Coma W3

Question 1

consciousness origination in brain?

Answer 1

reticular formation (arousal)
cerebral hemispheres and diencephalon (perception of content around you)

Question 2

coma pathophysiology?

Answer 2

impaired function of
both cerebral hemispheres
reticular activating system in brainstem or diencephalon
or both of above

Question 3

what factors cause coma?

Answer 3

structural lesions (20%)
metabolic (35%)
drugs and toxins (25%)
CNS infections
stroke
other

Question 4

what causes diffuse (widespread) hemispheric problems

Answer 4

trauma
ischaemia
hypoglycaemia/other met disorders
infection
drugs

Question 5

causes of bilateral changes in brain stem

Answer 5

haemorrhage
compression eg mass lesions
drugs

Question 6

structural causes of coma?

Answer 6

pressure on reticular acting system of brain stem which may lead to focal neurological signs eg hemiparesis, papilloedema or 3rd nerve palsy
especially common with posterior fossa masses

Question 7

what is hemiparesis?

Answer 7

weakness down one side of body

Question 8

what is papilloedema

Answer 8

swelling of optic disks

Question 9

what is uncal herniation

Answer 9

mass (eg brain tumor) pushes through uncus, medial temporal lobe compressed, problems with 3rd nerve and brain stem

Question 10

name of innermost part of temporal lobe (hook-shaped)

Answer 10

uncus

Question 11

what is coning?

Answer 11

progressive brain stem compression

Question 12

tonsil herniation? what does this cause/lead to

Answer 12

herniation through foramen magnum
causes loss of all brainstem reflexes leading to death

Question 13

metabolic cause of coma?

Answer 13

hypoxia
hypercapnia
deranged electrolytes (renal failure)
endocrine problems
hepatic encephalopathy (liver failure)
uraemia
hypothermia

Question 14

drugs and toxins causes of coma?

Answer 14

overdose
opiates (pinpoint pupils)
sedatives
alcohol
CO
poisons

Question 15

CNS infections causing coma?

Answer 15

meningitis, encephalitis

Question 16

other causes of stroke?

Answer 16

trauma
seizures

Question 17

management of coma?

Answer 17

resuscitation
history (circumstances - where and when)
general examination
neurological examination
investigations
supportive and specific treatments

Question 18

general examination for coma?

Answer 18

temperature? (fever, hypothermia)
meningism (neck stiffness, kernig’s sign)
trauma (blood, battles sign, racoon eyes etc)
skin (cyanosis, jaundice etc)
breath - alcohol?
BP

Question 19

neurological examination for coma aims to determine what?

Answer 19

level of consciousness
brainstem function
lateralisation of pathology

Question 20

neurological examination for coma?

Answer 20

pupil size and activity
eye movements (baseline position?)
corneal reflex intact? (indicates cranial nerves intact)
respond to painful stimulus with motor response?
tone and reflexes in arms and legs

Question 21

coma with no focal signs and no meningism indicates what cause?

Answer 21

metabolic eg:
drugs/toxins
hypoxic-ischaemic
seizure

Question 22

coma with focal signs and no meningism indicates what cause?

Answer 22

mass lesion
haemorrhage
infarction (stroke)

Question 23

coma with meningism and no focal signs indicates what cause?

Answer 23

meningitis
meningo-encephalitis
SAH (sub-arachnoid hemorrhage)

Question 24

brainstem functions

Answer 24

respiratory rate and rhythm
pupillary reaction
corneal reflex
spontaneous eye movements
reflex eye movements
gag/cough reflex

Question 25

examination of brainstem functioning?

Answer 25

examination of pupils
papilloedema
sub-hyloid haemorrhage
pupil size + reactions

Question 26

resuscitation and investigation for coma?

Answer 26

maintain airway
give dextrose if hypoglycaemic
consider thiamine + naloxone
treat seizures
antibiotics if there’s suggestion of infection

Question 27

what does thiamine reverse the effects of

Answer 27

alcohol excess

Question 28

what does naloxone reverse the effects of

Answer 28

opiate excess

Question 29

priority blood tests for coma?

Answer 29

electrolytes
arterial blood gas

Question 30

priority tests for coma?

Answer 30

urgent CT head
lumbar puncture