The coma is the life-endangering condition of violation of consciousness caused by damage of special structures of a brain and which is characterized by total absence of contact of the patient with the world around. The reasons of its emergence can be subdivided on metabolic (poisoning with products of a metabolism or chemical compounds) and organic (at which there is a destruction of sites of a brain). The main symptoms are unconsciousness and lack of reactions of opening of eyes even on strong irritants. In diagnostics of a coma plays an important role KT and MPT, and also laboratory blood tests. Treatment first of all means fight against the main reason for development of pathological process.
The coma is one of types of violation of consciousness at which the patient completely has no contact with the world around and mental activity. This state so deep that the patient cannot be brought from it even by means of intensive stimulation.
In coma of the patient always lies blindly and does not open them neither on a sound, nor on pain. The coma differs in it from other types of violation of consciousness. All other signs: the existence or lack of spontaneous movements kept or the died-away reflexes, ability to independent breath or full attachment to the life support device – depend only on the reason for which the patient fell into coma and extents of oppression of nervous system.
Not everyone, even very extensive, traumatic damages of a brain is capable to cause a coma. Its emergence requires damage of special sites which are responsible for wakefulness, not for nothing in translation from an Ancient Greek lump is transferred as "deep sleep".
The coma is not an independent disease, it represents the hardest complication from the central nervous system which cornerstone damage of nervous ways is. The cerebral cortex perceives signals of the world around not directly, and through retikulyarny a formation. It passes through all brain and is the filter which systematizes and passes through itself(himself) nervous impulses. If cages of a retikulyarny formation are damaged, the highest department of a brain loses touch with the outside world. The person falls into a state which is called a coma.
Nervous fibers of a retikulyarny formation can be damaged as directly actual path, and due to influence of various chemicals. Physical damage can arise at such states as a brain stroke, a trauma (a bullet wound, a bruise, hemorrhage). The chemical compounds leading to damage of nervous cages of a retikulyarny formation are divided into 2 types: 1) internal which are products of a metabolism and are formed as a result of diseases of internals; 2) external which come to an organism from the outside.
Act as the internal striking factors: the reduced content of oxygen in blood (hypoxia), high or low level of glucose and acetone bodies (at diabetes), ammonia (at a serious illness of a liver). External intoxication of nervous system can arise at overdose of drugs, hypnotic drugs, poisoning with neyrotropny poisons, influence of bacterial toxins at infectious diseases.
Classification of a coma
Who can classify by 2 groups of criteria: 1) depending on the reason which caused it; 2) on consciousness oppression level. Depending on the reasons of a coma are subdivided into the following types: traumatic (at craniocereberal injuries), epileptic (a complication of the epileptic status), apoplectic (result of a stroke of a brain), meningialny (develops as a meningitis consequence), tumoral (volume formations of a brain and skull), endocrine (at decrease in function of a thyroid gland, diabetes), toxic (at a renal and liver failure).
However such division is used in neurology not often as does not reflect a true condition of the patient. Bigger distribution was gained by classification of a coma by weight of violation of consciousness – Glazko's scale. On its basis it is easy to define weight of a condition of the patient, to construct the scheme of urgent medical actions and to predict a disease outcome. Cumulative assessment of three indicators of the patient is the cornerstone of Glazko's scale: speech, existence of movements, opening of eyes. Depending on extent of their violation points are put. On their sum the level of consciousness of the patient is estimated: 15 – consciousness is clear; 14 — 13 – moderate devocalization; 12 — 10 - deep devocalization; 9 — 8 – a sopor; 7 and less – coma.
On other classification which is used generally by resuscitators the coma is subdivided into 5 degrees: prekoma; a coma of I (in domestic medical literature call a stupor); coma II (sopor); coma III (atonichesky); coma IV (ultraboundary).
As it was already noted, the most important symptoms of a coma which are characteristic of any its type are: total absence of contact of the patient with the world around and lack of mental activity. Other clinical manifestations will differ depending on the reason which caused damage of a brain.
Body temperature. The coma caused by overheating is characterized by high temperature of a body to 42 — 43 of C ⁰ and dry skin. The alcoholic poisoning and hypnotic drugs, on the contrary, is followed by a hypothermia (body temperature 32 — 34 of C ⁰).
Breath frequency. Slow breath arises at a coma from a gipoterioz (low level of hormones of a thyroid gland), poisoning with hypnotic drugs or drugs from group of morphine. The deep respiratory movements are characteristic of coma against the background of bacterial intoxication at heavy pneumonia, and also of tumors of the brain and acidosis caused by uncontrollable diabetes or a renal failure.
Pressure and heart rate. Bradycardia (decrease in number of warm reductions in a minute) speaks about the coma which arose against the background of sharp pathology of heart, and the tachycardia combination (increase in number of warm reductions) to high arterial pressure indicates increase in intra cranial pressure.
Arterial hypertension is characteristic of patients in the coma which arose against the background of a stroke. And low pressure arises at a diabetic coma, poisoning with hypnotic drugs, massive internal bleeding, a myocardial infarction.
Color of integuments. Cerise skin color develops at poisoning with carbon monoxide. Posineniye of finger-tips and a nasolabial triangle points to the low content of oxygen in blood (for example, at a suffocation). Bruises, bleeding from ears and a nose, bruises in the form of points around eyes are characteristic of the coma which developed against the background of a craniocereberal trauma. Pronounced pale integuments testify to coma because of massive blood loss.
Contact with people around. At a sopor and an easy coma involuntary vocalizations – an izdavaniye of various sounds patients are possible, it is a favorable predictive sign. In process of coma deepening ability to say sounds disappears.
