ICP, hydrocephalus, TBI, Seizure Flashcards
Blood is _ dense than gray/white matter, meaning it will be _ on CT scan
Blood is more dense than gray/white matter, meaning it will be bright on CT scan
Name some things that will appear “bright” (hyperdense) on CT
Bone
Blood
Bullet
Contrast
ID the blood vessels shown
ID the structures
ID the structures
ID the structures
ID the structures
ID which is T1 and T2
ID type of scan
T2 flair
_ edema is caused by intracellular accumulation of fluid secondary to derangements of cellular metabolism that alter ionic gradients
Cytotoxic edema is caused by intracellular accumulation of fluid secondary to derangements of cellular metabolism that alter ionic gradients
* Generally affects white and gray matter
* Ex: ischemic stroke, hepatic encephalopathy, cardiac arrest
_ edema is caused by extracellular accumulation of fluid secondary to a dysfunction of the blood brain barrier leading to extravasation of ions from plasma (with water following)
Vasogenic edema is caused by extracellular accumulation of fluid secondary to a dysfunction of the blood brain barrier leading to extravasation of ions from plasma (with water following)
* Generally effects white matter
* Brain tumor, Posterior reversible encephalopathy syndrome
_ edema occurs due to displacement of CSF from the ventricular space into the brain interstitium
Hydrostatic edema occurs due to displacement of CSF from the ventricular space into the brain interstitium
* Affects the ependymal surface and horns of ventricles
* Ex: hydrocephalus
_ edema occurs due to osmotic gradient between brain and serum that favors water entry to brain; occurs after hypertonic therapy, water intoxication, etc
Osmotic edema occurs due to osmotic gradient between brain and serum that favors water entry to brain; occurs after hypertonic therapy, water intoxication, etc
* Affects the gray/white matter diffusely
A patient who is awake and has a unilateral dilated pupil may have _
A patient who is awake and has a unilateral dilated pupil may have compression of CN III (aneurysm) or albuterol toxicity
* Patients who have herniated are never awake and alert
How can a tumor lead to brain herniation?
An expanding supratentorial mass lesion leads to displacement of CSF and then brain tissue into an adjacent intracranial compartment
Cingulate herniation means brain tissue shifts under the _
Cingulate herniation means brain tissue shifts under the falx
* Also called subfalcine herniation
Central herniation means _
Central herniation means downward transtentorial herniation has occured
_ herniation is movement of brain tissue over the edge of the tentorium
Uncal herniation is movement of brain tissue over the edge of the tentorium
Cerebral tonsillar herniation involves a downward shift into the _
Cerebral tonsillar herniation involves a downward shift into the foramen magnum
Cingulate, transtentorial, uncal, and tonsillar herniation will lead to coma and death once the herniation produces _
Cingulate, transtentorial, uncal, and tonsillar herniation will lead to coma and death once the herniation produces brain stem compression
ID the central herniation
Subfalcine herniation causes compression of [vessel]
Subfalcine herniation causes compression of anterior cerebral artery (ACA)
* Leads to ischemia/infarction in ACA –> contralateral leg weakness
The uncus found at the [location]
The uncus found at the medial temporal lobe
A lesion that increases intracranial pressure can push the uncus on the lesion side through the _ (hole in tentorium cerebelli)
A lesion that increases intracranial pressure can push the uncus on the lesion side through the tentorial notch (hole in tentorium cerebelli)
Inside the tentorial notch is the _ ; which means it can be compressed in uncal herniation
Inside the tentorial notch is the midbrain ; which means it can be compressed in uncal herniation
* Ipsilateral midbrain is affected
* Ipsilateral oculomotor nerve affected
Uncal herniation will present with decreased consciousness due to compression of the _
Uncal herniation will present with decreased consciousness due to compression of the midbrain reticular formation
Uncal herniation presents with [pupil finding] due to compression of _
Uncal herniation presents with ipsilateral dilated pupil due to compression of CN III parasympathetic fibers
* Eye can also be down and out
Compression of the ipsilateral cerebral peduncle by uncal herniation can cause [manifestation]
Compression of the ipsilateral cerebral peduncle by uncal herniation can cause contralateral hemiplegia
_ are not true herniations because the patient remains awake
Tonsillar herniation are not true herniations because the patient remains awake; they are an exception
* Chiari I have tonsillar displacement
* Often will present with flaccidity, neck pain/stiffness
Central (transtentorial) herniations can occur secondary to _
Central (transtentorial) herniations can occur secondary to parasagittal or bilateral supratentorial masses
* Can be a mass in the frontal, parietal, occipital lobe
* Causes caudal displacement of the diencephalon, midbrain, pons
Uncal herniation can result from mass lesion in the _ lobe or middle fossa
Uncal herniation can result from mass lesion in the temporal lobe or middle fossa
Uncal herniation may compress [vessel]
Uncal herniation may compress the PCA
Patients with central herniations often present in coma with _ posturing
Patients with central herniations often present in coma with decerebrate posturing
* Affects the midbrain and pons and ascending reticular activating system
Cerebral perfusion pressure = [equation]
Cerebral perfusion pressure = MAP - ICP
What are some signs of early elevated ICP?
