week 9 : Acute neurological disorders Flashcards
Intracranial Regulation is closely linked to what?
perfusion
Intracranial regulation is affected when there is :
impaired blood flow
damage brain tissue
compromised neurotransmission
impaired glucose regulation
true or false. The brain cannot supply glucose, therefore it needs constant glucose?
this is true
Brain is sensitive to a lot of things, recall what she said in the lecture that the brain i highly sensitive to ?
brain is sensitive to hypoglycemia, therefrore when u have prolonged hypoglycmia that causes injury of the nuerons, hyperglycemia is also damaging causing worsening brain injury
Recall that compromised neurons causes intracranial regulation to be affected: define a type of attack that also causes compromised neurotransmission
seizures
For the brain to have normal transmission of nerve impulses what does it require ?
requires fully functioning neurons, nerves. and neurotransmitters. Degenerative diseases such as parkinson disease, is an example where there is loss of neurons and loss of neurotransmitter ( dopamine )
Recall that :
Intracranial regulation is affected when there is:
* Impaired blood flow
* Damage to brain tissue
* Compromised neurotransmission
* Impaired glucose regulation
when any of these situations occurs it can lead to ?
cerebral edema and/or increased intracranial pressure
True or false. Cerebral edema always lead to high icp?
true
initially when we are talking about neurological disorders, what are we talking about ?
intracranial pressure ( this is crucial )
What type of structure is a skull ?
can the volume change within the skull ? if so why ? if not why ? what is a term for this ?
The skull is a rigid and protective covering of the brain.
The total volume cannot change. A change in 1 component requires a change in another.
This is termed “The Monro-Kellie doctrine.”
How much percentage is the brain tissue consists? blood? cerebrospinal fluid ?
Brain Tissue = 78%
Blood = 12% Cerebrospinal Fluid = 10%
what does normal brain function depends on ?
consistent supply blood ( for oxygen and nutrients/glucose)
brain relies on healthy heart and lungs for perfusion
true or false. a fully functioning brain requires constant blood flow because this allow of oxygen and nutrients
true
What happens when heart doesn’t work in terms of perfusion ?
if the lungs doesn’t work what happen in terms of delievery ?
if the heart doesnt work, we dont get enough perfusion to other organs
if the lungs doesn’t work we dont get enough adequate gas exchange and oxygen delivery to our tissues
as the intracranial increases what happens to the cerebral perfusion?
it decreases
true or false. you need supply of blood to the brain for adequate nutrients and oxygen
true
what increases when u have brain trauma, infection?
you have increases in brain tissues, volume, and csf fluid
Cerebral perfusion pressure: define it’s description
pressure needed to ensure adequate brain tissue perfusion
what type of pressure undergoes cerebral perfusion pressure
CPP = MAP ( mean arterial pressure ) minus ICP ( intracranial pressure )
define what MAP and ICP mean ?
MAP- what drives or pushes the blood to the brain
ICP - the force that compresses the arteries and keep the blood flow out
if the blood pressure too low - ischemic
too high- it’s limited
what is the normal CPP ?
70-90 mmHg
what is CPP largely affected by ?
blood pressure and intracranial pressure
why does blood pressure and intracranial pressure highly affect CPP?
- Blood pressure (the lower the blood pressure, the lower cerebral blood flow will be)
- Intracranial pressure (the higher the intracranial pressure, the lower cerebral blood flow will be)
true or false. auto regulation will begin to fail as CPP decreases to low
true
how is cerebral perfusion pressure regulated?
MAP (mean arterial pressure) minus ICP (intracranial pressure)
how must cpp be maintained?
must be maintained narrow limits to maintain cerebral blood flow
Intracranial pressure normal and increased? what are the values ?
Normal = 5-15 mmHg Increased ICP = > 20mmHg
compensatory mechanisms
CSF volume
Autoregulation
- cerebral vasocon. or vasodial. based on :
1) carbon dioxide ( PaC02)
2) oxygen ( Pa02 )
3) pH
why does our brain constrict or dilate as a compensatory mechanism ?
by dialating and constricting the brain ensure blood flow
it causes diameter of cerebral blood vessels to change in response to metabolic demands
what is the purpose of autoregulation? ( again, again just wanna emphi )
the purpose of auto regulation is to ensure that the brain receives a constant supply in order to meet the demand of the brain and maintain cerebral perfusion
would carbon dioxide dilate or constrict when being utilize in autoregulating? ( when there is an increase in PaC02)
an increase in carbon dioxide will relax smooth muscle ( therefore it will vasodilate ) cerebral blood vessels and increase blood flow
would oxygen dilate or constrict when being utilize in auto regulating?
results in cerebral vasodilation because we need more oxygen to the brain tissue, this will increase blood flow to the brain as 02 levels drop into brain there is a build up of lactic acid ,this increases hydrogen ions in the brain - becomes acidic meaning our pH will drop
what happens when pH drops ? would this constrict or dilate ?
