Assessing the state of consciousness

When examining a patient with any disorders of consciousness, it is first necessary to assess the adequacy of the state of vital functions (respiratory and cardiovascular) and, if there are signs of their impairment, take urgent appropriate measures. Pay attention to the depth, frequency, rhythm of breathing, frequency and rhythm of heart contractions, pulse tension, and blood pressure.

Examination of a patient with impaired consciousness is carried out according to general principles, but due to limited contact with the patient or lack of contact, the examination has a number of features.

Anamnesis

When collecting anamnesis from relatives or witnesses of the development of the disease, it is necessary to find out whether the patient had any previous illnesses and complaints (recent craniocerebral trauma, headaches, dizziness, chronic somatic or mental illnesses in the anamnesis). It is necessary to find out whether the victim used any medications. It is necessary to establish what symptoms immediately preceded the change in consciousness, what is the rate of development of the disease. Sudden rapid development of coma without any previous factors in young people often indicates drug intoxication or subarachnoid hemorrhage. In elderly people, such development is typical for hemorrhage or infarction of the brain stem.

[ 1 ], [ 2 ]

Inspection

During a general examination, attention is paid to the presence of signs of trauma to the head, body and limbs, tongue bite, signs of general illness (color, turgor and temperature of the skin, nutritional status, rashes on the skin and mucous membranes, swelling, etc.), bad breath, traces of injections.

When conducting a neurological examination, special attention should be paid to the following groups of symptoms.

Patient's position. It is necessary to note the head throwing back, indicating a pronounced meningeal syndrome ( meningitis, subarachnoid hemorrhage), asymmetry of the limbs along the body axis ( hemiparesis ), the position of the arms and legs in a state of flexion and / or extension (decortication, decerebration). Pay attention to the presence of seizures (a manifestation of epileptic syndrome, intoxication in eclampsia, uremia), hormetonia (indicating bilateral damage to the medial structures of the diencephalon, typical for intraventricular hemorrhages), fibrillary twitching in different muscle groups (electrolyte disturbances), hyperkinesis, involuntary automatic movements (such as counting coins, walking, etc.). chaotic motor excitation (hypoxia), movements such as shaking off, pushing away imaginary objects (hallucinations), etc.

Speech contact and its features. The patient's speech may vary from detailed, intelligible to its complete absence. If a conversation with the patient is possible, his orientation in place, time, personal situation, tempo, coherence and intelligibility of speech are assessed. It is necessary to pay attention to the content of speech ( delirium, hallucinations). It should be remembered that speech disorders can be a local symptom of damage to the speech centers of the dominant hemisphere ( aphasia ), cerebellum (scanned speech), nuclei of the IX, X and XII pairs of cranial nerves in the brainstem (phonation disorder, dysarthria ). In these cases, they cannot be used to characterize the state of consciousness.

Completion of instructions and assessment of motor reactions. In the presence of speech contact, the execution of motor instructions is assessed: correctness, speed of inclusion in the task, pace of execution, exhaustion.

If the patient does not follow the instructions, the motor response to pain stimulation is assessed. The best reaction is considered to be one in which the patient localizes the pain and makes coordinated movements to eliminate the stimulus. The withdrawal reaction is less differentiated. A motor reaction in the form of tonic extension in the arm or leg, often global in nature with the involvement of both sides, should be recognized as pathological. The absence of any motor response to pain is prognostically unfavorable.

State of the reflex sphere. The state of physiological reflexes (increase, suppression, absence) and their dissociation along the body axis are assessed. The presence of pathological, grasping and protective reflexes, reflexes of oral automatism are noted. Assessment of the reflex sphere provides important information about the localization, level of brain damage, and the degree of suppression of its functions.

