Neurosurgery Flashcards
Review the initial management of SAH.
- BP control with something titratable (clevidipine or nicardipine) to less than 160 or 140 depending on guidelines
- Arterial line for BP control
- Control of coagulation (CBC for thrombocytopenia, PT/PTT)
- Head of bead to 30*
- Preventing Valsalva (antiemetics and cough control) to limit increases in BP and ICP
- Nimodipine in the first 24 hours to prevent vasospasm
Why does spinal cord injury cause hypotension and bradycardia?
The sympathetic nervous system arises at the spinal level all the way down to T6, whereas the parasympathetic nervous system primarily from the brainstem (like the vagus nerve). As such, spinal cord injury disrupts the SNS and causes unopposed PNS stimulation.
An elderly person falls and strikes their chin on a table. They now have UE weakness without LE weakness. What is the diagnosis?
Central cord syndrome
Hyperextension neck injuries (like falling and hitting your chin on something) can cause syringomyelia that preferentially affects the UE.
Impingement of the ______ nerve root causes weakness with plantarflexion and numbness of the lateral foot and ankle.
S1
The __________ is adhered to the inner surface of the skull.
dura mater
____-dural hematomas happen from bleeds of the middle meningeal artery.
Epi
______-dural hematomas happen from bleeds of the bridging veins.
Sub
The __________ cranial nerve can get damaged when the temporal lobe herniates.
III
What is the clinical presentation of uncal herniation?
Ipsilateral pupillary dilation without response to light and contralateral hemiparesis
Normal ICP is _______- mm Hg.
10
By the Monroe-Kellie doctrine, ICP rapidly increases after ____________.
venous blood and CSF have been pushed out of the brain
Cerebral perfusion pressure is equal to ________________.
MAP - ICP
Review GCS scoring.
Eyes: 4 possible (“four eyes”)
- 4: open spontaneous
- 3: open to command
- 2: open to pain
- 1: closed
Verbal: 5 possible
- 5: oriented
- 4: confused
- 3: inappropriate words
- 2: incomprehensible sounds
- 1: no verbal response
Motor: 6 possible
- 6: obeys commands
- 5: localizes pain
- 4: withdraws from pain
- 3: flexion with pain
- 2: extension with pain
- 1: no response
People with a GCS score of ____ or less are considered as having a severe brain injury.
8
9-12 are moderate and 13-15 mild.
If there are right/left or UE/LE differences in the GCS score, use the _________ one.
better one
Epidural hematomas typically happen in what region?
Temporoparietal
_____________ are prone to rapid progression and warrant consideration of repeat CTs.
Cerebral contusions
They can progress to cerebral hematomas with mass effect.
What are the five types of intracranial hematoma?
Epidural
Subdural
Subarachnoid
Intraparenchymal
Intraventricular
In a mild TBI, what factors warrant head CT?
- Vomiting (typically greater than two episodes)
- Signs of skull fracture on exam
- Signs of basilar skull fracture (otorrhea, rhinorrhea with CSF, Battle sign, raccoon eyes)
- Age > 65
- Anticoagulant use
- GCS < 15 at two hours from injury
- High mechanism of injury
- Pre-event amnesia
- Loss of consciousness
- Seizure
Review the management of severe TBI.
Respiratory:
- Maintain SpO2 > 98%
- Maintain PaCO2 32-38 mm Hg
Cardiovascular:
- Maintain SBP > 100 mm Hg for patients 50-69 yo and > 110 mm Hg for 15-49 and 70+
Neurologic:
- Use short-acting sedatives and paralytics when needed to avoid confounding the neurologic exam
- Give mannitol (0.25 - 1.0 mg/kg) or hypertonic saline 500 mL bolus
- Elevate head of bed
What are the four components of an emergent neurologic exam?
- Mental status
- Pupillary size and dilation
- Lateralizing signs (motor equal and symmetric)
- Signs of spinal cord injury (numbness and focal weakness)
Mannitol is contraindicated in ______________.
hypotensive patients
You can control scalp hemorrhage by _____________.
direct pressure
But be careful in using pressure if the skull feels unstable.
