Coma Flashcards
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
what is the glasgow coma scale?
measures coma in patients
mild 13-15
moderate 9-12
severe - 3-8
3 = coma
what 2 things is conciousness dependent upon?
an intact ascending reticular activating system to act as the alerting or awakening element of consciousness
a functioning cerebral cortex of both hemispheres which determines the content of that consciousness
what is responsible for arousal in conciousness?
Reticular activating system
what is responsible for awareness of environment in conciousness?
Cerebral hemispheres
what are causes of reduced GCS?
Toxic/metabolic states
Hypoxia/hypercapnia/sepsis/hypotension
Drug intoxication/renal or liver failure
Hypoglycaemia, ketoacidosis
Seizures
Damage to reticular activating system
Causes of raised intracranial pressure
tumour, stroke, EDH, SDH, SAH, hydrocephalus
what are examples of toxic/metabolic states?
Hypoxia/hypercapnia/sepsis/hypotension
Drug intoxication/renal or liver failure
Hypoglycaemia, ketoacidosis
what are causes of raised intracranial pressure?
tumour, stroke, EDH, SDH, SAH, hydrocephalus
what is first line management for resusitation?
Airway
Breathing
Circulation
what does depressed respiration indicate?
drugs overdose
metabolic disturbance
what does increased respiration indicate?
hypoxia
hypercapnia
acidosis
what does fluctuating respiration indicate?
brainstem lesion
following ABC what should be done further in a hospital setting?
blood samples
baseline bp, pulse, temp, IV acsess, neck stabalised
examine for evidence of meningitis
what is 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
There is arousal and wakefulness but the patient does not regain awareness or purposeful behaviour of any kind
what should be asked in the history of a patient experiencing coma?
? Predictable progression of underlying illness
? Unpredictable event in patient with previously known disease
? Totally unexpected event
? Head injury, sudden collapse, limb twitching, previous history of drug or alcohol abuse
what should be monitored and examined in a coma patient?
Temperature
Heart rate, Blood Pressure, CVS
Respiration
Skin, breath
Abdomen
Meningism
Fundal examination
what are neurological assessments of coma?
Glasgow Coma Scale
Brainstem Function
Motor Function + Reflexes
how is eye opening measure in GCS?
Spontaneous 4
To speech 3
To pain 2
None 1
how is best verbal response measured in GCS?
Orientated 5
Confused 4
Inappropriate words 3
Incomprehensible sounds 2
None 1
how is best motor response measured in GCS?
Obeying Commands 6
Localising to pain 5
Withdrawing from pain 4
Flexing to pain 3
Extending to pain 2
None 1
what cranial nerves are responsible for pupillary reactions?
II + III
what cranial nerves are responsible for corneal responses?
V+VII
what cranial nerves are responsible for spontaneous eye movements?
III, IV, VI
what cranial nerves are responsible for oculocephalic responses (Doll’s eye)?
III, IV, VI, VIII
what cranial nerves are responsible for Oculovestibular responses?
III, IV, VI, VIII
what cranial nerves are responsible for Respiratory pattern?
Medullary centre
how is motor function tested?
Motor response
Muscle tone
Tendon reflexes
Seizures (twitching posturing on limbs)
Coma without focal or lateralising signs and without meningism?
Anoxic/ ischaemic conditions
Metabolic disturbances
Intoxications
Systemic infections
Hyperthermia/ Hypothermia
Epilepsy
what are investigations for Coma without focal or lateralising signs and without meningism?
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
Coma without focal or lateralising signs but with meningism?
Subarachnoid Haemorrhage
Meningitis
Encephalitis
investigations for Coma without focal or lateralising signs but with meningism?
CT head scan
Lumbar puncture
Appearance
Cell count
Glucose level
Capsular antigen tests
Coma with focal brainstem or lateralising cerebral signs?
Cerebral tumour
Cerebral haemorrhage
Cerebral infarction
Cerebral abscess
Investigations for Coma with focal brainstem or lateralising cerebral signs?
CT or MRI obligatory
If CT/MRI not diagnostic, then investigate as for other causes of coma e.g. including
metabolic screens
lumbar puncture
EEG
“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 locked in syndrome?
patient has total paralysis below level of nthird nerve nuclei and although able to open elevate and depress eyes has no horizontal eye movement and no other voluntary eye movement
diagnosis depends on recognising that patient can open eyes voluntarily and signal numerically by eye closure
what factors affect prediction of outcome in coma?
Age
Cause of coma
Depth of coma
Duration of coma
Certain clinical signs, the most important of which are the brain stem reflexes
Prediction of Outcome in Coma in non traumatic coma?
Overall, only 15% of patients in non-traumatic coma for more than 6 hours will make a good or moderate recovery, the other 85% will die, remain vegetative or reach a state of severe disability in which they remain dependent
how is recovery in non traumatic cober > 6 H?
In non-traumatic coma >six hours, good recovery is seen in
35% of those with underlying metabolic cause
11% of those with hypoxic ischaemic insult
7% of those with cerebrovascular disease
how should care be continued for coma patients?
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
Consider the “Locked - in” Syndrome
how can head injury leas to focal neurological signs/ epilepsy?
Diffuse axonal injury
Contusion
Intracerebral haematoma
Extra-cerebral haematoma
Extra-dural haematoma
Sub-dural haematoma
how does subdural haematoma present on CT?
Subdural haematoma ellipse
convex/convex
how does extradural haematoma present on CT?
Extradural haematoma
concave/convex (lens)
how should a head injury be managed?
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
how is raised intracrainial presssure treated?
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)
what are clinical features of non epileptc attacks?
sinusoidal tremour not jerking
pelvic thrusting
side to dide head movements
eyes closed and resist openong
partial responsivness
what is the rosier scale used for?
It was created to aid first-line ER providers in determining which patients were likely experiencing a stroke, thus expediting referral to an acute stroke team. When compared to similar scales, such as the FAST, the ROSIER scale had greater sensitivity in acute stroke recognition.
what is a hemicraniectomy
decompressive surgeryf for severe cerebral swelling post stroke
GCS fails 24-72 hour post stroke
