Chapter 22 - CNS Part 1 Flashcards
What is the third leading cause of mortality in the U.S.?
Cerebrovascular disease (CVA)
What is the most common cause of neurological morbidity?
Cerebrovascular disease (CVA)
What are ways that a stroke can occur?
Thrombotic occlusion, embolic occlusion, vascular rupture (dissection)
What is the clinical term for a mini-stroke?
Transient ischemic attack (TIA)
What is a transient ischemic attack?
Temporary neurologic dysfunction without actual infarction or damage
What is the “FAST” acronym for recognizing and responding to a possible stroke situation?
Face drooping
Arm weakness
Speech difficulty
Time to call 911
Why is duration such an issue with strokes?
The more time that passes, the more destruction typically occurs
What is the number one leading cause of mortality in the U.S.?
Heart disease
What is the #2 leading cause of mortality in the U.S.?
Cancer
What condition involves the paralysis of the facial nerve results in a rapid onset of unilateral facial weakness?
Bell palsy
It is currently hypothesized that what virus is associated with Bell palsy?
HSV-1
How long does the inflammation of the facial nerve typically last in Bell palsy?
Self-limiting (2-8 weeks)
What is the most common age range for Bell palsy?
15-45
When Bell palsy is seen, what diagnoses should be considered and ruled out?
TIA/stroke, brain tumor, skull fracture
What is the treatment for Bell palsy?
Facial exercises, eye drops/patch
Corticosteroids, antivirals
Both stroke and Bell palsy cause paralysis of what part of the face?
Lower part
What part of the face has dual innervation?
Upper part
In strokes, what ability of the face is maintained that is still paralyzed with Bell palsy making it possible to distinguish the condition?
Wrinkling of the forehead (raising eyebrows)
What type of necrosis is seen with brain ischemia/hypoxia?
Liquefactive necrosis (infarct)
What are two causes of functional hypoxia?
Decreased oxygen partial pressure
Decreased oxygen availability
What can lead to decreased oxygen partial pressure (hypoxemia)?
High altitude
What can cause decreased oxygen availability?
Carbon monoxide (CO), anemia, cyanide
What is global cerebral ischemia?
Widespread ischemic-hypoxic injury
Cardiac arrest, shock, and severe hypotension’s effect on blood pressure leads to what condition?
Global cerebral ischemia
What can occur with severe global cerebral ischemia?
Widespread neuronal death leading to neurological impairment, coma, or death
What defines being in a comatose state?
Unconscious for more than 6 hours
What condition is cause by an arterial occlusion due to localized ischemia?
Focal cerebral ischemia
What type of tissue lacks a lot of collateral blood supply therefore making them more susceptible to ischemia?
Deep tissues (like the thalamus, basal ganglia, deep white matter)
What is the most common cause of focal cerebral ischemia?
Emboli
What are the most common locations of emboli that cause focal cerebral ischemia?
Middle meningeal artery and internal carotid artery
What is another name for a stroke?
Cerebral infarction
Neutrophils, red neurons, and edema are seen in what stage of a cerebral infarction?
First stage (roughly 12-48 hours)
Nuclear fragmentation (karyorrhexis) is seen in what stage of a cerebral infarction?
Second stage (rough to 48 hours to 2 weeks)
Macrophages and gliosis are most commonly seen in what stage of a cerebral infarction?
Third stage (roughly months to years, also cavitation)
What are the two types of strokes?
Ischemic or hemorrhagic
Ischemic strokes are treated with what kind of medication?
Thrombolytic
Liquefaction necrosis is seen in which type of cerebral infarction?
Ischemic
Is an intracranial hemorrhage considered a stroke?
No
How does an intracranial hemorrhage occur?
Due to vessel wall injury, structural malformations, or tumors
What is the most common cause of intracranial hemorrhage injury?
Hypertension
What are the steps of the extravasation of blood during an intracranial hemorrhage?
Coagulation, compression of parenchyma, cavitation
What is the condition involving a cerebral microbleed?
