Ischemia. Oxygen must be in steady supply, along with glucose, for the brain to operate normally
If the brain is not getting enough blood, what is the issue?
Oxygen and glucose
What two things does the brain need to function?
Increased intracranial pressure
5-15 mmHg normal pressure. Anything that causes swelling, bleeding, space occupying will increase this pressure. Results from an increase in intracranial content that occurs with tumor growth, edema, excess cerebrospinal fluid (CSF) or hemorrhage.
Edema in the CNS
an increase in the fluid inside of the cells
Increase fluid in the vascular space (blood supply to the brain).
...
Vasogenic Edema
most important type. caused by increased permeability of the capillary endothelium of the brain after injury to the vascular structure. causes disruption in the blood brain barrier. Plasma proteins leak into the extracellular spaces, drawing water to them
Blood brain barrier
a system of capillaries in the brain that restricts passage of most substances into the brain, thereby preventing large fluctuations in the brain's environment. Toxins and infections can cross the BBB.
1. Vasogenic Edema
2. Cytotoxic Edema
What are the two types of edema?
Cytotoxic Edema
�Intracellular edema.
�Results from failure in Na/K pump...Na and water accumulates in the cells
�Associated with hypoxia(suffocation, drowining)/anoxia (cardiac arrest), water intoxication, hyponatremia, SIADH
�Corticosteroids are NOT effective. Mannitol
Anaerobic Respiration. The brain cannot tolerate this.
What process does the brain go through when depleted of oxygen?
Space-occupying lesion
An abnormal mass somewhere in the nervous sytem that compresses delicate nervous tissue. The mass could be a tumor, an abcess or an enlarged normal structure.
Brain tissue
Blood supply
cerebralspinal fluid
What are the 3 components of the skull
1st stage of increased intracranial pressure compensation
1. CSF displaced from the ventricles and cerebral subarachnoid space to the spinal subarachnoid space to undergo increased absorption or decreased production
2. Blood in the cerebral venous system undergoes venous compression. Not symptomatic.
2nd stage of increased intracranial pressure compensation
start becoming symptomatic. Blood vessel restriction. Decrease blood flow to the brain as a result.
LOC (level of conciousness)
What is the first thing you will notice when assessing someone for increased intracranial pressure?
Stage 3 of increased intracranial pressure
This is when symptoms are noticable. ICP begins to equal the arterial pressure. Normal 5-15 so this increases and hypoxia begins. Cytotoxic edema occurs when cells begin taking on fluid. Widened pulse pressure, brachycardia, pupils are small and sluggish.
Chain stokes
an abnormal pattern of breathing characterized by progressively deeper and sometimes faster breathing, followed by a gradual decrease that results in a temporary stop in breathing called an apnea. The pattern repeats, with each cycle usually taking 30 sec
Apnea
Temporary cessation of breathing
Stage 4 of increased intracranial pressure
Autoregulation is lost
Dramatic increase in ICP
Decreased cerebral perfusion
Severe hypoxia and acidosis
the opposite of shock occurs
Brain contents herniate
symptoms: pupils dialate and become fixed.
shock
a failure of the cardiovascular system to keep an adequate supply of blood circulating to the vital organs of the body
Changes in LOC, dialated pupils, high systolic BP, changes in speech, seizures, pulse goes down, irregular respiratory pattern (chain stokes), vomiting (projectile style)
What are some signs/symptoms of increased intracranial pressure?
ipsilateral
on or relating to the same side (of the body)
contralateral
on or relating to the opposite side (of the body)
Basic Neurochecks
Check BP, pupil check, Pulse and strength check & Level of conciousness.
Decorticate posturing
Curling in to core. Characterized by upper extremities flexed at the elbows and held closely to the body and lower extremities that are externally rotated and extended. occurs when the brainstem is not inhibited by the motor function of the cerebral corte
Decerebrate posturing
Flex and rigid outward. Posturing in which the neck is extended with jaw clenched; arms are pronated, extended, and close to the sides; legs are extended straight out; more ominous sign of brain stem damage
*Remove the cause of the ICP
*Mechanical hyperventilation to medicated and comatose patient-not recommended anymore
Reduce blood pressure through diuretics, which slows production of
CSF and decreases blood-brain volume
*Drugs, us. Barbiturates to slow br
How do you treat increased intracranial pressure?
Traumatic Brain Injury
An acquired injury to the brain that is caused by an external physical force and that results in total or partial functional disability or psychosocial impairment, or both, that adversely affects educational performance
Closed (CBI) vs. Open
What are the 2 types of traumatic brain injuries?
