The term coma understandably generates feelings of anguish and fear, as it represents an alteration of the state of consciousness that in many cases can determine long-term or sometimes even irreversible repercussions.
However, the word coma is rather generic and does not provide the real entity of the subject’s clinical condition, so in this article we will try to explain in a simple and understandable way the different degrees of “depth” of this condition, focusing in particular on what concerns the irreversible coma and brain death .
The coma is onestate of profound and lasting alteration of consciousness , in which the individual has no awareness of himself or of the surrounding environment and of the stimuli that come from it.
It is a pathological condition from which the subject cannot re-emerge even as a result of strong external stresses such as painful (nociceptive) or acoustic stimuli and is the result of an alteration to the detriment of the cerebral hemispheres or of the reticular substance (which has seat in the brain stem), that is, of those areas responsible for maintaining the state of consciousness.
It is therefore a very complex condition that involves several medical disciplines: neurology, internal medicine, cardiology and forensic medicine. In today’s guide we will try to explain in a simple way what irreversible coma and brain death means .

The different entities of alteration of consciousness
To define the level of consciousness, a special scale called the Glasgow scale of coma is used , which is based on the evaluation of 3 parameters:

  • ability to express oneself;
  • ability to open eyes;
  • motor response.

For each of these parameters a score from 1 to 5 is provided, therefore by adding them the patient can fall within an interval between 15 (value that indicates the full state of consciousness and alertness) and the minimum score 3 (index of deep coma ).
It is then necessary to differentiate the coma from other states of alteration of consciousness but of a momentary and mild nature, such as:

  • Confusional state : the subject is confused and cannot orient himself in time and space, however he is conscious and responds to stimuli and substantially there is a slowing down of reflexes. In this case we also speak of a vigilant coma ;
  • Drowsy state : the subject is unable to remain alert unless he receives external stimuli such as acoustic and verbal, however alertness tends to decline again once the stimulus ceases;
  • Stupor state : in this case the subject does not respond to stimuli unless it is subjected to strong stimuli, therefore as a result of painful stimuli (nociceptive), but consciousness is lost again when they stop.

At this point, let’s analyze the main causes that can lead to an irreversible state of coma, what are the various degrees and what is the fundamental difference with cell death.
What are the

main causes of coma Coma constitutes about 4-5% of accesses in emergency medicine wards and the causes can be many. Here we have tried to report the most common ones:

  • Toxic causes: they are the most responsible factor for the prolonged loss of consciousness (coma). Among these substances we find the abuse of barbiturates (such as carrying out a suicide attempt), abuse of opiates, narcoleptics, alcohol ( ethyl coma ) or heavy metal intoxication;
  • Trauma: among the most frequent causes are traumas, therefore concussion and consequent intracranial hemorrhages due to impact, and therefore the formation of cerebral hematomas which can be extradural, subdural or intracerebral;
  • Vascular causes: including haemorrhages, cerebral, cerebellar or brain stem infarction, encephalopathy, venous thrombosis and vasculitis;
  • Infectious causes : meningitis, encephalitis and brain abscess stand out among these;
  • Thermal causes and therefore hyperthermia or, on the contrary, hypothermia;
  • Tumor causes;
  • Metabolic causes , among the main causes are hypoglycemia, hyperglycemia (better known as glycemic coma ), cerebral hypoxia (due to carbon dioxide intoxication or pneumonia), alterations in acid-base balance, cerebral ischemia, insufficiency renal or hepatic and endocrine alterations (pancreas, thyroid, adrenal, pituitary);
  • Neurodegenerative diseases such as Alzheimer’s, limbic encephalitis and Creutzfeldt-Jakob disease.

What are the degrees of depth of the coma
Coma is classified into 4 stages of severity according to the brain regions affected by a lesion corresponding to the depth of the unconscious state, let’s see them summarized below:

  • 1st degree coma: it is a slight coma in which the patient appears in a drowsy state, nevertheless he is able to respond, even if with difficulty, to verbal and painful stimuli. This is a reversible condition;
  • 2nd degree coma: it is a deeper state than the previous one, in which the subject does not respond to verbal stimuli, but instead maintains the ability to respond to painful stimuli. The pupillary and corneal reflexes are lost, as well as the ability to retain the sphincters (therefore there is a picture of incontinence). Also in this case the condition is reversible;
  • 3rd degree coma: it is a deep coma in which there is the total absence of response to external stimuli and the patient may experience an increase in body temperature ( hyperthermia ), an increase in heart rate ( tachycardia ) and important changes in the respiratory rate. Often in this state the outcome can persist for a long time and be unfortunate, however in many cases it is reversible even if with significant consequences;
  • 4th degree coma : this is the most serious and profound state of coma, which corresponds to the condition of irreversible coma , or brain death, in which the EEG ( electroencephalogram ) is flat . There is a loss of vegetative functions and therefore of the ability to breathe autonomously with a consequent drop in blood pressure and decrease in body temperature (hypothermia).

