Coma, Persistent Vegetative State, Brain Death

Question 1

What is a coma?

Answer 1

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

Question 2

When are patietns said to be in a coma using the GCS?

Answer 2

patients who fail to show eye opening in response to voice,perform no better thn weak flexion in response to pain and make, at . best, only unrecognisable grunting noises in response to pain are regarded as being in a coma

eye opening - 2 or less

verbal response 2 or less

motor response 4 or less

GCS < or equal to 8

Question 3

What does consciousness depend on?

Answer 3

1. intact ascending reticular activating system to act as the alerting or awakening element of consciousness

^{a set of connected nuclei in the brains of vertebrates that is responsible for regulating wakefulness and sleep-wake transitions}

2. a functioning cerebral cortex of both hemispheres which determines the contect of that consciousness

Question 4

What contorls consciousness?

Answer 4

1. aorusal - reticular activating system
2. awareness of environment - cerebral hemispheres

Question 5

What is locked-in syndrome?

Answer 5

a condition in which a patient is aware but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles in the body except for vertical eye movements and blinking

patient has total paralysis below level of 3rd nerve nuclei and, although able to open, elevate and depress the eyes, has no horiontal eye movements and no other voluntary eye movement

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

Question 6

What are the causes for decreasing GCS?

Answer 6

Question 7

What are the thing done and checked on resuscitation?

Answer 7

airwyas

breathing:

^{- depressed respiration - drug overdose, metabolic disturbance}

^{- increased respiration - hypoxia, hypercapnia, acidosis}

^{- fluctuation repsiration - brainstem lesion}

circulation

blood samples - glucose, biochemistry, haematology, blood gas, toxicology

establish baseline BP, pulse, temperature, IV access and stabilise neck

examine for evidence of meningitis - treat on susicion

Question 8

What needs to be found on when taking a history

Answer 8

is it a predictable progession of an underlying illness

is it an unpredictable event in the patient with a previously known disease

is it a totally unexpected event - head injury, collapse, limb twitching etc

Question 9

What would you need to examine and monitor in a patient?

Answer 9

temp

HR, BP, CVS

respiration

skin, breath

abdomen

meningism

fundal examination

Question 10

How do you carry out neurological assessment of someone in a coma?

Answer 10

GCS

brainstem function

motor function + reflexes

Question 11

What is the brainstem function?

Answer 11

Question 12

What motor functions should be tested in a coma?

Answer 12

motor response

muscle tone

tendon reflexes

seizures

Question 13

What is meningism?

Answer 13

Meningism is the clinical syndrome of headache, neck stiffness, and photophobia, often with nausea and vomiting

Question 14

What are the different presentations for the different causes of coma?

Answer 14

Question 15

What are the causes of a coma without focal or lateralising signs and without meningism?

Answer 15

anoxic/ischaemic conditions

metabolic disturbances

intoxications

systemic infections

hyperthermia/hypothermia

epilepsy

Question 16

What investigations can be done when someone has a coma without focal or lateralising signs and without meningism?

Answer 16

toxicology screenincluding alcohol levels

measure blood surgar and electrolytes

assess hepatic and renal function

acid- base assessment and blood gases

measure BP

consider carbon monoxide poisoning

Question 17

What are the causes of a coma without focal or lateralising signs but with meningism?

Answer 17

subarachnoid haemorrhage

meningitis

encephalitis

Question 18

What investigations would be done for someone with a coma without focal or lateralising signs but with meningism?

Answer 18

CT head scan

lumbar puncture - appearance, cell count, glucose level, capsular antigen tests

Question 19

What are the causes of a coma with focal brainstem or lateralising signs?

Answer 19

cerebral tumour

cerebral haemorrhage

cerebral infrction

cerebal abscess

Question 20

What are the investigations for someone in a coma with focal brainstem or lateralising signs?

Answer 20

CT or MRI obligatory

If CT/MRI not diagnostic, then investigate as for other causes e.g. including:

• metabolic screen
• LP
• EEG

Question 21

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

Answer 21

40% due to drug ingestion +/- alcohol

25% due to hypoxia e.g. secondary to MI

20% due to cerebrovascular event, either haemorrhage or infarction

15% metabolic e.g. diabetes, hepatic failure, renal failure, sepsis, hypercapnia/hypoxia

Question 22

What is done in order to continure the care of patients in a coma?

Answer 22

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 conractures

consider the locked-in syndrome

Question 23

head injury can lead to focal neurological signs/epilepsy due to?

Answer 23

1. diffuse axonal injury
2. contusion
3. intracerebral haematoma
4. extra-cerebral haematoma - extra-dural and sub-dural haematoma

Question 24

How do sub-dural/extra-dural haematoma show on CT?

Answer 24

Question 25

What is the management of head injury?

Answer 25

stabilise cervical spine

airway/breathing/circulation

if GCS less than or equal to 8 - intubation + ventilation

treat raised ICP

cranial imaging - may need decompressive surgery or removal of haematoma

neuro observation

Question 26

How do you treat raised ICP?

Answer 26

1. surgery to relieve pressure - haematoma, ventricular shunt
2. osmotic agents
3. nurse with head at 30-45 degress (venous return)
4. reduce pain
5. maintain good PO2 and reduce PCO2
6. reduce metabolism (reduce temperautre, barbiturates)

Question 27

What is the premorbid of non-epileptic attacks?

premorbid - preceding the occurrence of symptoms of disease or disorder

Answer 27

psychiatric history

recent stress

young, F>M

Question 28

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

Answer 28

sinusoidal tremor not jerking

pelvic thrusting

side to side head movements

eyes closed and resists opening

partial responsiveness

Question 29

What is hemicraniectomy?

Answer 29

decompressive surgery for severe cerebral swelling post-stroke

a surgical procedure where a large flap of the skull is removed and the dura is opened; this gives space for the swollen brain to bulge and reduces the intracranial pressure

CCS falls 24-72 post-stroke

patients <60 years old, NNT 2 to save a life, NNT 4 good outcome

Question 30

Coma summary - how is consciousness assessed?

Answer 30

GCS good scale for head injuries and communication between staff

consider brainstem refexes (+ pupil size and reaction)

focal vs non-focal CNS pathology

Consider general causes of depressed conscious level