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2H. Pathology- CNS > Trauma > Flashcards

Flashcards in Trauma Deck (73)
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1

The ___________ of the brain for functional repair are
major determinants of the consequences of CNS trauma

anatomic location of the lesion and the limited capacity

2

Injury of several cubic centimeters of
brain parenchyma
may be____________

, severely disabling),

or fatal ______________

  •  clinically silent (e.g., in the frontal lobe)
  •   (in thespinal cord)
  •  (in the brainstem)

3

The physical forces associated with head injury may result in_________, ______ and __________ ; all three can coexist. 

  1.  skull fractures,
  2. parenchymal injury,
  3. and vascular injury

4

The magnitude and distribution of a traumatic
brain lesion depend on the _______________, ____________ and __________ . A blow to the head may be penetrating or
blunt; it may cause either an open or a closed injury .

  • shape of the object causing the trauma,
  • the force of impact,
  • and whether the head is in motion at the time of injury

5

A fracture in which bone is displaced into the cranial cavity by a distance greater than the
thickness of the bone is called a _____________

displaced skull fracture 

6

7

The thickness of the cranial bones
varies
; therefore, their resistance to fracture differs greatly.

Also, the relative incidence of
fractures among skull bones is related to the pattern of falls. 

8

When an individual falls while
awake, such as might occur when stepping off a ladder, the site of impact is often in the
_________

occipital portion of the skull;

9

 in contrast, a fall that follows loss of consciousness, as might follow
a syncopal attack, commonly results in a______

 

 frontal impact. 

10

Symptoms referable to the lower cranial
nerves or the cervicomedullary region,
and the presence of orbital or mastoid hematomas
distant from the point of impact, raise the suspicion of a ____________, which typically
follows impact to the occiput or sides of the head. 

CSF discharge from the nose or ear and
infection (meningitis) may follow

basal skull fracture

11

. The kinetic energy that causes a fracture is dissipated at a
fused suture; fractures that cross sutures are termed______.

With multiple points of impact or
repeated blows to the head, the fracture lines of subsequent injuries do not extend across
fracture lines of prior injury.

 diastatic

12

PARENCHYMAL INJURIES

  1. Concussion
  2. Direct Parenchymal Injury
  3. Diffuse Axonal Injury

13

__________ is a clinical syndrome of altered consciousness secondary to head injury typically
brought about by a change in the momentum of the head (when a moving head is suddenly
arrested by impact on a rigid surface)
.

Concussion

 

"Concussion, from the Latin concutere ("to shake violently") or concussus ("action of striking together"

14

What is the characteristic neurologic feature of concussion?

 The characteristic neurologic picture includes

  • instantaneous onset of transient neurologic dysfunction, including loss of consciousness,
  • temporary respiratory arrest, and loss of reflexes. Although neurologic recovery is complete,
  • amnesia for the event persists.
  • The pathogenesis of the sudden disruption of neurologic
  • function is unknown; it probably involves dysregulation of the reticular activating system in the
  • brainstem.
  • Postconcussive neuropsychiatric syndromes, typically associated with repetitive injuries, are well recognized.

15

_______ and______are lesions associated with direct parenchymal injury of the brain

  1. Contusion
  2. and laceration

16

,
Direct parenchymal injury is either through transmission of kinetic energy to the brain and bruising analogous to what is
seen in soft tissues __________ or by penetration of an object and tearing of tissue____________

  • (contusion)
  •   (laceration).

17

In direct parenchymal injury what  are most susceptible, since this is
where the direct force is greatest. 

 crests of gyri

18

The most common locations for contusions correspond to the
most frequent sites of direct impact and to regions of the brain that overlie a rough and
irregular inner skull surfac
e, such as the _____________ and _________

Contusions are less frequent over the occipital lobes, brainstem, and cerebellum unless
these sites are adjacent to a skull fracture (fracture contusions).

frontal lobes along the orbital ridges and the temporal
lobes. 

19

Multiple contusions involving the inferior surfaces of frontal lobes, anterior
temporal lobes, and cerebellum.

20

B, Acute contusions are present in both temporal lobes, with
areas of hemorrhage and tissue disruption (arrows).

21

Remote contusions are present on
the inferior frontal surface of this brain, with a yellow color (associated with the term plaque
jaune).

22

A person who suffers a blow to the head may develop a contusion at the point of contact ____________-) or a contusion on the brain surface diametrically opposite to it (______________). 

  • (a coup injury)
  • a contrecoup injury) 

23

Since their macroscopic and microscopic appearance in Direct parenchymal injury is indistinguishable, the _________________ 

distinction
between them is based on forensic identification of the point of impact and the circumstances
attending the incident.

24

In general, if the head is immobile at the time of trauma, only a ___________
injury is found.

coup

25

 If the head is mobile, both __________ may be

 

coup and contrecoup lesions

26

Whereas
the coup lesion is caused by the ____________, 

y

27

the
contrecoup contusion is thought to develop when the brain strikes the opposite inner surface of
the skull after sudden deceleration. found. 

