Neurological Diseases Flashcards
Exam 3
CBF is modulated by what 5 things?
- cerebral metabolic rate
- cerebral perfusion pressure (CPP)
- arterial blood carbon dioxide (PaCO2)
- arterial blood oxygen (PaO2)
- various drugs and intracranial pathologies
CPP formula
CPP = MAP-ICP
With autoregulation, CBF is approx _____ brain tissue per minute; mL/min? __% of CO?
50 mL/100g
- 750ml/min
- 15% of COP
The intracranial & spinal vault contains what 3 things?
neural tissue (brain + spinal cord), blood, and CSF
The intracranial & spinal vault is enclosed by what?
the dura mater and bone
Under normal conditions, brain tissue, intracranial CSF, and intracranial blood have a combined volume of _______. At this volume, ICP is _______
1200-1500mL
5-15 mmHg
What is the Monro-Kellie hypothesis?
any increase in one component of intracranial volume must be offset by a decrease in another component to prevent an elevated ICP; eventually, compensatory mechanisms can fail, resulting in cerebral ischemia
The intracranial vault is considered ____________
compartmentalized
What are the meningeal barriers that separate the brain contents?
the falx cerebri and the tentorium cerebelli
__________ is a reflection of dura that separates the two cerebral hemispheres
the falx cerebri
____________ is a reflection of durathat lies rostral to the cerebellum and marks the border btw the supratentorial and infratentorial spaces
the tentorium cerebelli
Herniation syndromes are categorized based on what?
the region of brain affected
Herniation of hemispheric contents under the falx cerebri; typically, compressing branches of theanterior cerebral artery. What does this type of herniation lead to?
Subfalcine Herniation
- creating a midline shift
Herniation of the supratentorial contents past the tentorium cerebelli, causing brainstemcompression in a rostral to caudal direction. What does this type of herniation lead to?
Transtentorial Herniation
- This leads to AMS, defects in gaze and ocular reflexes, hemodynamic andrespiratory compromise, and death
A subtype oftranstentorial herniation, where the uncus (medial portion of temporal lobe)herniatesoverthe tentorium cerebelli. What does this type of herniation result in?
Uncal Herniation
- This results in ipsilateral oculomotor nerve dysfunction
What are the s/s of uncal herniation?
Pupillary dilatation, ptosis, and lateral deviation of the affected eye, brainstem compression and death
Herniation of the ____________ can occur due to elevated infratentorial pressure, causing the cerebellarstructures to herniate through the foramen magnum
cerebellar tonsils
What are the s/s of herniation of the cerebellar tonsils?
Sx: medullary dysfunction, cardiorespiratory instability and subsequently death
What are the 4 brain herniation examples?
- Subfalcine
- Transtentorial
- Cerebellar contents through foramen magnum
- Traumatic event causing herniation out of cranial cavity
What are the 4 causes of increased ICP?
Tumors, intracranial hematomas, blood in the CSF, and infections
What are the 3 ways that tumors can lead to increased ICP?
- directly because of their size
- indirectly by causing edema in surrounding brain tissue
- by obstructing CSF flow, as seen with tumors involving the third ventricle
What are the non-pharmacologic methods to decrease ICP?
- Elevation of the head: encourages jugular venous outflow
- Hyperventilation: lowers PaC02
- CSF drainage: external ventricular drain (EVD)
- Surgical decompression
What are the pharmacologic methods to decrease ICP?
- Hyperosmotic drugs: increase osmolarity, drawing fluid across BBB
- Diuretics: induce systemic hypovolemia
- Corticosteroids: decrease swelling and enhance the integrity of the BBB
- Cerebral vasoconstricting anesthetics (propofol): decrease CMR02 and CBF
What are the 6 genetic neurologic disorders?
- Multiple Sclerosis
- Myasthenia Gravis
- Lambert Eaton Syndrome
- Myasthenia Syndrome
- Muscular Dystrophies
- Myotonic Dystrophies