is one or two minutes. An aura appears before the attack begins. There is uncontrollable crying and screaming, repetition of words, and performance of certain movements. At the end of the seizure, patients are not oriented in space and time. A simple partial seizure of epilepsy can develop into a complex seizure.

Generalized seizures

Generalized seizures occur against the background of total brain damage. They are as follows:

• Tonic;
• Clonic;
• Tonic-clonic;
• Atonic;
• Myoclonic.

With tonic spasms, unconscious muscle contractions occur. Patients are bothered by severe pain in the muscles of the back, upper and lower extremities. Tonic convulsions rarely lead to fainting. The attack lasts no more than twenty seconds. Tonic seizures can occur during sleep.

Patients with epilepsy are less likely to experience clonic seizures. They manifest themselves as uncontrolled paroxysmal muscle contractions. During convulsions, foam is released from the patient's mouth. He loses consciousness. Paralysis may develop. Clonic seizures occur due to severe stress, traumatic brain injury, cerebrovascular accident, or brain tumor. During an attack, short-term muscle tension is replaced by relaxation. The attacks quickly follow each other.

The most typical and characteristic of an epileptic attack are tonic-clonic convulsions. Their duration varies from 1 to 3 minutes. If tonic-clonic seizures persist for a longer period of time, calling an ambulance is recommended. Neurologists distinguish tonic and convulsive phases in the course of an attack. In the tonic phase, the patient loses balance and consciousness, in the convulsive phase, involuntary muscle contractions occur. After the attack is over, patients do not remember what happened.

Tonic-clonic seizures may also be accompanied by the following symptoms:

• Increased salivation;
• Sweating;
• Involuntary tongue biting;
• Injury as a result of uncontrolled actions;
• Involuntary urination or defecation;
• Blueness of the skin.

Atonic seizures occur after a traumatic brain injury, stroke, infectious inflammatory processes, or in the presence of a brain tumor. During an attack, the patient loses consciousness for a while and falls. In some cases, convulsions can be expressed by twitching of the head. The attack lasts about 15 seconds. At the end of it, the patient does not remember what happened.

Myoclonic seizures are characterized by rapid jerking of various parts of the body. The attack resembles jumping inside the body. Most often, muscle contractions occur in the upper half of the body, the area of ​​the upper and lower extremities. Myoclonic spasms can occur when falling asleep or waking up. A symptom of an attack may be hiccups. The duration of the attack is several seconds. During myoclonic seizures, patients do not lose consciousness.