Nervous System Advanced Patho

Nervous System Advanced Patho

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The central or the peripheral nervous system are made of brain (cranial nerves) and spinal cord (spinal nerves)
Peripheral nervous system further divided into somatic- nerves that go to voluntary muscles and autonomic (sympathetic-fight & flight/parasympathetic- rest/digest) – no control over
Brain consists of cerebellum, cerebrum, and brain stem
Cerebellum function is coordination of movements, gait- d/o cause ataxia and intention tremors
Intention tremors or kinetic tremors the tremors you have when you expect to move- comes with cerebellar d/o-
Brain stem pons and medulla- vital centers- respiratory, cardio centers- can lose life-
Foramen magnum the hole in the base of the skull through which the spinal cord passes
What happens when you tap on patellar tendon? reflex movement, stimulated a sensory fiber- carries impulse to s. cord, enters from posterior aspect/horn- to anterior horn, motor neuron will initiate contraction reflex- doesn’t consult w/brain
Upper motor neuron all neurons higher than L2, in the brain (stroke), hemiplegia- you have paralysis and the reflexes more aggressive, tetanus- sustained/exaggerated movements- SPASTIC
Lower motor neuron composed of motor cells in s. cord, motor nerve fiber, neuromuscular junction (rich in Ach), and muscle itself
Lesion in lower motor neuron local- lower motor neuron- no movement/paralysis- reflex is absent/flaccid
Frontal lobe; prefrontal area goal-oriented behavior, issues would be personality changes- behavioral
premotor area part of basal ganglia system (extrapyramidal nervous system)
primary motor area corticospinal (pyramidal nervous system)- back of the frontal lobe
Broca area: motor speech area (LEFT side)
Parietal lobe primary sensory area
Occipital lobe issues primary visual cortex
Temporal lobe primary auditory cortex
Group of neurons cells ganglion
Groups of nerve fibers tract
pyramidal tract from primary motor area cross to the opposite side-supply the skeletal voluntary muscles- when crossed looks like a pyramid from the top- paralysis here is spastic on opp side
extrapyramidal tract/ premotor area do not follow same tract (different freeway)- go to the same muscle fibers- 1) controls muscle tone and 2) involuntary movements- if working too much you will be still w/involuntary movements (Parkinson’s)
premotor area normally inhibited- all the time by dopamine in the basal ganglia in the brain stem- that’s why you’re not stiff all the time and you don’t have tremors
Lesion in the basal ganglia causes increased tone/stiffness in skeletal ms and tremors/involuntary movements> extrapyramidal manifestations
Drugs with extrapyramidal s/s EPS> increased tone and involuntary movements
When the pt with extrapyramidal movements starts to move, what happens? the tremors disappear because the pyramidal, motor takes over
Pyramidal lesion= paralysis- spastic (stroke)
Lesion in the basal ganglia Parkinson’s, Dopamine goes down
3 layers of meninges Dura mater (tough mother), arachnoid mater (spider mother-projections), pia mater (delicate mother)-closest to the brain
3 spaces between meninges epidural space (extra dural hemorrhage- arterial) empty space, subdural space (subdural hemorrhage/ venous) and subarachnoid space (filled w/CSF- arteriovenous AVM)
Arteriovenous AVN normally, artery divides into capillaries and then into a vein. Abnormally, capillaries aren’t there> artery to vein= pressure, bulge> hemorrhage >Berry aneurism
subarachnoid hemorrhage (filled w/CSF- arteriovenous AVM)- not used to blood so it will hurt= headache- SUDDEN and SEVERE- neck rigidity- fever, altered LOC (50%)> sounds like meningitis- do CT
best test for suspected hemorrhage? CT w/o contrast-
