CNS I Path - CNS Trauma and Hemorrhages

Question 1

CT or MRI for path lesions?

Answer 1

CT! Cheaper and rapid, and can also see blood and hemorrhage far better than MRI

Question 2

Admission criteria for a head injury

Answer 2

Neuro deficits, new onset seizures, N/V, severe headache, fever, LOC, altered mental state, unexplained injuries

Question 3

Central Pontine Myelinolysis (from Robbins)

Answer 3

Loss of myelin (preservation of axons and cell bodies) in a roughly symmetric pattern involving the pons; extremely rare for the process to extend below the pontomedullary junction;

Most commonly associated with rapid correction of hyponatremia, though it can be associated with other severe electrolyte or osmolar imbalance, as well as orthotopic liver transplantation.

Presents clinically as RAPIDLY EVOLVING QUADRIPLEGIA; radiologic imaging usually localize the lesion to the BASIS PONTIS (basilar pons)

Myelin loss without evidence of inflammation; neurons and axons WELL PRESERVED;

Monophasic disease, all lesions appear to be at the same stage of myelin loss and rxn

Question 4

Define Concussions

Answer 4

Totally REVERSIBLE, transient cerebral malfunction which may be associated with a brief loss of consciousness or postural tone

Can be multiple and cumulative; likely a change of consciousness, easy to spot;

Repeated concussions can lead to CTE

Question 5

Other complications from head injury

Answer 5

Amnesia – dense retrograde (can’t remember what happened right at time of injury) or anterograde (can’t form new memories)

Primary complications (caused by initial trauma) –> scalp laceration, skill fractures, cerebral contusions, cerebral lacerations, intracranial hemorrhages, diffuse axonal injury

Secondary Complications –> show up later –> ischemia, hypoxia, cerebral swelling, infection

Question 6

Fractures

Answer 6

Can happen along suture lines; linear fractures or comminuted fractures (multiple breaks)

Contusions of the base of the brain may lead to bleeding around the eyes without injury to the face

Contusions of scalp lead to “goose eggs” on the skull –> press on them gives CREPTIUS SIGN – displacement of fibrin and clot material around the injured area, mimicking a fracture…

Question 7

Epidural Fracture

Answer 7

Fracture between the scalp and the dura

Common with fracture along the MIDDLE MENINGEAL ARTERY leading to hemorrhage

The largest problem with this is pooling of blood that may push the brain –> HERNIATION

Imaging studies can be used to tell if herniation is occurring by checking out compression of the ventricles

LENS SHAPED hemorrhage on CT

Question 8

Gyri vs. Sulci damage

Answer 8

Contusions of the brain and skull causes SHRINKAGE of the GYRI

Stroke will damage the SULCI

Question 9

Plaque Jaunes

Answer 9

Yellow plaques that may indicate an OLD CONTUSION injury

Question 10

Coup and Countrecoup

Answer 10

Coup = injury on the same side of head as the impact

Countrecoup = Injury on the opposite side of the initial impact

Weak blows – only coup seen

Harder blows – coup primarily, but some minor countrecoup (brain sloshes around in CSF and impact is so hard that it hits the opposite side of the skull too)

Question 11

What if a person is hit so hard with a baseball bat that they fall?

Answer 11

Initial Coup, immediate minor countrecoup, and then a larger countrecoup when the person hits the ground, and then an additional coup as a result on that impact!

Question 12

Epidural Hemorrhage

Answer 12

Bleeding outside the outer dura; MMA rupture commonly causes this

Question 13

Subdural hematoma

Answer 13

Bleeding beneath the outer dura

May be a slow bleed and present with a mild headache over weeks

Can be rapid, thus acute, subacute and chronic symptoms can all occur

Depends on how much volume is pushing on the brain and where the bleed is

Question 14

Subarachnoid/Parenchymal

Answer 14

Bleeding beneath the arachnoid layer; blood leaks in between the gyri and sulci; serious bleeds can push aside parenchyma, go into ventricles; many vessels in the arachnoid which can become ruptured or occluded

Question 15

What is the BIGGEST PROBLEM with cerebral hemorrhages?

Answer 15

HERNIATIONS!!!!!

Question 16

Types of Herniations

Answer 16

Cingulate – hemorrhage causes the cingulate gyrus to herniate underneath the hard falx cerebri

Sideways herniation – pushing brain to one side

Downward herniation – pushing downward, causing the temporal lobe to compress the cerebellar tentorium and the uncus (hippocampus underneath it), leading to uncal herniation –> may lead to swelling of the brainstem; downward herniation causes bleeds, hypoxia, ischemia and eventually LEADS TO DEATH

Tonsillar – tonsils of the cerebellum push on the foramen magnum, compressing the brainstem!!

