Exam III Flashcards
What are the conditions that can disrupt intracerebral perfusion?
- internal blockage of a vessel
- severe hypotension
- intracranial hemorrhage
- Loss of vessel integrity attributable to damage or excessive external pressure that exceeds perfusion pressure
This condition is the result of inadequate perfusion past a thrombus or embolus
Ischemic stroke
What are the most common inflammatory conditions of the brain?
- abscesses
- meningitis
- encephalitis
What population has a higher incidence of degenerative intracranial regulation problems?
The elderly
What population has a higher incidence of injury related intracranial regulation problems?
adolescent and young adult
Age, hypertension, diabetes, smoking, obesity, and cardiovascular disease are risk factors for _____?
Stroke
What are the three components of the skull?
- brain tissue (80%)
- blood (10%)
- cerebrospinal fluid (10%)
What is normal intracranial pressure?
Less than or equal to 15 mmHg
Intracranial pressure measuring greater than or equal to 20 mmHg is considered _____?
Intracranial hypertension
This is the capillary system of the brain consisting of a tight layer of endothelial cells located between the arterial and venous network?
Blood brain barrier
What is the function of the blood brain barrier?
It is a restrictive barrier that makes it difficult for neurotoxic substances to pass into the brain
What secondary condition compromises the blood brain barrier?
Decreased perfusion
The area of the brain between the arachnoid layer and the pia mater is referred to as the _____?
Subarachnoid space
The space contains cerebrospinal fluid
_____ is an inflammatory condition of the meninges
Meningitis
What are the three areas of the brain particularly sensitive to hypoglycemia?
- cerebral cortex
- hippocampus
- cerebellum
What are the detrimental effects of hyperglycemia with acute stroke?
- worsened ischemic damage
- increased infarction size
- increased blood brain permiability
Cerebral blood flow is normally maintained at a relatively constant rate by intrinsic cerebral mechanisms referred to as _____
Autoregulation
_____ adjusts cerebral blood flow in response to the brain’s metabolic demands by changing the diameter of cerebral blood vessels.
Autoregulation
The walls of these arteries are thinner because of a lack of smooth muscle and decreased thickness of the tunica media
cerebral
What are the three circumstances in which autoregulation becomes impaired?
- Mean arterial pressure <70mmHg or >170mmHg
- Intracranial Pressure >40 mmHg
- Localized or global cerebral injury
What is the rate of Cerebral Spinal Fluid production?
20 mL/hr
What are the six primary causes of cerebral edema?
- Mass lesions
- Head Injuries
- Brain Surgery
- Cerebral Infection
- Vascular Insult
- Toxic or Metabolic Encephalopathic conditions
What are the types of mass lesions that can cause cerebral edema?
- Brain abscess
- Brain Tumor (primary or metastatic)
- Hematoma (intracerebral, subdural, epidural)
- Hemorrhage (intracerebral, cerebellar, brainstem)
What are the complications that occur with head injuries and brain surgery that can cause cerebral edema?
- Contusion
- Hemorrhage
- Post traumatic brain swelling
What are the types of cerebral infections that can cause cerebral edema?
- Meningitis
- Encephalitis
What are the types of vascular insult that can cause cerebral edema?
- Anoxic and ischemic episodes
- Cerebral infarction (thrombotic or embolic)
- Venous sinus thrombosis
What are the toxic or metabolic encephalopathic conditions that can cause cerebral edema?
- Lead or arsenic intoxication
- Hepatic encephalopathy
- Uremia
____ is a compensatory mechanism that causes vasoconstriction, which reduces cerebral blood volume and ICP.
Hyperventilation
Carbon dioxide is a potent vasodilator
What is the intracranial pressure for Pathologic ICP?
Sustained pressure > or = to 20 mmHg
What conditions cause increased ICP?
- Traumatic brain injury (TBI
- Ruptured aneurysm
- CNS Infections
- Hydrocephalus
- Brain tumors
What are the symptoms of ICP?
- Headache
- Decreased LOC
- Vomiting
What are the signs of ICP?
- Cranial nerve VI palsies
- Papilledema
- Periorbital bruising
- Cushing’s triad
When doing a mental status exam what are the six categories to assess?
- general description
- emotional state
- experiences
- thinking
- sensorium
- cognition
What is the Glascow Coma Scale score for coma?
Adults < or = to 8
Children < or = to 5
Headache is an early sign of ICP for adults. What are the headache characteristics associated with increased ICP?
- Nocturnal awakening
- Pain worsened by cough/defication
- Progressive increase of frequency or severity
- Vomiting (not proceeded by nausea)
What are the symptoms of increased ICP for infants?
- Irritability
- Bulging fontanel
- Lethargy
- Flat affect
- Poor feeding
Retinal hemorrhage with increased ICP should raise suspicion of nonaccidental head trauma
At what level of Cerebral Perfusion Pressure is cerebral blood flow compromised and autoregulation impaired?
< 60 mmHg
What is the normal rate for cerebral perfusion pressure?
between 60 and 70 mmHg
Risk for adult respiratory distress syndrome occurs when CPP level are ______?