CSF in meningitis ^ proteins, vglucose (normal unlikely to be meningitis), bacterial so… leukocytes- enough to dx- it takes 3-4 days to culture organism- give anbx
Intracranial pressure brain (80%), water (10%) and blood (10%)- at first you may compensate but later blood cannot come up from heart to the brain
Cerebral perfusion pressure CPP=MAP(90)-ICP (15) difference from arterial pressure from heart and intracranial pressure CPP= 90-15 so CPP is 75, so if ICP was 55 (high), CPP=35 (low), less blood to brain= ALOC
ICP and vomiting brain/medulla tries to go down foramen magnum bc no space= projectile bc medulla has vomiting center
Papilledema increased pressure in the brain causes the part of the optic nerve inside the eye to swell. Symptoms = disturbances in vision, headache, vomiting
Resting nerve cell negative until stimulated by the dendrites- any positive charges= depolarizes (active) through Na+
Myelin sheath not continuous- impulses move faster when jumping through gaps- the larger the faster
Demyelinated d/o MS- nerve conduction is slower
Cells in the brain do not divide, what about cancer? can get it in the brain from different source
Sometimes dendrites receive negative impulses to the brain cell brain will sleep more
At the synapse, how is the impulse transmitted? Chemically from presynapse to post synapse neuron
Type of receptor some neurotransmitters can be excitatory and inhibitory, depending on the receptor (S1, S2, S3, DA1, DA2)- what is it doing to the postsynaptic receptor
In basal ganglia, DA is…? inhibitory, when released it inhibits the 2nd neuron? Ach>GABA>GABA>
If you inhibit DA for a schizophrenic pt (mesolimbic), you may inhibit DA in basal ganglia and cause what? EPS- extrapyramidal s/s
DA in the mesolimbic system is excitatory
Ach can be excitatory or inhibitory… mostly +- involved with muscles and memory (Alzheimer’s), myasthenia gravis
GABA off switch to the brain
Glutamic acid on switch
Parkinson’s imbalance of Ach and DA, competition and DA tends to keep Ach inhibited
Parkinson’s s/s tremors/involuntary movements, stiffness, shuffling, mask face, hyperemia
Parkinson’s problem is premotor area not inhibited by …? basal ganglia is degenerated (in brain stem)- 4 groups (ganglia) DA (normally inhibits>), Ach (not released), GABA (not released), GABA (does job), dopamine not working so Ach takes over & premotor cortex not inhibited
When Ach takes over in basal ganglia DA is not inhibiting Ach, so it excites 3rd neuron GABA, usually not released, which inhibits neuron 4 GABA and prevents it from inhibiting the premotor cortex
Tx for Parkinson’s levocarbidopa, anticholinergic (Cogentin)
Encephalitis infection of brain matter itself- viral
Hemorrhagic stroke a weakened blood vessel ruptures. Two types of weakened blood vessels usually cause hemorrhagic stroke: aneurysms and arteriovenous malformations (AVMs).
Ischemic stroke thrombosis blood clot in one vessel blocking or Embolic- clot forming in distal artery- detaches and circulates- tx with TPA, do CT w/o contrast
Anencephaly, Defects of Neural Tube Closure upper part of neural tube does not develop into full brain, so skull does not develop
Problems in lower part of neural tube spina bifida-Failure of fusion of the posterior vertebral laminae- hair tuft- securing of spinal cord- gait/foot abnormalities, bladder sphincter disturbance
Meningocele a sac-like cyst of meninges filled w/ CSF, protruding through the vertebral defect
Meningomyelocele (spina bifida cystica) Hernia protrusion of a meningocele containing a portion of the spinal cord with its nerves
Encephalocele herniation of brain and meninges through a defect in the skull
Congenital hydrocephalus enlargement of cerebral ventricles d/t CSF blockage- Pushes and compresses the brain tissue against the skull cavity.