Grimaces, reflex otdergivaniye of a hand in response to pain are characteristic of an easy coma.
Diagnostics of a coma
At diagnosis of a lump, the neurologist solves at the same time 2 problems: 1) clarification of the reason which resulted in coma; 2) direct diagnostics of a coma and its differentiation from other similar states.
Poll of relatives of the patient or casual witnesses helps to find out the reasons of falling of the patient into a coma. At the same time it is specified whether the patient had previous complaints, chronic diseases of heart, vessels, endocrine bodies. Witnesses are asked on whether the patient used drugs, whether empty blisters or jars from under medicines were found near him.
Speed of development of symptoms and age of the patient is important. The coma which arose at young people against the background of full health most often indicates poisoning with drugs, hypnotic drugs. And at elderly patients with associated diseases is heart and vessels the probability of development of a coma against the background of a stroke or a heart attack is high.
Survey helps to establish an alleged cause of emergence of a coma. Level of arterial pressure, pulse rate, respiratory movements, characteristic bruises, a smell from a mouth, traces of pricks, body temperature – here those signs which help the doctor to fill the right diagnosis.
Special attention should be paid on position of the patient. The thrown-back head with the raised tone of muscles of a neck speaks about irritation of covers of a brain which arises at hemorrhages, meningitis. Spasms of all body or separate muscles can be shown if the epileptic status, an eklampsiya was the reason of a coma (at pregnant women). Sluggish paralysis of extremities testifies to a brain stroke, and total absence of reflexes – to deep damage of a big surface of bark and a spinal cord.
The most important in differential diagnostics of a coma from other conditions of violation of consciousness is the research of ability of the patient to open eyes on sound and painful irritation. If reaction to a sound and pain is shown in the form of any opening of eyes, then it is not a coma. If the patient despite all efforts of doctors of an eye does not open, then the state is considered as coma.
Reaction of pupils to light is exposed to careful studying. Its features not only help to establish an estimated location of the center of damage to a brain, but also indirectly indicate the cause of coma. Besides, the pupillary reflex is a reliable predictive sign.
Narrow pupils (pupils point) which are not reacting to light are characteristic of an alcoholic poisoning and narcotic substances. Different diameter of pupils on the left and right eye speaks about increase of intra cranial pressure. Wide pupils – a sign of damage of a midbrain. Expansion of diameter of pupils of both eyes in total with total absence of their reaction to light is characteristic of an ultraboundary coma and is extremely adverse sign, confirming fast death of a brain.
Modern technologies in medicine made tool diagnostics of the reasons of coma of one of the very first procedures at arrival of any patient with consciousness violation. Performance of a computer tomography (brain KT) or MRT (magnetic and resonant tomography) allows to define structural changes in a brain, existence of volume educations, signs of increase in intra cranial pressure. On the basis of pictures the decision on treatment methods is made: conservative or urgent operation.
The nature of coma helps to confirm or disprove metabolic (failure in a metabolism) biochemical blood test. Determination of level of glucose, urea, blood ammonia is quickly carried out. And also the ratio of gases of blood and the main electrolytes (ions of potassium, sodium, chlorine) is defined.
If results of KT and MPT indicate that from TsNS there are no reasons capable to enter the patient into a coma, blood test on hormones (insulin, hormones of adrenal glands, a thyroid gland), toxic substances (drugs, hypnotic drugs, antidepressants), bacterial crops of blood is carried out. The major research which helps to differentiate types a lump is the electroencephalography (EEG). At its carrying out registration of electric potentials of a brain which assessment allows to distinguish the coma caused by a brain tumor, hemorrhage, or poisoning is made.
Treatment of a coma
Treatment of a coma has to be conducted in 2 directions: 1) maintenance of vital signs of the patient and prevention of death of a brain; 2) fight against the main reason which caused development of this state.
Maintenance of vital signs begins already in the ambulance car on the way to hospital and is carried out by everything to patients in a coma even before obtaining results of inspection. It includes maintenance of passability of airways (correction of the sunk-down language, clarification of an oral cavity and nasal cavity from emetic masses, an oxygen mask, insertion of a respiratory tube), normal blood circulation (introduction of the antiarrhytmic means, medicines normalizing pressure, the closed massage of heart). In chamber of resuscitation if necessary connection of the patient to the medical ventilator is made.
Introduction of anticonvulsive medicines in the presence of spasms, obligatory intravenous injection of glucose, normalization of body temperature of the patient (concealment and an obkladyvaniye hot-water bottles is made at a hypothermia or fight with great feeling), washing of a stomach at suspicion of poisoning with drugs.
The second stage of treatment is carried out after detailed inspection, and further medical tactics depends on the main reason which caused a coma. If it is a trauma, a brain tumor, an intra cranial hematoma, then urgent surgery is carried out. At identification of a diabetic coma the level of sugar and insulin is taken under control. If the renal failure became the reason, then the hemodialysis is appointed.
The forecast at a coma
The forecast at a coma completely depends on a damage rate of structures of a brain and the reasons it caused. In medical literature chances of the patient of getting out of coma are regarded as: at a prekoma, a coma of I – favorable, perhaps absolute recovery without the residual phenomena; to a coma of II and III – doubtful, that is exists as probability of recovery, and a lethal outcome; the coma of IV – adverse, in most cases comes to an end with the death of the patient.
Preventive measures come down to early diagnostics of pathological process, purpose of the correct methods of treatment and timely correction of states which can serve as the reason of development of a coma.