Question 17

Diffuse Axonal Injury

Answer 17

Widespread damage to axons within the CNS that results from SEVERE ACCELERATION or DECELERATION of the head

Most patients are comatose immediately after the injury, no lucid interval (temporary improvement right after), remain unconscious, vegetative or severely disabled until death

Requires imaging to detect, occurs when an injury is severe enough to cause a SHEARING of axons or a TORSIONAL ROTATION strong enough the cause breakage

White matter problem – corpus callosum, walls of the third ventricle, dorsolateral surface of brainstem

Question 18

Time Course of DAI (Harris said don’t worry, but who knows)

Answer 18

4-5 hrs –> focal axonal accumulations of BEA AMYLOID

12-24 hrs –> axonal varicosities evident on H&E

24 hours - 2 months –> axonal swellings and microglial nodules demonstrated on H&E –> microglia coming to eat dead tissue

Long Term –> Wallerian degeneration, atrophy

Question 19

Diffuse Edema

Answer 19

Ipsilateral edema underlying a subdural hemorrhage

Bi-phasic swelling after trauma in children due to abnormal vasoregulation

This type of injury is difficult to prevent in kids

Question 20

Diffuse Hypoxic Brain Damage

Answer 20

Occurs as a combo of one or more of the following –> brain shifts, raised ICP, systemic hypoxia, arterial spasm

Ischemic changes often seen at arterial boundary zones

Question 21

Pathology of Child Abuse/Shaken Baby Syndrome

Answer 21

Occurs with young children, present in a coma with a low Glasgow Coma Score

Common findings –> retinal hemorrhages, intracranial and cervical injury, including subarachnoid/subdural hemorrhage, DAI, or contusion of the cervical spinal cord

Less neck musculature in infants, so the movement is dramatic

Cortical tears can be present

Inconsistent history/physical and parental risk factors (age, socioeconomic status, education, family history) need to be considered

Question 22

Hypertensive Hemorrhages – Non-traumatic

Answer 22

Around the basal ganglia commonly

Middle cerebral artery gives rise to the LENTICULOSTRIATE arteries which come off at 90 deg angles

As we develop HTN, there are changes in the way the vessels are formed –> more hyalinized, resulting in thicker walls, which leads to decreased malleability

May lead to rupture of an artery –> hemorrhage –> parenchymal bleeds

Charcot-Bouchard Aneurysms

90% of the time this occurs in a person with UNCONTROLLED HTN

Question 23

Germinal Matrix Hemorrhages

Answer 23

Central portion of the FETAL BRAIN from which glioblasts and microblasts emerge

This are is SUSCEPTIBLE to bleeds because of the lack of MATRIX STRUCTURAL MATERIALS and lots of activity

Bleeding may occur into the ventricle or into the germinal matrix –> minor are OK, major bleeds fatal!

Question 24

Berry/Sacular Aneurysms

Answer 24

Form in the CIRCLE OF WILLIS

Often occur at the bifurcation of arteries, and can sometimes be OK, but can get LARGE and RUPTURE

Cause bleeds underneath arachnoid (subarachnoid hemorrhage) –> WORST HEADACHE ever

Survival determined by surgery

Aneurysms that are not causing problems can be clipped if patient wants to or if they have risk of rupture

Question 25

Vascular Malformations

Answer 25

Telangeiectasis (small dilated vessels near the surface of the skin, commonly on the face and eyes)

Cavernous hemangiomas – consist of greatly distended, loosely organized vascular channels with thin, collagenized walls and are devoid of intervening nervous tissue; occur most often in the cerebellum, pons, and subcortical regions

AV MALFORMATIONS –> People present with headaches, seizures, hemorrhages and can be dealt with via surgery –> microscopically, there are arterio and venous formations –> may be too large (death) –> not normal vessels (incomplete elastic lamina) –> basically these are abnormal connections between arteries and veins –>

“Tortuous group of vessels that are not well organized and prone to rupture” – Younger men more likely

Question 26

STROKE

Answer 26

• 85% = ischemic, 15% hemorrhagic
• Ischemia: 1. Thrombotic or 2. Embolic
  
  1. Thrombotic type of CVA is typically related to ATHEROSCLEROSIS in CNS, causing white infarcts
  2. Embolism can occur from an atherosclerotic plaque where a thrombus forms and emboli breaks off OR from the heart most commonly (vegetations or emboli from a thrombus) causing red infarcts.

Most commonly the MCA is involved and it is typically a non-convulsive event – evolves: SUDDEN ONSET (focal neurologic deficit – can’t speak, move arm, etc.), progresses for a while and then stops – patient can regain function, either over time or immediately