Random Neuro Flashcards
Cerebral perfusion is primarily driven by
PCO2
Use of therapeutic hyperventilation (decreased PCO2)
Helps decrease ICP in cases of acute cerebral edema (stroke, trauma) via decreasing cerebral perfusion
Rupture of middle meningeal artery (branch of maxillary artery)
Epidural hematoma
Rupture of bridging veins
Subdural hematoma
Rupture of aneurysm (such as berry)
Subarachnoid hemorrhage
Caused by systemic hypertension
Intraparenchymal (hypertensive) hemorrhage w/in brain parenchyma
Often due to fracture of TEMPORAL bone
Epidural hematoma
Often seen in elderly, alcoholics, blunt trauma, shaken baby syndrome
Subdural hematoma
WHOML
SAH
Has a lucid interval “talk and die”
Epidural hematoma
Slow venous bleed = less pressure = hematoma develops over time
Subdural hematoma
Rapid time course
SAH
Rapid expansion under systemic arterial pressure –> Compression of brain –> transtentorial herniation –> CN III palsy (down and out, fixed and dilated pupil); HA, vomiting, seizures
Epidural hematoma
Blood between dura and skull
Epidural hematoma
Blood between dura and arachnoid
Subdural hematoma
Blood in subarachnoid space
Subarachnoid hemorrhage
Typically occurs in basal ganglia and internal capsule
Intraparenchymal (hypertensive) hemorrhage
MCC of SAH
trauma, ruptured aneurysm, ruptured AV malformation
CT - biconves (lentiform) lens shaped that does not cross suture lines
Epidural hematoma
CT - Crescent-shaped that crosses suture lines
Subdural hematoma
Bloody or yello (xanthochromic - bilirubin) spinal tap
Subarachnoid hemorrhage
Irreversible brain damage begins after how many minutes of hypoxia
5 minutes
Areas most susceptible to ischemic damage
hippocampus, neocortex, cerebellum, watershed areas
Bright stroke on MRI
for 10 days
Dark stroke on noncontrast CT in
~24 hours
Bright areas on noncontrast CT indicate
HEMORRHAGE (tPA contraindicated)
Causes of thrombotic/ischemia stronke
a. fib, carotid dissection. patent foramen ovale, endocarditis
When can you give tPA
Only if pt. presents w/in 3 hours of onset, no major risk of hemorrhage: active bleeding, hx intracranial bleeding, recent surgery, severe HTN
Layers going through for LP @ L4/5
- Skin 2. Superficial space 3. Ligamnets (supraspinous, linterspinous, ligamentum flavum) 4. Epidural space 5. Dural mater 6. Subdral space 7. Arachnoid membrane *8. Subarachnoid space - GET CSF HERE
Flow of CSF
lateral ventricle –> R/L intraventricular foramina of Monro –> 3rd ventricle –> cerebral aqueduct of Sylvius –> 4th ventricle –> Foramina of Luschka and Foramne of Magendie –> Subarachnoid space
Decreased CSF absoprtion by arachnoid granulations –> increased ICP, papilledema, herniattion
Communicating hydrocephalus
Increased subarachnoid space volume, no increase in CSF, expantion of ventricles distorts fibers of corona radiatia –> urinary incontinence, ataxia, cognitive dysfunction (sometimes reversible)
Normal pressure hydrocephalus
Appearance of increased CSF in atrophy (Alzheimer’s, advanced HIV, Pick’s disease) ICP normal - looks like ventricles are enlarged
Hydrocephalus ex vacuo
Caused by a structural blockage of CSF circulation within the ventricular system (e.g. stenosis of aqueduct of sylvius) –> HA, papilladema, uncal herniation –> CN III palsy, increased ICP, death
Noncommunicating hydrocephalus
