Causes Flashcards
What are meningiomas?
Tumors (neoplasms) that grow between meninges. Encapsulated: boundary is clear. benign.
Not aggressive.
Solution: remove with surgery.
If it was placing pressure on anywhere, that pressure should be relieved. tumor itself isn’t problematic per-say
What are infiltrating tumours?
Grow diffusely through surrounding brain tissue
Malignant, aggressive, faster growing.
influtrating: no boundaries,
in order to remove, you must take healthy tissues
worse outcomes associated
What are metastatic tumours?
Some infultrating brain tumours that have grown from tumor fragments carried to the brain via bloodstream. Originate from breast or a lung cancer usually.
What is a glioblastoma?
most common malignant brain tumor (glioma)
Most malignant
Short survival rate
common, aggressive
famouse ppl: Gord Downie and Bob Moog
What are strokes? What are the associated areas?
onset of cerebrovascular disorders that cause brain damage.
common issues: trouble speaking, coordination, talking, drooping side of the body. Some symptoms go awaay
Infarct: area of dead/dying tissue. epicenter of the problem
Penumbra: dysfunctional area around infarct (may recover or die). it is getting some blood, so membrane polarity is retained, but it is functioning less than optimally. doctor’s goal is to save this part of ur brain.
What are the types of strokes?
Ischemic: cerebral ischemia, blockage in arteries, so blood doesnt reach till the ends of the arteries. - damage depends on where the blockage is. Larger clot - larger damage
Hemorrhagic: bleeding in the brain. BLood flowing freely (toxic to neurons) and placing fluid pressure on soft tissues (fire extinguisher on jello)
More dangerous then ischemic
What is an aneurysm?
Balloon type growth on an artery. Narrowing/tapering at the part where it connects. Expands like a water balloon with blood with the potential to burst!!
Congenital or develop later.
in base of brain (circle of willis)
Risk factors: diabetes, hypertension, smoking, alcoholism, aging. Usually an artery, Two treatments:
1) Clipping, requries surgery but lower rate of recurrence. Clip it shut at the neck and leave it in there (titanium clip that isn’t magnetic)
Better efficacy LONG term
2) Endovascular coiling. Less invasive, but higher rate of recurrence.
Traveling up through femoral artery, through heart, to the brain up to artery at risk. inside there is a cathedar with wire, shove wire into the aneurism that is made of platinum which causes coagulation/blood clots so that it won’t fill the hole up anymore!!
- real time x rays used.
What are the 3 main causes of Ischemia?
Distruption of blood to an area
1) Thrombosis: a plug, bubble of air, blocking flow of blood
2) Embolism: a moving thrombosis. Grew in a not dangerous place and moved to a smaller artery
3) Arteriosclerosis: narrowing of blood vessels themselves via cholesteral, fat deposits.
often a combo of these things and can build up over time
What are the 3 important properties for cerebral ischemia?
- it takes a while to develop (can be days)
- need to find markers for this! - Damage is more likely in some places of brain (hippo)
- cells are more active and require lots of 02 all the time which is why they are more sensitive to cutoff - Mechanisms for ischemia induced damage can vary between brain structures (excitotoxicity and apoptosis)
What is exitotoxicity?
When you get excessive glutamate release, often when you have a hard time maintaining RMP, so you depolarize membrane getting lots of APs. Glutamate has many receptors (ampa and nmda)
Ampar are for when its quiet (nmdar binds when its quiet but doesn’t do anything because of mg2 blocking it) .
as you depolarize, mg2 is pushed away and you have NMDA activity.
NMDA lets in sodium but ALSO calcium - great for strenghtening synapses and important for memory.
NMDAr receptors are usually active in development when we need to “prune” cells, because it triggers apoptosis.
when you have a stroke: gluatamate release, and therefor calcium release tells these cells to self destruct.
unfortunately blocking these receptors doesn’t really work, calcium can get in other ways. we block things that calcium signals too (downstream of NMDA)
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What are open head injuries?
typically fatal. High risk of infection.
