COMA : CLINICAL FEATURES , CAUSES , CLINICAL FEATURES AND APPROACH TO DIAGNOSIS

COMA : CLINICAL FEATURES , CAUSES , CLINICAL FEATURES AND APPROACH TO DIAGNOSIS

COMA

A coma is a prolonged state of unconsciousness. 

During a coma, a person is unresponsive to his or her environment. 

The person is alive and looks like he or she is sleeping. However, unlike in a deep sleep, the person cannot be awakened by any stimulation, including pain.

Comas can be derived by natural causes, or can be medically induced.

CLINICAL FEATURES OF COMA

Patient fails to respond normally to painful stimuli, light, or sound; lacks a normal wake-sleep cycle; and does not initiate voluntary actions.

Coma patients exhibit a complete absence of wakefulness and are unable to consciously feel, speak or move.

Clinically, a coma can be defined as the inability to consistently follow a one-step command.

 It can also be defined as a score of ≤ 8 on the Glasgow Coma Scale (GCS) lasting ≥ 6 hours. 

A coma is a medical emergency. Swift action is needed to preserve life and brain function. Doctors normally order a battery of blood tests and a brain CT scan to try to determine what's causing the coma so that proper treatment can begin.

CAUSES OF COMA

Coma can be caused by a variety of causes  including  traumatic head injury, stroke, brain tumor, drug or alcohol intoxication, or even an underlying illness, such as diabetes or an infection to  name a few.

Traumatic brain injuries. Traumatic brain injuries, often caused by traffic collisions or acts of violence, are common causes of comas.

Stroke. Reduced or interrupted blood supply to the brain (stroke), which may be caused by blocked arteries or a burst blood vessel, can result in a coma.

Opiod toxicity , Post ictal , Subrachnoid haemorrhage / SAH

Tumors. Tumors in the brain or brainstem can cause a coma.

Diabetes. In people with diabetes, blood sugar levels that become too high (hyperglycemia) or too low (hypoglycemia) can cause a coma.

Lack of oxygen. People who have been rescued from drowning or those who have been resuscitated after a heart attack may not awaken due to lack of oxygen to the brain.

Infections. Infections such as encephalitis and meningitis cause swelling (inflammation) of the brain, spinal cord or the tissues that surround the brain. Severe cases of these infections can result in brain damage or a coma.

Seizures. Ongoing seizures may lead to a coma.

Toxins. Exposure to toxins, such as carbon monoxide or lead, can cause brain damage and a coma.

Drugs and alcohol. Overdosing on drugs or alcohol can result in a coma.

CLINICAL APPROACH TO DIAGNOSIS

Because people in a coma can't express themselves, doctors must rely on physical clues and information provided by families and friends. 

Be prepared to provide information about the affected person, including:

Events leading up to the coma, such as vomiting or headaches

Details about how the affected person lost consciousness, including whether it occurred suddenly or over time

Any noticeable signs or symptoms prior to losing consciousness

The affected person's medical history, including other conditions he or she may have had in the past, such as a stroke or transient ischemic attacks

Recent changes in the affected person's health or behavior

The affected person's drug use, including prescription and over-the-counter medications as well as unapproved medications or illegal, recreational drugs

PHYSICAL EXAMINATION

In a physical exam, doctors will check the affected person's movements and reflexes, response to painful stimuli, and pupil size. 

A head to toe screen is performed looking at general condition of the patient including hygiene/ nutrition status which if inadequate can indicae alcohol or drug abuse.

Look for signs of drug abuse such as needle track marks

Doctors will observe breathing patterns to help diagnose the cause of the coma. Doctors also may check the skin for signs of any bruises due to trauma.

To determine the affected person's level of consciousness, doctors may speak loudly or press on the angle of the jaw or nail bed. Doctors will watch for signs of arousal, such as vocal noises, eyes opening or movement.

Doctors will test reflexive eye movements. These tests can help determine the cause of the coma and the location of brain damage.

Doctors also may squirt ice-cold or warm water into the affected person's ear canals and observe eye reactions.

Look for any signs of chronic liver disease which suggests Alcohol abuse.

Observe any signs of trauma and bruising on head or other parts of the body.

Observe the respiratory pattern : Cheynes stokes respiration indicates bilateral cortical damage , hyperventilation suggest Metabolic acidosis oor brainstem pathology.