Coma Flashcards
what is the definition of a coma ?
a state of unrousable psychological unresponsiveness in which the subject lies with eyes closed and shows no psychological understandable response to external stimulus or inner need
what two things does consciousness depend on?
- intact ascending reticular activating systems
2. cerebral cortex
how is the ascending reticular activating systems involved in consciousness?
acts as the alerting element of consciousness
- arousal
how is the cerebral cortex involved in consciousness?
determines the content of the consciousness
- awareness of environment
state some causes of reduced GCS ?
toxic/metabolic states
- hypoxia, renal/liver failure, hypoglycaemia
seizures
damage to reticular activating systems
raised ICP
- tumour, stroke, EDH, SAH, hydrocephalus
what is a vegetative state ?
patient has wakefulness but has very low awareness
- brain stem has recovered but cortical function is still damaged
what is locked in syndrome?
the patient has high wakefulness and awareness but has total paralysis below third nerve nuclei so can only elevate and depress their eyes
what could these different types of breathing suggest?
- depressed
- increased
- fluctuating
depressed
- drug overdose, metabolic disturbance
increased
- hypoxia, hypercapnia, acidosis
fluctuating
- brain stem lesion
what happens to respiration during hypoventilation?
fast, shallow breathes
- low O2 inout and can’t blow off CO2 properly
- CO2 builds up in blood
- protons increase in the blood and causes acidosis
- the central chemoreceptors detect the change and cause a decrease in respiration rate
what should be examined and monitored for a coma patient
temperature heart rate BP CVS Resp. rate Breath smell Meningism Abdominal problems
what assessment is used to determine consciousness?
Glasgow coma score
what are the three parts of the GCS?
eyes
verbal
motor
how many points are available for eyes in GCS?
4
- spontaneous
- to sound
- to pain
- none
how many points are available for verbal in GCS?
5
- orientated
- confused
- inappropriate words
- sounds
- none
how many points are available for motor in GCS?
6
- obey commands
- localising to pain
- flexing towards pain
- abnormal flexion towards pain
- extending to pain
- none
what score classes a person in a coma?
less or equal to 8
what nerves are involved in the pupillary reaction
optic and oculomotor
what nerves are involved in the corneal reaction
trigeminal and facial
what nerves are involved in the respiration pattern?
medullary centre
what is meningism?
set of symptoms similar to those of meningitis but not caused by meningitis
state some causes of coma without focal and meningism signs
- anoxia
- metabolic disturbances
- intoxications
- systematic infections
- hyper/hypothermia
- epilepsy
state some causes of coma without focal but with meningism signs
SAH
Meningitis
Encephalitis
state some investigations that should be done for a coma absent of focal and meningism signs ?
- toxicology for alcohol levels
- blood sugar and electrolytes
- hepatic and renal function
- ABG (arterial blood gases)
- blood pressure
- Carbon monoxide poisoning
what investigations should be done if meningism symptoms are present in a coma patient ?
CT head scan
Lumbar puncture
what are some causes of a coma with focal signs?
cerebral
- tumour
- haemorrhage
- infarction
- abscess
what investigations should be done for a coma patient with focal signs ?
CT/MRI if scans are not diagnostic - metabolic screens - lumbar puncture - EEG
what is the most common cause of a coma to last more than 5 hours ?
drug ingestion and alcohol
what factors effect the outcome of a coma?
age cause of coma depth of coma duration of coma clinical signs
what % of non traumatic coma patients will die or remain vegetative when in the coma >6hrs?
85%
rank these from best to worst recovery for cause of coma?
- hypoxic ischaemia
- metabolic
- cerebrovascular disease
metabolic
hypoxic ischaemia
cerebrovascular disease
what secondary care must be thought about for patients in a coma?
- care of skin
- avoid pressure sores
- attention to bladder and bowel function
- control of seizures
- prophylaxis of DVT
- consider locked in syndrome
how is a raised ICP managed ?
surgery to relieve pressure osmotic agents - mannitol raise head to 40 degrees reduce pain maintain good ventilation reduce metabolism
