Neurosurgery Flashcards
What is the incidence of head trauma?
70,000 fatal injuries per year in US (500,000 head injuries)
What percentage of trauma deaths result from head trauma?
50%
What is the Glasgow Coma Scale?
Objective assessment of the level of consciousness after trauma
What does unilateral, dilated, nonreactive pupil suggest?
Focal mass lesion with ipsilateral herniation and compression of CN III
What do bilateral fixed and dilated pupils suggest?
Diffusely increased ICP
What are the 4 signs of basilar skull fracture?
- Raccoon eyes (periorbital ecchymoses)
- Battle’s sign (postauricular ecchymoses)
- Hemotympanum
- CSF rhinorrhea or otorrhea
What is the initial radiographic neuroimaging in trauma?
- Head CT (if LOC or GCS < 15)
- C-spine CT
- T/L spine AP and lateral
Should the trauma head CT be with or without IV contrast?
Without
What is normal ICP?
5-15 mmH2O
What is the worrisome ICP?
> 20 mmH2O
What determines ICP?
- Volume of brain
- Volume of blood
- Volume of CSF
What is the CPP?
Cerebral Perfusion Pressure:
CPP = MAP - ICP
What is Cushing’s reflex?
Physiologic response to increased ICP:
- Hypertension
- Bradycardia
- Decreased RR
What are the 3 general indications to monitor ICP after trauma?
- GCS < 9
- Altered level of consciousness or unconsciousness with multiple system trauma
- Decreased consciousness with focal neurologic exam abnormality
What is Kocher’s point?
Landmark for placement of ICP monitor bolt
What nonoperative techniques are used to decrease ICP?
ICP HEAD: Intubate Calm (sedate) Place drain (ventriculostomy), Paralysis Hyperventilation to PCO2 = 35 Elevate head Adequate blood pressure (CPP > 70) Diuretic (e.g. mannitol)
Can a tight c-collar increase the ICP?
Yes (it blocks venous drainage from brain)
Why is prolonged hyperventilation dangerous?
It may result in severe vasoconstriction and ischemic brain necrosis
What is a Kjellberg?
Decompressive bifrontal craniectomy with removal of frontal bone frozen for possible later replacement
How does cranial nerve examination localize the injury in a comatose patient?
CNs proceed caudally in the brain stem as numbered.
Presence of corneal reflex and gag reflex indicates intact pons and medulla, respectively.
What is acute treatment for seizures after head trauma?
Benzodiazepines
What is seizure prophylaxis after severe head injury?
Phenytoin for 7 days
What is the significance of hyponatremia after head injury?
SIADH must be ruled out
What is an epidural hematoma?
Collection of blood between the skull and dura