Brief overview
- What is coma? A prolonged deep unconsciousness and the most severe form of impaired consciousness. There are different levels of coma from mild (patient reacts to certain stimuli) to deep (no longer reacts).
- Forms: In addition to the classic coma, there are waking coma, minimally conscious state, artificial coma and locked-in syndrome.
- Causes: e.g. diseases of the brain (such as stroke, craniocerebral trauma), metabolic disorders (such as oxygen deficiency, hyper/ hypoglycaemia), poisoning (e.g. by drugs, poisons, anaesthetics)
- When to see a doctor? Always! Call the emergency doctor immediately if someone falls into a coma.
- Therapy: Treatment of the cause, intensive medical care, artificial nutrition/ventilation if necessary, stimulation of the brain through massage, light, music, speech, etc.
Coma: Description
The term “coma” comes from the Greek. It means something like “deep sleep”. A person in a coma can no longer be woken up and only reacts to external stimuli such as light or pain to a very limited extent or not at all. In a deep coma, the eyes almost always remain closed. A coma is the most severe form of impaired consciousness.
Depending on the depth of the coma, a distinction is made between four coma stages:
- Light coma, stage I: Patients still react to painful stimuli with targeted defensive movements. Their pupils contract when exposed to light.
- Mild coma, stage II: Patients only defend themselves against pain stimuli in an untargeted manner. The pupillary reflex works.
- Deep coma, stage III: The patient no longer shows any pain defense reaction, but only untargeted movements. The pupillary reaction is only weak.
- Deep coma, stage IV: The patient no longer shows any pain reaction at all, the pupils are dilated and do not react to light.
A coma can last from a few days to a maximum of several weeks. Then the patient’s condition usually either improves quickly or brain death occurs.
Smooth transitions
Today, a coma is increasingly no longer seen as a static state, but as a changing process. Coma, vegetative state (apallic syndrome) and minimally conscious state (MCS) can merge seamlessly into one another. Some patients regain full consciousness but are almost completely paralyzed. Experts then speak of locked-in syndrome (LiS).
Coma as a protective reaction
Some neuropsychologists now believe that a coma is not a passive state, but an active protective reaction. It is assumed that those affected have withdrawn to a very deep level of consciousness following brain damage. With the help of therapy, however, they may be able to regain access to the world.
Coma: causes and possible diseases
A coma can be triggered directly by an injury or disease of the brain. Sometimes, however, severe metabolic imbalances also lead to a coma. Poisoning by drugs or other toxins can also be the cause of deep unconsciousness.
Diseases of the brain
- Stroke
- Craniocerebral trauma
- Meningitis (inflammation of the meninges)
- Inflammation of the brain (encephalitis)
- Cerebral hemorrhage
- Epileptic seizure
- Brain tumor
Metabolic disorder (metabolic coma)
- Circulatory failure
- Oxygen deficiency
- Low blood sugar (hypoglycemia)
- Hyperglycemia (hyperglycemia, hyperosmolar coma, diabetic coma)
- Renal insufficiency (uraemic coma)
- Liver insufficiency (hepatic coma)
Poisoning
- Drugs (e.g. alcohol, narcotics)
- poisons
- Narcotics
Coma: the most important forms
In addition to the classic coma, there are forms of coma in which consciousness still appears to be present to a certain degree.
Waking coma (apallic syndrome)
Due to their open eyes and their ability to move, those affected appear awake despite being unconscious. However, their gaze is either fixed or wanders unsteadily. Although patients in a vegetative state have to be artificially fed, they can, for example, grasp, smile or cry. In a real vegetative state, however, these movements are unconscious reflexes. The term “persistent vegetative state” (PVS) indicates that the functions of the vegetative nervous system, such as breathing, heartbeat and sleep rhythm, are still functioning, while higher cognitive functions are paralyzed.
The reason for the state of a vegetative state is damage to the cerebrum, which forms the outer layer of the human brain. It envelops the deeper brain structures like a cloak, which is why it is also referred to as “apallic syndrome” (Greek for “without a cloak”). The cerebrum processes all sensory impressions: Seeing, hearing, feeling, tasting and smelling. It stores memories and is the seat of consciousness. An injury, illness or lack of oxygen to the brain can cause it to fail almost completely.
Minimally Conscious State (MCS)
At first glance, minimally conscious state and vegetative state appear to be confusingly similar. Patients have a sleep-wake rhythm controlled by the autonomic nervous system. Due to their open eyes, movements and facial expressions, they appear awake at times.
However, while patients in a vegetative state are only capable of unconscious reflexes, at least according to the doctrine, patients in a minimally conscious state occasionally show purposeful reactions to external stimuli (such as sounds, touch) or even expressions of emotion in the presence of relatives.
As some patients slip from a vegetative state into a minimally conscious state, scientists and doctors increasingly see the boundaries between the two states as blurred.
The likelihood of someone waking up from a minimally conscious state is far higher than when they wake up from a vegetative state. If the condition does not improve in the first twelve months, the chance of the patient recovering decreases considerably. However, even awakened patients usually remain severely disabled due to their severe brain damage.
Artificial coma
Locked-in syndrome
Locked-in syndrome is not actually a form of coma. However, without closer examination, it can easily be confused with a vegetative state, which is associated with paraplegia. Patients with locked-in syndrome are awake and fully conscious, but completely paralyzed. Some at least still have control over their eyes and can communicate by blinking.
Coma: When do you need to see a doctor?
Unconsciousness is always a medical emergency. Therefore, always call an emergency doctor. Provide first aid until the doctor arrives. In particular, make sure that the patient is breathing. If this is not the case, start chest compressions immediately.
Coma: what the doctor does
It is often difficult to determine how deep a coma actually is. The fact that the patient does not respond to requests such as “Look at me” or “Squeeze my hand” does not necessarily say anything about their level of consciousness.
It can also be difficult to differentiate between a vegetative state and a minimally conscious state. It has been shown, for example, that some patients in a vegetative state can still process verbal utterances.
However, even such brain scans are not 100% reliable. For example, the diagnosis can be falsified if a patient with a minimally conscious state is in a deep unconscious state during the examination. In this case, conscious moments are not recorded. Experts are therefore calling for coma patients to be sent through the brain scan several times before a diagnosis is made.
Therapy
Coma therapy initially focuses on treating the illness that triggered the coma. In addition, people in a coma usually require intensive medical care. Depending on the depth of the coma, they are artificially fed or even ventilated. Physiotherapy and occupational therapy measures are also sometimes required.
For people in a vegetative state or with minimal consciousness, coma researchers are increasingly calling for permanent therapeutic measures that offer the brain sensory stimuli. A brain that is stimulated in this way is more likely to resume its work. Suitable stimuli include massages, colored light, movement in water or music, but above all loving touch and direct contact with the patient. Relatives play a central role in activation.
Coma: What you can do yourself
A person in a coma is dependent on help. In addition to physical care, this also includes human assistance. This is not only a question of ethics, there is also increasing evidence that the consciousness of many people in a coma is not completely extinguished. Loving and respectful treatment of the patient is therefore immensely important.
This has an effect, even if it is not always visible from the outside. Awake coma patients in particular often react to loving stimulation with a change in heart rate and breathing. Muscle tone and skin resistance also change.
Even if carers and relatives cannot know how much patients in a coma really perceive, they should always behave as if the patient can perceive and understand everything.