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2012-05-19 22:39:09
clinical medicine nervous system diseases

clinical medicine nervous system diseases
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  1. what is the most common cause of CNS problems?
  2. % of disabling injury, accidental death, and automobile death caused by brain injury
    • 10% disabling injury
    • 30% of all accidental deaths
    • 70% of all automobile deaths
  3. what are the different types of CNS injuries that usually result from trauma to the skull?
    • epidural
    • subdural
    • subarachnoid hemorrhage
  4. what is an epidural hematoma?
    • very fast accumulation of blood btwn the skull and dura
    • usually due to middle cerebral artery rupture
    • immediate surgery is only option or person will die
  5. what causes an epidural hematoma?
    • a blow to the side of the head that fractures the temporal bone
    • can be accompanied by loss of consciousness, recovery, and progressive neurologic deterioration leading to coma
  6. what is a subdural hematoma?
    • accumulation of blood in the subdural space
    • due to rupture of bridging veins passing btwn brain and large dural sinuses
  7. what causes a subdural hematoma?
    • inertial brain injury to frontal or occipital portion of the head w/o skull fracture
    • people tend not to remember the trauma bc it seems insginificant
  8. what is an acute vs chronic subdural hematoma?
    • acute: manifests after a few days
    • chronic: manifests after weeks or months by confusion that may lead to coma
  9. what is a subarachnoid hemorrhage?
    bleeding into the subarachnoid space (any etiology)
  10. what causes a subarachnoid hemorrhage?
    commonly caused by trauma or rupture of a pre-existing arterial aneurysm but can have any etiology
  11. what are CNS vascular diseases?
    • inherited disorders due to incomplete and/or abnormal resolution of embryonic vasculature
    • common
    • usually consist of a mixture of veins, arteries, and arterialized veins usually located in brain hemispheres ("arteriovenous malformations)
  12. what are CNS vascular diseases likely to cause?
    seizures and intracerebral hemorrhage from rupture
  13. what is the most common CNS vascular disorder/arteriovenous malformation?
    • saccular ("berry") aneurysms
    • present in 5-6% of general population
    • usually arise at the bifurcation of vessels in the middle cerebral artery and its branches
    • very lethal
    • typical at the base of the skull
  14. what arteries are more prone to rupture if they have saccular/berry aneurysm?
    ant cerebral and ant communicating artery
  15. what are the clinical symptoms of a saccular/berry aneurysm problem?
    • rupture (most lethal)
    • infarction
    • mass effect (compression)
  16. what is a cerebral (non traumatic) hemorrhage?
    a collection of usually bloody fluid w/in brain stem or cerebral hemispheres
  17. what is a hypertensive hemorrhage?
    • most common cause of non-traumatic hemorrhage
    • occurs most freq in basal ganglia where walls of vessels have been damaged by chronic hypertension or hypertensive microaneurysms
  18. compare cerebral infarction w/ cerebral hypertensive hemorrhage
    • infarction: localized to arterial distribution, destroy brain parenchyma
    • hemorrhage: affects any blood vessel in the brain, compresses the brain
  19. what causes cerebral infarction?
    • vascular thrombosis: internal carotid, vertebral artery, usually associated w/ a pre-existing atherosclerosis
    • embolism: thrombi from L hrt or carotid arteries, symptoms depend on location and size
  20. what is hydrocephalus?
    increased CSF volume causing vascular distention
  21. what causes hydrocephalus?
    • overproduction of CSP
    • inability of aracnoid villi to transfer CSF to venous drainage
    • blockage of CSF pathways
  22. what is noncommunicating hydrocephalus?
    blockage is within the brain
  23. what is communicating hydrocephalus?
    blockage in subarachnoid space
  24. what happens if blockage causing hydrocephalus occurs before cranial sutures close?
    resultant head enlargement mostly from top of skull
  25. what happens if blockage causing hydrocephalus occurs after cranial sutures close?
    causes symptoms related to increased intracranial pressure
  26. what types of infectious diseases affect the CNS?
    • bacterial
    • -- leptomeningitis
    • -- cerebral abscess
    • viral
    • -- viral meningitis
  27. what causes leptomeningitis?
    • bacterial infection caused by
    • - E. coli in newborns
    • - H. influenza in infants and children
    • - N. meningitis in adolesents and young adults
    • - Step. pneumoniae in adults and young children
  28. what occurs with leptomeningitis?
    • meninges become congested w/ purulent exudate
    • CSF shows increased pressure, increased neutrophils and protein, dec glucose
  29. what are the clinical symptoms of leptomeningitis?
    • agitation
    • headache
    • photophobia
    • stiff neck
    • postive meningeal signs (Brudzinki's and Kernig's)
  30. what causes a cerebral abscess?
    bacterial infection carried by the bloodstream usually from a sinus infection, ear infection, or mastoid infection
  31. how does an infection progress to a cerebral abscess?
    • starts as an acute inflammatory reaction w/ neutrophil infiltration and liquefactive necrosis associated w/ extensive cerebral edema
    • fibroblasts attempt to wall off the necrotic area
    • cavity evolves when dead tissue is removed
  32. what are the symptoms of a cerebral abscess?
    most are related to edema, incr intracranial pressure and area of involvement
  33. what is viral meningitis?
    • along w/ encephalitis is an important complication of systemic viral diseases and AIDS
    • results from virus spread hematogenous or along peripheral nerves (rabies)
    • clinical symptoms depend on virulence and site affected
  34. what are the different types of viruses that can lead to viral meningitis?
