Coma, Persistent Vegetative State, Brain Death Flashcards
What is a 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
When are patietns said to be in a coma using the GCS?
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
What does consciousness depend on?
- 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
- a functioning cerebral cortex of both hemispheres which determines the contect of that consciousness
What contorls consciousness?
- aorusal - reticular activating system
- awareness of environment - cerebral hemispheres
What is locked-in syndrome?
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
What are the causes for decreasing GCS?
What are the thing done and checked on resuscitation?
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
What needs to be found on when taking a history
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
What would you need to examine and monitor in a patient?
temp
HR, BP, CVS
respiration
skin, breath
abdomen
meningism
fundal examination
How do you carry out neurological assessment of someone in a coma?
GCS
brainstem function
motor function + reflexes
What is the brainstem function?
What motor functions should be tested in a coma?
motor response
muscle tone
tendon reflexes
seizures
What is meningism?
Meningism is the clinical syndrome of headache, neck stiffness, and photophobia, often with nausea and vomiting
What are the different presentations for the different causes of coma?
What are the causes of a coma without focal or lateralising signs and without meningism?
anoxic/ischaemic conditions
metabolic disturbances
intoxications
systemic infections
hyperthermia/hypothermia
epilepsy
What investigations can be done when someone has a coma without focal or lateralising signs and without meningism?
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
What are the causes of a coma without focal or lateralising signs but with meningism?
subarachnoid haemorrhage
meningitis
encephalitis
What investigations would be done for someone with a coma without focal or lateralising signs but with meningism?
CT head scan
lumbar puncture - appearance, cell count, glucose level, capsular antigen tests
What are the causes of a coma with focal brainstem or lateralising signs?
cerebral tumour
cerebral haemorrhage
cerebral infrction
cerebal abscess
What are the investigations for someone in a coma with focal brainstem or lateralising signs?
CT or MRI obligatory
If CT/MRI not diagnostic, then investigate as for other causes e.g. including:
- metabolic screen
- LP
- EEG
What are the medical causes of coma lasting more than 5 hours?
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
What is done in order to continure the care 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 conractures
consider the locked-in syndrome
head injury can lead to focal neurological signs/epilepsy due to?
- diffuse axonal injury
- contusion
- intracerebral haematoma
- extra-cerebral haematoma - extra-dural and sub-dural haematoma
How do sub-dural/extra-dural haematoma show on CT?
What is the management of head injury?
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
How do you treat raised ICP?
- surgery to relieve pressure - haematoma, ventricular shunt
- osmotic agents
- nurse with head at 30-45 degress (venous return)
- reduce pain
- maintain good PO2 and reduce PCO2
- reduce metabolism (reduce temperautre, barbiturates)
What is the premorbid of non-epileptic attacks?
premorbid - preceding the occurrence of symptoms of disease or disorder
psychiatric history
recent stress
young, F>M
What are the clinical features of a non-epileptic attack?
sinusoidal tremor not jerking
pelvic thrusting
side to side head movements
eyes closed and resists opening
partial responsiveness
What is hemicraniectomy?
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
Coma summary - how is consciousness assessed?
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
