Coma: duration, cause, what are the chances of waking up?

Whether alcoholic, diabetic, hydraulic or artificial, coma means an alteration in the state of consciousness which requires prompt and appropriate support. Among the causes, one can evoke a cerebral hemorrhage or an important alcohol abuse. How long can you stay in a coma? What are the causes of coma? What are the chances of waking up?

Definition: what is a coma?

Coma is defined as a altered state of consciousness in which the patient can no longer react to stimuli. In fact, the coma no longer allows the person who is a victim to have a relational life with those around him. Along with this lack of awareness, vital functions are preserved. When a person is in a coma, his alertness and consciousness are abolished. In some cases, appropriate treatment can address the cause. Her vital functions are maintained, but she has no more sensory perception and does not react to pain. The person in the coma cannot remain in this state for a long time without external assistance to meet his needs, whether it is his hydrationher feedbut also the protection of his skin. In effect, the person being unable to move, the weight of the body constantly rests on the same points of support, risking damage to the underlying tissues (what is called a bedsore). A person in a coma must therefore be mobilized regularly to prevent the appearance of these lesions. The evolution can be rapidly favourable, continue in this way for a very long time (sometimes years) or lead to death of the person. For this reason, a person in a coma should be treatment as soon as possible by a medical team.

What are the types of coma?

► Ethyl coma: a vital emergency. “Ethyl coma corresponds to a alcohol poisoning inducing disturbances of consciousness” explains Dr. Degremont. It is linked to excessive alcohol consumption, usually over a short period: the faster the alcohol is absorbed, the greater the risk of alcoholic coma. The blood alcohol level leading to alcoholic coma varies according to several parameters such as weight, amount of body fat, diet; alcohol addiction and drinking rate. It’s about a vital emergency that can leave neurological sequelae.

► Artificial coma. “An artificial coma is a coma induced for allow the treatment of a patient for example in intensive care“explains Dr. Degremont. It is caused by drugs sedativessuch as the midazolam where the propofol. The objective is to “put the brain to rest”. It is one of the basic treatments, especially in the event of post-traumatic coma or cerebral edema which risks causing intracranial hypertension. As it is an induced coma, it is by definition better controlled. Nevertheless, plunging the brain into a pharmacological coma is not without consequenceeven if it is sometimes essential to protect the brain in the acute phase.

► Diabetic coma. Diabetic coma is one of the three most serious complications of diabetes mellitus. These complications are diabetic ketoacidosis (blood hyperacidity following the abnormal accumulation of toxic elements called “ketone bodies”), hyperglycemic hyperosmolarity syndrome (caused mainly by hyperglycemia, therefore too high blood glucose levels) and severe diabetic hypoglycaemia (low blood glucose levels). Diabetic coma should lead to immediate hospitalization of the patient : not covered, it can lead to the death of the person.

► Hydraulic coma. Water coma results from a water intoxication also called hyperhydration. This occurs when the body absorbs too much water in a very short period of time.

How long does a coma last?

“The duration depends on the cause”, explains Dr. Degremont. “Generally the ‘toxic’ causes are short-lived, the cerebral causes rather long-lasting (either directly as a trauma or stroke ; either indirectly as on a cardiac arrest with cerebral suffering)” he specifies.

What are the symptoms of a coma?

Coma is a momentary or non-temporary loss of consciousness, which can be spontaneous or medically induced. The duration of a coma is more or less long depending on its origin. The coma is usually reversible. It can be caused by poisoning, trauma, or a neurological condition (such as epilepsy) that affects the cerebral cortex. Coma does not necessarily imply brain damage. We speak of a coma when the patient does not respond to pain, verbal prompts or other stimuli.

What is the cause of a coma?

Coma is often associated with a accidental event such as violent trauma during a accident on the road or on skis, for example. The brain undergoes a shock whose waves reverberate deeply undermining its functioning. Lesions as well as cerebral hemorrhage may occur and also be responsible for the coma. Coma can also be the result of severe poisoning. So the carbon monoxide which is a gas responsible for serious poisoning, sometimes fatal, in winter due to poorly adjusted heaters, can also lead to a coma. “There are also drug poisoning such as with benzodiazepines“ says Dr. Degremont. Metabolic disorders as in the case of diabetic coma may exist as well as infectious causes (meningitis For example). Some brain tumors or strokes may manifest as the sudden onset of a coma.

The diagnosis is made based on the glasgow score based on clinical assessment. “It is an objective score allowing from simple elements to evaluate the state of consciousness of a patient” explains Dr. Degremont. It allows to quantify the severity of the coma by developing a score from 3 (deep coma) to 15 (normal state of wakefulness and consciousness).

► This score evaluates eye opening rated out of 4 with 4 points for spontaneous opening, 3 for opening on demand, 2 for opening to pain, 1 for total absence of opening.

► It also assesses the verbal response rated out of 5 with 5 for oriented speech, 4 for confused speech, 3 for incoherent remarks with a few recognized words, 2 for sounds without understandable words, 1 for total silence.

► Finally, it makes it possible to assess motor response out of 6 with 6 for an act correctly performed on command, 5 for a localized reaction to pain, 4 for an unsuitable avoidance maneuver, 3 for a flexion reaction in response to pain, 2 for an extension response to pain, 1 for total absence of movement.

“The first thing to do in the event of a loss of consciousness is to call the emergency services”

Additional examinations are carried out in the event of a coma to find the cause and are directed according to the various clinical suspicions evoked by the context: blood test, brain scan, MRI in case of trauma and lumbar puncture if meningitis is suspected. As soon as an alteration of consciousness appears, care must be provided. If a person is in a coma, first aid must be given before the arrival of the medical teams in order to prevent their condition from worsening. “The first thing to do in the event of a loss of consciousness is to notify the emergency services, then to ensure that the person is breathing and place in a lateral safety position” details Dr. Degremont. Once the doctors and nurses are on site, they will endeavor to determine the origin of the coma in order to provide treatment if possible while maintaining the person’s vital functions.

What is the care of a patient in a coma?

In the event of a coma, the emergency medical care is essential. The subject should be placed under surveillance to ensure the maintenance of vital functions (blood circulation and therefore heartbeats and pulmonary respiration). A Glasgow score below 8 requires a intubation to ensure the patient’s respiratory function. Since the patient is unable to feed himself, he is fed by blood infusion or by digestive tube as long as the coma persists. We make sure to avoid the appearance of bedsores by mobilizations and a suitable mattress. The treatment is then done according to the causes.

What are the chances of waking up from a coma?

Evolution is most often unpredictable and mostly depends on the cause. Comas due to drug poisoning are usually good prognoses. The evolution of those with a traumatic origin mostly depends on age (younger people are more likely to see their condition improve). It is possible to see people remain in a deep coma for several years. Coma can sometimes be maintained artificially in some cases using sedative molecules.

Thanks to Dr. Julien Degremont, intensive care physician, for his details.