Opening the eyes in response to sound or pain is one of the most important signs of differential diagnostics of the state of wakefulness. If there is no reaction to opening the eyes, the state is considered comatose. It is necessary to take into account that in some cases failure to open the eyes may be due to special reasons, for example, bilateral pronounced edema of the eyelids, local damage to the nuclei of the oculomotor nerves in the brainstem. Sometimes the patient lies unconscious with open eyes (awake coma), which may be due to the state of tone of the corresponding muscles. For these patients, the absence of a blink reflex and involuntary blinking is typical. In such situations, it is necessary to rely on other cardinal symptoms that distinguish comatose states, primarily on verbal contact.

The position and movements of the eyeballs are very important for determining the level of brain damage and differentiating organic and metabolic lesions. In the presence of speech contact, voluntary eye movements are assessed, paying attention to upward gaze, the volume of gaze to the sides, and the compatibility of eye movements. In the absence of contact, reflex eye movements are examined: reflex upward gaze, the presence of oculocephalic and vestibulocephalic reflexes. In supratentorial processes, deviation of the eyeballs toward the lesion (damage to the adversive fields) can be observed. Unilateral ptosis and divergent strabismus indicate damage to the oculomotor nerve, which, in combination with progressive depression of consciousness, is typical for the development of tentorial herniation. For organic damage at the level of the midbrain, the following are typical: vertical spacing of the eyeballs (Magendie's symptom), downward abduction of the eyeballs (Parinaud's symptom), convergent or divergent strabismus, diagonal or rotatory mono- or binocular spontaneous nystagmus. With damage at the level of the brainstem, floating and spasmodic concomitant and multidirectional movements of the eyeballs, spontaneous binocular or monocular horizontal or vertical nystagmus can be observed. With a normal oculocephalic reflex, a quick passive turn of the head causes a deviation of the eyes in the opposite direction with a quick return to the original state. In pathology, this reaction may be incomplete or absent. The oculovestibular reaction consists of the appearance of nystagmus towards the irritant when irrigating the external auditory canal with ice water. It changes in the same way as the oculocephalic reflex. Oculocephalic and oculovestibular reactions are highly informative for predicting the outcome of the disease. Their absence is prognostically unfavorable and most often indicates the irreversibility of coma. It should be remembered that the oculocephalic reflex is not examined in case of cervical spine injury or suspicion of it.

Pupil status and their reaction to light. It is necessary to pay attention to bilateral pupillary constriction (may indicate damage to the pretectal area and pons, typical for uremia, alcohol intoxication, use of narcotic substances). The appearance of anisocoria may be one of the first manifestations of tentorial herniation. Bilateral pupillary dilation indicates damage at the midbrain level. It is also typical for the use of anticholinergics (eg, atropine). It is extremely important to examine the reaction of the pupils to light. Bilateral absence of pupillary reactions in combination with pupillary dilation (fixed mydriasis) is an extremely unfavorable prognostic sign.

When examining corneal reflexes, one should focus on the best reaction, since its unilateral absence may be due to a disturbance in corneal sensitivity within the framework of conductive sensitivity disorders, and not damage to the trunk.

Instrumental and laboratory research

With the current availability of neuroimaging methods, CT or MRI is mandatory when examining a patient with impaired consciousness, and in the shortest possible time. Also, studies allow you to quickly confirm or exclude the presence of structural changes in the brain, which is very important, especially in the differential diagnosis of disorders of consciousness of unknown etiology. In the presence of structural changes in the brain, CT and MRI results help determine the tactics of patient management (conservative or surgical). In the absence of CT and MRI, it is necessary to perform craniography and spondylography of the cervical spine to exclude damage to the bones of the skull and neck, as well as EchoES. If a patient is admitted early with suspected ischemic stroke and special examination methods are unavailable (CT perfusion, diffusion methods in MRI), repeated studies are necessary, due to the timing of the formation of the ischemic focus.

