Neurological Disorders Flashcards
Why is oxygen needed in the brain?
- needed to break down glucose into carbon dioxide and water
- need a continuous feed of supply
What areas are particularly vulnerable to oxygen loss?
- subcortical nuclei, limbic system, frontal lobes and cerebellum
What is anoxia and hypoxia?
- an absence of oxygen
- a deficiency in oxygen
What is an ischemic accident?
- loss of blood flow
- can be transient
- happen in the internal carotid, middle cerebral or the vertebral cerebral arteries
How do ischemic accidents affect stroke?
- higher risk of stroke by 20-35%
What is a hemorrage?
- escaping blood from a ruptured blood vessel
What is an embolism or embolic occlusion?
- a temporary block that clears with pressure
What are the symptoms of a transient ischemic attack?
- tingling or numbness in one side of the face
- confusion
- loss or impairment of speech
- slurring of speech and dizziness
- blurry or double vision
- other cognitive changes
- weakness on one side of body (arm or leg)
What is infarction?
- (obstruction of blood flow)
- cell death caused by occlusion of a blood vessel
What are infarctions mostly caused by?
- thrombotic or embolic vascular occlusion mostly caused by atherosclerosis
What artery is particularly vulnerable to infarction?
- middle cerebral artery (left hemisphere)
What are infarctions in small vessels called?
- lacunar infarctions
What is a thrombotic vascular occlusion?
- full block of an artery
What is a hemorrage and what are they commonly caused by?
- rupture of the vessel producing hematomas
- can be caused by aneursyms
What is a hematoma?
- collection of blood outside of blood vessels
What is an aneurysm?
- an abnormal enlargement in a blood vessel
- causing thinning in the walls
What areas are particularly vulnerable to hemorrhages?
- putamen, white matter, thalamus, pons, cerebellum, and caudate nucleus
What are the types of aneurysms?
- saccular aneurysm
- fusiform aneurysm
What is coiling?
- insert microcatheter into femoral artery and feed wire up to aneursym
- fill aneursym with coiled wire
- decreases chances of rupture
- but risk of embolism during procedure
What is a intracerebral hemorrhage stroke?
- vessel rupture
- increased intracranial pressure (ICP)
- neuronal death
What is a subarachnoid hemorrhage stroke?
- rupture occurs within the subarachnoid space
- increased intracranial pressure (ICP)
What is arteriovenous malformation?
- too much branching of capillaries producing thin and weak walls
- tangle of abnormal blood vessels
What are the neuropsychological effects (of stroke)?
- impaired inhibitory control
- impaired attention and attentional control
- motor and sensory impairments
- memory impairments
- deficits in abstract reasoning
- emotional and behavioural changes
What are characteristics of brain tumors?
- atypical, uncontrolled growth of cells
- cells do not serve a functional purpose
- tumor grows at the expense of healthy cells
What are infiltrating tumors?
- take over and “invade” neighbouring areas of the brain and destroy surrounding tissue
What are non-infiltrating tumors?
- encapsulated, well differentiated and non-invasive
What are malignant tumors?
- indicates that the properties of the tumor cells invade other tissue and that there is a propensity for regrowth
What are benign tumors?
- describes abnormal cell growth that is usually surrounded by a fibrous capsule and is non-infiltrative
- a much smaller probability for regrowth
What is grading?
- a classification system of tumor growth
- grading is in order of increasing malignancy from Grades 1 to 4
What types of brain tumors are infiltrating?
- gliomas
- glioblastoma multiforme
- astrocytomas
- oligodendrogliomas
What types of brain tumors are non-infiltrating?
- meningiomas
What are gliomas?
- a malignant tumour of glial tissue
What is a neuroma?
- begnign growth of nerve tissue between the toes
Why are traumatic brain injuries a big deal?
- number one killer of young Canadians
- annual cost about 3 billion
- 50, 000 Canadians annually
- high correlation with homelessness and prison
What are the leading causes of TBI?
- motor vehicle accidents
- sports injuries
- falls
- alcohol involved in 1/3 of all TBIs
Why is the brain vulnerable to TBIs?
- brain is consistency of congealed oatmeal
- skull is roughly as thick as 3 pennies
- technology has advanced faster than evolution
What are the different types of trauma?
- penetrating
- crush
- open
- closed
How does a penetrating trauma occur?
- by a hard object, such as bullet, scissors or knife
What are the primary and secondary risk of penetrating trauma?