Primary parenchymal hemorrhage
What is the most common age for a primary parenchymal hemorrhage?
Age 60
What is the most common cause of primary parenchymal hemorrhage?
Hypertension
What condition makes up 15% of the deaths in chronic hypertension patients?
Primary parenchymal hemorrhage
Where do primary parenchymal hemorrhages tend to occur?
Basal ganglia, thalamus, pons, cerebellum
When small, are primary parenchymal hemorrhages easy to detect?
No, clinically silent until large and lethal
What condition is so commonly associated with the phrase from patients, “This is the worst headache I’ve ever had.”?
Subarachnoid hemorrhage
What is the most common cause of a subarachnoid hemorrhage?
Ruptured saccular (berry) aneurysm
What are all of the causes of subarachnoid hemorrhages?
Saccular aneurysm, vessel malformation, history of head trauma, tumor
What defect is associated with a ruptured saccular (berry) aneurysm that most commonly causes a subarachnoid hemorrhage?
Tunica media defect
What is the fatality rate of a first episode of a subarachnoid hemorrhage?
25-50%
A saccular (berry) aneurysm makes up what percentage of all intracranial aneurysms?
80-90%
Where is the most common location in the circle of Willis for a saccular (berry) aneurysm?
Anterior circulation of the circle of Willis
What is the most common type of arteriovenous malformation?
Cerebrovascular malformation
What gender and age group are most at risk for arteriovenous malformation?
Males, age 10-30
What rare and severe case of arteriovenous malformation is seen among newborns?
High-output heart failure
What are the usual locations for hypertensive cerebrovascular disease?
Basal ganglia, white matter, brainstem
What is a lacunar infarct?
Occlusion of a single artery resulting from hypertension
What are the two terms used to describe the cavity left over following an intracerebral hemorrhage resulting from hypertension?
Lacunar infarct and slit hemorrhage
What diastolic blood pressure is seen with acute hypertensive encephalopathy?
> 130 which means there is severe increased intracranial pressure
What condition is a systemic autoimmune condition with fibrinoid necrosis involving the small cerebral arteries and heart that results from vasculitis within the CNS?
Polyarteriosis nodosa
Primary angiitis of the CNS is limited to what locations?
Spinal cord and brain
What is the most common gender and age group affected by primary angiitis of the CNS?
Males, age 30-60
What is the treatment for primary angiitis of the CNS and polyarteritis nodosa?
Immunosuppression
What gender is most likely to be involved in CNS trauma?
Males
What is the ABCD assessment for CNS trauma?
Airway, breathing, circulation, disability
What was the previous term for chronic traumatic encephalopathy?
Dementia pugilistica
Repetitive CNS trauma can lead to what serious condition that involves dementia and neurofibrillary tangles?
Chronic traumatic encephalitis
“Red neurons” is a sign present with which type of neuronal injury?
Irreversible
What occurs with reversible neuronal injury?
Decreased axonal transport, swelling of soma, displacement of the Nissl substance (central chromatolysis)
What occurs with irreversible neuronal injury?
Soma shrinkage, pyknosis, eosinophilia, “red neurons”, cerebral edema, loss of nucleolus and Nissl body
Neuronophagia is associated with what cells of the CNS?
Microglia
Where can ependymal cells be found?
Lining ventricles and the spinal cord
Cytomegalovirus infection can affect what CNS cell type?
Ependymal cells
What neuroglia cells produce cerebrospinal fluid?
Ependymal cells (choroid plexus)
What neural viral infection produces the sign of Negri bodies?
Rabies
What neural viral infection produces the sign of “owl’s eye”?
Cytomegalovirus
Which neurodegenerative disease is associated with Lewy bodies?
Parkinson’s disease
Which neurodegenerative disease is associated with neurofibrillary tangles, beta-amyloid plaques, and Tau proteins?
Alzheimer’s disease
What is intracellular inclusion is known known as the aging pigment due to lipid accumulation?
Lipofuscin
What are the two kinds of cerebral edema?