the drop in pH will also lead to vasodilation as than attempt to increase cerebral blood flow to correct depletion of oxygen
true or false. Carbon Dioxide (PaC02): a decrease in this will cause constriction of the cerebral vessels and there will be decrease cerebral blood flow
this is true
if one component has to decreased amongst auto regulating, what happens to the csf?
the brain will reduce the csf production and absorption to accomodate changes in volume of blood of brain tissue
true or false.when our blood pressure goes really really low or really really high that ability to auto regulate goes out the door
true
what happens when someone goes on hypotension, and our auto regulation has fall out of place.
in severe hypotension a person is in shock and their blood pressure drops
that perfusion to the brain is not going to happen and they will become in that case going to go into cerebral ishcemia and the brain cells will die because they’re not getting enough blood pressure to bring volume to the brain
what happens during a hypertensive crisis, when auto regulation fails
hypertensive crisis , we’re having an over amount of pressure and actually going to cause an increase in ICP and that’s not good for the brain
- risk of having rupture and stroke
what concepts are included in electrical impulses?
- Sodium-Potassium Pump
- Membrane Resting Potential
- Action Potential
- Depolarization
- Repolarization
True or false : recall When pressure are outside the range of 60-150 mmHg, the blood vessels ability to auto regulate pressure through dilation and constriction is lost and cerebral perfusion is determined by blood pressure without auto regulation, in essence what can hypotension or hypertension result ?
thus, hypotension can result in severe cerebral ischemia and hypertension can result in stroke or rupture
what is moving from the presynaptic to the postsynaptic
neurotransmitters
Increased ICP : causes
brain tissue : tumor
abscess
cerebral edema ( several causes )
blood : intracranial hemorrhage
intracranial hematoma
csf : hydrocephalus
what do seizures do?
fixes the excitatory and conduction if we have too much excitatory happening
what are the two outcomes when a neurotransmitter crosses a synapse
depolarization or causes inhibiton of impulse
what value is elevated icp ?
above 20 mmHg
true or false: when neurotransmitter crosses a synapse - needs a electrical or chemical conduction
true
True or false. Increased csf fluid would be from hydocephalus and meningitis
true
true or false: unexcited neuron maintains the resting action potential
true
true or false. elevated ICP, will decrease our blood flow, which can lead to ischemia and infraction.
true
what are the two neurotransmitter? are they excitatory or inhibitory?
glutamate - excitatory
GABA, gamma-aminobutyric acid - inhibitory
BALANCE IS REQUIRED
what is seizure?
“abnormal, sudden, excessive, uncontrolled electrical discharge of neurons within the brain that may result in change in level of consciousness, motor, sensory ability, and behavior”
what is this describing: “abnormal, sudden, excessive, uncontrolled electrical discharge of neurons within the brain that may result in change in level of consciousness, motor, sensory ability, and behavior”
symptom of an underlying condition
seizures
true or false.
cerebral edema , regardless of the type it’s always going to lead into problem.
true
what leads to an increase in brain size and it impacts perfusion and oxygenation to the brain
cerebral edema
pathogenesis unknown
seizures
chronic disorder in which repeated unprovoked seizure activity occurs. seizures at least 2 times in the last 24 hours
epilepsy
what are the risk factors? (age)
< 6 months old
Severe birth injury, congenital defects, infections
2-20 years old
Birth injury, infection, head injury, genetics
20-30 years old
Head injury, brain tumors, vascular disease
> 50 years old
Stroke, metastatic brain tumors
give the description for cerebral edema
increased fluid in intracellular or extracellular of brain tissue
is this true about seizures? metabolic changes that lead to seizures: These include hypoglycemia, hypoxia, alcohol electrolyte, imbalance, barbiturate
withdrawal, acidosis, dehydration and water intoxication, Water intoxication, dehydration, hypoglycemia and hypoxia. These all affect the brain cells
true
this can result in an increase in volume of brain tissue, leading o increases in ICP
cerebral edema
what are the 3 types of cerebral edema
vasogenic
cytotoxic
interstial
what leads to cerebral edema ?
neuro : ischemia, hemorrhage, hypoxia, brain trauma, infection, and hydrocephalus,
non neuro : HTN, hepatic encepalopathy ( liver failure )
what are the three broad categories of seizures?
generalized seizures
focal onset seizures
unclassified seizures
what is generalized seizures?
Affect both sides of the brain
* Include: tonic-clonic seizures, absence seizures, tonic seizures, clonic seizures, atonic seizures, and myoclonic seizures
* Because the entire brain is affected, there may be no warning signs or aura
* Often the patient loses consciousness for a few seconds to minutes
may be no warning signs, patient loses consciousness for few seconds to minutes
generalized seizures
tonic clonic seizures
aka grand mal, major motor seizures
* Patients may experience “auras”or warning signs before the seizure starts
* Characterized by loss of consciousness
* Lasts approximately 2-5 minutes