Brain Damage Flashcards
1
Q
What are 6 causes of brain damage?
A
- Brain tumours
- Cerebrovascular disorders
- Closed-head injuries
- Infections of the brain
- Neurotoxins
- Genetic factors
2
Q
What are tumours?
A
- A mass of cells that grows independently of the rest of the body (a cancer)
3
Q
What are the 3 types of tumours?
A
- Meningiomas
- Infiltrating
- Metastatic
4
Q
Describe meningiomas?
A
- About 20%
- Encased in meninges
- Encapsulated
- Usually benign, removable
- Large compression on brain
5
Q
What are infiltrating tumours?
A
- The majority
- Grow diffusely through surrounding tissue
- Malignant, difficult to remove/destroy (e.g. gliomas; originate in glial cells)
- Primary brain tumours
- BBB is good at protecting brain from chemicals (need high dose of chemotherapy)
- Borders are not clearly marked
6
Q
What are metastatic tumours?
A
- About 10%
- Originate elsewhere, usually the lungs
- In blood circulation (creates secondary tumours)
- A number of cells in different locations
7
Q
What is a neuroma?
A
- Benign, encapsulated tumour that grows on a nerve
- Type of meningioma that grows near nerves
8
Q
Where does the acoustic neuroma grow?
A
- On the vestibular-cochlear nerve (VIII)
9
Q
What is a stroke?
A
- A sudden-onset cerebrovascular event that causes brain damage
10
Q
What are the two parts of a stroke?
A
- Infarct: dead or dying tissue; directly damaged by event
- Penumbra: damaged tissue surrounding the infarct; it can be saved with early intervention
11
Q
What is a cerebral hemorrhage?
A
- Blood vessel ruptures
- Blood leakage damages brain
- Iron causes toxicity
12
Q
What is an aneurysm?
A
- Weakened point in a blood vessel
- Congenital
- Can use mesh to strengthen point
13
Q
What is cerebral ischemia?
A
- Disruption of blood supply
- Loss of vascularization/O2
14
Q
What are the 3 types of cerebral ischemia?
A
- Thrombosis: a plug (thrombus) forms in the brain
- Embolism: a plug from elsewhere moves to the brain
- Arteriosclerosis: thickened wall of blood vessels, usually due to fat deposits
15
Q
How does cerebral hemorrhaging cause damage?
A
- Fe is toxic
- Components in blood break down and free radicals are formed
- Free radicals break down lipid membranes, the BBB< and damage DNA
- Causes cell death by degrading lipid membrane
16
Q
How do ischemic strokes cause damage?
A
- Does not develop immediately
- Different in different brain areas
- Blood-deprived neurons become overactive and release glutamate
- Glutamate -> NMDA receptors -> Na+/Ca2+ influx -> More exocytosis of glutamate/kills cells
17
Q
How can you prevent ischemic strokes?
A
- Stent
18
Q
How would you treat the penumbra of an ischemic stroke?
A
- NMDA receptor antagonist
- Prevent secondary damage
- Tissue plasminogen activator dissolves blood clots
19
Q
What are closed-head injuries?
A
- Brain injuries due to blows that do not penetrate the skull
- Brain collides with the skull
20
Q
What are the 3 types of closed-head injuries?
A
- Direct/contrecoup
- Contusions (involve hematoma/bruise)
- Concussions (disturbance of consciousness with no structural damage)
21
Q
What is a direct closed-head injury?
A
- Brain collides with skull surface
22
Q
What is a countercoup closed-head injury?
A
- Blow to head, brain moves backwards and collides with skull opposite to site of impact
23
Q
What is chronic traumatic encephalopathy?
A
- While there is no apparent brain damage with a single concussion, multiple concussions may result in dementia
- Cognitive impairment
- Emotional dysregulation
24
Q
What is encephalitis?
A
- Inflammation of the brain caused by a microorganism
25
What are bacterial infections (2 types)? How are they treated?
- Abscesses: pockets of pus
- Meningitis: Inflammation of the meninges
- Treated with antibiotics
- Eg. syphilis
26
What are viral infections? How are they treated?
- Some preferentially attack neural tissues and affect the host's behaviour (e.g. rabies)
- Some don't have a preference for the CNS (e.g. mumps, herpes)
- Treated with vaccines and anti-viral drugs (specific)
27
How do exogenous neurotoxins travel?
- Enter general circulation and cross the BBB
| - Through inhalation, injection, etc.
28
What are some endogenous neurotoxins?
- E.g. antibodies (autoimmune disorders)
| - Excess excitatory neurotransmitters (e.g. glutamate in strokes)
29
What is toxic psychosis?
- Chronic insanity
| - E.g. mad hatter (mercury), crackpot (lead)
30
What is tardive dyskinesia?
- Involuntary motion caused by some antipsychotics
- Act on dopaminergic system
- Symptoms become permanent very quickly
31
What type of genes usually cause brain damage?
- recessive (usually don't live long enough to reproduce)
| - Mostly multiple genes/mutations for one disorder
32
Describe the genetic factors of down syndrome?
- 0.15% of births, probability increases with advancing maternal age
- Extra chromosome 21 created during ovulation
- Characteristic disfigurement, intellectual disability, other health problems, can have impaired motor controls
