Diseases and disorders of Nervous system Flashcards
layers of tissue covering brain
3 layers called meninges
innermost covering is the pia mater, middle layer is the archnoid and toughest, outermost covering is the dura mater
between dura mater and arachnoid membrane is subdural space
subarachnoid space btwn arachnoid membrane
pia mater is filled with cerebrospinal fluid that circulates here in the brain’s ventricles and in the subarachnoid space around the spinal cord
What is Cerebrospinal fluid (CSF)
clear liquid composed of water, protein, glucose and minerals
Regions of cerebrum?
outer region is cerebral cortex (distinctive wrinkled region described as gray matter because it consists of neuron cell bodies that appear dull gray)
inner region consists of axons and is described as white matter because axon’s myelin = white color
inner part of cerebrum also contains basal ganglia that controls muscle coordination and steady movement
3 types of neurons
interneurons - carries nervous impulses btwn neurons
sensory neurons - detect environmental stimuli like touch, light or pain and transmits messages to brain or spinal cord
motor neuron - conveys messages from CNS to muscles, causing contraction or to glands, triggering secretion
parts of the brain?
frontal lobe = voluntary muscle actions, muscles of speech, personality, judgment, memory and other cognitive function
temporal lobe = senses like hearing, taste, smell and ability to understand spoken language
parietal lobe = interpret meaning of incoming sensory signals from opposite side of bdy
occipital = interpreting visual input
thalamus = relays sensory information to correct areas of cerebral cortex
hypothalamus = controls vital body functions like temp, bp, breathing, appetite and sleep/wake cycle (produces some hormones, controls part of pituary gland, serves intermediary btwn nervous and andocrine)
cerebellum = below occipital lobe, controls smooth voluntary movements by coordinating sensory input with muscle actions (equilibrium and muscle tone)
medulla = bridges brain with spinal cord, regulates heart and respiratory rate, controls smooth muscle and bv
What is the spinal cord?
carries nerve impulses btwn brain and body (continuous with medulla oblongata through foramen magnum to first or second lumbar vertebra)
vertebrae, meninges, cerebrospinal fluid protect spinal cord
31 pairs of spinal nerves originate in spinal cord carrying bundles of sensory and motor neurons throughout the body
also directs some muscular reflexes in response to sensory input
divisions of peripheral nervous system?
somatic - controls voluntary muscle actions, receives input from sensory receptors and sensory organs (12 pairs of cranial nerves and 12 pairs o spinal nerves)
Autonomic - controls glands and involuntary muscles (cardiac muscle, smooth muscle in walls of bv, brochi, intestines and other and organs), 3 subdivisions
sympathetic - nerves arising from thoracic and lumbar areas of spinal cord (prepares organs and glands for “fight or flight” triggering causing bronchial dilation and increased heart rate and blood pressure)
parasympathetic - nerves arising from cranial and sacral regions, regulate resting functions of boy
enteric - nerves in and controlling GI organs
parts of neuron
extenstions called dendrites to carry info to cell body
axon to carrier info away from cell body
axons may have lipprotein covering called myelin sheath insulating and protecting neuron
deteriorating of myelin sheath decreases impulse velocity and impairs neuron function
What are the diagnostic tests and procedures of nervous system?
x-ray, CT, ultrasound, MRI, EEG, lumbar puncture (study CSF), myleography (radiopaque dye is injected into subarachnoid space to visualize the spinal cord sutrcture), angiography (visualization of cerebral circulation)
What is a traumatic brain injury?
damage to brain resulting from external physical forces
falls r leading cause, then motor vehicle accidents than sports and physical violence
abt 1.7 M ppl experience a TBI yrly in US
risk for TBI from fall is greatest for ppl over 65 and under 5
btwn 20 and 24 motor vehicle accidents = highest risk for TBI
s/s of mild TBI?
concussion is common type of mild brain injury (results from blow to head, sudden shaking or movement and may occur in contact sports, falls and automobile accidents)
- short-term loss of consciousness
- amnesia
- shallow respiration
- pulse rate drops
- muscle tone is flaccid
- headache
- NV
- sensitivity to light
- dizziness
- confusion
- inability to concentrate
- memory problems
- changes in mood, sadness, irritability, fatigue and sleep disturbance
2 forms of severe brain injury:
closed injury = result from sudden movement of brain in skill such as falls, automobile crashes and blows to head
open injury = result from penetrating wounds caused by firearms and sharp objects
s/s of Severe TBI?
serious short- and long-term impairments of brain function
- loss of consciousness
- amnesia
- muscle weakness and incoordination
- changes in emotion, personality and mood
1/2 of injury related deaths in US involve severe TBI
how to diagnose and treat TBI?
