Causes of Brain Dysfunction - Tumours, Strokes, and Head Injuries Flashcards
Tumours
Tumour/Neoplasm
An out of control growth of cells/cells rapidly dividing independently of the rest of the body.
Tumours
Meningioma
Where does it grow, what type, benign or malignant?
The “not that bad” brain tumour.
Location: Grows between the meninges.
Type: Encapsulated (growth has a membrane/outer casing outside of it). This means there is a clear deliniation between the tumour tissue and the healthy tissue.
Benign or Malignant? Benign, and grows slowly. If the tumour is removed, it is unlikely to grow back.
Tumours
Infiltrating Tumours (General Category)
Are they encapsulated? Are they benign or malignant?
Be sure to clarify why the tumour is benign or malignant. There are two reasons for its classification as one or the other.
Type: Not encapsulated, no clear delineation between healthy tissue and tumour tissue. Microscopic tumor tendrils are weaved into the healthy tissue.
Benign or Malignant: Malignant, grow at a much quicker rate/very aggressively. Also, when there is an attempt at removal, there will almost always be some of the tumour left behind due to the microscopic tumor tendrils.
Tumours
Metastatic Tumour
Where does it grow, what type, benign or malignant?
A type of infiltrating tumour (virtually always an infiltrating tumour).
Grow from tumour fragments carried to the brain from another body part via the bloodstream (common origins: breast and lung cancer).
Tumours
Most of our tumours do not originate from [answer] (since we are not producing new ones in adulthood), but rather [answer].
Most of our tumours do not originate from neurons (since we are not producing new ones in adulthood), but rather glia.
Tumours
Glioblastoma (AKA Glioma)
Where does it grow, what type, benign or malignant?
Also, what is a secondary symptom resulting from a glioblastoma?
Astrocytes growing out of control/an astrocytic tumour.
Extremely malignant infiltrating tumour, guaranteed to grow back after ‘removal.’
Median survival timeline is about 14 months, even with treatment.
Can cause personality dysfunction, e.g. acquired sociopathy.
About 40% of brain tumours are these.
Stroke
A sudden-onset cerebrovascular disorder/incident that causes brain damage. Cuts off oxygen and glucose to the brain. Can have catastrophic results.
Sodium-potassium pump breaks down and can no longer maintain resting membrane potential.
Infarct
The area of dead/dying tissue in a stroke.
The infarct will almost 100% be dead by the time you get to the hospital
Penumbra
Does the penumbra tissue recover?
Peripheral area/area around the infarct that has been getting a dysfunctional amount of blood flow. Tissue in the penumbra may either recover or die (sometimes a few days or weeks later, it will die).
Doctors try to maximize the chance of saving the penumbra.
Ischemic Stroke
Results from cerebral ischemia: A clot blocking blood flow to an area of the brain.
Better prognosis for recovery when compared with an equal hemorrhagic stroke.
Hemorrhagic Stroke
Especially bad for two reasons
Results from cerebral hemorrhage: A clot blocks blood flow to an area of the brain, BUT there is also the secondary issue of bleeding /hemorrhaging in the brain (bleeding inside/around brain tissue).
Bad for two reasons:
1. Blood itself is toxic to the brain
2. Blood carries pathogens into the brain, risk of infection is high
Worse prognosis for recovery when compared with an equal ischemic stroke.
Causes of Hemorrhage
TBIs, Aneurysms,
Aneurysm
Stretching of a blood vessel (usually an artery). If the aneurysm gets too large, it will burst/rupture and cause a very large hemorrhagic stroke.
Scary :(
Where do aneurysms commonly occur?
The base/ventral part of the brain, in the Circle of Willis (due to arteries connecting and the resulting pressure being higher in that area)
Risk factors of aneurysms
Diabetes, hypertension, smoking cigarettes, alcoholism, aging
Biggest predictor of aneurysms
Age
Aneurysms
Clipping
What is it, what’s the risk, why is it used, and what’s the downside?
A high-risk surgery due to being a craniotomy/open-head surgery. Involves cutting a hole in the head and putting a titanium clip on the neck of the aneurysm. It then becomes a sealed off bubble full of blood, which then hardens/coagulates. Lower rate of recurrence than treating with endovascular coiling (which is why it is still used as a treatment), but far more invasive.
Aneurysms
Endovascular Coiling
What is it, what’s the risk, why is it used, and what downsides?
Far less invasive than clipping. There is no cutting into the head. Instead, a surgeon cuts into the thigh’s femoral artery, running a tube through the body to the brain until you get to the aneurysm (often navigated with a real time x-ray machine).
This tube has a hole, unspools platinum coils into the aneurysm, causes a coagulation, and this causes blood to coagulate.
Downside: Slightly higher rate of recurrence/aneurysm to continue progressing than clipping. As well, there are some risks of blood clots escaping into the bloodstream, but overall is a lot less risky than clipping
Three main causes of ischemic stroke.
- Thrombosis - Plugs the artery and everything after.
- Embolism - A moving thrombosis (can be a piece of fat, oils, air bubble, etc.) that prevents things from passing through.
- Arteriosclerosis - Narrowing of arteries, the narrow artery/ies can then be blocked by a relatively small thrombus.
