chapter 5 Etiologies and Neurodiagnostic Tests Flashcards
the most common acquired communication problem in adults…
is a stroke (CVA)
Stroke Symptoms
- dizziness
- numbness on one side of body
- fainting
- cramping
- redness of face
- speech difficulty
- comprehension difficulty
- vision problems
- headache
- vomiting
- paresis to paralysis
stroke survival
- majority of people survive a stroke
- 2.5 million currently suffer effects from a stroke
- up to 25% will have noticeable communication problems(likely higher)
neurological insults results from
- CVAs (64%)
- TBI (25%)
- other (sports and other, 11%)
strokes are the ____ leading cause of death
3rd
CVA Risk Factors
- Age
- Gender
- Ethnicity
- Pre-existing conditions
- Heart related factors
- Other factors
CVA Risk Factors- Age
risk is 1/1000 at age 50+, 10/1000 at 70+, and 20/1000 at age 80+
CVA Risk Factors- Gender
Men are at higher risk, elderly women at higher risk due to living longer
CVA Risk Factors-Ethnicity
African Americans are twice as likely to have a CVA as caucasians
CVA Risk Factors-Pre-existing conditions
- diabetes increases risk of stroke due to impaired glucose metabolism
- previous CVA increases risk of a second stroke by 10x
- history of CVAs in family
what is an ishemic CVA
- occlusive type
- some blockage of a vessel has occurred
- infarct is dead tissue resulting from an injury
- 80% of all strokes are ischemic
what is a non-ischemic CVA
- nonocclusive type
- no blockage of vessels occur in this type of CVA
- the common form is an aneurysm
- other possible types are hemorrhage and arteriovenous malformation
what are the types of ischemic CVAs
- thrombosis
- embolism
- arteriosclerosis(*)
- transient ischemic attacks(TIAs)
what is thrombosis
- a clot that forms and stays in the same location in a blood vessel has occurred
- 67% of ischemic strokes are thrombic
- two thirds of all ischemic strokese are thrombotic in persons over 60 years of age
What is embolism
- a clot that forms away from the brain but travels to the brain
- 33% of ischemic strokes are embolic
- women are likely to have more embolisms than men b/c of the effects of birth control pills
what is arteriosclerosis
- hardening of the arteries as a result of plaque build-up from cholesterol
- from LDL (non metabolized low density lipoprotein) bad one, don’t want to increase
- plaque build up starts to narrow the vessel (lumin), this process is called stenosis
- stenosis impedes blood flow, increasing risk of clot formation (thrombosis) or increases the risk of plaque breaking off, causing an embolism
- risk factors include high fat diet, obesity/diabetes, smoking, hypertension
- atherosclerosis is degeneration of the blood vessel walls, especially at junctions (when they break down)
what is a transient Ischemic attack
- warning signs of a possible subsequent stroke
- symptoms mimic a real stroke, but resolve themselves quickly (hours to a day)
- typically caused by stenotic arteries, arteriosclerosis, or hypertension
- other causes can include anemia or thyroid problems
- one-third of TIA victims have CVAs within five years
what are the types of non-ischemic CVAs
- aneurysm
- Cerebral hemorrhage
- Arterio-Venous malformation
what is an aneurysm
- typically a congenitally weak blood vessel wall that may not be noticed until adulthood
- blood vessel balloons out, will need to be clipped or if untreated will burst
- majority of patients have a headache prior to it bursting (and leading to death)
- most are found on accident
what is a cerebral hemorrhage
- the result of an aneurysm that has burst, also from a head trauma or hypertension
- if the spilled blood solidifies, it forms a clot (hemotoma) in the brain
- the clot can be intracranial (epidural, subdural, or subarachniod hematomas)
- the clot can be intracerebral (any bleeding inside the brain)
- bleeding/ clotting can lead to intracranial pressure (and must be relieved)
what is artery-venous malformation
- congenital-based disorder in which a vessel is neither an artery or a vein
- these formations carry both oxygenated and deoxygenated blood which may create symptoms of a TIA
blood flow
- arteries take blood to the brain with oxygen
- veins take blood away from the brain, deoxygenated
What is another name for head injuries
Traumatic Brain Injury
TBIs can result in ________ and ________ injuries
open head or closed head
is the #____ killer of persons under ____. The majority of whom are between ___ and ____.
