Cause of brain dysfunction Flashcards
Encapsulated tumors
- Tumors, aka neoplasms
- Grow between the meninges
- Encapsulated - tend to be benign (not growing super fast/ aggressive, when removed, it won’t grow back)
Infiltrating tumors
Infiltrating tumours
Grow diffusely through surrounding brain tissue
Malignant
Infiltrating tumors
Tendrils in the tumors
In certain aggressive tumors, the boundaries between healthy tissue and the tumor are indistinct, making it difficult to determine where healthy tissue begins and where the tumor’s tendrils end.
impossible to remove all of the tumor, resulting in a high likelihood of recurrence
Metastatic tumors
- Some infiltrating brain tumors grow from tumor fragments carried to the brain from another body part via the bloodstream
- Commonly originate from a breast cancer or a lung cancer
Glioblastoma (glioma)
- Most common type of malignant brain tumors in adults (aka glioma)
- Median survival rate: 14 months (short survival rate)
- Most malignant
- Grows in CNS
Stroke
sudden-onset cerebrovascular disorders than cause brain damage
Stroke
Infarct
no longer any blood flow coming, area of dead/ dying tissue
Stroke
Penumbra
dysfunctional area surrounding the infarct; tissue in penumbra may either recover or die
Types of stroke
- Ischemic
- Hemorrhagic
What is Ischemic stroke
resulting from cerebral ischemia (blocked blood flow)
What is a Hemorrhagic stroke
- Resulting from cerebral hemorrhage (rupture in or around tissue)
- Additional problem: blood itself is toxic, bleeding into the brain
- Most common cause: aneurysm
Cerebral hemorrhage
What is aneurysm
- Water balloon swelling in our brain→ stretched out by blood
- Can be congenital or develop later
-** Commonly at base of brain** (e.g. Circle of Willis) - Risk factors: diabetes, hypertension, smoking cigarettes, alcoholism, aging (big predictor)
Cerebral hemorrhage
What is clipping?
-Open head surgery
- Pinch neck of aneurysm with titanium clips, all the blood will stay there and the blood will clot itself, close up
- Lower rate of recurrence
- 60-80 yr old can’t handle full anesthetic anymore because have anesthesia the whole body
Cerebral hemorrhage
What can treat cerebral hemmorhage
- Clipping
- Endovascular coiling
Cerebral hemorrhage
What is endovascular coiling?
- Much less invasive, less risk
- Slightly higher rate of recurrence than option 1
- Only surgical cutting is at the femoral artery (largest artery we have) insert tube into femoral artery and drive all the way up to brain with real time x ray→ driven to the site of aneurysm, unspools platinum coil into the aneurysm itself→ cause any blood in the aneurysm to clot together so no blood could come in again
3 main causes of cerebral ischemia
A disruption of blood supply to some area of the brain
Three main causes:
1. Thrombosis: a plug; blood clots block your blood vessels
2. Embolism: a moving thrombosis; refers to air bubble, fat, air tissue
3. Arteriosclerosis; narrowing of arteries, cholesterol thickening of arteries
3 can interact with 1 or 2
Ischemia-produced brain damage
- It takes a while to develop (can be days) - build up as malaise over days
- Damage is more likely in some parts of the brain (e.g. hippocampus- sensitive to insults related to stress, mental health)
- The mechanisms of ischemia-induced damage vary between brain structures (one example: excitotoxicity and apoptosis)
Autoreceptors important for negative regulating→ when it’s overwhelmed, we have these receptors for glutamates, some will be the NMDA receptors, let calcium into the cell triggers self destructing mechanisms (apoptosis)
Open-head injuries
- Aka penetrating (something entered into your skull), perforating (entered into your skull and comes out at another part) head injuries
- Typically very severe gunshots succumb to injuries at the site of crime
- High risk of infection, complications
- High velocity objects worse than low (speed of it)
Classic example: phineas gage
Close-head injuries
Contusion
Closed-head injuries that involve damage to the cerebral circulatory system
type of hemorrhage or hematoma- solid swelling of blood
When do contusions occur?
- Occurs where the brain slams against the skull
- It can be between meninges and skull (epidural), meninges and brain (subdural), within brain (intracranial)
-If you slam into something, your brain slams to the opposite side of head; hit immovable object (coup contrecoup), injury on the impact and also at the opposite side
Close-head injury
Mild traumatic brain injury (mTBI)
No obvious evidence of contusion or injury (bleeding in the brain) but have symptoms; relatively normal
Close-head injury
What is synonymous to concussions?
Mild traumatic brain injury (mTBI)- a checklist, collection of symptoms
- Can disrupt sleep, sensitivity to light, sleep problems, fatigue, headache, appetite
Close-head injury
Subconcussive mTBIs
can injure your brain without getting a concussion- can have bad sleep and mood but can’t consider as a concussion
Chronic traumatic encephalopathy (CTE)
Dementia pugilistica, punch-drunk syndrome
- A progressive, irreversible neurodegenerative disease
- Caused by repeated blows to the head
- professional athletes (any cotact sports, domestic abuse, kids on autism spectrum that bang their head on things)
In CTE, what does progressive, irreversible neurodegenerative disease mean?
keeps cascading, just gets worse and worse or just stabilizes; a form of dementia but not driven by age related processes
Progression of CTE
Stage 1: confusion, disorientation, headaches
Stage 2: lapses in memory, social norms, impulsivity, judgment
Stage 3/4: progressive dementia, movement disorders (esp. Parkinsonism), speech disorders, depression, suicidality
What are symptoms in steps 3/4 in CTE similar to?