Pharmacological coma: what it is
Pharmacological coma or induced coma is essentially a temporary state of coma in the sense that it is obtained by administering to the patient a well-calculated dose of drugs typically barbiturates, benzodiazepines or propofol in combination with opiates (morphine and derivatives) .
This is a necessary condition when you want to avoid the patient suffering from excessive pain, in fact this practice is very common following a strong trauma. The patient does not feel external stimuli as the degree of sedation is very high.

Irreversible coma and brain death
Including the distinctions between the different alterations of the state of consciousness and the different degrees of depth of the coma, as well as the characteristics of each one and the main causes of this condition, we can proceed by deepening the discussion on what concerns the irreversible coma and the medico-legal implications of the question.
We will therefore try to provide clarifications capable of answering the question:
what happens in case of irreversible coma Irreversible coma or brain death, also called depasse, corresponds to the deepest state of coma and is characterized by the complete disappearance of signs of cerebral activity, the lack of reflexes, the disappearance of autonomous breathing, in which, however, the heartbeat continues to persist and therefore the blood perfusion of the organs. Practically, once the doctors have decreed this situation there is no more possibility of awakening the patient.
Fundamental aspect for the possibility of organ donation. The fact that the heartbeat is often maintained out of affection, empathy or religious convictions, can lead one to mistakenly think that the person can recover and that vital functions are somehow recoverable, but in reality it is a condition for the ‘preciselyirreversible , as the name suggests.
At this point we can proceed by explaining the procedural process aimed at ascertaining the state of brain death . This diagnosis procedure is regulated by specific laws and decrees (Decree of the Ministry of Health of 11.04.2008 n ° 136, updated by the Decree of the Ministry of Health of 22.08.1994 n ° 582), according to which the Hospital Health Management, upon request of the ward or emergency room doctor who is treating the patient, convenes a board of 3 doctors, composed as follows:

  • A neurologist doctor;
  • A specialist in Anesthesia and Intensive Care;
  • A medical examiner (or alternatively a pathologist), who is invested with the role of guarantor of the correct conduct of the procedure.

The convened board of doctors has the task of examining the patient for a period of 6 hours, in order to ascertain the existence of 3 parameters necessary to declare the state of brain death:

  • Loss of consciousness and alertness that is accompanied by the loss of brain stem reflexes and the loss of autonomous breathing;
  • Absence of brain activity , detected by electroencephalogram (EEG);
  • Lack of cerebral blood flow , detected by performing a CT angiography of the skull, including cerebral angiography , brain scintigraphy or by a transcranial doppler.

The college therefore has the obligation to carry out two surveys of the aforementioned parameters, one at the beginning of the 6 hours of observation and one at the end, and if the criteria described above are respected there is a doubly confirmed and legally valid validation of the diagnosis of brain death.
At this point, if the general conditions allow it, based on the age of the subject or the concomitance of pathologies, it is possible to proceed with the removal of organs for donation, according to the Guidelines of the National Transplant Center and with the prior consent of family members. .
The diagnosis of brain deathallows you to interrupt health care services for a deceased person. Be careful, however, not to confuse with anything other than euthanasia, the latter procedure prohibited by law in Italy. In fact, precisely, in the event of brain death there is no longer a way for the person to restore brain functions, irreversibly compromised and which determine the person’s death by themselves.
As we have seen, the procedures for decreeing the state of irreversible coma , and therefore of brain death are articulated and complex, but above all subject to very clear directives and to the cooperation of several professionals.
In recent years, some clinical cases have been the subject of strong debates and media attention, generating a lot of confusion on the concept of coma , treating it as a generic condition. As we have seen, there are different criteria of severity and each one has specific characteristics that make it treatable or not.
With this article it is hoped that we have clarified the question and resolved some doubts and concerns, putting aside emotionality in favor of a scientific and objective awareness.
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