What is a Coma?

Coma is a type of total loss of consciousness and is a clinically critical illness. The occurrence of coma indicates that the patient's cerebral cortical function has severely impaired. The main manifestations are complete loss of consciousness, loss of voluntary movement, and slow or loss of response to external stimuli, but the patient still has breathing and heartbeat.

Feng Geng

(Chief physician)

Emergency Department of Beijing Emergency Center

Coma is a type of total loss of consciousness and is a clinically critical illness. The occurrence of coma indicates that the patient's cerebral cortical function has severely impaired. The main manifestations are complete loss of consciousness, loss of voluntary movement, and slow or loss of response to external stimuli, but the patient still has breathing and heartbeat.

There is also a coma called wakeful coma, also known as "glaring coma" or "decortical state". Patients are mainly free to open their eyes and close their eyes. The eyeballs are in an aimless roaming state, which is easily misunderstood as the existence of the patient's consciousness. However, the patient's thinking, judgment, speech, memory, etc., and the ability to respond to surroundings are completely lost. He cannot understand any problems, cannot execute any instructions, and actively respond to any stimulus. This situation is commonly known as "vegetative". The emergence of awake coma indicates that the patient's brainstem function exists and the cerebral cortex function is lost. In most cases, the function is difficult to recover, so the patient's prognosis is poor.

English name

coma

Visiting department

Department of Emergency Medicine, Neurology, Neurosurgery, Endocrinology

Common causes

There are two major types of intracranial and extracranial lesions

Common symptoms

Loss of complete consciousness, loss of voluntary movements, unresponsiveness or loss of response to external stimuli

Contagious

no

Cause of coma

Coma can be caused by a variety of conditions, and its etiology classification varies from different angles. It is clinically divided into two categories: intracranial and extracranial lesions (Figure 1).

Coma clinical manifestations

There are roughly three cases of clinically complete loss of consciousness, namely coma, syncope, and cardiac arrest. Syncope is a brief loss of consciousness, and the patient is usually awake within minutes. Cardiac arrest is the most serious case. This state is called "clinical death." If the patient cannot be rescued within minutes, irreversible biological death will occur. Therefore, when the loss of consciousness occurs, it is necessary to immediately identify whether the patient is unconscious, syncope, or cardiac arrest. Cardiopulmonary resuscitation must be carried out immediately on the latter to save patients' lives. The degree of coma is medically divided into:

Mild coma

The patient's loss of consciousness and voluntary movements may occasionally result in involuntary spontaneous movements. Passive posture, no response to external things, sound, light stimulation, occasional involuntary spontaneous movements and eye movements. Painful expressions can appear on strong stimuli such as the inner thighs or the supraorbital hole. If you use a needle to draw the soles of your feet, you can have deflective flexion or avoid movement. You cannot answer questions and perform simple commands. Various reflections and vital signs did not change significantly. In mild coma, various reflexes (such as swallowing reflex, cough reflex, corneal reflex, and pupil reflex, etc.) are present, and breathing, pulse, and blood pressure are mostly normal. Some patients have urine retention or incontinence.

2. Moderate coma

The patient did not respond to various stimuli, the eyeballs did not rotate, various reflexes were weakened (this is different from mild coma), and there was retention or incontinence. There may be changes in breathing, pulse, blood pressure and pathological reflexes.

3. Severe coma

The patient's muscles are loose, without any autonomous movements, and he may have an ankylosing phenomenon. He has no response to all external stimuli. The corneal reflex, pupil reflex, cough reflex and swallow reflex disappeared; all kinds of shallow and deep reflexes and pathological reflexes disappeared. Vital signs are unstable and incontinence.

4. Excessive coma

On the basis of deep coma, the patient has hypothermia, unstable brainstem reflex function, dilated pupillary fixation, and loss of spontaneous breathing function, which needs to be maintained by artificial respirator, and blood pressure also needs to be maintained by booster drugs. Electrical rest, brain stem evoked potentials disappeared. Excessive coma is a clinical manifestation of "brain death".

Coma check

Examination of the coma is not difficult. As long as the patient is given a certain stimulus, such as repeatedly tapping the patient and calling his name, if the patient is not responding and has the performance of respiratory heartbeat, a diagnosis of coma can be made. There are many tests to confirm the cause of coma, and they should be implemented and screened according to the specific situation.

Several important neurological examinations

Meningeal irritation

The main manifestations are neck rigidity, Kernig's sign (Kröig's sign), and Brukinsky's sign (Cloth sign). Positives are seen in subarachnoid hemorrhage, meningitis, and cerebral hernia. Checking for signs of meningeal irritation in a comatose patient is one of the procedures that must be performed by first aiders, but note that sometimes the patient's muscle tone is highly enhanced (angled arch) and can sometimes be confused with meningeal irritation. In addition, in deep coma patients, Meningeal irritation can disappear.

