Chapter 10: Brain Pathology Flashcards
what is a tumor?
a mass of cells that grow independently of the body
encapsulated tumours
- contained within a membrane
- can be surgically removed
infiltrating tumour
- doesn’t have a boundary and can spread to nearby cells
- prognosis is more serious
what is a meningioma?
an encapsulated tumour that grows within the layers of the meninges and pushes down on the brain, exerting pressure
how are meningiomas identified?
through neuroimaging (CT scan)
what are the risk factors associated with meningiomas?
- age (typically later in life, ~60 yrs)
- slightly more common in women due to progesterone
- underproduction of the protein merlin
what is a glioblastoma?
an infiltrating tumour (unregulated growth of glial cells)
which types of glial cells can make up a glioblastoma?
- astrocytes (more common)
- oligodendrocytes
what is the age of onset for a glioblastoma?
can occur in 30s and 40s but most common in 60s
what are the symptoms associated with glioblastomas?
- headache
- hemiparesis (numbness on one side of the body)
- seizures
how are glioblastomas identified?
through an MRI
low grade vs high grade glioblastomas
low grade: not readily spreading to the surrounding tissue. can stay this way for years
high grade: starts infiltrating and becomes more dangerous
what are the treatment options for a glioblastoma?
- stereotactic neurosurgery and radiation
- chemotherapy
- gene therapy
what is a metastic tumour?
a tumour that starts in one place and travels to the brain through the bloodstream
what is an acoustic neuroma?
an encapsulated tumour that presses against the auditory nerve
what are the symptoms associated with an acoustic neuroma?
- affects hearing in one ear (ringing or hearing loss)
- balance problems
what is an ischemic stroke?
a blockage of blood to a certain area of the brain, starving that area of oxygen (anoxia)
what is a hemorrhagic stroke?
a ruptured blood vessel that causes bleeding in the brain
what type of neuroimaging is used to diagnose a hemorrhagic stroke?
CT scan
what type of neuroimaging is used to diagnose an ischemic stroke?
MRI
what is an angiogram used to diagnose?
used to determine if there is a blockage of blood originating in the heart
what is thrombosis?
a blockage that occurs at a certain part of the brain (ischemic stroke)
what is an embolism?
a blockage that occurs near the heart and moves to the brain (ischemic stroke)
what is an aneurysm?
a rupturing of blood vessels that has no warning and is associated with a hemorrhagic stroke
what are the effects of stroke?
- excitotoxity
- necrosis
- infarct
- penumbra
excitotoxity
an extreme release of glutamate in nearby cells
necrosis
contents of the cell leak out and create responses in nearby cells
infarct
where cell death is occurring
penumbra
cells that are responding to cell death and may be damaged
what are the symptoms that can be associated with a stroke?
- contralateral effects (hemiparesis, visual deficits, loss of awareness)
- aphasia
- spatial neglect
what causes spatial neglect?
damage to the parietal lobe
what are the long-term treatment options for a stroke?
- diet change
- blood pressure medication
- blood thinners
what is a contusion?
the brain hitting the skull, resulting in a hematoma
what is a countercoup?
a secondary type of injury that occurs when the brain hits the opposite end of the skull from where the impact was
what is thought to cause chronic traumatic encephalopathy?
chronic concussions
what is levodopa?
medication used to alleviate unwanted Parkinson’s symptoms such as resting tremor
what is carbidopa?
medication taken in conjunction with levodopa and helps lessen tolerance and unwanted side effects, and allows more concentrated doses of L-dopa to enter the brain
what is epilepsy?
- electrical disturbances in the brain
- can be localized (usually to the temporal lobe) or generalized (spread between both hemispheres)
how is epilepsy diagnosed?
through brain imaging (EEG)
what are focal seizures?
a category of seizure that is localized to a specific region of the brain (originates mostly in the temporal lobe)
what are focal seizures characterized by?
- aura (can sense the seizure coming on)
- automatisms (rhythmic, repetitive movements)
- postural changes (become very rigid)
- changes in awareness ( zone out/loss of consciousness)
what are generalized seizures?
seizures that spread from an origin point (typically the temporal lobe) to areas throughout the brain
what are generalized seizures characterized by?
loss of consciousness and stereotyped motor activity
what are the stages of a generalized seizure?
- tonic stage (very rigid)
- clonic stage (shaking)
- postictal depression (confusion)
what are the characteristics of an absence seizure?
- develops in childhood
- loss of consciousness for a few seconds
- typically goes unnoticed
- kids can grow out of it
what are the treatment options for epilepsy?
- anticonvulsant medications
- surgery
how do anticonvulsant medications work?
- promotes the effects of the neurotransmitter GABA
- calms the brain
what are the types of surgery used to treat seizures?
- focal resection (remove part of the brain)
- corpus callosum resection (sever the corpus callosum)
what is encephalitis?
inflammation in the brain
meningitis
a bacterial infection in cerebrospinal fluid that can be treated with antibiotics if caught early enough
how is meningitis diagnosed?
through a spinal tap
syphilis
viral infection that causes general paresis and can lie dormant for years
rabies
a viral infection that attacks the brain and leads to inflammation. causes cognitive decline, behavioural changes, coma, and muscle paralysis
beta-amyloid plaques
plaques that build up in the brain and suffocate neurons
neurofibrillary tangles
string-like filaments associated with plaque buildup and death
which region of the brain is targeted first in Alzheimer’s disease?
hippocampus is attacked first, causing memory loss
acetylcholine antagonists
a treatment option for Alzheimer’s, helps to hold symptoms at bay
Multiple Sclerosis
an autoimmune disease where the immune system attacks and degrades myelin in the CNS
what are the symptoms of MS?
- ataxia (person loses fine motor control and becomes clumsy)
- numbness in limbs
- pain