28

Sudden impacts that result in violent posterior or lateral hyperextension of the neck (as occurs
when a pedestrian is struck from the rear by a vehicle) may avulse the pons from the medulla or
the medulla from the cervical cord, causing instantaneous death.

29

When seen on cross-section, contusions are________________

 wedge shaped, with the broad
base lying along the surface, deep to the point of impact

30

The histologic appearance of contusions is independent of the type of trauma. In the earliest stages, there
is __________, which is often pericapillary. 

During the next few hours, the
extravasation of blood extends throughout the involved tissue, across the width of the
cerebral cortex, and into the white matter and subarachnoid space.

edema and hemorrhage

31

Morphologic evidence of
neuronal injury ___________________-) takes about 24 hours to appear, although functional deficits may occur earlier.

  • (pyknosis of the nucleus,
  • eosinophilia of the cytoplasm,
  • and disintegration of the cell

32

Axonal swellings develop in the vicinity of damaged neurons or at great distances away.

The
inflammatory response to the injured tissue follows its usual course, with the ___________ followed by macrophages.

appearance of
neutrophils

33

Old traumatic lesions on the surface of the brain have
a characteristic macroscopic appearance. They are_______________ most commonly located at the sites of contrecoup lesions
(inferior frontal cortex, temporal and occipital poles).

  •  depressed,
  • retracted,
  • yellowish brown
  • patches involving the crests of gyri

34

Old traumatic lesions on the surface of the brain have
a characteristic macroscopic appearance. They are depressed, retracted, yellowish brown
patches involving the crests of gyri most commonly located at the sites of_______________-

 contrecoup lesions
(inferior frontal cortex, temporal and occipital poles).

The term plaque jaune is applied to
these lesions ( Fig. 28-9C ); they can become epileptic foci. More extensive hemorrhagic
regions of brain trauma give rise to larger cavitated lesions, which can resemble remote
infarcts. In sites of old contusions, gliosis and residual hemosiderin-laden macrophages

35

Diffuse Axonal Injury
Although it is most often affected, the surface of the brain is not the only region of damage in
traumatic injury.

Also affected may be the deep white matter regions (the corpus callosum,
paraventricular, and hippocampal areas in the supratentorial compartment), cerebral
peduncles, brachium conjunctivum, superior colliculi, and deep reticular formation in the
brainstem.

36

 The microscopic findings include_____________, indicative of diffuse axonal injury ,
and focal hemorrhagic lesions.

 

 axonal swelling

37

_________, in the absence of impact, can cause
diffuse axonal injury as well as hemorrhage. 

Angular acceleration alone

38

As many as 50% of individuals who develop coma
shortly after trauma, even without cerebral contusions, are believed to have diffuse axonal
injury.

The mechanical forces associated with trauma are believed to damage the integrity of
the axon at the node of Ranvier, with subsequent alterations in axoplasmic flow.

39

Diffuse axonal injury is characterized by the widespread but often asymmetric
axonal swellings that appear within hours of the injury and may persist for much longer.
These are best demonstrated with ___________________

 

Later, there are increased numbers of microglia in related areas of the cerebral cortex and,
subsequently, degeneration of the involved fiber tracts.

silver impregnation techniques or with immunoperoxidase
stains 

40

silver impregnation techniques or with immunoperoxidase
stains for 

axonally transported proteins, including amyloid precursor protein and α-synuclein.
 

41

TRAUMATIC VASCULAR INJURY

  1.  Epidural Hematoma
  2. Subdural Hematoma

42

__________- is a frequent component of CNS trauma. It results from direct trauma and
disruption of the vessel wall, and leads to hemorrhage. Depending on the anatomic posi tion of
the ruptured vessel, hemorrhage may occur in the epidural, subdural, subarachnoid, and
intraparenchymal compartments, sometimes in combination (
Fig. 28-10 ). 

Vascular injury

43

__________________ most often occur concomitantly in the setting of brain trauma
that also results in superficial contusions and lacerations. A traumatic tear of the carotid artery
where it traverses the carotid sinus may lead to the formation of an arteriovenous fistula.
 

  • Subarachnoid and
  • intraparenchymal hemorrhages

44

Normally the dura is fused with the periosteum on the internal surface of the skull. Dural
arteries, most importantly the___________ are vulnerable to injury, particularly with
temporal skull fractures in which the fracture lines cross the course of the vessel. In children, in
whom the skull is deformable, a temporary displacement of the skull bones leading to laceration
of a vessel can occur in the absence of a skull fracture.

 middle meningeal artery,

45

Once a vessel has been torn, the _______________ can cause the
dura to separate from the inner surface of the skull ( Fig. 28-11 ). The expanding hematoma
has a smooth inner contour that compresses the brain surface. When blood accumulates slowly
patients may be lucid for several hours before the onset of neurologic signs. 

extravasation of blood under arterial pressure

46

An epidural
hematoma may expand rapidly and is a neurosurgical emergency requiring prompt drainage.

47

Where does the subdural space lies?. 