Cerebral Palsy a group of non-progressive motor dysfunction d/t perinatal hypoxia
Coup/countercoup injury coup- area where person was hit, countercoup is 2nd injury produced where the brain was injured d/t the trauma
Primary injury direct result of trauma (e.g. contusion, hematoma) Secondary injury
Tertiary injury ALOC- aspirated- pneumonitis- systemic complications that contribute to further brain injury
Focal brain injury some hemorrhage in brain, 2/3 of head injury deaths Ex. Extradural (artery) and subdural hematomas
Classic concussion lose consciousness, even for 1 second (to 6 hrs)
Lucid interval initial loss of consciousness, even for 1 second, known in extradural hematomas, which could later result in death if not taken care of immediately (football player)
Subdural hematoma grandpa drowsy all the time- sleeps too much, talks slowly- half of skull is occupied with blood- in elderly and etoh (venous bleeding is slow)
Diffuse brain injury Concussions- most common head injury- no LOS or classic concussion- (LOS 1 sec to 6hrs)- headache- get retrograde or anterograde amnesia in both- dizzy, disoriented- post concussion syndrome
Retrograde amnesia can’t remember the past
Anterograde amnesia can’t retain info
Post concussion syndrome headache, don’t feel like yourself- nervous, aggressive
Lose consciousness for more than 6 hrs defuse axonal injury (DAR)- mild (24h), moderate (days to weeks) or severe (months to yrs)
defuse axonal injury (DAR) minor cuts in axons/wiring due to trauma- not severe enough to hemorrhage/too minor to show up in a CT
brain abscess infection spreads from middle ear to the brain- little kids- hepatitis B- frequent headache- don’t take lightly
headache make sure there is no evil- ie; secondary to tumor- never goes away, always gets worse- progressive and associated w/other s/s
subarachnoid hemorrhage headache more severe than meningitis
temporal arthritis inflammation of the endothelial lining of arteries- autoimmune conditions (SLE)- temporal artery- pain worst when touched –unilateral- biopsy most accurate- 1st step is prednisone/steroids v inflammation/blindness
migraine 60% cases unilateral- 20% aura, blood vessel issue, imitrex constricts, calcium channel, beta blockers relax if >month- abnormal spasm in cranial blood vessels- spastic
tension headache most common- lack of sleep, stress, hunger- bilateral- belt around head from back to front
cluster headache unilateral- icepick in the eye- severe- retro orbital- lacrimation, red eye, stuffy nose
A neurologist is teaching about the region responsible for motor aspects of speech. Which area is the neurologist discussing? Brocas area- respond incorrectly but Wernicke’s relates to sensory (don’t understand the question)
When a student asks which type of nerves transmit nerve impulses at the fastest rate, what is the best response by the nurse? large myelinated
Vomiting is due to disruptions in the medulla oblongata
When a student asks what can cause dilated, fixed pupils, what is the nurse’s best response? Dilated fixed pupils can be caused by brainstem hypoxia
Confusion: loss of ability to think rapidly and clearly, impaired judgment and decision making
Disorientation: beginning LOC, to time then place then people and last self. Impaired memory
Lethargy: limited spontaneous movement or speech; easy arousal with speech or touch, ± disorientation to time, place, and people.
Obtundation: mild to moderate reduction in arousal with limited response to environment; falls asleep unless stimulated; minimal response to questions
Stupor: deep sleep, aroused only by vigorous, repeated stimulation, response is often withdrawal or grabbing at stimulus
Coma: no verbal response to any stimulus
Light coma: associated with purposeful movements on stimulation
Coma: associated with nonpurposeful movements only on stimulation
Deep coma: NO response to any stimulus
While planning care for a patient with an extradural hematoma, which principle should the nurse remember? The main source of bleeding in extradural (epidural) hematomas is: arterial
Which of the following would increase a patient’s risk for thrombotic stroke? dehydration
A neurologist is teaching about encephalitis. Which information should the neurologist include? Most causes of encephalitis are: viral
Patients with myasthenia gravis often have tumors or pathologic changes in the thymus
A 72-year-old male demonstrates left-sided weakness of upper and lower extremities. The symptoms lasted 4 hours and resolved with no evidence of infarction transient ischemic attack (<24 h)

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