15-30 years. 3-6 months and elderly. Transportation accidents, violence, falls.
Who is at the highest risk for traumatic brain injury?
Contusion
A bruise-an injury that doesn't break the skin but results in some discoloration
Hematoma
A collection of blood under the skin as the result of blood escaping into the tissue from damaged blood vessels. bruise that is collected and walls itself off
Epidural Hematoma
Subdural Hematoma
Intracerebral Hematoma
What are the 3 types of hematomas?
Epidural Hematoma
Tear in an artery (spurting)
A collection of blood in the space between the skull and dura mater.
Most common in young
Can lead to brain herniation
Loss of consciousness regain consciousness rapid progression to unconsciousness
Surgical removal of hematom
Subdural Hematoma
Often due to tearing of veins or dural sinuses
Acts as an expanding mass ? IICP? herniation of brain
Classified- (Acute/Subacute/Chronic)
beneath the dura mater, between the dura and arachnoid layers of the meninges
Intracerebral Hematoma
Bleeding within the brain tissue (parenchyma) itself; also referred to as an intraparenchymal hematoma
Diffuse axonal injury
widespread axonal damage occurring after a mild, moderate, or severe traumatic brain injury; the corpus callosum and the brainstem are often affected.
Diffuse brain injury
shaking effect; injury to neuronal axons caused by stretching forces from brain injury; brain cells fire at once, massive electrical discharge, releasing glutamate, triggering brain cells to release K; Ca rushes into cells, impaint hypochondria creating a
Focal brain injury
Grossly observable brain lesions. I.e., Contusions, lacerations, extradural hematoma, subdural hematoma, intracerebral hematome, and open-head trauma.
Coup injury
Initial brain damage. A brain injury that occurs when force is applied to the head and energy transmission through the brain tissue causes injury on the opposite side of the original impact
Countercoup injury
Rechochette injury. Injury on the pole opposite the site of impact. Can result in lacerations, blood vessel damage, edema
Force of impact typically produces contusions
Intracranial Hematoma
Most common in frontal or temporal lobes
Associated with severe motion injury
Older persons and alcoholics
thrombotic stroke
the most common form of CVA that results when parts of clots, often associated with atherosclerosis, within major blood vessels of the brain break off and suddenly interrupt blood supply to portions of the brain
Cerebrovascular Accident (CVA)
Stroke, or Brain Attack
Any clinical event (hemorrhage, ischemia, or infarction) that leads to impairment of cerebral circulation (perfusion). A sudden loss of consciousness resulting when the rupture or occlusion of a blood vessel leads to oxygen lack in
Ischemic stroke
stroke that results from inadequate blood flow to the brain caused by partial or complete occlusion of an artery.
Thrombotic (formed inside of brain)
Embolotic (formed outside of the brain)
What are the two types of ischemic strokes?
TIA (Transient Ischemia Attack)
a brief period of inadequate cerebral perfusion causing a sudden focal loss of neurologic function
Full recovery of function usually occurs in 24 hours
May be result of intermittent obstruction by platelets accumulating at the site of a thrombosis or from
Hemorrhagic Stroke
Top 3 causes: anyeurism, AV malformation (BV's that don't communicate well), severe hypertension.
Hypertension, ruptured aneurysms or vascular malformation, bleeding into a tumor, anticoagulation, or head trauma may be the cause
Described as massive, smal
What are some risk factors for those who might suffer a CVA?
Arterial hypertension
Heart disease
Myocardial infarction or endocarditis
Atrial fibrillation
Elevated plasma cholesterol
Diabetes mellitus
Oral contraceptives
Smoking
Polycythemia and thrombocythemia
Thrombotic stroke
the most common form of CVA that results when parts of clots, often associated with atherosclerosis, within major blood vessels of the brain break off and suddenly interrupt blood supply to portions of the brain
Embolotic Stroke
a stoke caused by a clot forming, traveling, and lodging in the brain
Hemorrhagic Stroke
a stroke that results from bleeding into the brain tissue itself (intracerebral or intraparenchymal hemorrhage) or into the subarachnoid space or ventricles (subarachnoid hemorrhage or intraventricular hemorrhage).
Results of CVA
Disrupted blood flow results in ischemia and inflammation leading to death of neurons
The ischemic area coalesces into an infarcted core within hours of the onset of stroke
Vision loss
Visual field deficits
Diplopia
Dizziness
Ataxia
Aphasia
Decreased LOC
Severe headache
Sensory deficits
Vomiting
What are some clinical manifestations of a stroke?