Neurosurgery Lecture Flashcards
SCALP pneumonic for what all the scalp consists of
Skin Connective tissue aponeurosis loose connective tissue periosteum
Brain anatomy terms
Scalp Skull Dura mater Arachnoid Pia Brain (Gray matter and white matter)
what brain anatomy has nerve endings
scalp and Dura
Intraparenchymal means what
in the brain area
extraaxial
inside of scalp but outside of brain tissue
breast milk does what to brain
myelinates neurons and gives you white matter
myelin and brain tissue in relation to seizures
myelinated tissue is not as excitable
neonates and gray matter/white matter
does not have as much white matter. colostrum has cholesterol which helps to myelinate the brain to develop the white matter
brain stem is made up of how many parts
what are they
3
midbrain
pons
medulla
supratentorial
above posterior fossa
drooling, not managing secretions - from a neuro stand point, what part of the brain should you think about
think brain stem
how many ventricles do you have
4
CSF is being absorbed through what layer of the brain
arachnoid
80% of the CSF is produced where
Choroid plexus (in the 3rd ventricle)
part of brain controls balance or movement (coordination)
cerebellum
lobe that controls personality motor emotions problem solving reasoning
frontal lobe
lobe that controls
sensory
parietal lobe
lobe that controls
hearing
language
speech
temporal lobe
lobe that controls
vision
occipital lobe
CN in midbrain
3 -oculomotor
4 - trochlear
CN pons
5 - trigeminal
6- abducens
7- facial
8- vestibulocochlear
CN medulla
9- glossopharyngeal
10- vagus
11 - accessory
definition of brain death by the American academy of neurology (AAN) in 1995 and updated in 2010
“irreversible cessation of all functions of the entire brain, including the brain stem”
each facility will have their criterion
cant call Brain death if there is
- contribution of depressant drugs
- hypothermic
- metabolic/endocrine disturbance
- breathing on own
-patient condition must be compatible with irreversible brain damage
Brain death tests
pupil response
corneal reflex
vestibulo-ocular reflex (ear drum must be intact - inject cold water into ear while some one is holding the eyes open…eyes will shoot over to opposite side and produce nystagmus) (Dolls eyes test)
gag reflux (If intubated must be at the carina)
motor response (Train of 4 (TOF)) (needs to be central ie) sternal rub)
resp movements
each institution varies on who, repetition/timing
labs needed prior to neurosurgery
CBC (H&H and platelets - needs to be 100,000) - Hgb (10), HCT (30)
Coags (pt/inr/ptt)
BMP/Chem10 (sodium, potassium, BUN, creatinine)
type and screen
an impact, penetration or rapid movement of the brain within the skull that results in altered mental state
Traumatic brain injury
an insult to the brain, not of a degenerative or congenital nature, but caused by external physical force that may produce a diminished or altered state of consciousness
Traumatic brain injury
GCS associated with mild TBI
13-15 (brief change in mental status/consciousness)
GCS associated with moderate TBI
10-12
GCS associated with severe TBI
9 and below - extended period of unconsciousness or memory loss…death
results when the brain moves rapidly within the skull (coup - impact and contrecoup - non-impact (physiological due to force))
Traumatic brain injury
what lab that there are studies with brain injury
serial ____ levels
lactate
Changes in ionic fluxes after TBI
what’s going on
body is trying to repair itself
sodium and potassium will be depleted
when does frontal sinus develop
7-10 years old
sagittal view is
side view
when you see a bleed on a CT - bright white vs dull white
bright white is clotted blood, dull is fresh- still bleeding
when have a TBI, still have swelling. What electrolyte is important to follow and make sure they are keeping up?
sodium
what age is it that they have a better chance of the other parts of the brain taking over those functions
younger than 7 y.o.
general changes in brain function, such as confusion, amnesia, loss of alertness, disorientation (not cognizant of self, time, or place), defects in judgment or thought, unusual or strange behavior, poor regulation of emotions and disruptions in perception, psychomotor skills and behavior.
