Chapter 10 Brain Damage Flashcards
What are six causes of brain damage
- Tumours
- Strokes
- Closed Head Injuries
- Infection
- Neurotoxins
- Cerebrovascular disorders
What is a tumour?
Mass of cells that grow independently of the rest of the body
~20% of tumours are Meningiomas, what does this mean? How do they cause brain damage?
Meningiomas grow between the meninges
- encapsulated (have own membrane = easy to remove)
- Most are benign
- Damage results from pressure exerted on surrounding tissue
Most brain tumours are Infiltrating, what does this mean?
Grow diffusely throughout the brain
Non-encapsulated = difficult to remove
Most are malignant (cancerous)
10% of tumours are metastatic, what does this mean?
Transferred to brain from another part of the body through bloodstream
What is a stroke?
Sudden interruption in blood supply to the brain
- progressive
- symptoms depend on brain region effected
What are common outcomes of strokes?
Memory loss
Aphasia (impairment in language)
Paralysis
Vision loss
What are five signs of a stroke?
- weakness
- trouble speaking
- vision problems
- headache
- dizzyness
What is an infarct?
Dead brain damage resulting from a stroke
What is a penumbra?
“at risk” brain tissue around the infarct
-this is what stroke treatment aims to minimize
What are two major types of cerebrovascular disorders?
- Cerebral ischemia
2. Cerebral Hemorrhage
What is a cerebral ischemia? What are three things that can cause a cerebral ischemia?
Caused by disruption of blood supply resulting from blockage in blood vessel = three types of blockage:
- thrombosis
- embolism
- antioclerosis
What is thrombosis?
Plug formed in vessel
What is an embolism?
plug forms in large vessel and travels to small vessel
What is antiosclerosis?
Narrowing of blood vessel b/c of fat deposits usually following damage to the vessel
What is a cerebral hemorrhage?
when a blood vessel ruptures and blood seeps into surrounding tissue
- build up of blood causes damage
- result of aneurysm (balloon-like swelling in an artery caused by defective elasticity)
What are two things to remember about ischemia-induced brain damage?
- it takes time
2. does not occur equally in all parts of the brain - hippocampus generally suffers most damage
What are Closed Head Injuries?
Any blow to the head that does not penetrate the skull
What is a contusion?
Any CHI that involves damage to brains circulatory system
What is a Hematoma?
Build up of clotted blood (bruise) in brain following a contusion - causes pressure on underlying brain tissue
What are three types of Hematoma?
- Epidural Hematoma
- Subdural Hematoma
- Intracerebral Hematoma
What is an epidural hematoma?
Best case scenario
- Outside Meninges = doesn’t interfere with neurons
What is a subdural hematoma?
More severe
-can effect neurons
What is an Intracerebral Hematoma?
Worst Case Scenario
- Within corical area
- progressive
What is a concussion? Autopsy usually shows what? What is a defining feature?
Cognitive disturbance following CHI where there is no evidence of contusion or other brain damage
- loss of consciousness is a defining feature
- “punch-drunk syndrome”
- Damage only seen on autopsy = large amounts of tau protein
What is commonly caused from Bacterial Brain Infections?
Cerebral Abscesses:
pockets of pus in the brain
What is Meningitis?
Bacterial Brain infection that attacks Meninges
-fatal if left untreated
What are four common Bacterial Brain Infections?
- Meningitis
- Syphilis
- Rabies
- Herpes Encephalitis
What is syphilis?
Bacteria passed through genetal sores, can be dormant for years
- leads to severe brain damage
- General paresis
What is General Paresis?
Psychosis
-syndrome of insanity/dementia resulting from syphilitic infections in the brain
What is Rabies?
Transmitted via bite from infected animal
- affinity for nervous system
- attacks brain one month after contraction
- fatal if left untreated
What is Herpes encephalitis?
Does not have an affinity for the nervous system
herpes attacks all tissue, including brain
What are three toxins that can damage the nervous system (neurotoxins)
- Lead
- Mercury
- Pesticides
What is toxic psychosis?
chronic insanity produced by a neurotoxin
-tardive dyskinesia (TD)
What are four neuropsychological diseases?