- primary risk: depends on location
- secondary: infection and hemorrhaging
What causes crush trauma?
- skull and brain are crushed between two hard surfaces
What is open trauma?
- skull is fractured and there is an opening causing the brain to be exposed
What is a closed head injury?
- rapid acceleration and deceleration shake the brain in the skull (like jello)
- no direct impact is needed
What is acceleration and deceleration?
- acceleration: significant physical force propels it quickly from stationary to moving
- deceleration: brain is in motion then stopped abruptly
What are the primary effects of a closed head injury?
- coup: a contusion at the site of impact
- contra-coup: a contusion on the opposite site of impact
What is diffuse axonal injury?
- common and most likely at frontal lobes and temporal poles due to uneven “sandpaper-like” surface of the tentorial plates that hold them in place
- physical forces shear, tear and rupture nerves, blood vessels and covering of the brain
What are complications of diffuse effects?
- neuronal disruption, ischemia, hemorrhaging and edema
Why are frontal lobes vulnerable to TBI?
- bone shape on top of skull
- result in anosmia (inability to smell)
What is tensile strength?
- minimum stress required to rupture axon
What is retrograde degeneration?
- axon degenerates back to cell body resulting in cell death
What is anterograde degeneration?
- damaged cell bod leads to axon fibre degeneration
What is the Glasgow Coma Scale?
- standard rapid, reliable measure of coma depth
- assesses language, consciousness, motor, etc.
What do scores >13 say?
- mild confusional state
What do scores <5 say?
- deep coma
What scores mean the patient is in a coma state?
- 8 or less
- can’t open eyes, make recognizable sounds or follow commands
What scores predict good recovery?
- > 8
What secondary effects can there be with closed head injury?
- edema
- herniation
- extradural and subdural hemorrhage
- intracranial bleeding
- skull fractures
- post traumatic epilepsy
What is edema?
- swelling of the brain after trauma
- main cause of death
- brain swells and becomes compressed, blocking arteries
What is herniation?
- hemorrhages, tumours or infections displace and deform the brain
What is transtentorial herniation?
- swelling causes the brain stem to protrude through the opening at the base of the skull
- called coning and is often fatal
- compromises the brainstem which controls vital functions
What treatment is done to monitor transtentorial herniation?
- intracranial pressure monitored with catheter into ventricles or subarachnoid space
How is intracranial pressure controlled?
- blood pressure ca be reduced medically or with hyperventilation
- extreme cases are put in a pharmacologically induced coma
- last resort: sunt or removal of a lobe to make room
What is subdural hematoma?
- between dura and arachnoid space
- frequent and very dangerous but difficult to detect
When can subdural hematoma occur?
- 1 hour to 1 week after injury
What exactly occurs during a subdural hematoma?
- initial period of unconsciousness followed by normal conscious functioning
- bleed enlarges and pushes brain laterally and downward causing herniation and consciousness deteriorates quickly
What are the symtpoms of subdural hematoma?
- contralateral hemiparesis, ipsilateral pupil dilation, changes in consciousness
What is extradural hematoma (epidural hematoma?
- between dura and skull
- uncommon (1-3%)
- usually caused by rupture of an artery
How is a extradural hematoma treated?
- by drilling burr holes over parieto-occipital and temporal regions to drain blood before it coagulates
What is intracranial bleeding?
- bleeding within the brain
- difficult to remove
What occurs in 15% of fatal injuries (related to intracranial bleeding)?
- space-occupying clots
What is the most frequent cause of intracranial bleeding?
- microscopic hemorrhages formed by torn blood vessels
What may be required to treat intracranial bleeding?
- surgery to relieve pressure caused by a clot
What are the two types of skull fractures?
- linear fracture: benign, distinct straight line
- depressed: fragments of skull driven into dura and brain
What are the risks of skull fractures?
- infection, CSF leaks, bleeding
- can rupture meningeal arteries or venous sinuses resulting in epidural and subdural hematomas
When are post-traumatic epilepsy symptoms more likely?
- after penetrating head injuries (40%) than closed head wounds (10%) because they are related to presence of scar tissue
- onset can be delayed for up to 2 years
What precaution is taken against post-traumatic epilepsy?
- patients given anticonvulsant medication to control for possibility
What are acute treatments of TBI?
- ABCs (airways, breathing, circulation)
- control ICP with ventilation/diuretics
- steroid therapy to prevent edema
- temperature control to control metabolic rate
