Module 7: CNS: Hydrocephalus, epidural, subdural, subarachnoid and intracerebral Flashcards
Starting off CNS will be hydrocephalus, there are three different types with different pathogenesis. First starting with communicating hydrocephalus, what is the etiology of this?
Dilation of ALL ventricles (obstruction is due to arachnoid granulations)
–due to scarring or fibrosis of the arachnoid villi due to tumors or infections (TB,meningitis) or subarachnoid hemorrhage (ruptured berry aneurysm)
Under communicating hydrocephalus there is normal pressure hydrocephalus, what is the etiology for this?
Dementia, ataxia and urinary incontinence
–many respond to lumbar puncture/shunt
Under communicating hydrocephalus there is pseudomotor cerebri (benign intracranial HTN), what are the signs?
Female Obsese Headaches vision loss --many respond to lumbar puncture, diuretics, corticosteriods and shunt
The next type of hydrocephalus is non-communicating, what is the etiology for this?
Obstruction (usually by tumor) b/w lateral and 3rd ventricle or b/w 3rd and 4th ventricle —- dilation of ventricle proximal to the obstruction
(obstruction at the cerebellar aqueduct of Sylvius)
What is the most common location of the non communicating hydrocephalus?
Foramen of Monro
The last type of hydrocephalus is hydrocephalus ex vacuo, what is this?
Dilation of all ventricles due to cerebral atrophy (Alzheimer’s, senile atrophy or Nieman Pick in kids will present with cherry red macula) — compensatory increase in CSF
What is the presentation for Hydrocephalus in kids?
Increased Head Circumference b/c skull bones (fontanelles and sutures) have not fused yet so they expand
What is the presentation for hydrocephalus in adults?
Increased ICP
- headaches
- projectile vomiting
- blurry vision
- papilledema
What is seen on fundoscopy and MRI for patients with hydrocephalus?
Fundoscopy: papilledema with normal pressure
MRI (Best investigation)
lumbar puncture is contraindicated will cause an Uncal herniation
What are the complications associated with hydrocephalus?
Cushing’s Reflex (Warning sign): triad indicating an impeding herniation (huge ICP)
- elevated systolic pressure (wide pulse pressure)
- bradycardia
- irregular respirations (cheyne stokes)
What are the herniations associated with hydrocephalus?
Uncal/Trans-tentorial Herniation -oculomotor compression:unilateral foramen magnum (ipsilateral pupillary dilation aka blown pupil or Mydriasis due to compression of CN III) Tonsillar Herniation --More dangerous --Brain through foramen magnum --immediate death from resp failure
Explain the gross and radiograph seen on slide 1 of hydrocephalus?
non communicating hydrocephalus (see the dilation of just the proximal
Moving on to epidural hematoma, what is the etiology for this?
Lateral blow to temporal side of head
—fractured pterion – ruptures middle meningeal artery (Travels through the foramen spinosum) —blood collects in epidural space (b/w dura and calvarium)
What is the presentation for epidural hematoma?
Increased ICP
–headaches, projectile vomiting, blurry vision and papilledema
Loss of Consciousness
regain consciousness within minutes–lucid interval – talk and die – death
Explain the gross and CT image seen for an epidural hematoma on slide 2
Gross:
CT image: biconvex lens shaped hematoma
Xray: fracture (Not pictured)
What are the complications associated with epidural hematoma?
Uncal/Transtentorial Herniation (due to increased ICP)
–small flame shaped hemorrhages in the pons on autopsy