Flashcards in Module 7: CNS: Hydrocephalus, epidural, subdural, subarachnoid and intracerebral Deck (40):
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?
--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?
* projectile vomiting
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)
-irregular respirations (cheyne stokes)
What are the herniations associated with hydrocephalus?
-oculomotor compression:unilateral foramen magnum (ipsilateral pupillary dilation aka blown pupil or Mydriasis due to compression of CN III)
--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?
--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
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
What is the flow of CSF in the brain?
Production in lateral ventricles --- intraventricular foramina (foramen of monro) --- 3rd ventricle --- cerebral aqueduct --- 4th ventricle --- subarachnoid space
Moving on to subdural hematoma, what is the etiology?
Rupture of bridging veins (low pressure so gradual onset)
--recurrent mechanical falls in elderly -- stretch veins --- rupture
--alcoholism --- cerebral atrophy and ataxia
--shaken baby syndrome due to thin walls of veins (not well developed)
Is subdural hematoma or epidural hematoma a better prognosis?
Subdural hematoma better
--vein instead of artery
What is the presentation for subdural hematoma?
-headaches, projectile vomiting, blurry vision, papilledema
Focal neurological deficits, personality changes and memory loss
Note: gradual onset, days to weeks
What is seen on non contrast CT for subdural hematoma?
Crescent or banana shaped hematoma with a midline shift b/c closer to the brain
What are the complications associated with Subdural Hematoma?
--results from vagal nerve stimulation and increased acid production (patient will present with melena)
Next topic for this card deck is Berry Aneurysm also called Saccular Aneurysm, what is the location?
Most common location between anterior cerebral and anterior communicating artery (anterior circulation of circle of willis)
--not born with a berry, just born with a problem in the IEL of media of the vessels)
What conditions are associated with Berry Aneurysm?
AD polycystic kidney disease
When does the berry aneurysm rupture/
Ruptures during defecation or ejaculation
--before rupture asymptomatic
Subarachnoid Hemorrhage is a result of a ruptured berry aneurysm, what are some features?
Best differential is meningitis
--worst headache (thunderclap headache) of life b.c blood irritates leptomeninges and mimics meningitis (nuchal rigidity, photophobia, LOC and seizures)
What is seen on CT scan without contrast?
Lumbar puncture is contraindicated, what is seen however?
Check for papilledema first
--first 12 hours blood and RBCs
--longer than 12 hours xanthochromia (yellow and bilirubin)
What are complications associated with subarachnoid hemorrhage?
Die from cerebral infarcts due to cerebral vasospasms
Long term: Communicating Hydrocephalus
--blood causes fibrosis of the arachnoid granulations
What are the other two types of aneurysms in the brain?
Giant Fuisform: basilar artery
Mycotic: Healed arteritis after embolization of infected thrombus (endocarditis)
Next we are going to touch on Intraparenchymal/Intracerebral Hemorrhages. What is the etiology?
Considered a hemorrhagic stroke
Least common but worse prognosis
Long standing benign hypertension: hyaline arteriosclerosis
--Sudden Malignant HTN: direct rupture of arteries (most common risk factor)
causes: pheochromacytoma, Graves, Conn's syndrome, Cushings syndrome, AD polycystic kidney disease, Bilateral renal artery stenosis, acromegaly
The other etiology for intracerebral hemorrhage is non hypertensive hemorrhages, what are these?
Arterio-venous malformation: greatest potential for hemorrhages in 3rd and 4th decade
Cerebral Amyloid Angiopathy + HTN -- hemorrhage in basal ganglia
--without HTN = hemorrhage into lobes
CAA has strong association with Alzheimers disease
What is the 3rd etiology for intracerebral hemorrhage?
What is the most common location for intracerebral hemorrhage?
Basal ganglia (internal capsule)
--also can occur in thalamus, pons and cerebellum
What is the pathogenesis for intracerebral hemorrhage?
Long standing benign HTN -- hyaline arteriosclerosis of lenticulostriate arteries -- Charcot Bouchard Aneurysm (Slit hemorrhage)
--diabetes also causes charcot bouchard
What is the presentation for intracerebral hemorrhage?
Contralateral hemiparesis and sensory loss (like any other stroke)
More likely to increased ICP then cerebral infarct (reason for more damage)
--if it affects Broca Area (aphasia)
--if cerebellum then D (dysarthria) D (dysdiadochokinesia) A (Ataxia)N(nystagmus) I(intention tremor) S(slurred speech) H(hypotonia)
ALL SYMPTOMS ARE SAME FOR ALL STROKES
What is the best investigation for intracerebral hemorrhage?
Non contrast CT, hemorrhage
What are complications of intracerebral infarct in the brain?
Herniation and death (more common than ischemic stroke)
Another pathology in the basal ganglia is small lacunar infarcts, what are some features?
less than 1cm in diameter
always in penetrating artery distribution
--internal capsule/basal ganglia/diencephalic