Coma

Question 1

Define “coma”

Answer 1

a state of unrousable psychological unresponsiveness in which the patients lie with eyes closed and show no psychologically understandable response to external stimuli or inner need
GCS < 8

Question 2

What two things are needed to a person to be conscious?

Answer 2

1) an intact ascending reticular activating system to act as the alerting/awakening element of consciousness
2) a functioning cerebral cortex of both hemispheres to determine the content of consciousness

Question 3

Describe the causes of depressed consciousness

Answer 3

Toxic/metabolic states
Seizures
Raised ICP
Damage to the reticular activating system

Question 4

Describe the toxic/metabolic states that can cause a decreased level of consciousness

Answer 4

Hypoxia, hypercapnia, sepsis, hypotension
Hypoglycaemia, ketoacidosis
Drug intoxication, renal failure, liver failure

Question 5

What types of brain damage can affect the conscious level?

Answer 5

Diffuse hemisphere damage
Brainstem damage
Bilateral thalamic involvement
Midbrain compression from a supratentoral mass
Brainstem compression (direct or indirect)

Note: focal damage to the cortex does NOT affect the conscious level.