If you see partially exteriorized objects coming from the brain, then __________.
leave it in place
What are the neurologic criteria for brain death?
- GCS 3
- Non-reactive pupils
- Absent brainstem reflexes (corneal, gag, doll’s eyes)
- No spontaneous ventilation
- Absence of confounding factors such as hypothermia and alcohol intoxication
Aggressive hyperventilation leads to cerebral vaso-_________.
constriction
This is beneficial for decreasing edema but detrimental to maintaining CPP.
______________ syndromes present with disproportionate loss of UE motor sensation compared to LE.
Central cord
Burst fractures happen from what type of force?
Axial compression
___________ fractures occur from flexion of the thoracic spine, often from an improperly placed lap belt.
Chance
Axial loading with flexion causes ______________.
anterior wedge compression fractures
Patients with _____________ fractures are vulnerable to secondary injury with rolling.
thoracolumbar junction fractures
What types of spinal injury warrant further workup for carotid/vertebral artery injury?
C1-C3 fracture
Cervical spine fracture with subluxation
Fractures of the foramen transversarium
Patients with normal neck radiographs and neck pain should be considered for ___________ to rule out occult injury.
MRI or flexion-extension x-rays
If a spinal fracture is detected, you must get _________ to detect spinal soft tissue injury.
MRI
The most common location of spinal injury is _______.
C5
________________ can be a sign of spinal cord injury in men.
Priapism
Hyperextension injuries of the neck can cause _____________ fractures.
dens
True or false: a small, focal intraparenchymal hemorrhage is a contraindication to LMWH.
False
Review post-concussion guidelines.
- Abstain from strenuous physical activity until 24 hours after the event or while symptomatic
- Gradually return to activity (no sooner than 1 week to full, pre-injury level) and stop if symptoms develop
- Gradually ease into cognitive strain and limit screen time, school day, and HW if needed
The ____________________ surrounds the bones of the skull.
galea aponeurotica
This is why a cephalohematoma (which is a bleed under the aponeurotica) stays isolated to one bone.
The best way to differentiate between cephalohematoma and subgaleal hematoma is _______________.
rapid progression
Subgaleal bleeds progress fast and cause clinical decompensation, whereas cephalohematomas are stable.
True or false: in patients with multi-system trauma and a confirmed or suspected intracranial hemorrhage, permissive hypotension is recommended.
False
Intracranial hemorrhage increases the intracerebral pressure. If you allow for permissive hypotension (like you might in other kinds of trauma) then you may vastly decrease their cerebral perfusion pressure and cause brain damage.
Cerebral perfusion pressure = ________________.
MAP - ICP
Which type of ICH increases ICP most rapidly?
EDH (because these are arterial bleeds)
Review the CRASH-2 study.
This was a large, multicenter RCT that looked at the use of TXA vs placebo in severe TBI. It found that mortality and outcomes were improved but not to a statistically significant point.
Why are upright films obtained in evaluating spinal injuries even after a negative MRI?
The upright aspect helps to evaluate for ability to bear physiologic weight. Someone can have lax ligaments even with a negative MRI.
Isolated transverse fractures require what management?
Nothing
If there are multiple then get an upright film to evaluate for instability.
Compression fractures greater than ___% might be unstable and should be evaluated with upright films.
50
People with ankylosing spondylitis are at high risk of ________________ with spinal fractures, even minor ones.
epidural hematomas
“Image until negative”, meaning if they have back pain you CT and if CT is negative you MRI.
What is the dose (pediatric and adult) of hypertonic saline for TBI?
Pediatric: bolus 5 mL/kg of 3%
Adult:
- Bolus 250 mL of 3% (though you can give 7.5% at 2 mL/kg if you have a central line)
- Bolus can be repeated x1 if no improvement
- Continuous infusion of 30-50 mL/hr of 3% for goal sodium 145 - 155
If a person with a VP shunt has unstable hydrocephalus and you cannot get NSGY to help, what can you do to help before they are seen and evaluated by a neurosurgeon?
Tap the reservoir.
If a person with a VP shunt has hydrocephalus then they have some type of shunt malfunction. If it is a tubing problem that is distal to the shunt reservoir (which is behind the ear usually), then tapping it can decompress them and stabilize until NSGY can see.
