Impaired consciousness

Impairment of consciousness is a manifestation of dysfunction of the hemispheres, upper parts of the brain stem , or both of these areas at the same time. So, local damage to supratentorial structures can be widespread, or it can cause edema to displace brain structures, leading to transtentorial herniation, compression of the diencephalic parts of the brain and impaired function of the diencephalic activating system.

• Primary subtentorial processes (brain stem and cerebellum ) can compress or directly damage the reticular activating system between the middle divisions of the warolium bridge and the diencephalic region.
• Metabolic or infectious diseases can have a depressing effect on the function of the hemispheres and brain stem through the pathological content of blood components or a direct toxic effect.
• Impairment of consciousness can also be observed with a violation of cerebral circulation ( syncope and heart attack ) or with a change in the bioelectrical activity of the brain ( epilepsy ). Inadequate cerebral blood flow and chemical imbalance in the blood can also cause a disturbance in the electrical activity of the brain.
• Concussion and psychological disorders cause impaired consciousness without visible structural changes in the brain.

Violation of consciousness can be short-term and long-term , superficial and deep .

• Short-term loss of consciousness is observed with syncope . With convulsive seizures, loss of consciousness can last longer, and with a concussion can last up to 24 hours.
• Long-term impaired consciousness is observed with intracranial pathology or metabolic disorders.

Acute and subacute impaired consciousness:

• Stunning is manifested by a decrease in the level of wakefulness and is usually accompanied by drowsiness . There are moderate and deep stunning with very conditional boundaries ^[1] .
  • Nubilization (“nebula of consciousness”, English clouding of consciousness ) - a slight degree of stunning, slowing down reactions and “blurred” perception of reality.
  • Moderate stunning - partial disorientation, moderate drowsiness, the execution of all commands.
  • Deep stunning - disorientation, deep drowsiness, the execution of only simple commands.
• Sopor - severe depression of consciousness and pathological sleep, lack of compliance with instructions for patients, it is possible to obtain a reaction of opening the eyes with strong stimulation (for pain or sound) ^[1] .
  • Stupor ( English stupor ) - a concept in English literature, similar to stupor. In addition, the term is used in psychiatry to refer to a state of immobility with mutism and a weakening of reactions to irritations (including pain) ^[2] .
• Doubtfulness - mild impairment of consciousness, in which the patient often falls asleep, is inhibited, however, adequate reactions can be caused by short-term external stimuli.
• Coma is characterized by a lack of reaction and the impossibility of awakening. With a deep coma, even primitive reflexes may be absent.
  • Coma I - consciousness is lost, the patient does not open his eyes, in response to pain irritation responds with uncoordinated protective movements without localizing the pain.
  • Coma II, deep - consciousness is lost, there is no reaction to pain, there are no spontaneous movements.
  • Coma III, beyond - consciousness lost, bilateral mydriasis, areflexia, muscle atony, catastrophic state of vital functions.

Chronic impaired consciousness ^[1] :

• Akinetic mutism - a patient in a clear mind, lies motionless with his eyes open, does not talk and does not answer questions. All motor functions are suppressed (except for movements that fix the eyeballs).
• Apallic syndrome (waking coma) - a condition in which consciousness remains intact, the patient’s eyes are open, he rotates them in the orbits, but his eyes are not fixed, speech and emotional reactions are absent, verbal commands are not perceived by the patient and contact with him is impossible, but the patient is not lies motionless.
• The “locked man” syndrome (isolation syndrome) reflects the patient’s condition in which consciousness is preserved, but contact with him is impossible due to bilateral paralysis of all parts of the body, except for eye movements, which the patient encodes his response. Various diseases can lead to this condition, which is the result of bilateral damage to the cortico-spinal tract between the midbrain and the pons, or with massive damage to the lower motor neurons (the front horns of the spinal cord). Strictly speaking, it is not a violation of consciousness, but is often mistaken for it. This condition is also sometimes called "pseudocom."
• A vegetative state is defined as the inability to spontaneous mental activity due to extensive damage or dysfunction of the cerebral hemispheres while maintaining the activity of the diencephalic region and brain stem, preserving vegetative and motor reflexes, as well as a cycle of sleep and wakefulness.
• Brain death is a state of complete loss of consciousness and all brain functions.

Confusion Syndromes in Psychiatry

Confusion, disturbances of reflection of the surrounding reality:

• Amentive Syndrome
• Aura of consciousness
• Delirious syndrome
• Onyroid syndrome
• Twilight stupefaction
• Narrowing of consciousness (observed with affect , as well as with dissociative and conversion disorders )

Supratentorial Volumetric Processes

• Epidural hematoma
• Subdural hematoma
• Cerebral infarction or intracerebral hemorrhage
• A brain tumor
• Brain abscess

Subtentorial Damage

• Brainstem infarction
• Brain stem tumor
• Brainstem hemorrhage
• Cerebellar hemorrhage
• Brain stem injury

Diffuse and metabolic brain disorders

• Injury (concussion, brain injury, or bruising)
• Anoxia or ischemia (syncope, cardiac arrhythmia, pulmonary infarction, shock, pulmonary failure, carbon monoxide poisoning, vascular collagen diseases)
• Epilepsy
• Condition after an epileptic seizure
• Infections ( meningitis , encephalitis )
• Subarachnoid hemorrhage
• Exogenous toxins (alcohol, barbiturates, glutethimide, morphine, heroin, methyl alcohol, hypothermia)
• Endogenous toxins and metabolic disorders (uremia, hepatic coma, diabetic acidosis, hypoglycemia, hyponatremia)
• Psychomotor status epilepticus

• 0-3 mm - Full consciousness (alert)
• 3-4 mm - Drowsiness (drowsy)
• 6-8.5 mm - Stuporous (stuporous)
• 8-13 mm - Coma (comatose)

The possibility of carrying out artificial ventilation of the lungs to maintain the activity of the lungs and heart for a long time, despite the violation of the functions of other organs, has led to widespread legal and public recognition that human death is determined by the complete absence of brain activity , especially brain stem. To establish this diagnosis, the doctor should be based on knowledge of the structural or metabolic causes of brain death , while excluding the possibility of the influence of anesthetizing or paralyzing drugs, especially taken by the patient on his own. Hypothermia correction (below 30 ° C) is necessary.

• Impaired consciousness. Per. from English N. D. Firsova (2019)