Trauma to the Nervous System

Question 1

linear vs. depressed skull fracture

Answer 1

• linear-2/2 a more diffuse force applied to the skull

- depressed-2/2 focal/localized force

Question 2

brain contusions

Answer 2

-superficial hemorrhages at the tops of cortical gyri near pt of impact (coup) or more remotely in the brain (contrecoup) from movement of the brain within the skull

Question 3

where do brain contusions most often occur

Answer 3

-basal or ventral surfaces of the frontal and anterior temporal lobes where the bony skull is rough (orbital surface of frontal bone) or protuberant (edges of sphenoidal wings)

Question 4

what are the angles of brain contusions

Answer 4

-caused by angular or rotational, not linear acceleration of the brain

Question 5

cerebral autoregulation

Answer 5

-range of 60-140

Question 6

Cushings response/reflex

Answer 6

• observed in the setting of severely increased ICP
• indicated by elevation of systemic bp to preserve cerebral blood flow
• accompanied by PS resp: bradycardia and slowed resp rate

Question 7

subfalcine herniation

Answer 7

cingulate gyrus may be pushed beneath the unyielding falx cerebri

Question 8

uncal herniation

Answer 8

medial temporal lobe (uncus) compressed against the midbrain causing a fixed and dilated ipsi pupil

Question 9

tonsillar herniation

Answer 9

shifting of the lower BS and cerebella tonsils down the foramen magnum becomes fatal as medullary cardiorespiratory centers fail

Question 10

acute subdural hematoma

Answer 10

• occurs after focal laceration of bridging cortical veins which empty into larger venous sinuses of the brain
• clot forms beneath dura and compresses underlying cerebral cortex

Question 11

who is more susceptible to subdural bleeds

Answer 11

-elderly atrophic brain is more susceptible since cortical bridging veins are stretched over a larger subdural space and subdural bleeding can occur after minimal head trauma

Question 12

chronic subdural hematoma

Answer 12

• may develop in elderly pt after repeated often mild head injuries and may be b/l
• CP: subtle HA, confusion, or AMS rather than obvious focal neurological deficits

Question 13

tx of subdural hematoma

Answer 13

-remove clot and often its surrounding fibrous capsule

Question 14

epidural hematoma

Answer 14

• 2/2 rupture of a meningeal artery or vein or rarely from a torn venous sinus
• often a temporal bone fracture that lacerates the MMA
• clot forms between skull and dura

Question 15

clinical cours of epidural hematoma

Answer 15

-initial loc followed by a lucid interval then neurological worsening

Question 16

cerebral (intraparenchymal) hemorrhages

Answer 16

-observe pts and ICP monitored

Question 17

Monro-Kellie doctrine

Answer 17

• intracranial volume=sum of brain, vascular, and CSF volumes
• intact skull maintains a constant intracranial volume, development of brain edema increases the ICP

Question 18

mechanical hyperventilation

Answer 18

-reduces arterial pCO2 which causes arterial vasoconstriction=reduced intracranial blood volume and reduced ICP

Question 19

how do osmotic diuretics like mannitol reduce elevated ICP

Answer 19

by removing water across the intact BBB of nml brain tissue=reduce brain volume

Question 20

postconcussion syndrome

Answer 20

• HA or neck ache
• impaired concentration or memory
• positional dizziness or vertigo

Question 21

what may major head injury lead to

Answer 21

-chronic cognitive behavioral or neurological deficits

Question 22

major head injury imaging

Answer 22

• may be minimal or no obvious brain lesions
• micro: diffuse shearing of cerebral white matter with axonal damage and retraction, ischemic neuronal damage from previously impaired cerebral blood flow

Question 23

post traumatic epilepsy

Answer 23

may develop and require anti convulsants

Question 24

types of spinal cord trauma

Answer 24

• direct physical trauma
• ischemia from compression, bleeding, and hypoperfusion of the sc
• cellular level: edema and free radical formation impair neuronal function

Question 25

high cervical spinal cord lesion

Answer 25

• produce quadriplegia with respiratory paralysis since diaphragm is innervated by C3,4,5 nerve roots
• sympathetic pathways may be involved=bradycardia, fluctuating bp, hypothermia

Question 26

central cervical cord syndrome

Answer 26

• old pts with advanced degenerative arthritis of the sc who fall forward and hyperextend the neck
• produces ctl hemorrhage of the cervical spinal cord=predominant weakness of the upper limbs by affecting the medial portion of the corticospinal tract and cervical anterior horn cells

Question 27

role of dex

Answer 27

if administered within 8hrs of injury high dose iv corticosteroids (dex) contrib to a more likely neurological recovery

Question 28

how quickly do nerves regenerate

Answer 28

one inch per month

Question 29

traumatic neuroma

Answer 29

when a misdirected regrowing axon may form a painful, swollen, bulbous ending