Symptoms of impaired consciousness

Variants of impaired consciousness

Below are some concepts used to denote disorders of consciousness. The definitions of these concepts may not completely coincide among different authors.

Acute and subacute disturbances of consciousness

Clouding of consciousness - with a slight decrease in the level of wakefulness, the perception and assessment of the environment is reduced and distorted. Excitement, delirium, hallucinations, various affects are possible, due to which the patient may perform inappropriate actions. Typical for intoxications, psychoses. May precede the development of a comatose state.

Confusion of consciousness is characterized by a disruption of the sequence and slowing down of all thought processes, memory, attention. Disorientation in place, time, personal situation is typical. The level of wakefulness is slightly reduced. It can be a consequence of intoxication, intracranial hypertension, acute and chronic circulatory disorders and other conditions.

Twilight consciousness is a peculiar state when perception and awareness of the surrounding reality are sharply limited or completely absent, but the patient is able to perform a number of unconscious sequential habitual actions. The most typical example is an epileptic seizure in the form of complex automatisms. Similar states can also be encountered in acute transient circulatory disorders (states like global amnesia).

Delirium is an acute disorder of consciousness, manifested primarily by agitation, disorientation in the surroundings and impaired perception of sensory stimuli, dream-like hallucinations, during which the patient is absolutely inaccessible to contact. A patient in a state of delirium may be aggressive, verbose, suspicious. The course of the delirious state can be wave-like, with relatively clear intervals, during which elements of contact and criticism appear. The duration of the delirious state usually does not exceed 4-7 days. It occurs with exogenous and endogenous intoxications, including alcohol, as well as with severe craniocerebral trauma at the stage of recovery from a comatose state.

Stupor is a condition in which the level of wakefulness is significantly reduced in the absence of productive symptoms. Speech contact with the patient is possible, but it is significantly limited. The patient is lethargic, drowsy, mental processes are slowed down. Disturbances in orientation and memory are characteristic. At the same time, the patient performs various motor tasks, the physiological position in bed is maintained, as well as complex habitual motor acts. Rapid exhaustion is typical.

A distinction is made between moderate and profound stunning. The boundary between these states is quite arbitrary.

• With moderate stunning, the patient's speech activity is preserved in the form of answers to questions, although the speech is monosyllabic, there is no emotional coloring, the answers are slow, and often they can only be obtained after multiple repetitions of the question.
• In deep stupor, the decrease in wakefulness increases, the patient's speech activity is practically absent, but the understanding of addressed speech is preserved, which is manifested in the performance of various motor tasks. When differentiating the state of stupor, it should be remembered that the cause of speech impairment may be focal damage to the temporal lobe of the dominant hemisphere.

Sopor is a condition that translates as "deep sleep". A soporous condition is usually understood as a deep depression of consciousness with the development of pathological sleep. There is no execution of instructions. However, the patient can be "awakened", that is, receive a reaction of opening the eyes to sound or pain. Vital functions, as a rule, are not significantly impaired. Facial and purposeful coordinated motor reactions to the corresponding strong irritation, for example, to a pain stimulus, are preserved. Various stereotypical movements and motor restlessness in response to irritation are possible. After the stimulus ceases, the patient again plunges into a state of areactivity.

Stupor - in English-language literature, a concept that is practically analogous to sopor. It is also used to denote psychogenic areactivity, which occurs as an element of a complex of symptoms in catatonia (catatonic stupor).

Coma (comatose state). The main manifestation of a comatose state is the almost complete absence of signs of perception and contact with the environment, as well as mental activity (areactivity). The patient lies with his eyes closed, it is impossible to "wake him up" - there is no reaction of opening the eyes to sound or pain. In all other respects (position in bed, spontaneous motor activity, reaction to various stimuli, degree of preservation of stem functions, including vital ones, state of the reflex sphere, etc.), comatose states are extremely diverse. The neurological symptom complex of a comatose patient consists of various symptoms of irritation and loss, depending on the etiology of the injury, its localization and severity.

Not every brain injury, even a very extensive one, causes coma. A necessary condition for the development of this condition is damage to the structures that ensure wakefulness. In this regard, comatose states in supratentorial pathological processes are possible only with significant bilateral damage involving the activating conduction systems that go from the reticular formation and the thalamus to the cerebral cortex. Coma develops most quickly when the damaging factor affects the medial and mediobasal sections of the diencephalon. When the subtentorial structures are damaged, comatose states develop as a result of primary or secondary dysfunction of the brainstem and are caused primarily by the effect on the oral sections of the reticular formation. The close functional connection of the reticular formation with the nuclei of the cranial nerves that ensure vital functions (respiratory and vasomotor centers) causes rapid disruption of breathing and blood circulation, typical of brainstem injury. The development of comatose states is typical for acute pathological processes in the brainstem (circulatory disorders, traumatic brain injury, encephalitis). In slowly progressing diseases, long-term compensation is possible (tumors and other volumetric processes of the posterior cranial fossa, including the brainstem, multiple sclerosis, syringobulbia).

