Flashcards in Neuro- Brain Injury, CVA, Guillain Barre Syndrome Deck (18):
cranium is made up of (% of each)
- blood 10%
- CSF 10%
- Tissue 80%
What is CPP?
How is it calculated?
Cerebral Perfusion Pressure (70-100mmHg) = Mean Arterial Pressure minus Inter Cranial Pressure (5-15mmHg)
How do you calculate MAP?
MAP = Systolic + (2x Diastolic) Divided by 3
MAP = 83 3
(MAP) 83- 10 (average of 5-10 mmHg) = 73 (is in the average of 70-100mmHg)
At what CPP is brain schema likely?
Brain ischemia when CPP 40mmhg
What is the Monroe-Kellie Hypothesis?
o Physiologic Minor fluctuations in blood, tissue and CSF vol
o Compensate for each other to keep ICP range
What are the 3 kinds of compliance to compensate for inc ICP?
- skull is non-expandable
- 1st – compliance = displacement of CSF into spinal cord and then CSF is reabsorbed
- 2nd – compliance = displacement of blood )limited because needs perfusion.
- 3rd – compliance = compression and displacement of brain tissue →causes death! Pushing against the cranium, or the brain stem pushes out through the hole in the bottom hole the foramen magnum
How can trauma affect ICP?
trauma→abnormal variation in volume of one or
more components→inc Inner Cranial Pressure
- inc ICP often associated with proliferating lesion (eg/ tumor, hemorrhage)
What is Cushing's Reflex?
- Also brains response to inc ICP
- the body’s response triggered by CPP dropping causing brain ischemia
- inc MAP (up to 270) ∴inc bp and inc heart rate d/t inc blood to area
What is Cushing's Triad?
1) widening pulse pressure is difference of systolic and diastolic (often w/ HTN) d/t inc bp
2) Reflexive bradycardia
3) irregular breathing
Path of hemorrhage/ hematoma
o Vascular trauma -> hemorrhage -> hematoma
o l/o neural fx (affected area)
• both at site of hemorrhage and at “target” area of neuro
Three areas of hemorrhage and Hematoma
• Intracerebral vessel
o Hemorrhage into brain tissue
o Between dura and arachnoid mater
o Encapsulated mass -> cell lysis -> inc -> fluid influx
o Between skull and dura mater
o d/t head injury and fracture
o normally middle meningeal artery
What is Guillain Barre Syndrome
Characterized by an autoimmune attack on peripheral nerve myelin causing paralysis. Oddly, is reversible with tx.
Etiology of GBS
Though is autoimmune and preceded by upper respiratory Tract or GI infect (1-4weeks)
What Microbe is often responsible for GBS trigger?
Mostly Campylobacter jejuni
• (Poultry, water, unpasteurized milk)
Gram Negative Bacillus
Also, could be Virus as well (eg EBV)
?WHY ALWAYS EBV?
Patho of GBS
Preceded by upper respiratory Tract or GI infect (1-4weeks)
Abs and T-cells target myelin sheath (d/t IR)
• Schwann cells (if not dmg by IR, will be by INLFM)
MNFTS of GBS
o Those of URT or GI infect (may be present)
o Progressive, ascending muscle weakness and paralysis
o Deep muscle pain (in the shoulder and thigh)
o Without intervention complete paralysis will happen
o Can lead to resp. failure (mortality of about 30%)
Dx of GBS
o Hx (proceeding inf.? Ascending paresthesia?)
o Physical exam (is it muscular or neuro or combo?) CHECK Muscle weakness and reflexes
o Measure nerve conduction- Dec nerve conduction
o Inc protein in CSF (3 things you’d see in CSF??)