Early elevated ICP signs…
* Headache
* Diplopia
* Vomiting
* Lethargy
* Photophobia
* Nystagmus
* Seizure
Cushings triad can occur in “late” elevated ICP; it includes _ , _ , _
Cushings triad can occur in “late” elevated ICP; it includes increased systolic BP , bradycardia , irregular respirations
Kernohan’s phenomenon explains why patients can get _ lesional hemiparesis
Kernohan’s phenomenon explains why patients can get ipsilesional hemiparesis
* Lesion shifts brain towards the opposite side
* Opposide side of brain presses up against kernohan’s notch and causes ipsilesional motor deficits
Elevated ICP can cause both ipsilesional and contralesional pupil changes; _ comes first
Elevated ICP can cause both ipsilesional and contralesional pupil changes; ipsilesional comes first
Recall that excess CSF gets reabsorbed into the venous circulation via _
Recall that excess CSF gets reabsorbed into the venous circulation via arachnoid granulations
Name 4 important cisterns (areas where the subarachnoid space enlarges)
- Cerebellomedullary cistern (aka cisterna magna- largest)
- Quadrigeminal cistern
- Pontomedullary cistern
- Interpeduncular cistern
ID the arrows
_ is ventriculomegaly that results from loss of brain tissue (brain atrophy)
Hydrocephalus ex vacuo is ventriculomegaly that results from loss of brain tissue (brain atrophy)
_ is a cause of hydrocephalus that involves hypoplasia of the vermis, cystic dilation of the fourth ventricle, and enlargement of posterior fossa
Dandy walker malformation is a cause of hydrocephalus that involves hypoplasia of the vermis, cystic dilation of the fourth ventricle, and enlargement of posterior fossa
Normal pressure hydrocephalus affects [demographic] and is defined as _
Normal pressure hydrocephalus affects the elderly and is defined as only a transient increase in CSF pressure that does not actually cause increased subarachnoid space volume
* Expansion of the ventricles distorts fibers of the corona radiata
* It is idiopathic
TBI is defined as _
TBI is defined as alteration in brain function or pathology caused by an external force
* Must have traumatic mechanism and neuro deficits
* Use GCS: 15 is normal
First order sympathetic neurons are found in [location]
First order sympathetic neurons are found in hypothalamus -> descending brainstem to C8-T2
Second order neurons of the sympathetic system (going to eye) are found in [location]
Second order neurons are found in exiting T1, ascending in sympathetic trunk (near lung apex/ subclavian vessels)
Third order neurons of the sympathetic system are found in [location]
Third order neurons of the sympathetic system are found in traveling to effector muscle
* E.g to the eye it is the long ciliary nerve
* Travels along the internal carotid artery, through cavernous sinus to the smooth muscle of the eyelids
Sympathetic innervation to the pupil is carried by the (long/short) ciliary nerve
Sympathetic innervation to the pupil is carried by the long ciliary nerve
* Long ciliary nerve makes pupil longer
The first order neuron of the parasympathetic system (to the eye) is found in the [location]
The first order neuron of the parasympathetic system (to the eye) is found in the ciliary ganglion
* Travels from EW nucleus –> exits midbrain with CN III
The second order neuron of the PS (to the eye) is found in the [location]
The second order neuron of the PS (to the eye) is found in the short ciliary nerve –> sphincter pupillae
* Short ciliary nerves shorten the pupil
Diagnosis?