diagnose - assessment of brain function, info abt probable cause of injury, brain imaging, measure mental function, sensory responsiveness and motor ability with Glasgow Coma scale (Higher score = better function), and MRI and CT
treat - depends on severity, most resolve over time with rest (avoid physical and mentally strenuous activities until fully recovered
no specific treatment for severe brain injury, surgery to removed foreign objects or broken bone, drug to induce coma to reduce brain metabolism and inflammations
survives often need intensive physical, occupational, and seepch + language therapy)
how to prevent TBI?
reducing the risk for falls in the home, wearing seatbelts, and wearing helmets while playing contact sports, bicycling, and motorcycling.
What is spinal cord injury?
compression, bruising, fracture or swelling of spinal cord
causes include falls, automobile and motorcycle accidents, sports-related injuries, knife and firearm wounds and swimming in shallow water (also results from severe osteoarthritis, metastatic cancer or herniated discs)
SCI s/s
vary and depends on location of injury
motor, sensory, internal organ functions may be partly or completely lost
how to diagnose and treat SCI?
diagnose - history and assessment of motor and sensory functions, CT, x-ray and MRI determine spinal cord damage (after swelling subsides motor and sensory functions are tested again)
treat - aims to reduce risk of further injury and promote healing. immobilize neck and head, surgery to remove fluid or bone fragments or fuse broken discs (spinal ocrd damage is essentially irreversible)
s/s of cervical injury?
Inability to breathe, paralysis of the breathing muscles
Loss of bowel or bladder control
Numbness
Weakness, paralysis
Pain
Uncontrolled spastic muscle movements
s/s of thoarcic injury?
Loss of bowel or bladder control
Numbness
Changes in sensation
Pain
Weakness and paralysis
Symptoms affect the legs
s/s of lumbar and sacral injury?
Loss of bowel or bladder control
Numbness
Changes in sensation
Pain
Weakness and paralysis
What is epilepsy?
CNS disorder characterized by abn electrical activity in brain
may cause seizures, including loss of consciousness, loss of motor control, and sensory disturbance
cause is related t abnormal brain electrical activity
what are risk factors of epilepsy?
family history of epilepsy, stroke, brain injury and infections like meningitis, age (early childhood and after age 60)
s/s of epilepsiy?
vary widely, epilepsy has been classificed by location and characteristics of seizure (if focal than affecting 1 part of brain, if general then abn electrical activity on both sides and in many areas)
seizure characteristics wary from staring spells to complete loss of motor function and unconsciousness
may entail ivoluntary contraction of muscles w/ disturbances in consciousness and sensory phenomena
how to diagnose and treat epilepsy?
diagnose - EEG, MRI and CT, cerebral angiography may identify vascular changes, skull radiography for fractur, blood serum
treatment - anticonvulsant meds (no cure tho) (in rare cases, surgical intervention to excise identified lesion in brain, implanted vagus nerve stimulator (VNS) which sends impulses of elecetrical energy through vegus nerve to brain to prevent seizures)
What is a stroke>
aka cerebrovascular accident or brain attack
sudden interruption of blood flow to part of the brain caused by a blood clot or a burst blood vessel within the brain (Lack of oxygen causes brain cells to die within minutes
of a stroke’s onset)
each yr stroke affects 800,000 and kills 130,000 ppl in the US
vascular disease so stroke and heart disease have similar risk factors
more strkoes r caused by a blood clot, r classified as ischemic stroke
About 15% of strokes result from a
burst blood vessel and are described as hemorrhagic strokes. These may be caused by a brain
aneurysm
What are types of epilepsy?
Focal:
Simple focal - No loss of consciousness; minor sensory and motor disturbances; tingling and flashing lights, involuntary movements
Dyscognitive focal seizure - Loss of awareness or consciousness; staring and purposeless movements
Generalized seizures
Absence seizure - Petit mal seizure: staring into space or “daydreaming”
Tonic seizure - Stiffening of muscles
Clonic seizure - Repeated jerking movements of muscles on both sides of the body
Myoclonic seizure - Jerking or twitching the upper body, arms, or legs
Atonic seizure - Loss of normal muscle tone
Tonic-clonic seizure - Grand mal seizure: mixture of all symptoms
risk factors for stroke?
Controllable
- high bp
- atrial fibrillation
- high cholesterol
- diabetes
- atherosclerosis
- tobacco use and smoking
- alcohol use
- physical inactivity
- obesity
Uncontrollable risk factors
- age
- gender
- family history
- prior stroke or TIA
- patent foramen ovale
s/s of stroke?
