Coma, Persistent Vegetative State, BrainDeath Flashcards by Sarah Anderson

What two factors does consciousness depend upon

An intact ascending reticular activating system

Functional cerebral cortex of both hemispheres

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What is the function of the reticular system in consciousness

Arousal -acts as the alerting or awakening element of consciousness

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What is the function of the cerebral cortex in consciousness

Awareness of the environment -determine the content go consciousness

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What is the affect of the two components of consciousness in a coma

Low level of consciousness (wakefulness) - RAS

Low content of consciousness (awareness) - CH

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What is the affect of the two components of consciousness in a vegetive state

Low content of consciousness (awareness)

High level of consciousness (wakefulness)

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What are potentially causes of decreased consiousness

Toxic metabolic stress
eg ischaemia, hypoglycaemia, hepatic or renal failure

Seizures

Damage to the reticular activating system

Causes of raised intracranial pressure

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What are causes of toxic metabolic stress that results in decreased consciousness

Hypoxia/hypercapnia/sepsis/hypotension

Drug intoxication/renal or liver failure

Hypoglycaemia, ketoacidosis

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What are causes of raised intracranial pressure that results in decreased consciousness

tumour, 
stroke, 
Extra dural haematoma
Sub dural haematoma
Subarachnoid haemorrhage 
hydrocephalus

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What pathological affects can result in decreased consciences

Diffuse hemisphere damage

Focal damage

Brainstem involvement

herniation
compression (mass)

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Define coma

A state of unrousable 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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What is the pathology of a persistent vegetative state

A state in which the brain stem recovers to a considerable extent but there is no evidence of recovery of cortical function

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What is the affect of persistent vegetive state

There is arousal and wakefulness but the patient does not regain awareness or purposeful behaviour of any kind

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What is the affect of “locked in” syndrome

able to open, elevate and depress the eyes, nut has no horizontal eye movements and no other voluntary eye movement

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What does the diagnosis of locked in syndrome depend upon

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

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Define resuscitation

the action or process of reviving someone from unconsciousness or apparent death

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What should first be considered in resuscitation

ABC
Airway
Breathing
Circulation

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Why is it important to listen to breathing pattern

can give indication to the problem

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What doe depressed respiration potentially indicate

Drug overdose

metabolic disturbance

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What does increased respiration potentially indicate

Hypoxia
Hypercapnia
acidosis

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What does a fluctuating respiration potentially indicate

Brainstem lesion

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What is important to retrieve from unconscious patient to help determine cause of state

Blood sample:

Glucose, biochemistry, haematology, blood gas and toxicology

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What is additional steps in resuscitation

Establish base line (BP, pulse, temp)

Find IV access

Stabilise neck

examine evidence for meningitis

Why is it important to gain a history of unconscious patients

if this was a predictable progression of underlying illness

An unpredictable event in previous known disease

A totally unexpected event in the patient

If a totally unexpected event in patient history what additional information do you need to gather

Head injury
sudden collapse
limb twitching
previous history of drug or alcohol abuse

What do you examine and monitor in a unconscious patient

``` Temperature Heart rate, Blood Pressure, CVS Respiration Skin, breath Abdomen Meningism Fundal examination ```

What are three version for neurological assessment of coma

Glasgow Coma Scale Brainstem Function Motor Function + Reflexes

What is the Glasgow coma scale for eye opening

Spontaneous 4 To speech 3 To pain 2 None 1

What is the Glasgow coma scale for best verbal response

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

What is the Glasgow coma scale for best motor response

``` Obeying Commands 6 Localising to pain 5 Withdrawing from pain 4 Flexing to pain 3 Extending to pain 2 None 1 ```

How does the Glasgow coma scale define if someone is in a coma

“Patients who fail to show eye opening in response to voice, perform no better than weak flexion in response to pain and make, at best, only unrecognisable grunting noises in response to pain are regarded as being in coma”

What is the Glasgow coma scale score of a coma

Eye opening - 2 or less Verbal response - 2 or less Motor response - 4 or less GCS <8 =

How do we access brain stem function

Pupillary reactions Corneal responses Spontaneous eye movements Oculocephalics response (Doll's eye) Oculovestibular responses Respiratory pattern

What cranial nerves does pupillary reaction test in the brain stem

CN II + III

What cranial nerves does corneal response test in the brain stem

CN V + VII

What cranial nerves does spontaneous eye movement test in the brain stem

CN III, IV, VI

What cranial nerves does oculocephalic reflex response test in the brain stem (tested by holding the eyes open and rotating the head from side to side or up and down)

CN III, IV, VI, VIII

What does respiratory pattern access in the brainstem

Medullary centres

How do you access motor function in an unconscious patient

Motor response Muscle tone tendon reflex seizure evidence

What is the potential cause of coma without focal or lateralising signs and without meningism

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

What is the investigations for a coma without focal or lateralising signs and without meningisml

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

What is the causes of a Coma without focal or lateralising signs but with meningism

Subarachnoid Haemorrhage Meningitis Encephalitis

What is investigations for Coma without focal or lateralising signs but with meningism

CT Head scan Lumbar puncture

What is assessed in the lumbar puncture in a coma with meningism

Appearance of CSF (cloudy) Cell count Glucose level Capsular antigen tests

What is the potentially causes of a coma with focal brainstem or lateraling cerebral signs

Cerebral tumour Cerebral haemorrhage Cerebral infarction Cerebral abscess

Investigations for Coma with focal brainstem or lateralising cerebral signs

CT or MRI obligatory investigate as for other causes of coma: - metabolic screens - lumbar puncture - EEG

What is the medical cause of comas lasting more than 5 years

Drug ingestion ± alcohol (40%) Hypoxia e.g. secondary to MI (25%) Cerebrovascular event, either haemorrhage or infarction (20%) Metabolic e.g. diabetes, hepatic failure, renal failure, sepsis, hypercapnia/hypoxia (15%)

What factors affect the outcome of a coma

Age Cause of coma Depth of coma Duration of coma Certain clinical signs, the most important of which are the brain stem reflexes

What is the predicted outcome of a non traumatic coma

15% of patients incoma for more than 6 hours will make a good or moderate recovery 85% will die, remain vegetive or reach a state of severe disability in which they remain dependent

What is the management of patients in a coma

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 (hardening of muscle, tendon tissue etc)

What should be considered in coma patients

"locked-in" syndrome

Head injury can lead to focal neurological signs/epilepsy as causes the development of what

Diffuse axonal injury Contusion (bruise) Intracerebral haematoma Extra-cerebral haematoma - Extra-dural haematoma - Sub-dural haematoma

How do you diagnose a head injury

CT scan

What is the management of a head injury

Stabilise cervical spine Airway/Breathing/Circulation If GCS≤8 - intubation+ventilation Treat raised ICP Cranial imaging - may need decompressive surgery or removal of haematoma Neuro observation

What is 6 different ways in treating and manage increased intracranial pressure

Surgery to relieve pressure (heamatoma, ventricular shunt) Osmotic agents e.g. mannitol Nurse with head at 30-45% (Venous return) Reduce pain Maintain good PO2, reduce PCO2 Reduce metabolism (reduce temperature, barbiturates)