altered mental status
Pediatric decreased mental status differentials
acute demyelinating encephalomyelitis (ADEM) fever electrolyte disturbance sepsis/meningitis Respiratory head injury hydrocephalus abscess of brain seizure ruptured AVM/aneurysm narcotics benzo
focal brain injury is a
contusion
2 types of diffuse brain injury
concussion
DAI (direct axonal injury)
types of hemorrhages
epidural
subdural
subarachnoid
intracerebral (in brain tissue)
4 major causes of brain injury
falls
MVA
bicycle accident
child abuse
what does intraparenchymal hemorrhage mean
bleeding inside the brain
where is bleeding for a subdural hemorrhage
between the arachnoid mater and dura mater - irritates the brain faster, may cause seizures faster
where is bleeding for a subarachnoid hemorrhage
bleeding in the subarachnoid space
where is bleeding for epidural hemorrhage
between the dura mater and the skull
if bleeding does not clear during LP (from tube 1 to tube 4)
subarachnoid hemorrhage
if it clears its a dirty lp
subarachnoid hemorrhage think what on differential causes
subarachnoid hemorrhage
what type of bleed is confined by sutures
subdural
where does blood accumulate in an epidural
between skull and dural membrane
what artery tear is most common cause of epidural hematoma
middle meningeal artery
R pupil is fixed and dilating, what side of the brain is the bleed
R
clotted blood, up to 48 hours (subdural hematoma classification)
acute
2-3 days to 2-weeks, clot lyses (subdural hematoma classification)
subacute
> 3 weeks, fluid mass (subdural hematoma classification)
chronic
stroke - what is the hour time frame to be able to see on MRI
immediately
narcotic use in head injury - pros and cons
decrease agitation and pain so the blood pressure and ICP doesn’t increase
works as a CNS depressant by slowing down neural activity in the brain and body (PNS)
downside - no effect on cerebral metabolic rate of oxygen (CMRO2) or cerebral blood flow but they have been reported to increase ICP in some cases
CNS depressants
cautious alert to think about for when you are ordering benzos for treating seizure (What should you be double checking before giving a benzo for seizure
treating a seizure with benzo has major effects on the CNS. Are you treating a seizure? or could this be posturing?
Benzos and ICP
no effect on ICP
downside of Benzos
have a coupled reduction in cerebral metabolic rate of oxygen and cerebral blood flow and no effect on ICP
CNS depressant
what stage of sleep has highest ICP
REM
normal ICP ranges
1-15mm Hg
causes of increased ICP
trauma (contusion, EDH, SDH), infection, neurosurgery/neurosurgical procedures, overdose of/toxic reactions from meds, disease that affect nervous system, stroke, hydrocephalus (malfunctioning shunt/ETV)
signs symptoms of Increased ICP
lethargy/change in LOC
bradycardia
HTN
unequal pupils (esp if one is not reactive at all)
ICP mgmt
decompressive craniectomy (most invasive) pentobarbital coma EVD Mannitol/hypertonic saline sedatives, paralytics, hyperventilation general measures (least invasive)
why would you give 23% mannitol/hypertonic saline vs 3%
less volume
ICP general measures
elevate HOB (enhances venous outflow)
Loosen C-collar (if present), keep neck midline which enhances venous outflow, prevents “kinking”
maintain euvolemia
avoid hypotension
control pain/agitation
CSF production vs CSF absorption
not consistent over time and among individuals
Production not affected by ICP
but as ICP increases (usually >14cm H20) -> absorption increases
most common etiologies for hydrocephalus
intraventricular hemorrhage (IVH) of newborn chiari II (myelomeningocele) aqueductal stenosis post infectious tumors congenital brain malformations
types of hydrocephalus
obstructive
Communicating
over-production
what type of hydrocephalus can bacterial meningitis cause
communicating Hydrocephalus (HCP)
flow of CSF is blocked along one or more of the narrow pathways connecting the ventricles
Obstructive hydrocephalus
occurs when the flow of CSF is blocked after it exits from the ventricles
communicating hydrocephalus
mongolian spot, hair, tissue are all what type of markers
cutaneous