- 1; 34
- 15; 24
how may TBIs occur annually
how many result in death
- about 1 million
- 56,000 deaths
what is the percentage breakdown of causes of TBIs
- vehicle accidents(50%)
- falls(21%)
- firearms (12%)
- sports (10%)
how many TBIs require therapy?
1/3
TBI can range from a _________ to a ___________.
concussion, coma
what are the five c’s of head injury?
- concussion
- contusion
- coma
- coup
- contra-coup
what is a concussion
an injury with no cisible signs of head trauma, but the person experiences headache, nausea, dizziness, concentration problems, (visual focus problems) etc.
what is a contusion
a bruise resulting from an injury with no torn skin (can see)
what is a coma
a state of unconsciousness and unresponsiveness
what is a coup
the internal site of injury to the brain
what is a contra-coup
an internal injury at the opposite point of coup injury
What else may TBIs lead to
- seizures
- uneven heart functions
- intracranial hemorrhage
- neck stiffness
- visual problems
- hearing problems
- vomiting
what is diffuse axonal injury
microscopic damage to neurons from abrupt changes in velocity (sudden stopping of a car tends to shear the neurons resulting in widely spread but undetectable breakage
-symptoms are very minor (headache, memory) but can slowly worsen over years mimicking alzheimers or other degenerative diseases
what is cerebral inflammation
- redness/swelling of tissue in response to an injury/ infection
- infection can be from bacteria or a virus, only bacteria respond to drugs
- meningitis is inflammation of meninges (constricting the lumina, increasing pressure)
- encephalitis is inflammation of cerebral tissue due to a virus
- both meningitis and encephalitis can cause an abscess (tiny area of tissue destruction)
- inflammation can also be caused b long-term diseases, such as rheumatic disease, syphilis, leukemia, and sickle cell disease; all of these cause vascular system disruption
what is neurodegenerative diseases
gradual irreversible destruction of brain tissue
what are the different types of neurodegenerative diseases
- multi-infarct CVA
- Picks Disease
- alzheimer’s
- late onset alzheimer’s disease
- non-genetic causes
- Others
what is multi-infarct CVA
a series of strokes, either TIAs, occlusive strokes or atherosclerosis
what is picks disease
- a rare degeneration of frontal/ temporal lobes
- occurs as early as 20 years of age
- referred to as one of the possible presenile dementias
- personality changes, odd behaviors
what is alzheimers disease
- 2/3 of all dementias are caused by alzheimers
- fourth leading cause of death, with 100,000 deaths per year
- also one of the presenile dementias if occurs before age 60
- cause is a defective chromosome 14, typically inherited
what is late onset alzheimer’s disease
variation of AD, caused by defective chromosome 12 and 21
what are some non-genetic causes of AD
some cases of AD have been attributed to children born of young fathers or who had poor linguistic abilities in early life (toxins, mercury)
what are other disease that cause brain degeneration
- creutzfeld-jakob disease
- progressive supranuclear palsy
- parkinson’s
brain tumors
- typically form from astrocytes or oligodendrocytes
- can be low grade/benign to fast growing/dangerous tumors
- deep seated(cant get to it) tumors are difficult to remove surgically and are therefore life threatening
- disruption in the flow of CSF may give symptoms of a tumor or other anomalies
Epilepsy
- idiopathic epilepsy is so termed because there is no definite cause
- non-idiopathic epilepsy is a symptom resulting from a CVA, TBI, or tumor
- petit mal seizures produce whole body twitches/jerks perhaps unconsciousness
- in jacksonian seizures, the twitching starts small and spreads to whole body
Substance abuse includes
- stimulants
- depressants/ sedatives
- alcohol
- neurotoxins
- anoxia
- other potential causes
stimulants
- affect release/uptake of neurotransmitters
- can affect the vascular system
- includes amphetamines/speed, methamphetamines/meth, cocaine, steroids, solvents, nitrites, antidepressants
- symptoms include high blood pressure, heart pressure, heart rate and blood velocity
