Prolonged disorder of consciousness, brainstem death, and coma

Question 1

What is a prolonged disorder of consciousness?

Answer 1

Any disorder of consciousness that has continued for at least 4 weeks following sudden onset brain injury

Question 2

What is wakefulness?

Answer 2

State in which eyes are open and degree of motor arousal

Question 3

What is sleep?

Answer 3

State of eye closure and motor quiescence

Question 4

What is awareness?

Answer 4

Ability to have, and having of, experience of any kind

Question 5

What is a coma?

Answer 5

State of unrousable unresponsiveness lasting more than 6 hours in which a person is

• Unconscious and cannot be awakened
• Fails to respond normally to painful stimuli, light or sound
• Lacks a normal sleep-wake cycle
• Doesn’t initiate voluntary actions

Question 6

What is a vegetative state?

Answer 6

A state of wakefulness without awareness in which there is preserved capacity for spontaneous or stimulis-induced arousal - evidenced by sleep-wake cycles and a range of reflexive and spontaneous behaviours
Absence of behavioural evidence for self or environmental awareness

Question 7

What is a minimally conscious state?

Answer 7

State of severely altered consciousness in which minimal but clearly discernible behavioural evidence of self or environmental awareness is demonstrated
Inconsistent, but reproducible responses above level of spontaneous or reflexive behaviour indicating some degree of interaction with their surrounds

Question 8

What is damaged in a persistent vegetative state?

Answer 8

Damage to cortex and hemispheres

Question 9

What is damaged in locked-in syndrome?

Answer 9

Damage to ventral pons

Question 10

What is locked-in syndrome?

Answer 10

Disruption of voluntary control of movement without abolishing either wakefulness or awareness

Question 11

What should you do to assess an unconscious patient?

Answer 11

Causation
- Nature of injury - location, extent, reversibility
- Additional causes - medications, complications, another disorder
Aetiology
- Trauma, vascular event, hypoxic/hypoperfusion, infection/inflammation, toxic/metabolic
Imaging
- Brain imaging - nature, extent, location
- Assess fluctuating for deteriorating patient
- Determine extent and location of brain damage for clinical decision-making or to aid in prognosis
Check primary neurological pathways are intact - hear, see, feel

Question 12

What are the 3 types of behavioural responses?

Answer 12

Spontaneous - no external stimuli - try not to mistake behaviour in response to stimuli
To normal incidental stimuli
To structured planned stimuli

Question 13

What should you do to assess behavioural responses?

Answer 13

Auditory function
Visual function
Motor function
Oromotor/verbal function
Communication
Arousal

Question 14

What should you do to optimise response to treatment?

Answer 14

Excellent physical care
Appropriate seating
Sleep and rest - prevent altering circadian rhythm eg not feeding at night
Quiet room
Arousal

Question 15

How is brainstem death diagnosed?

Answer 15

Made by at least 2 medical practitioners who have been registered for > 5 years and competent in conduct and interpretation of brainstem testing - at least one must be consultant
Testing performed completely and successfully on 2 occasions with both present

Question 16

What needs to be present to diagnose brainstem death?

Answer 16

Pupils fixed and dilated and don’t respond to sharp changes in light intensity
No corneal reflex
Oculo-vestibular reflexes absent, no eye movements seen on slow injection of at least 50ml ice cold water
No motor responses within cranial nerve distribution
No cough reflex response to bronchial stimulation
No evidence of spontaneous respiration or respiratory effort during apnoea test

Question 17

What is stupor?

Answer 17

State of near-unconsciousness or insensibility

Question 18

What is obtundation?

Answer 18

State similar to lethargy in which the patient has lessened interest in the environment, slowed responses to stimulation, and tends to sleep more than normal with drowsiness in between sleep states

Question 19

What are the structural causes of coma?

Answer 19

Extra-dural haemorrhage
Sub-dural haemorrhage
SAH
Intracranial bleeds
Malignant MCA syndrome
Tumour
Hydrocephalus
(Encephalitis)

Question 20

What are the non-structural causes of coma?

Answer 20

Diabetic - hypo, DKA, hyperosmolar
Hypoxia
Drugs - opiates, benzodiazepines, others
Hypercapnia
Meningitis
Sepsis 
(Encephalitis)
Wernicke's
Other metabolic - like hepatic failure