Coma + PVS + Brain Death

Question 1

Difference between UMN & LMN facial palsy?

Answer 1

The upper face is supplied by fibres from both sides but via a common LMN.

Therefore damaging the UMN will result in weakness of the lower face, the upper face will be partially spared.

But damaging the LMN will cause weakness of the entire one side of the face (This type is Bells Palsy)

Question 2

Define Coma

Answer 2

“State of unrousable psychologcial unresponsiveness”

Eyes closed & no perceivable response to external stimulus or inner needs.

Question 3

Consciousness depends on what 2 things

Answer 3

Arousal:
Intact Asc Reticular Activating System to alert/awaken consciousness

Awareness:
Functional Cerebral Cortex to determine the content of your consciouness

Question 4

What could cause your GCS to fall (alter consciousness)

Answer 4

• Toxic/Metabolic states such as intoxication, hypoxia/hypercapnia, sepsis, hypotension, hypoglycaemia, acidosis
• Seizures
• Damage to Reticular Activating System
• Raised ICP such as tumour, stroke, haematoma, SAH or hydrocephalus

Question 5

Define a Persistant Vegetative State?

Answer 5

After reduced consciousness (mainly comas) the Brain stem recovers to a considerable extent but no recovery of coritcal function

High wakefulness but very low awareness

Question 6

Define Locked in Syndrome?

Answer 6

Total Paralysis below III nuclei so:

• Can open and vertically move eyes
• But cant move horizontal

Diagnosis relies on spotting the patient can voluntarily open their eyes and signal by eye closure4

(Both high wakefullness and awareness)

Question 7

What causes locked in syndrome?

Answer 7

Brainstem Strokes (e.g. Pontine Arteries)
Brainstem Lesions
Traumatic Brain Injury

Question 8

Whats involved in resus for a patient with reduced consciousness?

Answer 8

ABCD
(Breathing patterns can indicate a specific condition)

Bloods (Glc, biochem, haematology, ABGs, toxicology)

BP/pulse/temp/IV acces

Stabilise neck in case of trauma

Look for evidence of meningitis

Question 9

Neuro exam of coma?

Answer 9

GCS
Brainstem function
Motor function & reflexes

Question 10

At what glasgow coma scale score do we call it Coma

Answer 10

GCS 8 or less, specifically:
Eye - 2 or less (pain or none)
Verbal - 2 or less (grunting)
Motor - 4 or less (weak flexion)

Question 11

How do we assess brainstem function?

Answer 11

Brainstem reflexes:

• Pupill reflexes (2&3)
• Corneal Reflex (5 & 7)
• Spontaneous eye movement (3/4/6)
• Oculovestibular (Caloric Stimulation) (3/4/6/8)
• Resp Pattern (Medullary Centres)
• Oculocephalic (normal nystagmus) (3/4/6/8)

Question 12

Causes of Coma without focal brainstem or lateralizing cerebral signs or meningism?

Answer 12

• Ischaemia
• Metabolic
• Intoxication
• Epilepsy
• Infection
• Hyper/Hypothermia

Question 13

How would you investigate someone with coma without focal signs or meningism?

Answer 13

Toxicology
Bloods
Hepatic/renal function
ABGs
BP

Question 14

Causes of Coma:

Answer 14

No focal signs or meningism = Toxic(Alcohol)/metabolic(hypoxia)/systemic

Meningism = SAH/meningitis/encephalitis

Focal brainstem or lateralizing signs = Tumour, infarct etc

Question 15

How would you continue to care for a coma patient?

Answer 15

• Maintain their vital functions
• Care for their skin, particularly pressure sores
• Attend to bowel/bladder function
• Control seizures
• Prophylaxis for DVTs or Peptic ulcers
• Prevent Contractures
• Assess for Locked in Syndrome

Question 16

What results of a head injury could lead to focal neuro signs?

Answer 16

• Diffuse axonal injury
• contusions
• Haematoma (intracerebral, extradural, subdural)

Question 17

How do you manage a head injury?

Answer 17

• Stabilize the C spine
• ABC
• If in coma (GCS <8) intubate and ventilate
• Treat raised ICP
• CT (may need surgery)

Question 18

In what ways can you treat raised ICP?

Answer 18

• Surgery (depends on cause)
• Osmotic Agents e.g. mannitol
• Head at 30-45 degress to increase venous return
• Analgesia
• Maintain PO2
• Lower brain metabolism by lowering temp and barbiturates to induce coma