- meth stays in system longer; affects the limbic system
- meth behavioral symptoms include agitation, anxiety, psychoses, confusion, memory problems, attention problems, (weight loss, skin lesions, bad teeth)
depressants/sedatives
- downers
- have a calming effect; increase serotonin levels or inhibit excitatory neurotransmitters
- includes PCP, opium, LSD, heroin, morphine, demerol
- specific sedatives include barbiturates (phenobarbitol/luminol)
- also include benzodiazepines (valium Halicon, xanax)
alcohol
- alcohol consumption is highly associated with TBI incidence
- can be lethal in combination with other drugs
- affects brain function, as well as other body organs (liver)
neurotoxins
- toxic metals include arsenic, lead, manganese, mercury, and tin
- toxic solvents are those that dissolve fats, oils, resins, waxes, plastics, polymers
- toxins are easily found in household and most industry-related businesses
anoxia
- can result from a heart attack if no oxygen reaches the brain for five minutes
- subsequently, if brain exhausts its 10 minute reserve of oxygen, glutamate is released which kills neurons
- within a day, widespread degeneration of neurons begins due to chromatolysis
- days later, brain tissue disintegrates, being replaced by scavenger cells
other potential causes of brain insult
- microwave radiation, especially from cell phones(in rats)
- nerve gas exposure, as seen in soldiers suffering from post-traumatic syndrome
Test for Medical Diagnosis and Lesion Localization
*Computer Axial Tomography (CAT/CT)
*Magnetic Resonance Imaging (MRI)
MR Spectroscopy
MR Projection Angiography
Magnetoencephalogoraphy (MEG)
*Functional MRI (fMRI)
MRI
*Spinal Tap/ Lumbar Puncture
*Electroencephalography (EEG)
*Evoked Potentials
Brain Electrical Activity Mapping (BEAM)
*Brain Scan
*Angiography
*Doppler Sonography
*Positron Emission Tomography (PET)
What is Computerized Axial Tomography
(CAT/CT scan)
- xray camera rotates about the head taking a picture every 2-10 mm intervals
- if successful, lesion will show up as a dark spot
What is Magnetic Resonance Imaging
MRI
- patient is put inside cylindrical chamber
- series of images are recorded over several minutes; all are collapsed to get a 3-D version of the brain, allowing a computer to rotate/slice the picture from different angles
- does not used radiation, no metals can be inside chamber due to magnetic forces applied
What is MR Spectroscopy
analyzes chemical composition of body tissue/organ
what is MR Projection Angiography
views blood vessels/ blood flow
what is magnetoencephalogoraphy
(MEG)
measures normal vs abnormal neural activity
what is functional MRI
fMRI
-shows blood flow to active areas of brain (vs rest/damaged areas)
what is MRI- Tensor Diffusion Imaging
measures water flow in nerves, esp. in multiple sclerosis
What is Spinal Tap/Lumbar Puncture
analyzes CSF in spine for bleeding , infection, pressure
what is electroencephalography
EEG
-measures electrical activity via surface electrodes
what is evoked potentials
measurement of electrical activity to visual stimuli (visual evoked responses-VER) suditory stimuli (AER or ABR) or proprioceptive stimuli
what is brain electrical activity mapping
(BEAM)
displays evoked potentials as lateral views of the brain
what is Brain Scan
- radioactive material is injected into the carotid artery
- xrays of videotaping images are taken to see where the isotope pools
- infarcted areas absorb this substance
what is an angiography
isotope is injected into carotid or vertebral artery and the circulating dye is followed to examine the diameter of blood vessels
what is a doppler sonography
high frequencies are aimed at a target area, echoes are measured and displayed as visual images; also known as ultrasound
what is positron emission tomography
(PET)
patient inhales or recieves injection of a positron emitter and an isotope tracer
combined these two light up active areas of the brain
a modified version is SPECT (single photon emission computed tomography) which measures particular areas of blood flow in the brain, called regional cerebral blood flow (rCBF)