Diffuse axonal injury
Arrows point to blood
_ injuries occur when there is blunt force to one side of the skull followed by injury to the opposite side due to inertia of the brain
Coup countercoup injuries occur when there is blunt force to one side of the skull followed by injury to the opposite side due to inertia of the brain
Fracture at the _ can result in CSF leakage through the nose and anosmia
Fracture at the cribiform plate can result in CSF leakage through the nose and anosmia
Define seizure:
Define seizure: transient alteration in behavior due to abnormal, synchronized, high-frequency neuronal firing
Child who appears to be daydreaming and shows 3 Hz spike and waves on EEG most likely has [seizures]
Child who appears to be daydreaming and shows 3 Hz spike and waves on EEG most likely has absence seizures
Management for status epilepticus often starts with [medical management]
Management for status epilepticus often starts with benzodiazepine
* Lorazepam, diazepam, midazolam
Syncope is a transient loss of consciousness due to _
Syncope is a transient loss of consciousness due to reduced cerebral blood flow from impaired autoregulation
* Causes: vasovagal, orthostatic hypotension, carotid stenosis, cardiac disease
Name (4) broad spectrum seizure drugs
Name (4) broad spectrum seizure drugs
1. Valproate
2. Lamotrigine
3. Levetiracetam
4. Topiramate
Many anti-seizure drugs like [list drugs] work by blocking VG Na+ channels and thus decreasing glutamate release at the presynaptic membrane
Many anti-seizure drugs like valproate, topiramate, lamotrigine, carbamazepine, phenytoin, fosphenytoin work by blocking VG Na+ channels and thus decreasing glutamate release at the presynaptic membrane
Gabapentin also inhibits glutamate release at the presynaptic membrane; however it does this via _
Gabapentin also inhibits glutamate release at the presynaptic membrane; however it does this via inhibiting Ca2+ channel
* Specifically L-type channels
* Note that valproate can also do this somewhat
Levetiracetam work by [mechanism], decreasing glutamate release from pre-synaptic membrane
Levetiracetam work by inhibiting SV2A, decreasing glutamate release from pre-synaptic membrane
Phenytoin _ CYP450
Phenytoin induces CYP450
* Thus speeding up metabolism of drugs, making them less effective
_ is an anti-seizure medication that causes gingival hyperplasia
Phenytoin is an anti-seizure medication that causes gingival hyperplasia
IV phenytoin should not be used because of _ syndrome
IV phenytoin should not be used because of purple glove syndrome
* Instead use IV fosphenytoin for status epilepticus
Phenytoin exhibits _ clearance kinetics
Phenytoin exhibits dose-dependent clearance kinetics
* At a high dose, phenytoin time of clearance is proportional to the dose so dose loading can be very dangerous
[anti-seizure drug] needs to be carefully monitored at high doses due to zero order clearance kinetics
Phenytoin needs to be carefully monitored at high doses due to zero order clearance kinetics
Phenytoin and _ are two seizure medications that induce CYP450
Phenytoin and carbamazepine are two seizure medications that induce CYP450
_ is a seizure medication that inhibits CYP450
Valproate is a seizure medication that inhibits CYP450
_ and _ are two seizure drugs that inhibit post-synaptic glutamate signaling
Topiramate and Ethosuximide are two seizure drugs that inhibit post-synaptic glutamate signaling
Ethosuximide works by [MoA]
Ethosuximide works by blocking T-type Ca2+ channels
* On the post-synaptic membrane
Topiramate works by [MoA] at the post-synaptic membrane
Topiramate works by blocking ligand-gated Na+ channel (AMPA) at the post-synaptic membrane
* Recall that at the pre-synaptic membrane it blocks VG Na+ channels
_ and _ are two seizure drugs that act as presynaptic potentiators of GABA release
Vigabatrin and Tiagabine are two seizure drugs that act as presynaptic potentiators of GABA release
* Valproate also does this somewhat
_ blocks the GABA reuptake channel, GAT-1
Tiagabine blocks the GABA reuptake channel, GAT-1
_ blocks GABA breakdown by GABA transaminase
Vigabatrin blocks GABA breakdown by GABA transaminase
Benzos and Barbiturates potentiate GABA action at the _ synaptic membrane
Benzos and Barbiturates potentiate GABA action at the post-synaptic membrane