what age should you have head circumferences
2 years and younger
hydrocephalus signs/symptoms
abnormal enlargement of head
AF (anterior Fontenelle) tense/bulging when child is sitting up and quiet
scalp appears thin and glistening
scalp veins prominent
separated suture lines
vomiting, sleepiness, irritability, sunsetting eyes
seizures
difficulty feeding
position child should be in when checking fontanelle
upright
what week gestation is the germinal matrix max size
23 weeks (2.3mm)
common mistake with assessing eye movement tracking
signs without sound
what week gestation is the germinal matrix 1.15mm
32 weeks
what week gestation is the germinal matrix involuted
36 weeks
what week gestation is the germinal matrix gone
39 weeks
what grade (intracranial hemorrhage)
hemorrhage limited to subpendymal matrix
grade 1
toddler specific hydrocephalus s/s
if sutures not closed, head enlargement
sutures closed -s/s increased ICP
HA, vomiting, nausea, blurred or double vision, irritable, tired
balance problems, delayed walking, talking, poor coordination
loss of previous abilities
seizures
eye signs for hydrocephalus
setting sun (Parinaud’s syndrome)
nystagmus
VI nerve paresis
higher risk time frame for infection with shunt
6 months after insertion or manipulation of any sort
a small catheter is passed into a ventricle of the brain. A pump is attached to the catheter to keep the fluid away from the brain. Another catheter is attached to the pump and tunneled under the skin, behind the ear, down the neck and chest and into the peritoneal cavity. The CSF is absorbed in the peritoneal cavity
Ventriculoperitoneal shunt (VP shunt)
a typical shunt infection lowers IQ by how many points
10
testing for meningitis in an shunted pt
still need to
labs for shunt infection
CRP
Procalcitonin
CSF esosinophilia (>7% suggests infection)
procalcitonin is an inflammatory marker that checks for what
bacterial infection
what inflammatory marker checks for viral infection
CRP
what hour marker does vancomycin reach steady state
24 hour
when do you start drawing vanc trough levels
24 hour mark
so if you are vanc q 8 draw 30 min prior to 3 rd dose
if you are vanc q 6 hours draw 30 min prior to 4th dose
what vanc trough level do you want to maintain for shunt infection treatment
> 15-20
10-15 without shunt
other than shunt placement for treatment of hydrocephalus (surgical)
cranial morcellation
what type of bleed
“thunderclap headache/worst headache of life”
subarachnoid and can be intraventricular as well
star of death pattern on CT
aneurysm
work up for aneurysms
Labs
CTA or MRA/MRV
may get diagnostic angiogram as well
Treatment for aneurysms
usually involves clipping or open case
TIGHT BLOOD PRESSURE CONTROL WITH ARTERIAL LINE
High risk for stroke
High risk for vasospasm ->leads to stroke
Post aneurysm how many days are critical risk for stroke, in ICU
21 days
clinical presentation of brain injury - shift/herniation
progressive loss of consciousness
coma
irregular breathing
resp arrest
irregular pulse
cardiac arrest
loss of all brainstem reflex (blink, gag, pupillary reaction to light)
hydrocortisone and Decadron -whats better for treating adrenal insufficiency
hydrocortisone
tumor that grows slow
benign
tumor that grows fast
malignant
what type of tumor does chemo and radiation target
targets mitosis
malignant
posterior fossa tumors - what CN deficits
Primarily V, VI, VII, VIII
V - ptosis, moves mandible chewing
VI - eyes cant abduct
VII - facial palsy
VIII - balance and hearing
amount of contrast they use for a contrasted CT (Isovue300)
2cc/kg: max of 100cc
> 50kg - max of 100cc
75kg - case dependent, may choose to use Isovue 370
imaging that demos intracranial vessels in 2D/3D
CTA (Computed Tomography Angiography)
gold standard for evaluating
Vessel occlusion/stenosis
aneurysm/AVM
Abnormal tumor circulation
Angiography
why are they ordering an MRI
stroke
evaluation of ETV (CINE)
Tumor/post surgery
AVM/aneurysm
Non-bony items
Ligamentous injury
Brain anatomy (any plane)
MRI vs CT
no radiation with MRI
more detailed for MRI
isotonic IV solution
what is it?
what does it do to the cells?
what does it do to the vascular volume?
