2. The functional repair of brain injury depends
on:
1- Anatomic location of lesion.
2- Limited capacity of brain for repair.
E.g., several cubic cm of brain parenchyma
may be silent in frontal lobe, yet severe
disabling in spinal cord injury or fatal in
brainstem trauma.
3. The physical forces associated with head injury may
result in:
◦ Skull fractures
◦ Parenchymal injury
◦ Vascular injury
All three can coexist
Three common sequelae of CNS trauma
Hydrocephalus
Dementia (Punch Drunk Syndrome)
Diffuse Axonal Injury (white matter)
Other important sequelae are epilepsy, infections and
psychiatric disorders.
4. Concussion
◦ Concussion is a clinical syndrome of alteration of
consciousness secondary to head injury typically brought
about by a change in the momentum of the head
(movement of the head arrested by a rigid surface)
◦ There is 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
◦ Postconcussive neuropsychiatric syndromes are well
recognized
5. Direct Parenchymal Injury
◦ Contusion and laceration are lesions associated with direct
parenchymal injury of the brain
◦ A blow to the surface of the brain, transmitted through the
skull, leads to hemorrhage, tissue injury, and edema
◦ A patient who suffers a blow to the head may develop a
cerebral injury at the point of contact (a coup injury) or
damage the brain surface opposite to it (a contrecoup
injury)
◦ Both coup and contrecoup lesions are contusions
7. Vascular injury is a frequent component of
CNS trauma and results from direct trauma
and disruption of the vessel wall, leading to
hemorrhage
Hemorrhage will occur in any of several
compartments (sometimes in combination):
epidural, subdural, subarachnoid, and
intraparenchymal
8. Epidural hematoma (left) in which rupture of meningeal artery, usually
associated with a skull fracture, leads to accumulation of arterial blood
between the dura and the skull. In a subdural hematoma (right), damage to
bridging veins between the brain and the superior sagittal sinus leads to the
accumulation of blood between the dura and the arachnoid.
9. Epidural Hematoma
◦ Vessels that course within the dura, most importantly the
middle meningeal artery, are vulnerable to injury,
particularly with skull fractures
◦ The expanding hematoma has a smooth inner contour that
compresses the brain surface
◦ Clinically, patients can be lucid for several hours between
the moment of trauma and the development of neurologic
signs
10. Epidural hematoma covering a portion of the dura. Multiple small contusions
are seen in the temporal lobe.
11. Subdural Hematoma
Trauma leads to damage to bridging veins between the brain
and the superior sagittal sinus leads to the accumulation of
blood between the dura and the arachnoid
Venous bleeding is self-limited; breakdown and organization
of the hematoma take place in time
Clinically Subdural hematomas most often become
manifest within the first 48 hours after injury
Neurologic signs commonly observed are attributable to
the pressure exerted on the adjacent brain
The clinical manifestations are nonlocalizing and include
headache and confusion
12. A, Large organizing subdural hematoma attached to the dura. B,
Coronal section of the brain showing compression of the hemisphere
underlying the hematoma.
13. Cerebrovascular disease is the third leading
cause of death (after heart disease and
cancer) in the United States
The term cerebrovascular disease denotes any
abnormality of the brain caused by a
pathologic process of blood vessels
14. Cerebrovascular diseases include three major
categories:
◦ Thrombosis
◦ Embolism
◦ Hemorrhage
“Stroke” is the clinical designation that applies
to all these conditions, particularly when
symptoms begin acutely
15. Cerebrovascular diseases may be considered
as two processes:
◦ Hypoxia, ischemia, and infarction resulting from
impairment of blood supply and oxygenation of the
CNS tissue
◦ Hemorrhage resulting from rupture of CNS vessels
16. Two principal types of acute ischemic injury
are recognized:
◦ Global cerebral ischemia (ischemic/hypoxic
encephalopathy) occurs when there is a generalized
reduction of cerebral perfusion, such as in cardiac arrest,
shock, and severe hypotension
◦ Focal cerebral ischemia follows reduction or cessation of
blood flow to a localized area of the brain due to large-
vessel disease (such as embolic or thrombotic arterial
occlusion, often in a setting of atherosclerosis) or to small-
vessel disease (such as vasculitis or occlusion secondary to
