Coma, Persistent Vegetative State, Brain Death Flashcards

1
Q

What is a coma?

A

A state of unarousable psychological unresponsiveness in which the subjects lie with eyes closed and show no psychologically understandable response to external stimulus or inner need

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2
Q

What is used to assess a coma?

A

Glasgow coma scale (GCS)

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3
Q

What does GCS stand for?

A

Glasgow coma scale

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4
Q

What are the 3 responses assesses in the GCS?

A

Eye opening response

Verbal response

Motor response

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5
Q

Describe the scores for the eye opening response part of the GCS?

A
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6
Q

Describe the scores for the verbal response part of the GCS?

A
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7
Q

Describe the scores for the motor response part of the GCS?

A
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8
Q

What are the 3 classes of injury from the GCS?

A

Minor brain injury

Moderate brain injury

Severe brain injury

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9
Q

What points on GCS is minor brain injury?

A

13-15

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10
Q

What points on GCS is moderate brain injury?

A

9-12

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11
Q

What points on GCS is severe brain injury?

A

3-8 points

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12
Q

What does consciousness depend on?

A
  • Intact ascending reticular activating system to act on the alerting or awakening element of consciousness
    • (arousal)
  • A functioning cerebral cortex of both hemispheres which determines the content of that consciousness
    • (awareness of environment)
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13
Q

What are some causes of decreased GCS?

A
  • Toxic/metabolic states
    • Hypoxia/hypercapnia/sepsis/hypotension
    • Drug intoxication/renal or liver failure
    • Hypoglycaemia, ketoacidosis
  • Seizures
  • Damage to reticular activating system
  • Causes of raised intracranial pressure
    • Tumour, stroke, EDH (epidural haemorrhage), SDH (subdural haemorrhage), SAH (subarachnoid haemorrhage), hydrocephalus
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14
Q

What are some causes of raised ICP?

A
  • Tumour, stroke, EDH (epidural haemorrhage), SDH (subdural haemorrhage), SAH (subarachnoid haemorrhage), hydrocephalus
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15
Q

What can cause toxic/metabolic stress and lead to decrease in GCS?

A
  • Hypoxia/hypercapnia/sepsis/hypotension
  • Drug intoxication/renal or liver failure
  • Hypoglycaemia, ketoacidosis
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16
Q

What can increased respiration be due to?

A

Hypoxia

Hypercapnia

Acidosis

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17
Q

What can depressed respiration be due to?

A

Drug overdose

Metabolic disturbance

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18
Q

What can fluctuating respiration be due to?

A

Brainstem lesion

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19
Q

What blood samples should be done for patients who go into a coma?

A
  • Glucose, biochemistry, haematology, blood gas
  • Toxicology
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20
Q

What are some causes of a patient going into a coma?

A
  • Predictable progression of underlying illness
  • Unpredictable event in patient with previously known disease
  • Totally unexpected event
    • Head injury, sudden collapse, limb twitching, previous history of drug or alcohol abuse
21
Q

What parts of examination are important for coma?

A
  • Temperature
  • Heart rate, blood pressure, CVS
  • Respiration
  • Skin, breath
  • Abdomen
  • Meningism
  • Fundal examination
22
Q

What parts of neurological assessment are important for coma?

A
  • Glasgow coma scale
  • Brainstem function
  • Motor function and reflexes
    • Motor response
    • Muscle tone
    • Tendon reflexes
    • Seizures
23
Q

How is brianstem function tested?

A
24
Q

What is useful for establishing the causes of a coma?

A

Tabulate coma, meningism and focal brainstem or lateralising cerebral signs

25
Q

Coma without focal or lateralising signs and without meningism could be due to?

A
  • Anoxic/ischaemic conditions
  • Metabolic disturbances
  • Intoxications
  • Systemic infections
  • Hyperthermia/hypothermia
  • Epilepsy
  • Investigations to determine this
26
Q

What investigations can be done to determine the cause of a coma without focal or lateralising signs and without meningism?

A
  • Toxicology screen including alcohol level
  • Measure blood sugar and electrolytes
  • Assess hepatic and renal function
  • Acid-base assessment and blood gases
  • Measure blood pressure
  • Consider carbon monoxide poisoning
27
Q

Coma without focal or lateralising signs but with meningism (clinical syndrome of headache, neck stiffness and photophobia, often with nausea and vomiting) could be due to what?