NS
nothing to cells
increases volume
hypertonic saline
what is it?
what does it do to the cells?
what does it do to the vascular volume?
3%
so this adds sodium to the vascular
pulls water out of the cells into the vascular
shrinks cells
increases vascular volume
hypotonic saline
what is it?
what does it do to the cells?
what does it do to the vascular volume?
.45%
this pulls water from the vascular to the cells
enlarges cells
what color is blood and bone on a CT
White
What color is tissue on CT
black
decreased density on a CT means…
presence of surrounding edema
increased density on a CT means…
tumors with high nuclear to cytoplasmic ratio
CT Head with contrast will show what
areas of increased vascularity and breakdown of blood -brain barrier
A standard plane for Brain CT is selected to avoid excessive radiation to the ______
lens of the eye (retina)
Isovue 300: Contrast max dose rules
2cc/kg: max of 100cc
>50kg: max of 100cc
>75kg: case dependent, may choose to use Isovue 370
This is what they have to give to get a contrast study. If they have had one contrasted study, must wait 24 hours to get another study
Does MRI use Radiation
no
imaging type characterized by altered attenuation
CT
Imaging type characterized by signal intensity
MRI
what color is air and bone on MRI
black
What is the stronger/more detailed MRI magnet
3T
Renal precautions for MRI contrast
MRI Gadolinium can not be dialyzed
If GFR <60 (stage 3 or 4 renal disease, no gadolinium)
If they are a dialysis pt, you cant do this…
There is another med for off label use (Ferumoxytol (Feraheme)
Off label med as an alternative to Gadolinium for contrast for MRI in pt on dialysis
Ferumoxytol (Faraheme)
IV 2-5mg/kg (max reported dose: 510mg)
for US (sonography) ______ stops the frequency beam completely
Bone
Imaging type that uses high frequency sound
Ultrasound
CTA and MRA
which imaging type requires contrast
CTA (Computed Tomography Angiography)
MRA (Magnetic Resonance Angiography) does not require contrast.
what imaging type uses signals that demonstrate vessels, aneurysms, and AVM
MRA
Imaging type that evaluates intra and extracranial vessels
- Vessel occlusion/stenosis
- Aneurysms/AVM
- Abnormal tumor circulation
**This can be diagnostic and interventional
Angiography (Angiogram)
-catheter inserted into femoral artery and maneuvered up to carotid or vertebral origin (guidewire/image intensifier)
Iodinated contrast used
After an AVM that has ruptured and pt has stabilized, 7 days later what are you looking to do imaging/interventional
MRA to view
Angiogram to intervene
why do you want to use MRI instead of CT for stroke protocol
It takes a min of 6 hours to be able to see a stroke on CT, but can take 12 hours to show
If your worried about a head bleed, what do you order?
CT Head without contrast
what does MRI evaluate
Stroke Evaluation of ETV (CINE) Tumor/post surgery AVM/aneurysm Non-bony items Ligamentous injury Brain anatomy (any plane)
stroke protocol vs Rapid MRI
Stroke protocol - T1, T2
Rapid - T2 only
what imaging is used to evaluate vessel injury/abnormality but uses less radiation than angiography
CTA
what imaging is used to
- evaluate blood supply to/from region
- evaluate anatomy of vessels looking for stenosis, occlusion, dissection
MRA/MRV
What imaging is the gold standard for aneurysm/AVM
Angiogram
what are the risks with MRI
sedation risks
if kidney problem - metals in contrast
How is an MRI diff then CT
MRI is less radiation
MRI is more detailed….the CT showed that something that was wrong but the MRI is going to give us more information
Headache
subjective fever
Abdominal pain
Vomiting
What lab do you need to draw?
What are you looking for?
