Exam 2 Ch. 22 Flashcards
What is a irreversible neuronal injury?
Acute neuronal injury
“Red neurons”
Frequently from acute hypoxia
What is it called when the soma becomes shrunken?
Red neurons
Irreversible injury
What do astrocytes do?
Perform gliosis
Activation from gemistocytic astrocyte
They become enlarged and eosinophilic
What do oligodendrocytes do
Produces myelin in the CNS, enlarge when activated
This is the site for viral inclusions
What are microglia
Are phagocytes of the CNS
Perform neuronophagia
Proliferate and enlarge after injury
what are ependymal cells
Line ventricles and spinal cord
May become infected from cytomegalovirus
May cause choroid plexus dysfunction
What produces Negri body
Rabies
What is CMV
Owl’s eye appearance
WHat disease produces levy bodies
Parkinson’s disease
What are symptoms of Alzheimer’s
Neurofibrillary tangles
B-amyloid plaques (tau) proteins
What is lipofuscin
Aging and lipid accumulation
What can increase intra cranial pressure
Blood, pus, tumor, edema
What is vasogenic edema
Blood-brain-barrier disruption
Results in extracellular edema
What can cause vasogenic edema
Severa trama
Can be localized due to tumors, infection, inflammation
What is cytotoxic edema
Nueronal/glial membrane injury
INTRACELLULAR EDEMA
What causes cytotoxic edema
Hypoxic-ischemic injury or toxic exposure
What are three symptoms of cerebral edema
Flattened gyri
Narrowed sulci
Ventricular compression
What causes an increase in CSF within the ventricles
Hydrocephalus
What is the most common cause of hydrocephalus
Choroid plexus tumor which increases production of CSF
What is the cutoff for hydrocephalus in age
< 2 years old= cranial enlargement
> 2 years old=increased ICP and enlarged ventricles
How is it caused and treated hydrocephalus
Unknown incidence 50% idiopathic
Treatment is shunting; aka ventriculoatrial shunt
If untreated results in respiratory arrest and death
What is a herniation in the CNS
Shifting/protrusion of CNS tissue following a increase in ICP
What is the process of herniation
- Vessels compress
- Displacement of CSF
- Cerebrum shifts(herniation)- across the dura or through foramen magnum
Results in ischemia then leads to infarction
IS A POSITIVE FEEDBACK LOOP
What is the most common herniation?
Subfalcine (cingulate)
Displaced cingulate gyrus, under falx cerebri
Abnormal posturing, coma
Transtentorial herniation is
Aka uncinate, displaced temporal lobe under anterior tentorium
CN III- oculomotor, “blown pupil” / abnormal vision
Hemiparesis, brainstem compression
Duret hemorrhage
What is a tonsillar herniation
Cerebellum tonsilis through Foramen Magnum
Results in cardiorespiratory arrest, hydrocephalus, and headache
What are two types of abnormal posturing
Decorticate rigidity
Decerebrate rigidity
Decorticate rigidity results in
Brachial flexion
Extension of legs along with internal rotation
Injury between the cortex and red nuclei
Decerebrate rigidity results in
Extension of all 4 limbs
Pronation of arms, plantar flexion
Injury to brainstem- between red nuclei and vestibular nuclei
What is a duret hemorrhage cause by
Transtentorial (uncinate) herniation
Disrupts the vessels in the pons
Aka “flame shaped”
What is mydraisis
Dilation of a pupil
Indicates compression of CN III
What causes mydriasis
A transtentorial herniation
What is anisocoria
Unequal pupil size
Which from of Arnold chiari malformations are worse?
Type II is the sever form
What is the most common Arnold chiari malformations
Type I
Found mainly in ADULTS
Low lying cerebellar tonsils
WHich type of chiari occurs in infants
In utero or infants
What is the 5th most common cause of mortality in the USA
1 cause of neurological morbidity
Cerbrovascular disease
Ex. Stroke
What is a stroke?
Acute dysfunction due to cerebral infarction
Thrombosis or emboli occlusion
Vascular rupture
What is mini stroke
Transient ischemic attack
What is the difference between a stroke and a transient ischemic attack
A Transient ischemic attack no infarction occurs
Neurological dysfunction lasts less than 24 hrs
What are the signs of a stroke
Face drooping
Arm weakness
Speech difficulty
Time to call 911
Bell’s palsy occurs ___________ and affects paralysis of what CN ____
Unilateral facial weakness
CN VII
What causes Bell’s palsy
Viral association HSV-1
Inflammation of the facial nerve self limited within 2-8 weeks
Stoke vs. Bell’s Palsy
Stroke-contralateral lower facial weakness. Weak smile (dysarthria). Preserves upper face motor function
Bell’s Palsy- asymmetrical forehead weakness
What are the brain requirements
2% of body mass, 15% of cardiac output 20% of O2
FUnctional hypoxia occurs from
Increase in altitude and anemia, cyanide, CO
Different types of Ischemia
Hypotension, occculsion aka clot
Transient=TIA
Permanent=stroke
What is global cerebral ischemia
Widespread ischemic hypoxia injury
Cardiac arrest, sever hemorrhage
Mild confusion its TIA, severe is a stroke
WHen severe what causes neuronal death
Global cerebral ischemia
Cerebral edema, red neurons, gliosis
results in coma, impairment, death
Mechanic ventilation=aka autolysis
What causes Focal Cerebral Ischemia
A localized arterial occlusion
What protects against focal cerebral ischemia
Circle of wills will provide some collateral flow
What is the most common Focal Cerebral Ischemia
MC Emboli-cardiac mural thrombi, valve disease, arrhythmia
Thrombi- atherosclerotic plaques (carotid arteries)
What occurs during non hemorrhagic cerebral infarction aka stroke
Red neurons
Liquefaction necrosis
Thrombocytic meds
What is the mc cause of intracranial hemorrhage
HTN
Injury to vessel walls
Tumors
Trauma
What is a microbleed?
Spontaneous intraparenchymal bleed
HTN is the most common cause
Average age 60 years old
Clinically silent or lethal,
15% of deaths in chronic HTN patients
Bleed-Clot-Cavitation
What causes a subarachnoid hemorrhage
1/3 from increased ICP, straining and orgasm
Often described as the “worst headache ive ever had” nausea and vomiting
25-50% lethal, commonly re occur
What is the MC cause of subarachnoid hemorrhage
MC-Ruptured Saccular aneurysm
Malformed vessel or a tumor
What is also known as a Berry aneurysm
Saccular Aneurysm
It is 80-90% of all intracranial aneurysms
What is berry aneurysm is associated with
Polycystic Kidney Disease