- numbness
- loss of vision
- muscle weakness on one side of face or body
- confusion
- difficulty walking, speaking and understanding
- sudden severe headache
- sudden aphasia, dysphasia, difficulty understanding language
- diplopia
- sudden onset of dizziness, loss of balance, loss of coordination
how to diagnose and treat stroke?
diagnose - assessment of cognitive, motor and sensory function to determine the extent and location of stroke. CT, MRI and cerebral angiography, electroencephalography, to pinpoint location of strkoen and whether itś stroke is ischemic or hemorrhagic
treat - ischemic stroke (treated with clot-busting drugs injected IV or directly into brainś bv near the blood clots using a catheter)
hemorrhagic strokes (treated with medicine to reduce bp, control Intracranial pressure or counteract blood-thinning meds if pt was taking those) may need surgery to repair blood vessels in brain (intense rehabilitation may be needed for physical, speech, cognitive and emotional complications of a stroke)
What is a transient ischemic attack (TIA)?
mini-stroke a temproary interruption of blood flow to brain (cause is embolus formed by atheroscelrosis)
less severe s/s (sudden weakness, numbness down 1 side of body, dizziness, dysphagia, confusion, difficulty seeing w/ one eye, loss of balance, suddenonset headache, recurring) but may require immediate medical attention bc it may be a precursor to stroke
What do disorders of cranial neves?
may affect eyes, hearing, balanace and muscles of face or shoulder
inflammation to the cranial nerves is commonly associated with facial or ocular palsy as well as facial pain
etiology of cranial nerve inflammation is often idiopathic but may include viral or bacterial infections of stroke
most common known cranial nerve disorders r trigeminal neuralgia and Bellś Palsy
What is trigeminal Neuralgia?
severe chronic pain resulting from dysfunction of the 5th cranial nerve, known trigeminal nerve which transmits sensory info from face and jaw (one side)
aka tic douloreux, rare, after 50 mostly
pain may be triggered by touching face, chewing, drinking, or talking
most painful medical condition
etiology is uncertain, thought to be compression of nerve root by trumor or vascular lesion, sequeala of multiple sclerosis or herpes zoster, demyelination of trigeminal neurons
diagnose and treat trigeminal neuralgia
diagnose - physical exam and history (protect face and avoid temp extremes)
treat - antiseizure med, antidepressants, muscle relaxants, and analgesics
What is Bell´s Palsy?
paralysis of facial muscles caused by inflammation of the facial nerve.
r
isk factors include recent respiratory infections
and pregnancy.
A viral infection or immune disorder probably triggers the nerve inflammation (compression of the nerve in the bony canal) that causes Bell’s palsy.
s/s of bell´s palsy?
inability to salivate, form tears, blink and move facial muscles which results in a drooping eyelid, lips and expressionless face
diagnose and treat bell´s palsy?
diagnose - physical exam of the face and a history to rule out stroke, Lyme disease, and tumors, CT or MRI to confirm and to view possible structural causes of inflammation
treat - anti-inflammatory medication and antiviral meds if paralysis is related to a viral infection (most ppl recover within a few weeks) (warm moist heat, gentle massaage, facial exercise, analgesics, artifical tears and eye patch, electrotherapy)
What is meningitis?
acute inflammation of the first two meninges that cover the brain and spinal cord: the pia mater and the arachnoid mater
most common r acute bacterial meningitis and viral meningitis
in recent yrs bacterial meningitis has caused more than 4,000 causes and abt 500 deaths annually in US
rare auses of meningitis include fungi and cancer
What is bacterial meningitis?
severe infectionthat requires immediate medical attention ot prevent serious complication or death
What bacterias cause bacterial meningitis?
The most common bacterial cause is Streptococcus pneumoniae (the pneumococcus).
Other bacterial causes include Group B streptococci, Neisseria meningitides (the meningococcus), Listeria monocytogenes, and Haemophilus influenzae type b (Hib).
spread in respiratory droplets and secretion (usually during close contact as when kissing)
(listeria monocytogenes is acquired through contaiminated food)
s/s of bacterial meningitis?
