Traumatic Brain Injury Part 2 Flashcards
Why are concussions not visible through standard imaging techniques?
The damage it has on axons are microscopic
What are complications of axonal tearing
- inflammation
- necrosis
- disruption in communication between neurons
The damaged axons may contribute to symptoms of concussions such as;
-dizziness, nausea, vomiting
- memory and concentration problems
- sensitivity to light
- fatigue
Why is it challenging to distinguish post concussive symptoms from mental health disorders like depression, bipolar, and PTSD?
These symptoms can overlap with mental health disorders. Concussions impact cognitive and emotional functioning mimicking symptoms
What are post concussive syndrome symptoms
- headache/dizziness
- irritability
- difficulty concentrating
- sleep disturbances/fatigue
-sensitivity to light and noise
When does the timeline for post concussive syndrome start, how long do symptoms typically last
Starts when symptoms first appear and not when the head injury occurred. Most symptoms resolve within 6-12 months from their onset
What are 5 treatments for concussions and PCS?
- rest and rehabilitation
- medications
- cognitive behavioural therapy
- physical therapy
- avoiding re injury
What medications migh be used for treatment with concussions and PCS
- analgesia to manage headache
- antidepressants and anxiolytics
- sleep aides like melatonin
What is the consequences of increased ICP?
- brain tissue compressions (vessels and nerves)
- reduced blood flow leading to ischemia and hypoxia in the brain
- herniation of the brain
What are ways to manage increased intercranial pressure?
- draining CSF through a craniotomy
- medications to reduce welling such as mannitol
- hypertonic saline to decrease ICP
What is Space occupying lesions?
Anything that occupies space and increases pressure in the cranial vault
The dura mater contains the Dural sinuses. What is the dural sinuses function?
A space that drains blood from the brain back to the venous system
What is the function of the Pia matter
To contain the CSF keeping it from leaking into the brain tissue
Beneath the temporal bone lies this artery which is often ruptured in cases of epidural hematoma
The middle meningeal artery
Why is nausea and vomiting a common symptom for increased ICP?
Because the pressure is irritating the medullary centre of the brain (vomiting centre)
What happens when the herniation centres in the medulla oblongata are irritated?
It can affect various cranial nerves particularly the vagus nerve.
What does the vagus nerve influence?
The nerve extends through the foremen magnum and influences the PSNS function of the body including the GI system. Irritation can lead to projectile vomiting due to PSNS response
Where does hemipligia often occur?
Contra-lateral to the bleed
Where would pupil dilation occur?
Ipsilateral to the bleed
What is normal ICP (in mmHg)
1-10 mmHg
What is cerebral perfusion pressure? (CPP)
The amount of pressure needed to ensure that blood can adequately perfume the brain
How is CPP calculated
MAP-ICP=CPP
What happens to cerebral perfusion as ICP increases
Cerebral perfusion becomes more difficult
In order to have adequate CPP. The MAP must be ______ than ICP for perfusion
MAP must be greater than ICP
What would happen if there is a significant drop in CPP?
It can lead to brain ischemia
What is typical MAP for an adult?
70-100 mmHg
How might the body compensate for an increased ICP
- systemic vasoconstriction through alpha 1 adrenergic activation (increasing BP,Increasing MAP)
- widened pulse pressure (systolic pressure significantly higher than diastolic)
As ICP increases, ischemia occurs. What is the ischemic casscade that happens
Ischemia - hypoxia - cell damage - Na/k+ pump fails - cell swelling - further increase to ICP - necrosis
For every 5 mmHg increase in ICP, the body will try to increase MAP by how much to maintain perfusion?
5mmHg
Cushings triad is an indicator of increase ICP. What is this triad?
- hypertension (widening pulse pressure)
- Brady cardia
- respiratory irregularity (Cheyenne stokes breathing)
Why is bradycardia present during an increase in ICP
Because the Systolic pressure is high, the baroreceptors in the carotid body and aortic arch trigger the vagus nerve which causes bradycardia
Why do Cheyenne stokes respirations occur in cases with increased ICP
As ICP raises, pressure it put on the brain stem, particularly the medulla oblongata which controls respiratory function
