Clinical Lecture 1: Brain Death

Question 1

What is consciousness?

Answer 1

Awareness (of self and the environment)
Alertness (or can be woken up!)
Make appropriate (and differential) responses
But is it also:
Thinking, feeling, functioning, planning, self-monitoring

Question 2

What is wakefulness?

Answer 2

Wakefulness: activity of reticular activating substance from the brainstem
Integrated with:
The connections between cells and areas of the cerebral cortex – essentially the information being relayed through the brain.

Question 3

How do you define a coma?

Answer 3

• The patient’s eyes do not open either spontaneously or to external stimulation
• The patient does not follow any commands
• The patients doe into mouth or utter recognisable words
• The patient does not demonstrate intentional movement (may show reflective movement such as posturing, withdrawal from pain or involuntary smiling)
• The patient cannot sustain visual pursuit movement of the eyes through 45 degree arc in any direction when the eye are help open manually

Question 4

What is the most common cause of a coma?

Answer 4

Metabolic coma e.g. diabetic hypoglycaemia

Question 5

Give an example of a test used in the diagnosis of a coma?

Answer 5

Glasgow Coma Scale

Question 6

What is locked-in syndrome usually as a result of?

Answer 6

Brainstem stroke. There is no cure and recovery is rare.

Question 7

What is a Persistent Vegetative state?

Answer 7

• Diagnosed if no change at 30 days
• 50% chance of improvement within 6 months, though the vast majority remain severely disabled
• Disorder of consciousness in which patients with severe brain damage are in a state of partial arousal rather than true awareness.

A vegetative state is when a person is awake but is showing no signs of awareness.

A person in a vegetative state may:

• open their eyes
• have a sleep-wave cycle
• have basic reflexes (such as blinking when they’re startled by a loud noise or withdrawing their hand when it’s squeezed hard)
• They’re also able to regulate their heartbeat and breathing without assistance.

But a person in a vegetative state doesn’t show any meaningful responses, such as following an object with their eyes or responding to voices.

They also show no signs of experiencing emotions.

Question 8

What is a Minimally Conscious State?

Answer 8

Severely altered consciousness. Reproducible but inconsistent intentional/purposeful behavioural responses

Question 9

How can we assess Prolonged Disorders fo Conciousness?

Answer 9

• Gold standard assessment is the Sensory Modality Assessment and Rehabilitation Techniques (SMART)
• Others are used (Wessex Head Injury Matrix, Ranchos Los-Amigos, JFK coma recovery scale)
• All rely on serial, standardised assessments of spontaneous behaviours and responses to a range of stimuli (SMART also uses family)

Question 10

What are the features of brain stem death?

Answer 10

• Unable to breathe and unconscious
• Destroyed reticular formation (brain stem)
• No electrical activity
• No clinical evidence of brain function

Question 11

What are the precondition dittos and exclusions for brain stem death?

Answer 11

• Preconditions: diagnosis compatible with brain stem death; presence of irreversible structural brain damage, apnoeic
• Exclusions: Drug effects, hypothermia, metabolic abnormalities, endocrine abnormalities, intoxication

Question 12

What clinical tests are done in brain stem death?

Answer 12

Clinical Tests:
- Absent brain stem reflexes (pupils, corneal, no motor response in cranial nerves, gag, cough, vestibulo-ocular)
- Persistent apnoea
This requires 2 practitioners (one consultant) on 2 occasions