Coma, Persistent Vegetative State, Brain Death

Question 1

What does consciousness depend on?

Answer 1

Intact descending reticular activating system to act as the alerting or awakening element of consciousness
Functioning cerebral cortex of both hemispheres which determines the content of the consciousness

Question 2

Causes of decreased GCS

Answer 2

Toxic metabolic states e.g. hypoxia, hypotension, drug intoxication, renal failure, hypoglycaemia, ketoacidosis
Seizures
Damage to reticular activating system
Causes of raised ICP e.g. tumour, stroke

Question 3

What is a coma?

Answer 3

State of unrousable psychological unresponsiveness in which the subjects lie with eyes closed and show no psychologically understandable responses to external stimuli or inner need

Question 4

What is a persistent vegetative state?

Answer 4

State in which the brainstem recovers to a considerable extent but there is no evidence of recovery of cortical function. There is arousal and wakefulness but the patient does not regain awareness or purposeful behaviour of any kind.

Question 5

What is locked in syndrome?

Answer 5

Where the patient has paralysis below the level of the third nerve nuclei. They can open, elevate and depress the eyes but have no horizontal eye movement and no other voluntary eye movement.

Question 6

What does the diagnosis of locked in syndrome depend on?

Answer 6

Recognising that the patient can open their eyes voluntarily and signal numerically by eye closure

Question 7

Important points of history of a patient in a coma

Answer 7

Predictable progression of underlying illness
Unpredictable event in patient with previously known disease
Totally unexpected e.g. head injury, sudden collapse, limb twitching, previous history of drug/alcohol abuse

Question 8

Important points of examination and monitoring of a patient in a coma

Answer 8

Temperature 
Heart rate 
BP 
Respiration 
Skin, breath 
Abdomen 
Meningism signs 
Fundal exmaination 
Neurological assessment using GCS, brainstem function, motor function and reflexes

Question 9

Glasgow coma scale - eye opening criteria and scoring

Answer 9

Spontaneous - 4
To speech - 3
To pain - 2
None - 1

Question 10

Glasgow coma scale - best verbal response criteria and scoring

Answer 10

Orientated - 5 
Confused - 4 
Inappropriate words - 3 
Incomprehensible sounds - 2 
None - 1

Question 11

Glasgow coma scale - best motor response criteria and scoring

Answer 11

Obeying commands - 6 
Localising to pain - 5
Withdrawing from pain - 4 
Flexing to pain - 3 
Extending to pain - 2 
None - 1

Question 12

What GCS score indicates coma?

Answer 12

< 8

Question 13

Cranial nerves tested by pupillary reactions

Answer 13

II and III

Question 14

Cranial nerves tested by corneal responses

Answer 14

V and VII

Question 15

Cranial nerves tested by spontaneous eye movements

Answer 15

III, IV, VI

Question 16

Cranial nerves tested by oculocephalic responses

Answer 16

III, IV, VI, VIII

Question 17

Cranial nerves tested by oculovestibular responses

Answer 17

III, IV, VI, VIII

Question 18

Nerves tested by respiratory pattern

Answer 18

Medullary centre

Question 19

Blood tests done for a patient in a coma

Answer 19

Glucose 
Biochemistry 
Haematology 
Blood gas 
Toxicology

Question 20

What needs to be established in a patient in a coma?

Answer 20

Baseline blood pressure, pulse, temperature
IV access
Stabilise neck

Question 21

Conditions to consider in coma without focal or lateralising signs and without meningism

Answer 21

Anoxic/ischaemic conditions 
Metabolic disturbances 
Intoxications 
Systemic infections 
Hyperthermia/hypothermia 
Epilepsy

Question 22

Investigations to be done for a patient in a coma

Answer 22

Toxicology screen including alcohol level 
Measure blood sugar and electrolytes 
Assess hepatic and renal function 
Acid-base assessment and blood gases 
Measure BP 
Consider carbon monoxide poisoning

Question 23

Conditions to consider in coma without focal or lateralising signs but with meningism and investigations to do

Answer 23

Subarachnoid haemorrhage
Meningitis
Encephalitis

CT head
Lumbar puncture

Question 24

Conditions to consider in coma with focal brainstem or lateralising cerebral signs and investigations to do

Answer 24

Cerebral tumour
Cerebral haemorrhage
Cerebral infarction
Cerebral abscess

CT/MRI
Metabolic screen, lumbar puncture, EEG

Question 25

Medical causes of coma lasting > 5 hours

Answer 25

40% drug ingestion +/- alcohol
25% hypoxia
20% cerebrovascular event
15% metabolic

Question 26

Factors affecting prognosis of patients in a coma

Answer 26

Age 
Cause 
Depth of coma 
Duration of coma 
Clinical signs, most importantly brainstem reflexes

Question 27

What percentage of patients in a non-traumatic coma for more than 6 hours will make a good or moderate recovery?

Answer 27

15%

Question 28

Management of patients in a coma

Answer 28

Resuscitation - ABCs 
Maintenance of vital functions 
Care of skin 
Bladder and bowel function 
Control of seizures 
Prophylaxis of DVT and peptic ulceration 
Prevention of contractures 
Consider locked-in syndrome

Question 29

Head injury can lead to focal neurological signs/epilepsy due to

Answer 29

diffuse axonal injury
contusion
intracerebral haematoma
extracerebral haematoma

Question 30

Management of head injury

Answer 30

Stabilise cervical spine
Airway, breathing and circulation stabilisation
Intubation and ventilation if GCS 8 or less
Treat raised ICP
Cranial imaging
Neuro-observation

Question 31

Treatment of increased ICP

Answer 31

Surgery to relieve pressure
Osmotic agents
Maintain good PO2, reduce PCO2
Reduce metabolism