Vasogenic and cytotoxic
What is disrupted enabling increased permeability with vasogenic edema?
Blood-brain-barrier
What can cause localized vasogenic edema?
Tumors, infection, inflammation
What can cause generalized vasogenic edema?
Severe trauma
Which is associated with extracellular edema: vasogenic or cytotoxic edema?
Vasogenic
Which is associated with intracellular edema: vasogenic or cytotoxic edema?
Cytotoxic
What kind of injury is the cause of cytotoxic edema?
Neuronal/glial membrane injury (hypoxic-ischemic injury, toxic exposure)
What is hydrocephalus?
Increased cerebrospinal fluid volume within ventricles
What specific structure produces cerebrospinal fluid?
Choroid plexus
What resorbs the CSF produced by the choroid plexus?
Arachnoid granulations (villi)
What does hydrocephalus most commonly result from?
Disturbed flow/resorption
What rare condition can cause overproduction of CSF?
Choroid plexus tumor
What is the effect of hydrocephalus in those under two years of age?
Cranial enlargement
What is the effect of hydrocephalus in those above two years of age?
Increased cranial pressure, ventricular enlargement
What is the frequency for congenital hydrocephalus?
3/1,000 live births
Lethal tonsillar herniation (and eventually respiratory failure) occurs when what condition is left untreated?
Hydrocephalus
What is the most common treatment for hydrocephalus?
Shunting (ventriculoatrial shunt)
What condition involves compensatory hydrocephalus accompanied by infarct and neurodegeneration?
Hydrocephalus ex vacuo
Explain the dangerous feedback loop of brain herniation?
Cerebrum shifts (herniations) —> compression of neurons & vessels —> decreased blood supply —> infarction —> swelling
What are the three types of brain herniations?
Subfalcine (cingulate), transtentorial (uncinate), tonsillar
What is the most common type of brain herniation?
Subfalcine (cingulate)
Which type of brain herniation involves a displaced cingulate gyrus (located under falx cerebri)?
Subfalcine (cingulate)
What can result from subfalcine herniation?
Abnormal posturing, coma
What type of brain herniation involves a displaced temporal lobe (under the anterior tentorium)?
Transtentorial (uncinate)
Which cranial nerve can suffer from compression from a transtentorial brain herniation, and what is the result?
Cranial nerve III (oculomotor) resulting in abnormal vision (“blown pupil”)
What is the secondary hemorrhage associated with transtentorial brain herniations?
Duret hemorrhage
Which type of brain herniation is associated with brainstem compression and hemiparesis?
Transtentorial (uncinate)
Which type of brain hemorrhage involves displaced cerebellar tonsils through the foramen magnum?
Tonsillar
What form of abnormal posturing involves brachial flexion, extension of the legs along with internal rotation?
Decorticate rigidity
What is the location of injury associated with decorticate rigidity?
Between the cortex and red nuclei (midbrain)
What form of abnormal posturing involves extension of all 4 limbs, pronation of arms, and plantar flexion?
Decerebrate rigidity
What is the location of injury associated with decerebrate rigidity?
Between red nuclei & vestibular nuclei (brainstem)
What type of hemorrhage is also known as the “flame-shaped” hemorrhage?
Duret hemorrhage
What type of hemorrhage occurs when vessels that enter the pons are disrupted by herniation?
Duret hemorrhage
What is the more common type of Arnold-Chiari malformation?
Type I
Which type of Arnold-Chiari malformation is more severe?
Type II
Which type of Arnold-Chiari malformation is more mild?
Type I
Type I Arnold-Chiari malformation occurs among what population?
Adults
Type II Arnold-Chiari malformation occurs among what population?
Infants
Which Arnold-Chiari malformation involves the low-lying cerebellar tonsils and downward extension through the foramen magnum?
Type I
Which Arnold-Chiari malformation involves the small posterior fossa, misshaped midline cerebellum, and downward extension through the foramen magnum?
Type II
What is the treatment for Arnold-Chiari malformations?
Neurosurgery (decompression)