Parkinson’s Disease
- moving in slower, shuffling way, trouble moving around the world, problems with speech and cognitions, high rate of suicidality; paranoia, aggression, jealousy
CTE
Tau
A protein that binds to cytoskeleton and stabilizes it, when its time to change cytoskeleton, Tau released for it to grow and shrink
CTE
When does Tau not bind to cytoskeleton?
When tau is hyperphosphorylated, it aggregates and cytoskeleton becomes unstable
- No longer binds to cytoskeleton but binds to other Tau molecules
Tau in CTE
- Not necessarily cause of CTE
- A clear marker of CTE, but relies on postmortem staining
CTE
Tau progression in the brain
Aggregating in the sulci
Different trajectories neuro
CTE
Tauopathies
- Neurofibrillary tangles are evidence of cellular stress and damage, not the cause itself
- class of neurodegenerative diseases characterized by the aggregation of abnormal tau protein. (like alzheimer’s)
- Trying to develop PET tracer for CTE diagnosis in the living, but not there yet
Bacterial infections
- Can cause inflammation of the brain (encephalitis).
- bacteria attacking brain often lead to the formation of cerebral abscesses (pus pockets)
Encephalitis
- Inflammation of the active tissues of the brain caused by an infection or an autoimmune response
- Benign bacteria in our intestinal, if it reaches brain= devastating results
- Encephalitis can be bacterial or viral
Bacterial Infections
Meningitis
- Bacteria often attack the meninges, producing an inflammation known as meningitis
- Can be bacterial or viral, ¼ chance you die is bacterial
- Neck stiffness
- Treat it well, have antibiotics to it; how late you get to it and how fast it responds
- Challenge in identifying it
Bacterial infections
Syphilis
A type of bacteria that can attack the brain→ easy to spot, we have antibiotics today
iBacterial infections: Syphilis
General paresis
The syndrome of psychosis/dementia that results from a syphilitic infection of the brain.
15 years after initial infection
Viral infection
- Those that have a particular affinity for neural tissue (e.g. rabies)
- Those that attack all tissues indiscriminately, including nervous tissue (e.g. herpes simplex)
What can viral infections cause?
Encephalitis and meningitis
Viral infections
Rabies Infection
- The rabies virus has an affinity for the nervous system
- In order for virus to get into NS, it has to get into a specific axon of a motor neuron
Rabies process
- Animal bites (virus in mouth), bite somewhere with motor neurons, uses proteins to travel backwards into spinal cord into the brain
- If it’s the specific part; almost always fatal
- Large scale changes to the brain→ hydrophobia rabies because animals show a revolution to water (change in the NS near the hypothalamus)
What about COVID-19?
- ~35% of those symptomatic have neurological symptoms
- Effects on brain small but significant
decreased gray matter in OFC (orbitofrontal cortex) and parahippocampal gyrus, global reductions in brain size - saw greater cognitive decline vs. controls
Effects largest on oldest participants (above age 70)
What are 2 types of parasite infections?
- toxoplasma gondii
- neurocysticercosis
Parasite infections
Toxoplasma gondii
- eukaryotic parasite
- Why it’s not recommended to be around cats when pregnant
- Requires multiple hosts in a life cycle
Parasite infections
Toxoplasma gondii on rodents
selectively damages part of their brain (amygdala), affects some circuits (circuits related to cats) → not afraid of cats; approach them instead of being scared
Parasite infections
Neurocysticercosis
Tapeworm in the brain
Parasite infections
How to detect neureocysticercosis
- CT scan can’t scan but MRI can
- Invade soft tissues (brain, skin)> digestive system
- Spread through contamination of food or someone who did not fully wash their hands well
Toxic psychosis
Psychosis that is caused by the use of psychoactive substances, such as drugs, chemicals, plants, or medications
Mercury
Dangerous if it is evaporated and inhaled (liquid form isn’t as dangerous)
Minamata disease
Severe type of mercury poisoning; caused by severe methylmercury poisoning (industrial waste);
Easily visible: usually motor coordination; ataxia, numbness, muscle weakness, damage to vision/hearing/speech,
More extreme symptoms: paralysis, coma, death; congenital effects
started in wildlife, see it in newborn children
Is methylmercury common in America?
Now considered rare
Ethylmercury
Things found in our injections, exposure to these are small amounts and not harmful
Relationship between vaccines and autism?
They think that MMR Vaccine→ autism
No control group to compare
One study→ pronounced effect→ vaccine hesitancy went all the way up
Lead
Can also lead to toxic psychosis
Where can lead be found before?
Tea sets/ porcelain can have lead lining through the middle→ Crackpot “mentally unwell”
Is there any levels of lead that is acceptable for humans to contain?
No. Any lead consumption is harmful.
Lead in water
Flint michigan used old lead pipes→ children would drink from it (harmful for them)
- cause a variety of neurological problems in adults.
