Forensic Medicine
Clinical Features of Coma, Syncope and Asphyxia

Clinical Features of Coma, Syncope and Asphyxia

Mode of death refers to the abnormal physiological state that pertained at the time of death. It generally refers to the system that stopped its function which initiated the process of death.

As per Gordon, there are 4 modes of death:- Anoxic anoxia, Anemic anoxia, Stagnant anoxia, Histotic anoxia. But Xavier Bichat who was a French physician stated three modes of death depending on whether death begins in one or the other three systems, irrespective of what the remote cause of death may be. Those three modes of death are Coma, Syncope and Asphyxia.

  • COMA:-  Death due to failure of brain function/nervous system.
  • SYNCOPE:- Death due to failure of heat function/circulatory system.
  • ASPHYXIA:- Death due to failure of lung function/respiratory system.

Here, in this article we will discuss the clinical features of these different modes of death.

Clinical Features of Coma

It is a state of prolonged unconsciousness. In other words, it is a state of unarousable, unconsciousness determined by the absence of any external psychologically understandable response to external stimuli or inner need.

It is a clinical symptom and not a cause of death but as it’s a medical emergency, quick action should be taken in order to preserve life and brain function.

Problems that can cause coma are:

  1. Tumor in the brain or brainstem, disorder and infection like Encephalitis Meningitis.
  2. Lack of oxygen (sometimes after drowning or heart attack), diabetes, stroke.
  3. Ongoing seizures.
  4. Brain injuries, compression of brain.
  5. Intoxication due to drugs like opium, hypnotics, cocaine, atropine.
  6. Overdosing of alcohol.  

Signs and symptoms of Coma

  1. No movement of the limbs
  2. Irregular breathing
  3. No response to painful stimuli except for reflex movement
  4. Pupil not responding to light
  5. Closed eyes
  6. Depressed brainstem reflexes.

All of these can cause a lot of complications like pressure sores, infections, blood clotting and a lot more. Even though there are chances of recovery, they might have major or minor disabilities.

 If a person in a coma dies, autopsy results might indicate injuries or disease in the brain, congested lungs, brains and meninges and splanchnic pooling of blood.

Clinical Features of Syncope

It is the sudden stoppage of the function of heart that can prove to be fatal due to consequent cessation of circulation. It is also known as fainting which happens due to vasovagal attacks resulting from reflex parasympathetic stimulations.

It is caused by reflex bradycardia or asystole, or by reflex splanchnic vasodilation and blood pressure due to the changes in the circulatory system, causing cerebral anemia and unconsciousness. Generally, in cases of syncope recovery is common.

The different types of syncope are Vasovagal syncope, Situational syncope that happens due to fear, anxiety, hunger, emotional stress and so on. Postural syncope, Neurologic syncope due to stroke or transient ischemic attack or migraine, postural orthostatic tachycardia syndrome caused by rapid heart rate.

Signs and Symptoms of Syncope

  1. lightheadedness
  2. Fainting
  3. Nausea
  4. Fatigue and sweating
  5. Slow or fast heart rate
  6. Palpitation
  7. Blurred vision
  8. Weakness and unsteadiness

 The major causes of syncope are anemia due to sudden and excessive hemorrhage, poisoning, myocardial infarction, aortic stenosis, pulmonary stenosis, vagal inhibition, exhausting disease.

On conducting an autopsy on a person who dies due to syncope, the heat will appear contracted and the chambers will be empty if death occurred from anemia and if it’s due to asthenia from deficient power of heart muscles then chambers will have blood. The lungs, brain and abdominal organs will appear to be pale, splanchnic pooling of blood also occurs. 

Clinical Features of Asphyxia

Adelson defines asphyxia as a state in living organisms in which there is acute lack of oxygen available for cell metabolism associated with the inability of body to eliminate excess carbon dioxide. Lack of oxygen causes unconsciousness or death. As the brain uses 20% of the total available oxygen in the body, deficiency of oxygen majorly affects the nervous tissues.

Causes of Asphyxia

  • Mechanical causes: Hanging, Strangulation, Throttling, Smothering, Drowning, Choking, Compression over chest.
  • Toxic causes: Opium poisoning, Carbon Monoxide poisoning.
  • Pathological causes: Laryngeal spasm, Tumor, Bronchitis, Pneumonia, Acute oedema of glottis.
  • Environmental causes: Suffocated places like being trapped in a well, high altitude.

Signs and Symptoms of Asphyxia

  1. Nasal flaring or abdominal breathing due to difficulty in breathing
  2. Weak muscle tone
  3. Slow heart rate
  4. Blurred vision
  5. Sore throat
  6. Confusion

Autopsy findings of a person died due to asphyxia shows cyanosis, edema, engorgement of the right side of the heart, petechial hemorrhages, Tardieu’s spots, viscera congested, decreased fluidity of blood.   


Death is said to be from any of the three primary modes, a combination of any two or one followed by another. These modes of death are associated with three chief vital organs of the body.

The three conditions: coma, syncope and asphyxia do not necessarily cause death in all cases but when we consider that death happens due to any one of these, we can better comprehend their significance. 

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