arteriosclerotic lesions seen in hypertension
17. Global Cerebral Ischemia :
◦ Mild cases may show transient confusional states with complete
recovery while in severe cases widespread brain infarction with
death or deep coma or brain death
◦ Morphologically the brain is swollen, the gyri are widened, and
the sulci are narrowed
◦ Early changes, occurring 12 to 24 hours after the insult, include
acute neuronal cell change (red neurons)
◦ Subacute changes, occurring at 24 hours to 2 weeks, include
necrosis of tissue, influx of macrophages, vascular proliferation,
and reactive gliosis
◦ Repair, seen after approximately 2 weeks, is characterized by
neuronal loss and gliosis
Morphology
18. Infarction from Obstruction of Local Blood
Supply (Focal Cerebral Ischemia)
◦ The majority of thrombotic occlusions are due to
atherosclerosis
Occlusive cerebrovascular disease is frequently associated
with systemic diseases such as hypertension and diabetes
19. Infarction from Obstruction of Local Blood
Supply (Focal Cerebral Ischemia)
◦ Embolism to the brain occurs from a wide range of origins
Cardiac mural thrombi are among the most common
sources; myocardial infarct, valvular disease, and atrial
fibrillation are important predisposing factors
The territory of distribution of the middle cerebral artery
is the brain region most frequently affected by embolic
infarction
20. Infarction from Obstruction of Local Blood Supply
(Focal Cerebral Ischemia)
◦ Infarcts are subdivided into two broad groups based on their
macroscopic and corresponding radiologic appearance
Hemorrhagic (red) infarction is characterized by petechial
hemorrhages, and is typically associated with embolic events
Nonhemorrhagic (pale, bland, anemic) infarcts are usually
associated with thrombosis
◦ The clinical management of patients with these two types of
infarcts differs greatly: for obvious reasons, anticoagulation may
be used in cases of thrombosis but is contraindicated in
hemorrhagic infarcts
21. Infarction from Obstruction of Local Blood
Supply (Focal Cerebral Ischemia)
◦ Clinical Features
A sensory deficit, blindness, aphasia, or some other
deficit, evolves over time, and the outcome either is fatal
or is characterized by some degree of slow improvement
during a period of months
22. A, Sections of the brain
showing a large,
discolored, focally
hemorrhagic region in the
left middle cerebral artery
distribution (hemorrhagic,
or red, infarction)
23. Intracerebral (Intraparenchymal) Hemorrhage
◦ Spontaneous (nontraumatic) intraparenchymal
hemorrhages occur most commonly in middle to late adult
life, with a peak incidence of about age 60 years
Hypertension is the most common underlying cause of
primary brain parenchymal hemorrhage
Other causes include systemic coagulative disorders
Open heart surgery
Neoplasms
Amyloid angiopathy , vasculitis and vascular
malformations .
24.
25. Subarachnoid Hemorrhage and Ruptured
Saccular Aneurysms
◦ The most frequent cause of clinically significant
subarachnoid hemorrhage is rupture of saccular (berry)
aneurysm
◦ It may also be the result from extension of a traumatic
hematoma, rupture of a hypertensive intracerebral
hemorrhage into the ventricular system, vascular
malformation, hematologic disturbances, and tumors
26. Subarachnoid Hemorrhage and Ruptured
Saccular Aneurysms
◦ Saccular (berry) aneurysms (congenital aneurysm) is the
most common type of intracranial aneurysm
◦ The aneurysm is usually single
◦ Occurs in the circle of Willis
◦ Results from congenital defect of smooth muscles of tunica
media of the arterial wall
◦ Women are affected more than men.
◦ 25%-50% of patients die with the first rupture
27. Common sites of saccular (berry) aneurysms in the circle of Willis
28. View of the base of the brain, dissected to show the circle of Willis with
an aneurysm of the anterior cerebral artery (arrow).
29. C, Section through a saccular aneurysm showing the hyalinized fibrous
vessel wall.
30. Effect of Hypertension on the brain:
◦ Hypertensive hemorrhages.
◦ Lacunar infarcts (tiny infarcts deep at basal ganglia).
◦ Slit Hemorrhages.
◦ Acute hypertensive encephalopathy:
it is a clinicopathological syndrome characterized by evidence
of diffuse cerebral dysfunction (headaches, confusions,
convulsions and coma). Due to sudden rises of blood
pressure.
33. The most common cause of intracerebral
hemorrhage is
A) Hypertension
B) Amyloid angiopathy
C) Vasculitis
D) Systemic coagulation disorders