Between the inner surface of the dura mater and the outer arachnoid layer of the
leptomeninges lies the

48

Bridging veins travel from the convexities of the cerebral
hemispheres through the subarachnoid space and the subdural space to empty into the
_______________-

superior sagittal sinus

49

. Similar anatomic relationships exist with other dural sinuses. These
vessels are particularly prone to tearing along their course through the subdural space and are
the source of bleeding in most cases of subdural hematoma.

It is thought that the brain, floating
freely bathed in CSF, can move within the skull, but the venous sinuses are fixed.

Thedisplacement of the brain that occurs in trauma can tear the veins at the point where they
penetrate the dura. In elderly individuals with brain atrophy, the bridging veins are stretched out
and the brain has additional space for movement, hence the increased rate of subdural
hematomas in these patients, even after relatively minor head trauma

 

50

Why are infants also
particularly susceptible to subdural hematomas ?

because their bridging veins are thin-walled

51

Morphology. On macroscopic examination, the acute subdural hematoma appears as a:

  • collection of freshly clotted blood along the brain surface, without extension into the depths of sulci ( Fig. 28-12 ). 
  • The underlying brain is flattened and the subarachnoid space is often clear.
  • Typically, venous bleeding is self-limited; breakdown and organization of the  hematoma take place over time. 

52

The underlying brain is flattened and the subarachnoid space is often clear. Typically, venous bleeding is self-limited; breakdown and organization of the  hematoma take place over time.

This usually occurs in the following sequence:
 

• Lysis of the clot (about 1 week)
• Growth of fibroblasts from the dural surface into the hematoma (2 weeks)
• Early development of hyalinized connective tissue (1 to 3 months)

53

Typically, the organized hematoma is firmly attached by fibrous tissue only to the inner surface of the dura and is not adherent to the underlying smooth arachnoid, which does not
contribute to its formation.

The lesion can eventually retract as the granulation tissue
matures, until there is only a thin layer of reactive connective tissue (“subdural membranes”)

.

54

 A common finding in subdural hematomas, however, is the ______________________

The risk of repeat bleeding is greatest in the
first few months after the initial hemorrhage.

occurrence of
multiple episodes of repeat bleeding (chronic subdural hematomas), presumably from the
thin-walled vessels of the granulation tissue. 

55

Subdural hematomas most often manifest within ___________hours of injury. 

48 

56

Where are subdural hematomas most common?

They are most common over
the lateral aspects of the cerebral hemispheres and are bilateral in about 10% of cases.
 

57

How many percent is subdural hematoma bilateral?

10 %

58

Neurologic signs commonly observed in subdural hematomas are attributable to the pressure exerted on the adjacent
brain. There may be focal signs, but often the clinical manifestations are :

nonlocalizing and include headache and confusion.

Slowly progressive neurologic deterioration is typical, but
acute decompensation may occur.

59

 The treatment of subdural hematomas is to ________________

remove the
blood and associated organizing tissue

60

A broad range of neurologic syndromes may become manifest months or years after brain
trauma of any cause.

These have gained increasing notice in the context of legal medicine and litigation involving issues of compensation for those in the civilian work force and the military
services.

 

61

Post-traumatic hydrocephalus is largely due to _________________

obstruction of CSF resorption from
hemorrhage into the subarachnoid spaces

62

Post-traumatic dementia and the punch-drunk
syndrome (dementia pugilistica) follow repeated head trauma during a protracted period; the
neuropathologic findings include _____________________.

 

  • hydrocephalus,
  • thinning of the corpus callosum,
  • diffuse axonal injury,
  • neurofibrillary tangles (mainly in the medial temporal areas), and
  • diffuse amyloid β (Aβ)- positive plaques (see “Alzheimer Disease”)

63

Other important sequelae of brain trauma include
:

  1. post-traumatic epilepsy,
  2.  tumors (meningioma),
  3. infectious diseases,
  4. and psychiatric
    disorders

64

The spinal cord, normally protected within the bony vertebral canal, is vulnerable to trauma
from its_____________ 

 skeletal encasement.

65

Most injuries that damage the cord are associated with
displacement of the vertebral column, either rapid and temporary or persistent.

66

______________ determines the extent of neurologic manifestations: 

 The level of
cord injury

67

lesions involving the thoracic
vertebrae or below can lead to 

paraplegia

68

; cervical lesions result in 

quadriplegia;

69

 those above
C4 can, in addition, lead to 

respiratory compromise from paralysis of the diaphragm. 

70

Segmental
damage to the descending and ascending white matter tracts isolates the distal spinal cord from
its cortical connections
with the cerebrum and brainstem; this interruption, rather than the
segmental gray matter damage that may occur at the level of the impact, is the principal cause
of neurological deficits

71

The histologic changes of traumatic injury of the spinal cord are___________________

  •  similar to those found at other sites in the CNS.

72

In spinal cord injury , at the level of injury the acute phase consists of
 

  • hemorrhage,
  • necrosis,
  • and axonal swelling in the surrounding white matter. 
  • The lesion tapers above and below the level of injury.
  • In time the central necrotic lesion becomes cystic and gliotic;
  • cord sections above and below the lesion show secondary ascending and descending wallerian degeneration, respectively, involving the long white-matter tracts affected at the site of trauma.

 

73