> 70 mmHg
What is the appropriate CPP level for children?
50 to 60 mmHg
Not well established
What are the different pharmacotherapies for intracranial regulation?
- Osmotic diuretics
- Sedatives
- Analgesics
- Antiepileptics
- Glucocorticoids
- Antipyretics
- Anti-hypertensives
- Anti-Parkinsonians
- Cholinesterase inhibitors
Which osmotic diuretics are commonly used for intracranial regulation?
Mannitol
Which sedatives are commonly used to decrease ICP by reducing metabolic demand?
- Propofol (Diprivan)
- Lorazepam (Ativan)
Which analgesics are used for intracranial regulation?
- Fentanyl (less effects on BP)
- Morphine
Which antiepilectics are used for intracranial regulation?
- Phenytoin (Dilantin)
- Valproic acid (Depakote)
Which glucocorticoids are indicated for cerebra edema related to tumors, abscesses, and CNS infections?
Dexamethasone (Decadron)
Which anti-hypertensives are used for intracranial regulation?
- Labetalol (Trandate): 1st choice
- Transdermal nitroglycerin paste
- Intravenous Nicardipine (Cardene)
Which Anti-Parkinsonian dopaminergic drugs are used for intracranial regulation?
- Levadopa (Sinemet): most common
Replaces dopamine, increasing the level in the brain. Given with carbidopa which prevents the conversion to dopamine until Levadopa reaches the brain.
Which Anti-Parkinsonian dopamine agonist drugs are used for intracranial regulation?
- Pramipexole (Mirapex)
- Ropinirole (Requip)
- Bromocriptine (Cycloset)
These mimic the effect of dopamine by stimulating the same cells as dopamine
Which cholinesterase inhibitors are used for mild to moderate dementia/intracranial regulation?
- Donepezil (Aricept)
- Rivastigmine (Exelon)
- Galantamine (Reminyl)
Which cholinesterase inhibitors are used for moderate to severe dementia/intracranial regulation?
- Memantine (Namenda)
What is the purpose of a decompressive craniotomy?
It removes rigid confines of the skull, allowing for expansion or cranial contents and lowers ICP
Complications include herniation, spinal fluid leak, infection, and hematoma (epidural and subdural)
What is the purpose of a craniotomy?
- remove lesions or tumors
- repair damages area
- relieve pressure
- drain blood from hematoma
What is the purpose of Stereotactic procedures?
- dissection
- biopsy
What is the purpose of Shunt procedures?
creates an artificial pathway for excessive CSF to drain from the brain
What is the proper positioning of the head for a patient with ICP?
- HOB 30 degrees
- Head midline
True/False
Patients with ICP should have all nursing care and tasks clustered at once.
False
This will increase oxygen demand and may compromise cerebral perfusion. Care and tasks should be distributed over a longer period of time.
True/False
Suctioning of patients with ICP causes no harm and should be performed as needed.
False
Suctioning stimulates coughing which increases ICP. If suctioning is absolutely necessary patient may need to be sedated.
True/False
Prophylactic hyperventilation in TBI is not recommended because it increases perfusion.
True
This negatively impacts oxygen delivery. This should only be done temporarily to reduce elevated ICP
This is caused by an interruption of perfusion to any part of the brain
Stroke
What are the two things the brain cannot store?
- Oxygen
- Glucose
Cerebral tissue death is called an ____
infarction
What are the two classifications of stroke?
- Ischemic (occlusive)
- Hemorrhagic
What are the two types of ischemic strokes?
- Thrombotic
- Embolic
This type of stroke is sudden but can be gradual if caused by HTN?
Hemorrhagic
With this type of stroke the patient is typically awake?
Ischemic
With this type of stroke the patient is typically in a deepened stupor or comatose?
Hemorrhagic
What are the two contributing factors for thrombotic stroke?
- HTN
- Atherosclerosis
What is the contributing factor for embolic stroke?
Cardiac Disease
What are the two contributing factors for hemorrhagic stroke?
- HTN
- Vessel disorders
This type of stroke usually presents with seizures?
Hemorrhagic
In this type of stroke the CSF presents bloody?
Hemorrhagic
In this type of stroke the CSF presents normal?
Ischemic
Protein may be present with thrombotic stroke
What are the neurologic deficits with thrombotic stroke and when do they present?
Deficits during the first few weeks
- slight headache
- speech deficits
- visual problems
- confusion
What are the neurologic deficits with embolic stroke and when do they present?
Maximum deficit at onset
- paralysis
- expressive aphasia
What are the neurologic deficits with hemorrhagic stroke?
Severe, frequent focal deficits
What is the duration of effects from a thrombotic stroke?
Improvements over weeks to months with permanent deficits possible
What is the duration of effects from a embolic stroke?
Rapid improvements
What is the duration of effects from a hemorrhagic stroke?
Variable recovery with permanent neurologic deficits possible
This type of stroke most often occurs in patients with A-fib, heart valve disease, prosthetic heart valves, or with mural thrombi after an MI
embolic stroke
Which type of hemorrhage is caused by sustained HTN ?
Intracerebral hemorrhage
Which type of hemorrhage is caused by a ruptured aneurysm, arteriovenous malformation, or trauma?