High velocity is worse than low velocity.
penetrating: enters thru skull into brain
perforating: comes out the other side.
Radial wounds: travels around and around head.
What are closed head injuries?
Contusions (bruise) Damage to cerebral circulatory system, producing internal hemmorhaging and resulting in hematoma (brain slams against skull) 1) epidural (within menigies) 2) Subdural (within meningies still) 3) worst - intracranial
Coup contrecoup (backlash, bouncing bath and forth, jostling riccoshet)
When does coup contrecoup happen?
When you hit something stationary.
What is mTBI?
mild traumatic brain injury. Blow to the head with no evidence of structural damage.
Same as concussion (syndrome)
But you can injure your brain without getting a concussion (subconcussive mTBIs: repeated hits to the head with a cumulative effect, even if you never get a single concussion)
Successive concussions: multiple before 1st has healed
What is CTE?
chronic traumatic encephalopathy.
- Dementia pugilistica (punch drunk syndrome)
- progressive, irreversible neurodegenerative disease caused by repeated blows to the head.
loss of tissue in the brain.
not just concussion or in professional athletes. (ppl with epilepsy, autism, victims of domestic abuse)
What is a clear marker of CTE postmortem?
Tau and neurofibrillary tangles.
- tau stabilizes the cytoskeleton fixing it in place, and when it is hyperphosphoylated (gets extra groups added to it, it binds to ITSELF instead of cytosteleton/ it aggregates and cytoskeleton becomes unstable. (not CAUSE but correlated)
Seen in Alzheimers and parkinson’s too.
relies on after death staining.
How does Tau progress?
Sulci first, buildup of iron deposits from hemmorhages. The progression is different in CTE and in AD
How do we see Tau
since it is a protein, you can use PET to trace where it binds, (give radioactive molecule (FDDNP) and see binding of tau (hyperphosphorylated binding)
however this isn’t yet good enough to diagnose or do things.
What is the difference between bacteria and viruses? How do they get into our brains?
Bacteria: living cells, their own entities
Viruses: self replicating using our own machinery
Both get into our brain through bloodstream, randomly pass BBB even with efforts to keep them out.
We know BBB is more porous in some areas and things could slip in here but it is mostly dumb luck.
If they get in = infection occurs
What are some Bacterial infections?
Cerebral absecesses (pus pockets) Attack meningies (inflammation known as meningitis) Syphilis
What is Meningitis?
Inflammation of meningies. (can be bacterial- more fatal or virus. only assessed post mortum if you have it)
- fever
- fatigue
- confusion/disorientation
- tiredness
- sensitivity to light
- in kids its hard to diagnose
example: stupid dad who tried to help his kid ‘naturally’ showed persistent symtoms. tried cold blast and mustard seed, only called 911 when he was siezing, and then he died.
appealing viral meningitis so nothing would have helped anyways.
What is syphilis
Bacteria that can affect the brain.
GENERAL PARESIS: syndrome of psychosis that results from syphilitic infection of the brain (long term untreated)
easy to test for it (partially on our skin, can treat with antibotics easily)
dormant and can take decades to show up. Common transmission is genital
What are the two types of viral infections?
- affinity for neural tissue
- attack all tissues indiscriminately.
Viruses are clumbs of protiens with RNA that use our machinery to reproduce.
May be a bigger role player in psychiatric disorders than we thought initially.
We can pass dormant viruses onto other who will get symptoms
What is rabies?
a viral infection with an affinity for the nervous system.
If a rapid animal bites you, you have a 15% chance of getting rabies.
TRAVELS RETROGRADE through motor neurons to brain.
Symptoms: make you more aggressive, and in turn, more likely to bite and spread the disease.
Is lethal but takes about a month to attack the brain.
Malaise, Pain, fevers, TROUBLE SWALLOWING, hydrophobia, kind of like meningitis.
Total mania, then lethargy, coma then die of respiratory issues.
