Neuro Flashcards
GCS: Eyes
4: Eyes open spontaneously
3: Eye open to verbal command
2: Eye open to pain
1: No eye response
GCS: Best verbal response:
5: Orientated
4: Confused
3: Inappropriate words
2: Incomprehensible sounds
1: No verbal response
Best motor response
6: Obeys commands
5: Localises to pain
4: Withdraws from pain
3: Flexion to pain
2: Extension to pain
1: No motor response
Indications for CT head within 1 hr:
-GCS <13 on initial assessment in emergency -department
-GCS <15 at 2 hrs after the injury on assessment in emergency department
-Suspected open or depressed skull fracture
-Any sign basal skull fracture (haemotympanum, ‘panda’ eyes, cerebrospinal fluid leakage from the ear or nose, Battle’s sign
-Post traumatic seizure
-Focal neurological deficit
-> 1 episode vomiting
Indications for CT head within 8 hrs
In those who have had some LOC or amnesia:
-Age 65 or older
-Any history of bleeding or clotting disorders
-Dangerous mechnism (Fall >1m, 5 stairs, pedestrian or cyclist struck by vehicle, occupant ejected from vehicle)
->30mins amnesia of events immediately before injury
-anticoagulation
What are different categories for CT head indications in nice guidelines?
CT within 1 hr
CT within 8 hrs
What is cushing’s reflex?
-Mixed vagal and sympathetic stimulation that occurs in response to raised ICP
-Results in hypertension and bradycardia
Cushings triad:
-irregular decreased respirations (due to decreased brain stem function)
-systolic hypertension (widened pulse pressure)
-bradycardia
How is cerebral perfusion pressure calculated?
Mean arterial pressure - intracranial pressure
In what circumstances would it be appropriate to admit a pt with a head injury?
-When CT not available
-Abnormal CT
-Prolonged loss of or deteriorating consciousness/abnormal GCS
-Focal neurological deficit
-Headache
-Penetrating head injury/skull fracture
-Alcohol/drug intoxication
-CSF leak (rhinorrhea/otorrhea)
What is definition of brainstem death?
Defined as irreversible cessation of brainstem function
What preconditions need to be met for a diagnosis of brainstem death?
-Apnoeic coma requiring ventilation and a known cause of irreversible brain damage
-Pt not sedated
Brainstem death test: Pupil responses (nerves involved and reaction)
-CN II, III
-No direct/indirect reaction to light
Brainstem death test: Corneal reflex
-CN V,VII
-No reaction to direct stimulation with cotton wool
Brainstem death test: Pain reflex
-CN V and VII
-Pain tested in facial distribution
-Brainstem death cannot be diagnosed if response to central pain
Brainstem death test: Caloric test
-CN 3, 6, 8
-Cold water instilled into auditory canal, nystagmus towards stimulation is looked for
-Absent in brainstem death
Brainstem death test: Gag reflex
-CN 9 and 10
Brainstem death test: apnoea test
-Pre-oxygenate and then disconnect from ventilator
-Insufflate oxygen into trachea, observe for sign of respiration until PaCO2 is above 6.65 kPa
What are creterion for performance of brainstem death tests?
-2 doctors on 2 separate occasions
-Each must be >5 years post full GMC registration
-Death is deemed to have occured after first set of tests, this is time on death cert.
What tests of brainsteam death are there?
-Pupil responses
-Corneal reflex
-pain reflex
-Caloric test
-Gag reflex
-Apnoea test
-If there are no signs to these tests when performed by appropriate clinicians, brainstem death can be diagnosed
What are symptoms of raised ICP?
-Headache
-Nausea and vomiting
-Reduced level of consciousness
What is normal ICP?
0-10mmhg in adults in supine position
Explain Monro-Kellie doctrine
-Cranial vault is fixed space consisting of 3 components: blood (10%), CSF (10%), Brain parenchyma (80%)
-Expansion of any one of these components results in compensatory decrease to maintain ICP
-When compensatory mechanism is exhausted, there is an exponential increase in ICP even with small increase in volume of increased content/mass
What are effects of raised ICP
-Decreased cerebral perfusion pressure causing iscahemia
-Midline shift causing ventricular obstruction
-Brain herniation, coma, eventually death
How can ICP be reduced?
Reduced blood
-Regulate ventilation to maintain PaCO2 4-4.5 kPa (infreased vasoconstriction)–> co2 is vasodilator
-Use of hypertonic saline
-Diuretics: mannitol 20% 0.25-0.5 g/kg
-Upward tilt of head of bed to 20 degrees
Reduced CSF
-Direct tapping CSF from ventricular catheter
Reduced parenchyma
-Surgical debulking
-Craniectomy
Other
-Steroids may reduce swelling around tumours, but not in trauma situation
-Barbiturate coma
-Sedation +/- use of paralysis (reduced mro2)
How can ICP be monitored?
-Subarachnoid bolt
-Epidural bolt (less accurate, less infection risk)
-External ventricular drain (can use to therapeutically remove csf)
