CNS Disorders Flashcards
A critical factor in determining neuronal cell fate after injury
ATP depletion
Ischemia & Hypoxia
-decreased____at the ____level
-results in ___neurologic dysfunction due to ____
-O2; cellular level
-immediate; inability to generate ATP
2 mechanisms that can cause brain cell death
- anaerobic metabolism
- deterioration of ion gradient
Cellular energy failure
-how long w/o O2 for irreversible brain damage
5-10 min
Excess glutamate (an excitotoxin) stimulates
neurons that take up large amounts of injurious calcium ions – calcium overload injury = cytotoxic edema and swelling
Reperfusion Injury and free radicals?
free radicals:
when O2 reenters cells; produces reactive O2 products that behave as free radicals: hydroxyl radicals,superoxide,peroxide
Increased intracranial pressure (ICP) normal levels
0-15mmHg
primary brain injury
a direct result of initial insult
secondary injury
progressive damage resulting from body’s physiological response to the initial insult
clinical manifestations of ICP
-headache, vomiting, decreased consciousness (drowsiness)
-blurry vision, edema of the optic disk (papilledema)
Herniation
result of increased ICP
protrusion of brain tissue through opening of brain – DEADLY
papilledema
edema of optic disk
Diagnostic test for brain injury
CT or MRI
general treatment for brain injury
focus on managing cerebral oxygenation
-surgery, CPP (cerebral perfusion pressure) > 60mmhg for no ischemia
Coma
Complete loss of consciousness
indicator of altered brain function
Change in level of consciousness
Glasgow coma scale evaluation
- eye opening
- motor response
- verbal response
Somnolent
excessive drowsiness, only responds to stimuli with incoherent mumbles + disorganized movement
Glasgow Coma Scale: Evaluation component:
Mild (>12), moderate (9 to 12), to severe (<8)
Most important eval in Glasgow coma scale
motor response
Manifestaions of Brain injury: Pupil reflex
indicates function of the brainstem and cranial nerves _ and _
2 and 3
which cranial nerves control eye movements
CN 3,4,6
Oculovestibular reflex
impaired reflex implies brainstem dysfunction
Doll’s eye movement
eyes move in opp direction to head rotation
Cold calorics
injection of cold water into ears. Normal response: tonic deviation of both eyes towards water
Leading cause of death and disability in the U.S
TBI (traumatic brain injury)
Primary injury
initial injury on brain cells
focal injuries (coup)
localized site of impact
polar injuries (coup contracoup)
accel-decel movement of brain in skull
Mechanisms of TBI
Concussion, contusion, intracranial hematoma
contusion
CT or MRI reveals an area of brain tissue damage (necrosis, laceration, bruising)
3 types of intracranial hematomas
- epidural
- subdural
- subarachnoid
intracranial hematoma
localized collection of blood within the cranium
location of epidural
caldevia bone + dura mater, middle meningeal A
location of subdural
dura + arachnoid membrane
location of subarachnoid
arachnoid + pia mater
Epidural hematoma
-collection of blood between dura and skill
-involves arterial injury –> rapid onset of symptoms
Manifestations of epidural hematoma
brief disturbed consciousness followed by normal cognition (lucid interval), then rapid decrease in consciousness
Treatment for epidural hematoma
surgery
Acute subdural hematoma symptom onset
24 hrs after injury
subarachnoid hemorrhage
rupture of bridging veins
commonly associated with rupture of cerebral aneurysms or arteriovenous malformations
Treatment for subarachnoid hemorrhage
-cardiopulmonary stabilization – cerebral oxygenation
-maintain body temp (mild hypothermia, PaCo2, serum glucose, intravascular volume
treatment for acutely elevated ICP
administer mannitol (osmotic diuretic)
sedation
hypothermia
mild hyperventilation
barbiturate coma
treatment for severely high ICP
diuretics, hypertonic saline, moderate hyperventilation, and barbiturate coma
open head injury treatment
prophylactic antibiotics
Base skull fracture
fracture of temporal, occipital, sphenoid, frontal, ethmoid bone
Halo Test
CSF can seep out as clear fluid from ears or nose
black eyes “raccoon signs”
bilateral periorbital hematomas
Battle’s signs
bruising under ear
Cerebrovascular disease and stroke epidemiology
Transient ischemic attacks (TIA), ischemic stroke, hemorrhagic stroke
most common form of stroke
ischemic
ischemic stroke
sudden occlusion of cerebral artery secondary to thrombus formation or emboli
clinical manifestations of ischemic stroke
contralateral hemiplegia, hemisensory loss, contralateral visual field blindness
treatment for ischemic stroke
salvage penumbra, anticoagulants, antiplatelet, endarterectomy, angioplasty TREATMENT MUST BE INSTITUTED WITHIN 3 HRS OF SYMPTOM ONSET
Transient ischemic attack
Nuerologic symptoms last _____, but may last ____.
Symptoms may resolve ____ without evidence of ____.
only minutes; 24 hrs
completely; neurologic dysfunction
Treatment for TIA
daily aspirin
TIA are important warning signs
of thrombotic disease and carry a significant risk for subsequent stroke
Hemorrhagic stroke usually occurs secondary to ____
severe, chronic hypertension
hemorrhagic stroke occurs in
basal ganglia or thalamus
treatment for hemorrhagic stroke
blood pressure management
Motor and Sensory Deficits
initially motor deficits occur as ____or ______; recovery of motor function occurs with ____
flaccidity; paralysis; onset of spasticity
Sensory disturbances occur in same locations as ____ and may involve ____
motor paralysis; neglect or visual impairment
Aphasia
Brain damage to ____ and can involve ___ language modalities
language deficit, dominant cerebral hemisphere; all language modalities
Broca Aphasia (Verbal motor, expressive)
Consists of ___ articulation and ___ vocabulary
poor; sparse
Evidence of cognitive deficits
language impairment, impaired spatial relationship skills, short-term memory, poor judgement, concentration, memory, reasoning impairment
CNS infection risk factors
immunocompromised, debilitation, poor nutrition, radiation, steroid therapy, contact w/ vectors
Meningitis – bacterial or viral infection
bacterial
encephalitis – bacterial or viral
usually viral
Most common bacteria for meningitis
streptococcus pneumonias
classic s/s of meningitis
headache, fever, stiff neck (meningismus), signs of cerebral dysfunction (confusion, delerium)
Encephalitis – inflammation of brain caused by ____
west nile virus, western equine encephalitis, herpes simplex
S/S of herpes
fever, headache, seizure, confusion, stupor, coma
Brain abscess – localized collection of ___
pus within brain parenchyma