Chronic disturbances of consciousness

Chronic disorders of consciousness are usually called conditions that develop as a result of acute disorders. There is no clear time boundary between acute, subacute and chronic disorders of consciousness. A condition that develops approximately one month after the disturbance of consciousness appeared is considered chronic. The criterion for a chronic disorder should also be considered stabilization of the condition at a certain level and the absence of changes in one direction or another over a fairly long period of time (at least several days).

Vegetative state (vegetative status, awake coma, apallic syndrome). The listed terms describe a condition characterized by relative preservation of brainstem functions with a complete absence of signs of functioning of the cerebral hemispheres. A vegetative state, as a rule, develops as a result of coma. Unlike the latter, it is characterized by partial, stable or unstable restoration of the awakening reaction in the form of spontaneous or induced opening of the eyes, the appearance of an alternation of sleep and wakefulness. Spontaneous breathing is preserved and the work of the cardiovascular system is relatively stable. At the same time, there are no signs of contact with the outside world. Other symptoms can be quite variable. Thus, motor activity can be completely absent or manifest itself as a facial or non-purposeful motor reaction to pain; chewing, yawning, involuntary phonation (groaning, screaming), reflexes of oral automatism, and a grasping reflex can be preserved. Various changes in muscle tone of the pyramidal or plastic type are possible. The clinical picture corresponds to morphological changes in the brain, characterized by the absence of microfocal changes in the brainstem with pronounced extensive bilateral changes in the telencephalon, especially its anteromedial parts, or these changes are insignificant.

A vegetative state may be a stage of the patient's recovery from a coma. In such cases, it is usually short-lived, and contact with the patient soon becomes possible (the first signs are fixation of the gaze, tracking, reaction to speech addressed to him). Nevertheless, a complete restoration of mental functions in a patient who has experienced a vegetative state almost never occurs.

In the absence of positive dynamics, the vegetative state can persist for many years. Its duration depends mainly on good care of the patient. The death of the patient usually occurs as a result of infection.

Akinetic mutism is a condition in which a patient with all the signs of a fairly high level of wakefulness, intact brainstem functions, elements of contact with the outside world (awakening reaction, alternation of sleep and wakefulness, fixation of gaze, tracking an object) does not show any signs of motor and speech activity, either spontaneous or in response to a stimulus. At the same time, there are no signs of damage to the motor pathways or speech zones, which is proven by cases of complete restoration of motor and speech activity with a favorable outcome of the disease. The syndrome develops, as a rule, with bilateral damage to the medial parts of the hemispheres with the involvement of the reticulocortical and limbic-cortical pathways.

Dementia is a condition when, with a preserved high level of wakefulness, severe, persistent or steadily progressing disorders of mental activity (the content, cognitive component of consciousness) are revealed. Dementia can be the outcome of many extensive and diffuse organic lesions of the cerebral cortex (outcomes of craniocerebral trauma, acute and chronic circulatory disorders, prolonged hypoxia, Alzheimer's disease, etc.).

Locked-in syndrome was described by F. Plum and J. Posner in 1966. It occurs with extensive infarctions of the brainstem at the base of the pons. It is characterized by a complete absence of voluntary motor activity, with the exception of vertical eye movements and blinking. These movements ensure contact with the patient. The syndrome is not strictly considered a disorder of consciousness, but it is important to know about it, since the state of isolation is often confused with a coma or a state of akinetic mutism.

Brain death is a condition in which all brain functions are lost. It is characterized by complete loss of consciousness, absence of spontaneous breathing, tendency to arterial hypotension, diffuse muscle atony, areflexia (individual spinal reflexes may remain), and bilateral fixed mydriasis. In conditions of preserved cardiac function and artificial ventilation, with appropriate care, the patient's life can be extended for a fairly long time. The problems associated with defining the criteria for brain death are extremely complex, especially from an ethical point of view. In many countries, these criteria are summarized in specially adopted protocols. Determining brain death is of great importance for transplantology.

[ 1 ], [ 2 ], [ 3 ], [ 4 ]