Which type of head bleed is seen most often in trauma?
SAH
What is the typical prognosis of traumatic SAH?
Those with isolated traumatic SAH actually do quite well. The most common serious outcome is vasospasm leading to CVA (which nimodipine is given for).
What is the mnemonic for unstable neck fractures?
Jefferson Bit Off a Hangman’s Thumb:
- Jefferson burst fracture
- Bilateral facet dislocation
- Odontoid fracture (types II and III)
- Hangman’s fracture
- Teardrop fracture
What injury causes a Jefferon’s burst fracture?
Axial load (like diving into shallow water)
What is a Jefferson’s burst fracture?
Multiple breaks in the anterior and posterior arches
The superior cervical facets are _______ to the inferior cervical facets.
posterior
What are the types of odontoid fractures?
- I: superior tip
- II: mid shaft
- III: base
The dens is on the __________ part of C__.
anterior; 2
A hangman’s fracture is what?
Bilateral pars interarticularis fracture
What causes hangman’s fractures?
Extreme extension
What are teardrop fractures?
Hyperflexion or hyperextension of the neck can cause avulsion
The biggest difference of the presentation of conus medullaris vs cauda equina is _____________.
symmetric vs asymmetric
The most common cause of VP shunt malfunction is what?
Proximal occlusion at the choroid plexus
When evaluating for spinal epidural abscess, order films of what the _____ spine.
entire
Review the naming for which nerves come from above and below the corresponding disc.
C1-C7 exit upwards and C8-L5 exit downward.
Example: L4 exits at thee L4-L5 disc and C6 exits at the C5-C6 disc.
Hyperextension injuries of the neck can cause _____________, which presents with weakness of the hands.
central cord syndrome
What property describes the volume of the intracranial space?
The Monro-Kellie doctrine
This states that the intracranial space is a fixed volume and the three parts that determine it’s pressure and volume are brain, blood, and CSF.
In patients who have had uncal herniation, the dilated pupil is on the ______-lateral side.
ipsi
What MAP goal is recommended for spinal cord injury?
85 - 90 mm Hg
What type of injuries cause anterior cord syndrome?
Hyperflexion injuries and anterior cord hematomas
Which bone is most often fractured in epidural hematomas?
Temporal
Which kinds of scalp hematomas are less concerning in children?
Frontal
Which type of teardrop fracture (flexion or extension) leads to spinal cord injury?
Flexion
Both flexion and extension teardrop fractures lead to a teardrop avulsion of bone from the anterior-inferior vertebral body, but flexion also injures the posterior longitudinal ligament which destabilizes the spine.
What mm of shift calls for emergent OR?
6 mm or more
Compare and contrast central cord syndrome from anterior cord syndrome.
Central:
- Forced hyperextension causes buckling of the ligamentum flavum that compresses the cord (which affects the central part worst)
- Motor and sensory deficits
- Upper > lower deficits
- Distal > proximal deficits
Anterior:
- Vascular insult or hyperflexion
- Motor deficits only (dorsal columns spared)
The goal MAP for spinal cord injury with neurogenic shock is what?
85 - 90 mm Hg
Spinal cord injuries have to be above what level to cause neurogenic shock?
T5
Small juxtacortical hemorrhages on a non-con CT can be a sign of what? (Particularly in a person with HA and CVA symptoms.)
DVST
The increased pressure from a clot can cause small hemorrhages, focal edema, or densities in the sinus.
What is normal ICP?
≤ 15 mm Hg
Remember that mm Hg is not the same as cm of H20 (what we measure in LPs). The conversion is as follows:
1 mm Hg = 1.36 cm H20
So 15 mm Hg is about 20 cm H20.
What cranial nerve is most commonly injured in basilar skull fracture?
CN VII
What is the grading system for SAH?
Hunt and Hess
Goes grades I-V. Predicts mortality.
When does vasospasm occur after SAH?
2-21 days
Review decorticate and decerebrate posturing.
Decorticate: arms flexed, legs extended (arms flexed to the “CORe”)
Decerebrate: arms extended, legs extended (think of decerebrate having two E’s for Extended x2)