- positive Kernig sign (resistance to leg extension after flexing thighs on the body)
- Brudzinski sign (neck flexion causing flexion of hips from supin poistion)
- severe headache
- stiff neck (nuchal rigidity)
- high fever
- chills
- vomiting
- confusion
- sensitivity to light
- increased DTR
- irritability
- hypersensitivity of skin
In infants: - bulging fontanel
- irritablity
- poor reflexes
Meningingococcal meningitis also causes a skin rash
how to diagnose and treat bacterial meningitis?
diagnose - physical exam, history and analysis of cerebrospinal fluid obtained by lumbar puncture (splinal tap) for bacteria. in bacterial meningitis CSF has low glucose and elevated leukocytes and proteins + CT
treat - IV antibiotics, anticonvulsive, glucocorticoids, aspirin or acetaminophen, corticosteriods to control swelling, immediate treatment is needed (even with treatment complicatations like hearing loss, cranial nerve damage, mental disabilites or paralysis can occur)
What is viral meningitis?
more common rhan bacterial meningitis
enteroviruses r most cases of viral meningitis
other causes r herpes simplex virus, HIV, West Nile virus, and mumps
no specific treatment, s/s r treated with rest, analgesics and antiinflammatories
What is encephalitis + cause?
inflammation of brain, most often caused by viral infection
rare in US, most cases r mild, if severe than v. dnagerous and brings serious compplications
viral causes include arboviruses (transmitted by mosquitoes, enterovriuses, and viruses that cause herpes simplex, chickenpox and shignel)
West Nile virus causes a type of encephaliytis
only way to prevent is avoid mosquitoes
s/s of encephalitis?
- headache
- stiffness of neck and back
- visual disturbances
- lethargy
- fever
- muscle and joint aches
- weakness
Rarely, severe cases occur and include symptoms: - severe headache
- confusion
- perceptual changes
- weakness
- seizures
Diagnosis and treatment encephalitis?
diagnose - lumbar puncture for analysis of CSF, blood may be drawn for analysis, CT or MRI for brain swelling, EEG
treatment - no specific, s/s r treated with rest, analgesics and anti-inflammatories, antipyretic, anticonvulsants, antibiotics, antiviral for HSV encephalitis,
What is poliomyelitis?
aka polio, crippling, potentially fatal viral infection of anteroir horm cells of gray matter of spinal cord, causing selective destruction of the motor neurons
last case of polio in US occurred in 1979
risk factors for polio include lack of vaccination and travel to areas with endemic polio
transmitted orally and infects motor neurons = muscles weaken, atrophy and may become paralyzed (Death floows respiratory and cardiac failure)
s/s of poli?
- fever
- sore throat
- malaise
- flaccid paralysis
- headahce
- weakness
- vomiting
- stiff neck
- back ache
What is rabies?
viral infectio nof brain in wild mammals (mainly bats, raccoons, coyotes, foxes and skunks) can also unvaccinated domestic dogs and cats
can be transmitted to humans through bite, scratch, saliva or urine of an infected animal
affects abt 1 person a yr in US
risk is highest for people who work with animals, such as veterinarians, animal control officers, and wildlife biologists
following entry into human tissue, typically through bite or scratch the virus moves to spinal cord and brain (incubation is 1 motnh to yr based on location)
s/s of rabies?
occur late in course of disease (days before death0
- fever
- headache
- agitiation
- confusion
- hallucination
- difficulty swallowing
- excess salivation
- fear of water (hydrophobia)
- insomnia
- partial paralysis
how to treat rabies?
begin as soon as exposure is suspected
- immunoglobulin injectoins near wound (neutralize virus before it can move into nervous system)
- series of five vaccination are given in arm to stimulate the body’s immune system to fight the virus
- prevented by vaccinating domestic dogs and cats
What is shingles?
aka herpes zoster
acute painful dermatomal inflammation of sensory neurons caused by reactivation of latent chickenpox virus (varicella zoster virus)
affects nearly 1 M ppl
mainly in ppl over 50 and those who are immunocompromised (risk is associated with prior chickenpox infection and with age)
incubation is 7 to 21 days, onset to recovery is 10 days to 5 weeks, if all vesicles appear within 24 hours total duration is usally shorter, mostly skin overlyign thoracic dermatomes, can occur on face, neck and salp
s/s of shingles?
painful, red, watery blisters around trunk, often on one side along the course of the peripheral nerves or dermatmes that r affected
these may occur on face around eyes or other areas
burning or tingling 2-3 days before appearance of lesions and sometinmes accompanied by fever
in some cases pain continues after rash clears, a condition called postherpetic neuralgia
diagnosis and treatment for shingles?
diagnose - characteristic pattern and painful viesicles, clutre of virus, blood sample for VZV antibodies
treatment - no specific treatment, antiviral agents, ice, lotions and anti-inflammatories, analgesics, mild tranquilizers or sedatives, antipruritic steroids, drying agents
prevented with chickenpox vaccine in children or shingles vaccine in adults
What is tetanus?