Subarachnoid hemorrhage
This condition occurs during embryonic development and is a tangled collection of malformed, thin walled, dilated vessels without a capillary network?
Arteriovenous malformation (AVM)
This is a sudden and periodic constriction of a cerebral artery that often follows a subarachnoid hemorrhage or bleeding from an aneurysm or AVM rupture?
Vasospasm
results in reduced perfusion and contributes to secondary cerebral ischemia and infarction
What type of diet is recommended for stroke prevention?
- High fruits/vegetables
- Low saturated fats
- Light to moderate alcohol consumption
Which ethnic group has the highest prevalence of stroke?
- American Indian
- Alaskan Native
Black men/women have higher instance of stroke thn white
What are the modifiable risk factors for stroke?
- Smoking
- Substance use (particularly cocaine)
- Obesity
- Sedentary lifestyle
- Oral contraceptive use
- Heavy alcohol use
- Use of phenylpropanolamine (PPA), found in antihistamine drugs
This type of stroke tends to occur during activity?
hemorrhagic stroke
What questions are necessary when a stroke is suspected?
- activity when stroke began
- how did symptoms progress
- time symptoms began
- severity of symptoms (getting better or worse)
- visual problems
- gait problems
- changes with reading/writing
What assessments should be done when a stroke is suspected?
- LOC
- cognitive/memory impairment
- difficulties with speech/hearing
- check for hypoglycemia (w/decreased LOC)
- o2 saturation
What medical history is important to collect with suspected stroke?
History of:
- HTN
- Diabetes
- Heart disease
- head trauma
- anemia
- obesity
- personal habits (smoking, drug use)
What are symptoms of subarachnoid hemorrhage?
- headache (worst ever)
- nausea/vomiting
- photophobia
- cranial neuropathy
- stiff neck
- change in mental status
What are the five most common symptoms of stroke?
- Sudden confusion or trouble speaking or understanding others
- Sudden numbness or weakness of the face, arm or leg
- Sudden trouble seeing in one or both eyes
- Sudden dizziness, trouble walking, or loss of balance/coordination
- Sudden severe headache with no known cause
To assess cognition changes check for which four signs?
- Denial of illness
- Spatial and proprioceptive dysfunction
- Impairment of memory, judgement, or problem solving and decision making abilities
- Decreased ability to concentrate and attend to tasks
What are the signs of right cerebral hemorrhage?
- Spatial and proprioceptive dysfunction
- Disoriented to time, place, and person
- Inability to recognize faces
- Personality changes such as poor impulse control and poor judgement
- Impaired sense of humor
- Loss of depth perception
- Visual special deficits
- Neglect of left visual field
- Impulsiveness
- Lack of awareness of neurologic deficits
- Confabulation
- Euphoria
- Constant smiling
- Denial of illness
- Poor judgement
- Overestimation of abilities
- Loss of ability to hear tonal variations
What are the signs of left cerebral hemorrhage?
- Aphasia (inability to use or understand language)
- Alexia/Dyslexia (reading problems)
- Agraphia (difficulty with writing)
- Acalculia (difficulty with math calculations)
- Possible memory deficits
- Deficits in right visual field
- Slowness
- Cautiousness
- Anxiety when attempting a new task
- Depression r/t illness
- Sense of guilt
- Feelings of worthlessness
- Worries over future
- Quick to anger and feelings of frustration
- No hearing changes
What are the motor changes that take place with stroke?
- Hemiplegia/Hemiparesis
- Hemiparesis/Quadriparesis (w/brainstem or cerebellum damage)
- Hypotonia/Flaccid Paralysis (reduced muscle strength)
- Hypertonia/Spastic paralysis (contractures)
What are the sensory changes that take place with stroke?
- decreased sensation on affected side
- Unilateral body neglect (primarily w/right cerebral hemisphere stroke)
- pupil constriction/dilation
- ptosis
- visual field deficits
- pallor and petechiae of the conjunctiva
- amaurosis fugax (brief episode of blindness in one eye)
- hemianopsia (blindness in half of the visual field)
- nystagmus
What is the name for a brief episode of blindness in one eye?
Amaurosis fugax
What is the name for blindness in half of the visual field?
Hemianopia
What is the name for blindness in half of the visual field of both eyes (same side)?
Homonymous Hemianopia
What is the name for blindness in half of the visual field of both eyes (opposite sides)?
Bi-temporal Hemianopia
Patients with this type of stroke may have a heart murmur, dysrhythmias (a-fib), or hypertension
Embolic stroke
What is the blood pressure necessary to maintain cerebral perfusion after an acute ischemic stroke?
150/100 mmHg
higher pressure may lead to another stroke
A patient who laughs and then cries unexpectedly for no apparent reason suffers from what condition?
Emotional lability
Which labs are drawn and what potential lab results are associated with stroke?
- increased H&H (compensation for lack of oxygen)
- increased WBCs (infection/inflammation)
- increased cardiac enzymes (if cardiac causes of stoke)
PT/INR and PTT are requested to establish baseline in the event anticoagulant therapy is needed