Neuro Emergencies Flashcards
Monroe-Kellie Hypothesis
“We have a perfect environment inside our cranium”
Cranial vault is a fixed space. If we had any increase in one component(blood, brain, CSF) there has to be a decrease in another component.
Normal ICP measurement
0-15mmHg
What is CBF
Cerebral Blood Flow- requires 15-20% of cardiac output to meet metabolic demands and is maintained by cerebral autoregulation
What is CPP
Cerebral Perfusion Pressure- Gradient that drives CBF and is calculated as follows: CPP=MAP-ICP
Normal CPP 60-80mmHg
Brain requires 60-70 for optimal CBF
Adult goal = >70mmHg
Peds goal = >60mmHg
CPP <50mmHg = infarction
MAP and Pulse pressure calculations
MAP=[(DBPx2)+SBP]/3
Pulse pressure= SBP-DBP
How to maintain CBF
increase MAP and decrease ICP
*CO2 affects chemical regulation is cerebral vascular resistance
Hypocapnia will cause Vasoconstriction(could lead to infarct)
Hypercapnia will cause Vasodilation(causes an increase in ICP)
**New standard is to prevent the 3 H’s( Hypoxia, Hypotension, Hyperventilation)
Causes of secondary TBI
Hypoxia, Hypo/Hypertension, Hypo/Hypercapnia, Ischemia, Edema, Vasodilation, and increased ICP
Signs of increased ICP
Change in LOC, pupil size/reaction, motor response, signs of herniation(decorticate/decerebrate/blown pupils), and Cushings Triad( HTN/widening pulse pressure, bradycardia, Cheyne-Stokes respirations) Standard ICP patient will initially see tachycardia instead of brady.
Elevated ICP treatment
limit suction, noise, and atmospheric pressure changes.
Fluid balance
Normothermia
Normal electrolytes
Sedation and analgesia(consider long acting paralysis)
head to bed elevated to 30 degrees
Osmotherapy with mannitol or hypertonic saline
Concave vs Convex CT head scans
Concave always means an Epidural bleed.
Convex is always a Subdural bleed.
Subdural bleed
40-60% mortality rate.
VENOUS BLEED
Causes: HTN, ruptured aneurysm, and trauma.
Occurs between dura and arachnoid.
typically have immediate LOC
Subdural bleed treatment
advanced airway management(maintain ETCO2 35-50mmHg)
adeqaute fluid resuscitation
osmotherapy (mannitol, lasix, 3% saline)
maintain serum Na+ at upper limit of 155mEq/L
higher serum osmolarity(<320mOsm)
anticonvulsants for seizure prevention
CT findings
If the bleed is lighter in color(white) then its fairly new. Darker in color(grey or black) its an older bleed
Epidural Bleed
ARTERIAL BLEED(usually from middle meningeal artery) temporal lobe damage(side of the head)
occurs between cranium and dura
often associated with skull Fx
**classic presentation is initial LOC with a lucid interval, followed by neurological deterioration
causes rapid compression of the brain stem
Epidural Bleed treatment
Decrease ICP
Evacuate bleed ASAP
Low mortality if treated in timely fashion
Subarachnoid Bleed treatment
Treatment: Maintain SBP<140mmHg and decrease ICP
Complications: rebleed, cerebral ischemia, vasospasm, hydrocephalus
Overall morbidity/mortality is high
Subarachnoid Bleed
ARTERIAL BLEED
occurs between arachnoid and Pia
Causes: Trauma, ruptured cerebral aneurysm, rupture of arteriovenous malformation(AVM)
S/S: AMS-coma, Seizures, sudden onset of severe HA, N/V
Intraventricular Bleed
Primary sources: trauma(shearing forces), anuerysm, and vascular malformation
Usually a secondary bleed
Found in frontal and temporal lobe injuries
Intraventricular Bleed Treatment
Prevent further insult, maximize CPP > 70mmHg, maintain SBP < 160mmHg, and control ICP. Hypertonic saline
Diffuse Axonal Injury(DAI)
Often not fatal
clinical signs of TBI
small tears(petechial hemorrhage) from cu contra cu(frontal-occipital impacts)
Treatment: prevent secondary injuries, avoid the following: hypotension, hypoxia, cerebral edema, and elevated ICP.
Brown-Sequard Syndrome
Ipsolateral cord legion(TEST Q)*
Hemisection of the cord(usually cervical region) that is very rare, reduced or loss of motor/power on side of lesion however pain and temperature are preserved, reversed on opposite side.
Central Cord Syndrome
Greater motor weakness in upper extremities than the lower with varying degree of sensory loss
Anterior Cord Syndrome
Complete motor, pain, and temp loss below the legion with sparing proprioception, vibration and touch.(most common)
SCIWORA syndrome
Spinal cord injury without radiograph abnormality
(spinal shock or spinal contusion)
Neurogenic shock symptoms
Hypotnsion, Peripheral vaso-dilation(flushed/red skin), and bradycardia
Autonomic dysreflexia
Potentially life threatening HTN
occurs in individuals with spinal cord injury above T6
causes imbalance in reflex sympathetic discharge
check foley cath for kinks and drain slowly
think of other noxious stimuli that may be the cause(could be a neurogenic bladder)
Neurgenic bladder
Urinary bladder malfunction due to neurogenic dysfunction
Little tidbits of neurogenic shock info
One episode of hypoxia or hpypotension increases mortality by 50%, CPP is the key end point for resuscitation efforts, Hypercarbia leads to increased cerebral blood flow and increased ICP, and Hypocarbia leads to decreased cerebral blood flow and possible cerebral ischemia.
Quiz question
How does an epidural hematoma present?
Answer: unconsciousness, followed by a brief period of lucidity, and a period of rapid decrease in LOC
Quiz question
How does a patient with Brown-Sequard syndrome present?
Answer: Ipsilateral motor loss, contralateral pain loss
Explanation: results from loss of sensation and motor function caused by a lateral hemi section of the spinal cord
