Neurological Conditions Flashcards
Increased Intracranial Pressure
Swelling of the brain, you would see an increased BP, decreased MAP, slow breathing
What are the layers of the meninges?
Dura Mater: outer layer, tough, thick, and firbous
arachnoid: thin, intermediate layer
pia matter: delicate, internal, vasculated layer
Cerebral Spinal Fluid
Located between the arachnoid and pia matter
Cushions the brain and spinal cord
Constantly absorbed and replenished
Normal amount is 100-150 mL
What is the Monroe-Kellie Hypothesis?
Cerebral spinal fluid, intravascular blood, and brain tissue must all exist in equilibrium. If there is a change in any of these, it will result in IIP.
What is normal ICP?
5-15 mmHg
At what level will ICP require treatment?
> 20 mmHg
What does the MAP tell us?
It is the average measurement of the systemic arterial pressure. Reflects the perfusion pressure. It is a better indicator for perfusion than the systolic BP.
What is the normal MAP value?
65-105 mmHg`
At what level MAP is perfusion to vital organs severely jeprodized?
<50 mmHg
How to calculate MAP?
Systolic BP + 2(Diastolic BP)/3
What is cerebral perfusion pressure (CPP)?
The pressure required for the heart to supply blood to the brain
Increased ICP leads to decreased CPP and decreased blood flow to the brain
How do you calculate the CPP?
MAP-ICP
What is normal CPP?
50-100 mmHg
What level CPP will cause irreversible neurologic damage?
<50 mmHg
What causes IIP?
- intracranial mass lesions (tumors)
- cerebral edema
- increased CSF production
- decreased CSF absorption
- obstructive hydrocephalus
- obstruction of venous outflow
- idopathic ICH
Cushing’s Triad
CNS Ischemic response reflex, initiated by hypothalmus
- HTN
- bradycardia because of compression of vegas nerve
- bradypnea because of compression of brain stem
IIP Clinical Manifestations
ALOC - most sensitive indicator
-headache, drowsiness, pupillary changes, widening pulse pressure, purposeless movements, hyperthermia (late stage), posturing
Decorticate Posturing
Limbs pulled towards core. Lesions above brainstem
Decerebrate Posturing
Lesions of the brain stem
Limbs extended and rigid.
IIP Diagnostic Tests
During physical exam check pupils - they will be dilated
Spinal Tap - after spinal tap lay flat on back for 4-6 hours
MRI
CT Scan
Mannitol
Osmotic Diuretic, pulls h2O out of brain. It begins to lower ICP in 1-5 minutes. Measure I&O while on it - normal urine 30 mL/hour
Thins blood
Starting dose 1.5-2 g/kg IV infusion
IIP Management
Keep O2 sat above 95, continuous pulse ox
Monitor fluid so BP doesnt drop too low
Keep head of bed at atleast 30 degrees to maximize venous outflow
Thermoregulation - no fever because it increases ICP. Shivering also inreases ICP
Stool Softner
Anti-Seizure medication
IIP Surgical Management
- Evacuation of blood clot
- Resection of a tumor
- CSF diversion: ventriculostomy drain 1-2 mL
Traumatic Brain Injury
Injury resulting from external force
Primary: direct result from mechanical injury at time of accident
Secondary: physiologic response to the initial injury