Neuro of the CNS Flashcards
What does brain injury change?
level of consciousness and alterations in cognitive, motor, and sensory function
What is focal brain injury
focal neurologic deficits that may or may not alter consciousness.
What is a global brain injury?
altered levels of consciousness, ranging from inattention to stupor or coma.
Injury involving the _________ and _______ have a more predictable pattern
diencephalon, brainstem
What are key clinical signs when it comes to brain lesions in the diencephalon, midbrain, pons, and medulla
- diencephalon: impaired consciousness, small reactive pupils, intact oculocephalic response, abnormal flexion posturing- cheyne- stoke respirations
- midbrain- coma, fixed midsize pupils impaired oculocephalic response, central nuerogenic hyperventialtion, extension posturing
- Pons- coma, fixed small pupils, disconjugate gaze, impaired oculovestibular response, loss of corneal reflex
- Medulla- coma, fixed pupils, flaccidity, loss of gaf and cough reflexes
What is consciousness?
state of awareness of self and environment and of being able to orient to new stimuli
What are the two divisions of consciousness?
(1) arousal and wakefulness: require function of both cerebral hemispheres and an intact reticular activating system (RAS)
(2) content and cognition: requires functioning cerebral cortex
What is RAS?
is a network of neurons located in the brainstem that has fibers projecting to various parts of the brain
What is the glascow coma scale?
- one way to measure altered status
-scale that is used in response to eye opening, motor response and verbal response and they are scored.
-best possible score is 15 and worst is 3
Persistent Vegetative State
Loss of all cognitive functions and unawareness of self and surroundings. —Reflex and vegetative functions remain, including sleep–wake cycle
-sufficiently preserved hypothalamic and brain stem function; bowel and bladder incontinence
-variably preserved cranial nerve and spinal cord reflexes
ICP is normally ≤
15 mmHg in adults
Pathologic intracranial hypertension (ICH) is ≥
20 mmHg
What are S/S of ICP?
HA, CN palsies, papilledema, Cushing triad
What may ICP result in?
cerebral herniation, decreased perfusion, and secondary infarction of the affected areas
What pathologies may cause an increase in the pressure of the closed system from ICP?
Cerebral Edema
Hydrocephalus
Intracranial mass lesions (eg, tumor, hemorrhage)
Obstruction of venous outflow (eg, venous sinus thrombosis, jugular vein compression
What is cerebral edema?
Increased fluid leakage from blood vessels and injury to various cells of the CNS
What is Vasogenic edema?
increase in extracellular fluid caused by BBB disruption and increased vascular permeability, allowing fluid to shift from the intravascular compartment -> intercellular spaces of the brain. Edema may be either localized or generalized
What is Cytotoxic edema?
increase in intracellular fluid neuronal, glial, or endothelial cell membrane injury, i.e. generalized hypoxic/ischemic insult or with a metabolic derangement
Hydrocephalus
-enlarged ventricular size
-Normal pressure
-excess CSF accumulation within ventricular system
from impaired flow or resorption of CSF
What are the symptoms of Hydrocephalus?
Symptoms range from headache, visual changes, dementia, incontinance
Papiledema
sign of increased ICP- symptom = visual changes
Cerebral herniation
-Displacement of brain tissue past rigid dural folds or through openings in the skull because of increased intracranial pressure.
What is cerebral herniation mostly caused by?
mass effects, either diffuse (generalized brain edema) or focal (tumors, abscesses, or hemorrhages)
What are examples of trauma of the brain
- Parenchymal injury
Concussions, Contusion (edema and hemorrhage), lacerations - Diffuse Axonal Injury
- Vascular injury
Epidural, subdural, subarachnoid, Intraparenchymal
What is a Spontaneous (non-traumatic) Subarachnoid Hemorrhage?
rupture of a saccular (“berry”) aneurysm in a cerebral artery
What are the risk factors associated with Subarachnoid Hemorrhage?
-Genetics?
-Developmental anomalies?
-Smoking?
-Htn?
-Female, fifth decade
-Acute increase ICP
-Worst HA of life
-Sentinel bleed- “warning”
What is the most common types of vascular malformations?
Most common are:
- arteriovenous malformations
Male predominance. Age 10-30
Middle cerebral artery most common territory - cavernous malformations
dilated, thin walled capillaries with a simple endothelial lining
What are the two types of cerebrovascular diseases?
aka stroke
1. Ischemic/hypoxic- embolism»>thrombosis
2. Hemorrhagic
Tissue infarction is the ultimate consequence of both
One of leading cause of death in US
What is a stroke?
injury to the brain as a consequence of altered blood flow
1. Ischemic/hypoxic- embolism»>thrombosis
2. Hemorrhagic
^^ tissue infarction is the ultimate consequence of both ^^
Penumbra
area of “at-risk” brain- region of transition between necrotic tissue and the normal brain
Lacunar infarct
Single deep penetrating arteries supplying the internal capsule, basal ganglia, or brain stem
Border zone (“watershed”) infarcts
the border zones between arterial territories
When blood flow to a portion of the brain is reduced, the survival of the tissue at risk depends on:
-collateral circulation- circle of willis
-Duration, magnitude and rapidity of the reduction of flow.
-These factors determine anatomic site, size of the lesion the clinical deficit.
What is hemorrhagic?
-Spontaneous (non-traumatic) rupture of a small intraparenchymal vessel -> primary hemorrhage within the brain, -> sudden onset of neurologic symptoms
middle to late adult life, with a peak incidence at about 60 y.o, Female
-Hypertension is most common risk factor
compression leads to secondary infarction of the affected brain tissue
What is Vascular Dementia defined by?
multiple, bilateral, gray matter (cortex, thalamus, basal ganglia) and white matter infarcts over course of months to years.
What are neurodegenerative diseases characterized by?
rupture of a small intraparenchymal vessel -> primary hemorrhage within the brain, -> sudden onset of neurologic symptoms
In which population does Hemorrhagic cerebrovascular disease most occur in
middle to late adult life, with a peak incidence at about 60 y.o
What is the most common risk factor of hemorrhagic cerebrovascular disease?
Hypertension
______ leads to secondary infarction of the affected brain tissue.
Compression
What is vascular dementia?
multiple, bilateral, gray matter and white matter infarcts over course of months to years. These appear with dementia like symptoms and in imaging it shows signs of silent/covert cerebrovascular brain injury, which indicates a vascular contribution to the dementia.
What is parkinson’s disease marked by?
hypokinetic movement disorder that is caused by loss of dopaminergic neurons from the substantia nigra
What is clinical SYNDROME of parkinsonism?
-diminished facial expression (often termed masked facies)
-stooped posture
-slowing of voluntary movement
-festinating gait (progressively shortened, accelerated steps)
Rigidity
-“pill-rolling” tremor
What is the triad of parkinsonism?
tremor, rigidity, and bradykinesia
What is Parkinsons disease clinical impression confirmed by?
symptomatic response to L-Dopa replacement therapy
Mean onset age of Parkinson disease?
57 yo