aka lockjaw
acute muscle rigidity and paralysis caused by bacterial nerve toxin
rare, affects 30 ppl yrly (1 M throughout world, mainly in underdeveloped nations w/o vaccination)
caused by tetanus toxin, a nerve toxin produced by bacterium Clostridium tetani (binds with motor neurons, stimulates them and causes muscles to be continually stimulated to contract)
35% mortality rate
s/s of tetanus?
characteristic muscle rigidity
painful muscle spasms
difficulty swallowing (oisthotonos)
respiratory failure
rigid, flexed jaw called trismus
extremely febrile (temp > 101F)
irrritable
sweats profusely
face spans
what is the tetanus bacteria (where is it found, etc.)
bacteria live in animal and human intestines
bc retanus bacteria r excreted in animal feces and can persist in soil bacterial is often found in manure or in soils fertilized with manure
deep, penetrating wound containing contaminated soil can introduce bacteria into tissue
bc tetanus bacteria is anaerobic (not required o2) they thrive in deep wounds that lack oxygen
how to diagnose and treat tetanus?
diagnose - usin pt history (inadequate immunization, acutely ill)
tetnus - can be cured, need to clean and disinfect wound, if person is unimmunized than immunoglobulin injections to neutralize toxins, if person last tetanus vaccination was 10+ yrs ago than immunization with inactive toxin is needed, sedatives, muscle relaxants for spasms and seizures, quire, dark environment for rest
What is botulism?
condition of muscle weakness and paralysis caused by bacterial nerve toxin (rare in US, affects abt 145 ppl annually)
occurs in 3 forms: Infant botulism (most common), foodborne and wound
muscles become weak and paralyzed and r unable to contract (condition called flaccid paralysis)
risk factor for botulism?
for infants: eating honey
- consuming home-canned foods
- injection drug use (esp heroin)
s/s of botulism
infants:
- constipation
- floppy babies (unable to hold up head and move muscles)
- difficulty crying and swallowing
- may drool and having difficulty sucking and feeding
Food born botulism (Wound botulism resembles it) :
- droppy facial and eye muscles
- difficulty swallowing or speaking
- nausea
- double vision
- vomiting and cramps
- difficulty breathing
botulism bacteria (what is it, where is it)
nerve toxin produced by the bacterium Clostridium botulinum that binds motor neurons and
prevents them from sending signals to muscles
for contraction
thrive in anaerobic conditions, found in soil and can contaminate food and wounds
infants may digest bacteria or their spores in soil to honey
foodborne botulism is usually transmitted by eating improperly canned low-acid foods like green beans, beets, corn
garlic-infused oil has been linked to botulism
wound botulism follows a deep, contaminated wound that permits bacteria to grow in anaerobic conditions (mostly in heroin users)
how to diagnose and treat botulism?
diagnose - physical exam and pt history
treat - infants can be treated with botulism immunoglobulin, foodborne botulism can be treated with meds to promote vomiting and bowel movement, botulism can also be treated with injected antitowxin, respiratory assitane ma be needed , restoration of nerve and muscle function may be slow and require phscial therapy
What is Reye syndrome?
UNCOMMON BUT POTENTIALLY DISTABLING OR FATAL NEUROLOGICAL ILLNESS THAT OCCURS IN CHILDREN AFTER A VIRAL INFECTION
infants who use aspirin during flu and chickepox infection r at risk for RS
liver and brain inflimmation (persistant vomiting, rash, lethargy abt 1 wk after viral infection, serious cases = seizure)
How to diagnose and treat Reye Syndrome?
diagnose - pt history, liver biopsy for defintive diagnosis (shows fatty changes in the microvasculature in liver tissue), blood tests may reveal elevated fatty acid
treat - nonspecific, aims to lower intracranial pressire, many children recover but w/ intellectuall disability, seizure diorder, cranial nerve damage and motor nerve damage
What is Alzheimer’s disease (AD)?
most common form of dementia, result of progressive destruction of memory and nearly all other important brain function
risk is linked with age (abt 1/2 of ppl over 85 have AD)
causes r unknown: only 5% of cases r linked to known genes and considered heredity (bnormality found on chroosome 21)
in AD connections btwn neurons die as do neurons themselves + tangles of protein called neuro-fibrillary tangles
Death results from pneumonia, other infections, or injuries from falls and accidents.
s/s of AD?
often begin with memory loss and confusion
loss of short-term memory, inabiltiy to concentrate, incapabicty to learn new info, impairement of reasoning, subtle changes in personality
inherited forms may have an early onset (in the 40s or 50s)
over time ppl lose memory, spatial and temporal orientation, become more confused and exhibit swings in emotion and personality changes