Before starting treatment, it is necessary to urgently conduct laboratory tests to determine at least the following parameters: blood glucose, electrolytes, urea, blood osmolarity, hemoglobin content, and blood gas composition. Secondly, depending on the results of CT and/or MRI, tests are performed to determine the presence of sedatives and toxic substances in the blood and urine, liver function tests, thyroid gland, adrenal glands, blood coagulation system, blood cultures if a septic condition is suspected, etc. If a neuroinfection is suspected, it is necessary to perform a lumbar puncture (after excluding congestive optic nerve discs during ophthalmoscopy ) with a study of the cerebrospinal fluid composition, glucose content, bacterioscopic and bacteriological examination.

An important study of an unconscious patient is EEG. It helps differentiate organic, metabolic and psychogenic coma, and also allows characterizing the degree of depression and disintegration of brain function. EEG is of exceptional importance in determining brain death. Some help in determining the functional state of the brain is provided by the study of evoked potentials for various types of stimulation.

Types of states of consciousness

The following types of states of consciousness are distinguished:

1. clear consciousness;
2. unclear consciousness, in which the patient, although intelligent, answers questions with a delay and is not sufficiently oriented in the surrounding environment;
3. stupor - numbness; when emerging from this state, answers questions insufficiently intelligently;
4. stupor - dullness; the patient reacts to the environment, but the reaction is episodic, far from adequate, and the patient cannot coherently explain what happened or is happening to him;
5. unconscious state - coma (depression of consciousness, often with muscle relaxation).

Impaired consciousness may depend on various pathological processes in the central nervous system, including those associated with cerebral circulatory disorders, which most often occur in elderly people with dynamic circulatory disorders as a result of vascular spasm, but may be associated with persistent anatomical disorders in the form of hemorrhage or cerebral ischemia. In some cases, consciousness may be preserved, but speech disorders may be expressed. A soporous state may develop with infectious brain lesions, including meningitis.

Impaired consciousness, including comatose states, occur more often with significant shifts in the homeostasis system, which leads to severe damage to internal organs. Usually, in all cases of such endogenous poisoning, there are some or other respiratory disorders (Cheyne-Stokes breathing, Kussmaul breathing, etc.). The most common are uremic, hepatic, diabetic (and its varieties), hypoglycemic coma.

Uremic coma due to terminal renal failure and in connection with the retention of primarily nitrogenous waste in the body develops gradually against the background of other signs of usually advanced kidney damage (anemia, hyperkalemia, acidosis); less often, it occurs with acute renal failure.

Hepatic coma in severe liver damage can develop quite quickly. It is usually preceded by mental changes that can be regarded as random phenomena reflecting the patient's character traits (nervousness, sleep inversion).

Diabetic (acidotic) coma can develop quite quickly against the background of satisfactory health, although there is often a pronounced thirst with the release of a large amount of urine, which the patients themselves do not think to tell the doctor about, which is accompanied by dry skin.

Hypoglycemic coma can occur in diabetes mellitus as a result of insulin treatment. Although diabetics are well aware of the feeling of hunger - the precursor of this condition, coma can also develop suddenly (on the street, in transport). In this case, it is important to try to find the patient's "Book of the Diabetic", which indicates the dose of insulin administered. One of the clear signs of this coma, which distinguishes it from the diabetic one, is the pronounced moisture of the skin.

Alcohol coma is not so rare. In this case, it is possible to detect the smell of alcohol from the mouth.

Attacks of short-term loss of consciousness are quite common. Upon exiting this state, satisfactory or good health returns fairly quickly. Most of these attacks are associated with a temporary decrease in cerebral blood flow or, less frequently, epilepsy.

A decrease in cerebral circulation can develop when various mechanisms are activated.

Simple (vasovagal) fainting is based on reflex reactions that slow down the heart and at the same time dilate the blood vessels, especially in the skeletal muscles. This can result in a sudden drop in blood pressure. Apparently, the state of the left ventricular receptors is important, which should be activated with a significant decrease in its systolic output. Increased sympathetic tone (which increases ventricular contraction) combined with decreased ventricular filling pressure (as a result of bleeding or dehydration) especially often leads to loss of consciousness. Pain, fear, excitement, crowds of people in a stuffy room are very often factors that provoke fainting. Loss of consciousness usually occurs in a standing position, rarely sitting and especially lying down. Fainting does not occur during exercise, but can happen after great physical exertion. Before fainting, many often feel weakness, nausea, sweating, a feeling of heat or chills. The patient seems to sink to the ground, looks pale. Consciousness is usually lost for no more than a minute.