- Epilepsy
- Multiple Sclerosis
- Alzheimers
- Parkinson’s
What is epilepsy
chronic seizures caused by underlying brain abnormalities
-overactivation of neurons in the brain from defective inhibitory system
What are partial seizures vs generalized seizures?
Partial: involve only part of the brain: focal = simple
Generalized: involve entire brain
What are epileptic auras?
psychological changes that occur prior to a seizure
What causes epilepsy?
Many things: brain damage, toxins, viruses, tumors, genetics, improper inhibitory synapses
Epilepsy diagnosis relies heavily on what?
EEG recordings - shown by sudden onset of high amplitude waves
What are Simple partial seizures?
Safer
Symptoms are primarily sesnory or motor or both
Waves down cortex ( motor twitch or sensory tingling)
What are Complex Partial Seizures?
Temporal lobe epilepsy
- Patients engage in compulsive, repetetive, simple behaviours called automatisms
- routine of simple beh (button and unbutton shirt) with no memory after the fact
What are two types of partial seizure?
Simple and complex
What are two types of Generalized Seizure?
- Petit Mal
2. Grande Mal
What is a petit mal seizure?
“absent siezures”
- No convulsion
- primary symptom is abscence (disruption of consciousness, vacant look, fluttering eyelids)
What is a Grande Mal Seizure?
Tonic Clonic
Loss of consciousness, loss of equilibrium, violent tonic-clonic convulsion
What is Multiple Sclerosis?
A progressive autoimmune disorder that destroys myelin in the CNS
- typically onsets in early adulthood
- starts with microscopic damage, later leads to axon degeneration
- Periods of remission up to 2 years
What are four symptoms of MS?
- Visual disturbances
- Muscular weakness
- Ataxia (loss of muscle coordination)
- cognitive deficits
In MS what is being attacked?
Myelin (glial cells) = creates plaque
Axon damage leads to cell death and creates tumour mass
What are 3 genetic considerations of MS?
- Higher concordance rate in monozygotic vs dizygotic twins
- 3x higher in females
- higher rates in caucasians
What are 3 environmental considerations of MS?
- Higher rates in colder climates
- Risk of developing MS changes with migration between climates
- Smokers are at greater risk for developing MS
What is Alzheimers Disease?
most common cause of adult dementia
-terminal progressive neurodegenerative disease
What do the early stages of Alzheimers look like?
decline in memory functions, attention problems, personality changes
What do the intermediate stages of alzheimers look like?
confusion, irritablity, anxiety, deterioration of speech
What do the advanced stages of alzheimers look like?
lose control over bodily functions
What are neurofibrillary tangles?
tangles of protein in teh neural cytoplasm
- destroys microtubules
- tau protein
What are amyloid plaques?
clumps of scar tissue made up from dying neurons and beta amyloid protein
What cortex is destroyed during alzheimers?
association cortex
What are the three nuclei of the Basal Ganglia?
- Caudate
- Putamen
- Globus Pallidus
What 3 things does the Basal Ganglia do?
- Recieves input from most areas of cortex
- plays a critical role in modulating the force of movements
- plays important role in motor learning
What is parkinsons disease?
Results from death of dopamine secreting cells in the substantia nigra
What is the result of an absence of dopamine?
not enough inhibition of the GPi (internal globus pallidus) in the direct pathway and too much excitation of the GPi in the indirect pathway
What are four characterizations of Parkinsons?
- Muscular Rigidity
- Hypokinesia
- Resting Tremor
- Cognitive impairments
What are three animal models that help us understand neurological diseases?
- Kindling Model of Epilepsy
- Transgenic Mouse Model of AD
- MPTP Model of Parkinson’s
What is the kindling model of epilepsy?
Brain stimulations elicit convulsions similar to those seen in some forms of human epilepsy
-similar to epilepsy developed following a head injury
What is the Transgenic Mouse Model of AD?
Only humans and few primates develop the amyloid plaques seen during alzheimers
-transgenic means genes of another species have been introduced that accelerate human amyloid synthesis intorduced in mice
What is the MPTP Model of Parkinsons disease?
Heroin with MPTP toxic to Dopamine = given to monkeys creates parkinson’s disease-like symptoms
*Found that DEPRENYL blocked effect of MPTP