2. Pupil examination

Bilateral pupil narrowing is needle-like: common in organophosphorus, morphine, sleeping drug poisoning, and axillary hemorrhage;

(1) Bilateral pupillary enlargement is seen in ethanol, atropine and cyanide poisoning, hypoglycemic coma, seizures, ventricular hemorrhage and advanced cerebral hematoma, and excessive coma; pupils are often seen in cerebral edema or early hernia;

(2) The bilateral pupils are unequal in size seen in brain hernias. But pay attention to ask the patient if there is a history of glaucoma, a history of cataracts, a history of eye surgery, and a history of installation of prosthetic eyes, so as not to cause misunderstanding and false alarm.

3. Reflection inspection

(1) Brainstem reflex corneal reflex, mandibular reflex, pupil reflex, palmar plantar reflex, eye-cardiac reflex, etc .;

(2) Superficial corneal reflex, pharyngeal reflex, abdominal wall reflex, testicular reflex, and anal reflex, etc .;

(3) Deep reflex radial periosteum reflex, biceps and triceps reflex, Hoffmann sign, knee and Achilles tendon reflex;

(4) Pathological reflex Babinski's sign, Oppenheim's sign, Gordon's sign, etc.

4. Other inspections

Electrocardiogram, blood oxygen saturation, and blood glucose measurement are helpful to the diagnosis of coma and should be fully utilized.

Coma diagnosis

Judgment based on medical history and clinical manifestations

Incidence of coma

Acute and chronic cerebrovascular disease, poisoning and hypoglycemia are the diseases with the highest incidence of out-of-hospital coma;

2. the onset of illness

Sudden onset: acute cerebrovascular disease, poisoning, hypoglycemia, brain trauma and epilepsy; slow onset: brain tumors, infections and metabolic disorders such as uremia, pulmonary encephalopathy, liver encephalopathy, etc .;

3. Judgment based on the patient's previous medical history

(1) Acute cerebrovascular disease with history of hypertension and arteriosclerosis ;

(2) history of diabetes, hypoglycemia, ketoacidosis, hypertonic coma;

(3) History of other diseases Epilepsy, chronic kidney disease, liver disease, lung disease, intracranial space-occupying disease, etc. can occur in their respective coma.

4. Judgment based on incidents

(1) Fever is more common in infections, hyperthyroidism crisis, heat stroke, cerebral malaria, etc .;

(2) The smell of garlic is seen in organophosphate poisoning, rotten apple smell is seen in ketoacidosis, urinary odor is seen in uremia, liver odor is seen in liver coma, and alcoholic taste is seen in alcoholism;

(3) Convulsions are more common in epilepsy and cerebrovascular disease;

(4) headache is more common in intracranial diseases;

(5) Hypotension is more common in shock, Alzheimer's syndrome, hypothyroidism, diabetes, adrenal insufficiency, sedation or sleeping pills poisoning.

(6) Hypertensive acute cerebrovascular disease, hypertensive encephalopathy, etc .;

(7) Meningeal irritation, intracranial infection, subarachnoid hemorrhage;

(8) Acute cerebrovascular disease with localized signs of the nervous system ;

(9) Skin flushing is more common in infections and alcoholism; cherry red is more common in CO poisoning; cyanosis is more common in hypoxic diseases such as heart and lung diseases and nitrite poisoning; pale is more common in anemia, blood loss, shock; yellow stain Found in hepatobiliary disease or hemolysis.

5. Other

(1) History of poison exposure to pesticides, carbon monoxide, etc .;

(2) Traumatic brain contusion, intracranial hematoma, etc .;

(3) Environmental factors such as temperature and altitude.

Coma treatment

Once the coma occurs, no matter what the reason, it indicates that the patient is critically ill and the patient must get effective on-site first aid as soon as possible.

1. On-site first aid principle for coma

(1) All patients need to go to the hospital for further diagnosis and treatment, so they should be sent to the hospital as soon as possible, and it will not be good for the patients to stay at home or in the community for observation and treatment (Figure 2).

(2) Keep the patient's airway unobstructed, clean up airway foreign bodies in time, use the oropharyngeal tube for those with greater respiratory resistance, and enable the patient to use a stable lateral position. Drainage to prevent aspiration due to reflux of the contents of the digestive tract. Therefore, the lateral position is the position that a comatose patient must take before being admitted to the hospital.

2. Supportive and symptomatic treatment

Provide oxygen, establish venous channels, maintain blood pressure and hydroelectricity balance, provide respiratory support for people with abnormal breathing (mask airbag artificial respiration, tracheal intubation, respiratory stimulants, etc.), give diazepam to convulsants, and for high intracranial pressure Patients are given dehydration medication.

3. Etiology treatment

According to the primary diseases and causes of coma, take targeted treatment measures, such as antibiotic treatment for infections, oxygen supply measures for hypoxic coma, and supplementary sugar measures for hypoglycemia.