Orthostatic syncope often occurs when moving from a lying to a standing position as a result of vasomotor reflex disorder, often when taking various medications, for example, during active treatment of arterial hypertension. Orthostatic hypotension occurs in elderly patients, especially with vascular damage to the autonomic nervous system, which is especially common with prolonged bed rest.

Fainting associated with head movements (turning) can be caused by increased sensitivity of carotid sinus receptors or impaired vertebrobasilar blood flow, which is confirmed by the appearance of bradycardia with short-term pressure on the carotid sinus; vertebrobasilar insufficiency is often accompanied by dizziness or diplopia (double vision).

Fainting during a coughing fit is sometimes observed in chronic bronchitis in obese, plethoric patients who abuse alcohol and smoking. This is sometimes also facilitated by hyperventilation, which causes peripheral vasodilation and cerebral vasoconstriction.

The Valsalva maneuver (straining with the glottis closed), sometimes used as a functional test in cardiology and pulmonology, can reduce cardiac output so much that it leads to syncope. Syncope during physical exertion can occur in patients with severe heart disease with obstructed (obstructed) ejection of blood from the left ventricle ( aortic stenosis ).

Syncopal attacks occur with various heart rhythm disorders, leading to a decrease in cardiac output and disruption of the blood supply to the brain, especially in elderly patients. The nature of such attacks is clarified by long-term electrocardiographic observation ( Holter monitoring ).

Epileptic seizures are another important cause of short-term loss of consciousness due to disturbances in electrical processes in the brain neurons. These disturbances occur in a limited area of the brain or are widespread. Less often, they occur during fever or menstruation in response to a flash of light or a loud noise. A grand mal seizure is characterized by a sudden onset and development of convulsions. The eyes remain open and tilted to one side, the legs are straight, and the face is full of blood. A sudden fall can cause head injury. Involuntary urination and biting of the tongue are common.

In a minor seizure (petit mal), the loss of consciousness is very short-lived, the patient appears to be absent for several seconds, such seizures can be repeated daily. Sometimes, with epilepsy, consciousness does not completely disappear, although visual hallucinations are possible, followed by a complete loss of consciousness. Most patients do not remember what happened to them during the seizure.

Sometimes such seizures in people with epilepsy in the family, having begun in childhood, can be repeated for many years, which indicates the absence of a focus of organic damage in the brain. Seizures that began in adulthood can be associated with the growth of a brain tumor. The appearance of headaches and other focal brain symptoms confirms these assumptions.

Seizures occurring in the morning on an empty stomach or after a prolonged fast suggest a tumor secreting insulin (episodes depend on hypoglycemia). Epileptoid seizures can be provoked by some medications, especially during the period of their rapid withdrawal (some sedatives and hypnotics).

Epileptic seizures sometimes mimic narcolepsy and catalepsy. Narcolepsy is characterized by attacks in which the patient feels an irresistible desire to sleep. Catalepsy is characterized by an attack of severe weakness, from which the patient may fall without losing consciousness.

Hysterical attacks are sometimes accompanied by clouding of consciousness and such manifestations as urinary incontinence and tongue biting. However, there is no deviation of the eyes to one side, increased blood filling and cyanosis of the face (as in epilepsy). Hysterical attacks occur more often in the presence of other people. The movements of the limbs are usually coordinated and often directed aggressively against the surrounding people.

Thus, attacks with loss of consciousness can be associated with different causes, provoked by different factors, and their nature is recognized as a result of identifying and analyzing the symptoms accompanying them.