CBC
low platelets
ORDER CT! This is the start of alot of neuro bleeds….(remember sepsis case study)
This set of symptoms is very common for early symptom of a severe neuro problems
Platelet requirement for neurosurgery to take pt to OR
100,000
white matter is what
myelinated tissue
myelin is made up of what
cholesterol
white matter and gray matter
what is on outside and what is on inside of brain
White matter is inside
gray matter is outside
cranial nerves that arise from the midbrain
CN III (oculomotor) CN IV (trochlear)
cranial nerves that arise from the pons
CN V (trigeminal) CN VI (abducens) CN VII (facial) CN VIII (vestibulocochlear)
cranial nerves that arise from the medulla
CN IX (glossopharyngeal) CN X (vagus) CN XI (accessory)
part of the brain that controls balance and coordination
cerebellum
Part of brain that regulates basic body functions
Brainstem - breathing, digestion, heart rate, blood pressure, being awake and alert
what cranial nerve is eyes moving side to side
6th
if your L eye does not move to the side then that is a L sided CNVI palsy
what CN is eye conversion (when you have them follow finger follow to their nose)
4th
What CN controls eyelid movement
3rd
Brain death exams and problems with insurance
To declare someone brain dead, it requires 2 examinations. Sometimes there is a requirement for time in between the 2 exams. After 2nd one is done, pt is declared dead. Most insurance companies won’t pay after this. So if they change their mind…this can have significant implications.
There is only one organ that can be donated even if your cold and not producing urine
Cornea
Shunt problem Neurosurgery will have to have what imaging first
CT
CBC number requirements for Neurosurgery
must be at least
Hgb - 10
HCT - 30
platelets - 100,000
surgical prep product info
Hibiclens is preferred
Chloraprep is flammable (hair catches fire)
Hibiclens is not safe for meninges so for LP needs to be iodine or chloraprep
In a brain bleed situation, when is a reasonable time to re-scan if no changes
4-6 hours
Bright or Dark
MRI - T1
Dark
Bright or Dark
MRI-T2
Bright (white)
The deeper in the brain the injury, the _______amount of force that caused it
Greater
what type of bleed
accumulation of blood between skull & dural membrane
Epidural hematoma
What is the most common cause of an epidural hematoma
Epidural hematoma
unilateral pupil dilatation - 2 potential causes
compression of a 3rd nerve
think seizure or bleed
if it goes away…seizure….
on CT there is a hematoma that is described as a well-defined mass, maintains boundaries within cranial sutures
Epidural hematoma
collection of blood below dura but external to the brain and arachnoid membrane
Subdural hematoma
Subdural hematoma classification:
clotted blood - up to 48 hours
Acute
Subdural hematoma classification:
2-3 d to 2-3 wks, clot lyses
subacute
Subdural hematoma classification:
>3 weeks, fluid mass
Chronic
the displacement of brain tissue, cerebrospinal fluid and blood vessels outside the compartments in the head that they normally occupy
Herniation
shaken baby syndrome is now called
Abusive head trauma
other reasons for shaken baby symptomes
underlying hematologic or metabolic problem
Osmotic therapy for ICP management with doses
Hypertonic saline
3% (3-5ml/kg)
23% (0.5.1ml/kg)
what can decrease CSF production
infection
Does Increased ICP affect CSF production
no, but as ICP increases (usually >14cm H20) absorption
germinal matrix is at its max size at how many weeks gestation
23 weeks (2.3 mm)
at 32 weeks (1.15 mm)
Involuted at 36 weeks
Gone at 39 weeks
hydrocephalus eye signs
Setting sun (Parinaud’s syndrome)
VI nerve palsy/paresis (means same as palsy) (can’t look up)
nystagmus (from pressure to the cerebellum)
95% of shunt infections occur within the first ______ months of operation
3 (very unlikely in a fever in a child that had a shunt infection more than a year ago)
Fever in a shunt pt …what labs need to be drawn
CBC
ESR
CRP
Treatment in a pt with shunt infection
Broad spectrum abx (including vanc), replaced by organism specific antibiotics
Shunt needs to be replaced with an external ventricular drain (EVD) and a new shunt be replaced after CSF sterile
Posterior Fossa Tumor Work up
MRI brain and spine w and w/o contrast
Start Dexamethasone: (symptomatic reasons- vasodemic edema): 0.25-0.5mg/kg/day divided q 6 hours
PPI
If decompensating due to HCP - may need EVD placement prior to OR/MRI
labs