A
  • Subarachnoid haemorrhage
  • Meningitis
  • Encephalitis
28
Q

What investigations could be done to determine the cause of a coma without focal or lateralising signs but with meningism?

A
  • CT head scan
  • Lumbar puncture
    • Appearance, cell count, glucose level, capsular antigen tests
29
Q

What is meningism?

A

Clinical syndrome of headache, neck stiffness and photophobia, often with nausea and vomiting

30
Q

Coma with focal brainstem or lateralising cerebral signs could be due to what?

A
  • Cerebral tumour
  • Cerebral haemorrhage
  • Cerebral infarction
  • Cerebral abscess
31
Q

What investigations can be done to determine the cause of a coma with focal brainstem or lateralising cerebral signs?

A
  • CT or MRI obligatory
  • If CT/MRI is not diagnostic then investigate as for other causes of coma such as
    • Metabolic screens
    • Lumbar puncture
    • EEG
32
Q

What are some medical causes of coma lasting more than 5 hours?

A
  • 40% due to drug ingestion with or without alcohol
  • 25% due to hypoxia, could be secondary to MI
  • 20% due to cerebrovascular event, either haemorrhage or infarction
  • 15% metabolic, such as diabetes, hepatic failure, renal failure, sepsis, hypercapnia/hypoxia
33
Q

What is the ‘locked in’ syndrome?

A
  • Condition where patient is aware but has paralysis below the level of the third nerve nuclei, so can open, elevate and depress the eyes but do nothing else and cannot communicate verbally
  • Diagnosis depends on recognising that the patient can open their eyes voluntarily and signal numerically by eye closure
34
Q

What can occur after coma where the patient is aware but has paralysis below the level of CN III?

A

Locked in syndrome

35
Q

What does the continuing care of patients in coma include?

A
  • Maintenance of vital functions
  • Care of skin, avoidance of pressure sores
  • Attention to bladder and bowel function
  • Control of seizures
  • Prophylaxis of DVT, peptic ulceration
  • Prevention of contractures
  • Consider the ‘locked in’ syndrome
36
Q

How can a head injury lead to focal neurological signs/epilepsy?

A
  • Diffuse axonal injury
  • Contusions
  • Intracerebral haematoma
  • Extracerebral haematoma
    • Extradural haematoma
    • Subdural haematoma
37
Q

What is the difference between an extradural and a subdural haematoma on a CT scan?

A

Subdural - convex/convex

Extradural - concave/convex

38
Q

What is involved in the management of a head injury?

A
  • Stabilise cervical spine
  • Airway/breathing/circulation
  • If GCS less than or equal to 8
    • Intubation and ventilation
  • Treat if raised ICP
  • Cranial imaging
    • May need decompressive surgery or removal of haematoma
  • Neuro observation
39
Q

Explain the treatment of raised ICP?

A
  1. Surgery to relieve pressure
    1. Haematoma, ventricular shunt
  2. Osmotic agents
    1. Such as mannitol
  3. Nurse with head at 30-45% (venous return)
  4. Reduce pain
  5. Maintain good PO2, reduce PCO2
  6. Reduce metabolism (reduce temperature, barbiturates)
40
Q

What are the clinical features of a non-epileptic attack?

A
  • Sinusoidal tremor, not jerking
  • Pelvic thrusting
  • Side to side head movements
  • Eyes closed and resists opening

Partial responsiveness

41
Q

What scale is used to assess stroke and conscious level?

A

ROSIER (the recognition of stroke in the emergency room)

42
Q

What does ROSIER range from?

A

-2 to 5

43
Q

How are scores allocated in ROSIER?

A
  • -1 for
    • Seizure activity
    • LOC (altered level of consciousness)
  • +1 for
    • Face, arm or leg weakness
    • Speech disturbance or visual field defect
44
Q

A ROSIER score of what predicts stroke?

A

>0

45
Q

What is hemicraniectomy?

A

Is decompressive surgery for severe cerebral swelling post stroke

46
Q

What is a haemorrhagic stroke due to?

A

Occurs due to hypertensive haemorrhage:

  • Small perforating arteries in
    • Brainstem or
    • Basal ganglia
47
Q

What is consciousness?

A

The state of being aware and responsive to one’s surroundings

48
Q

What is a vegetative stage?

A

Absence of responsiveness and awareness due to overwhelming dysfunction of the cerebral hemispheres, with sufficient sparing of the diencephalon and brainstem to preserve autonomic and motor reflexes and sleep/wake cycles