    • poliomyelitis: any inflammation of the gray matter of SC
    • rabies: causes encephalitis
    • herpes simplex type I and II
  35. what is the most common CNS demyelinating disease?
  36. what is the etiology of MS?
    • unknown
    • may be autoimmune reaction after a virual infection against brain cells called oligodendroglia
  37. what occurs with MS?
    numerous patches of demyelination throughout the white matter "plaque" is the hallmark of MS.
  38. what are the symptoms of MS and its onset?
    • onset in young adults (relapsing or remitting)
    • symptoms relate to leasions of the optic nerve, brain stem, or SC that may progress to blindness, ataxia and paraplegia
  39. what are degenerative diseases of the CNS?
    • alzheimers
    • parkinson's
    • amyotrophic lateral sclerosis
    • huntington's disease
  40. what are the characteristics of Alzheimer's disease?
    • progressive neurologic disease
    • loss of recent memory
    • dementia
    • insomnia
    • anxiety
    • progressive intellectual impairment leading to inability to comprehend, communicate or care for oneself
  41. what occurs physiologically w/ Alzheimer's disease?
    • involved of chromosome 21 and amyloid protein
    • meninges are thickened, gyri atrophic w/ dilation of ventricles due to cortical atrophy
    • death is often secondary to respiratory infections
  42. what are the characteristics of Parkinson's disease?
    • onset in 5th and 6th generation
    • loss of neurons in the substantia nigra, loci cerulei, and dorsal motor nucleus of the vagus
  43. what are the clinical signs of Parkinson's?
    resting "pill-rolling" tremors and bradykinesia which progress to rigidity and postural changes, slowness of voluntary movements, poor balance, shuffling gate, mask-like faces, and dementia (50%)
  44. what are the characteristics of ALS?
    • relatively uncommon
    • onset in the 6th decade
    • gradual progressive wasting of extremities and motor weakness leading to respiratory failure
    • sensory and mental function remains intact
  45. what happens physiologically w/ ALS?
    • degeneration of upper motor neurons in the SC and brain stem
    • damage to the corticospinal tracts and degeneration of anterior horn cells resulting in denervation atrophy of mm groups.
  46. what are the characteristics of Huntingtons's disease?
    • autosomal dominant inherited disease
    • onset in 4th decarde
    • involuntary movement of all parts of the body and facial grimaces
    • (opposite of parkinson's symptoms)
  47. what happens physiologically w/ Huntington disease?
    • marked atrophy of the caudate and putamen nucleus w/ corresponding ventricular enlargement
    • onset of symptoms to death is about 15 years
  48. what are the signs/sx of CNS neoplastic disease?
    • nothing specific
    • depend on local effects (irrative, compressive, destructive effects on the the sites involved) and general effects (inc pressure, edema, hemoorhage)
  49. Are CNS neoplasms generally malignant or benign?
    • malignant but rarely metastases
    • "malignant by location"
  50. what are the two different origins of CNS neoplasms?
    • depends on the cells involved
    • - neuroglial origin
    • - meningeal origin
    • - metastatic origin
  51. what are the types of neuroglial CNS neoplasms?
    • astrocytoma
    • oligodendroglioma
    • ependymoma
  52. what is an astrocytoma?
    • CNS neoplasms of neuroglial origin
    • derived from astrocytes w/ a wide spectrum of differentiation
  53. what are the grades of an astrocytoma?
    • grade I: well differentiated
    • grade II and II: anaplastic astrocytoma and glioblastoma which is highly malignant and the most common
  54. what are the symptoms of an astrocytoma?
    • seizures
    • motor deficits
    • mental changes
  55. what is an oligodendroglioma?
    • a CNS neuroglial neoplasm
    • derived from oligodendrocytes
    • primarily turmors of adults manifested by seizures
  56. what is an ependymoma?
    • a neuroglial CNS neoplasm
    • occur most frequently in 4th ventricle (hydrocephalus) during 1st and 3rd decade
  57. what are CNS neoplasms of meningeal origin?
    • secondary tumors
    • called meningioma
    • generally slow growing, benign
    • occur most freq in middle-aged adults
    • may or may not be symptomatic
    • prognosis depends on accessibility to surgical removal
  58. what are the primary sites of CNS neoplasms of metastatic origin?
    • (in order of freq)
    • lungs, breasts, melanoma, kidney, GI
    • symptoms include headach, seizures.. etc
  59. what are examples of PNS disorders?
    • Wallerian degeneration
    • Distal axonopathy
    • Segmental demyelination
    • Neuropathies
    • -- diabetic neuropathy (most common)
    • -- Guillain-Barre disease
  60. what is Wallerian degeneration?
    • a PNS disorder w/ degenerative changes in distal segment of a transected nerve
    • accumulation of organelles in the proximal and distal axonal stumps
    • atrophy of Schwann cells replaced by fibrose tissue
  61. what is Distal axonopahty?
    • "dying back"
    • a PNS disorder involving toxic and metabolic neuropathies proximal axon is intact
    • regeneration possible if the cause is removed
  62. what is segmental demyleination?
    changes that result from damage of myelin sheaths
  63. what is diabetic neuropathy?
    • most common PNS symmetrical polyneuropathy
    • involve sensory and autonomic nerves w/ extensive segmental demyelination secondary to axonal degeneration
  64. what is Guillain-Barre disease?
    • an autoimmune PNS neuropathy
    • progressive ascending motor paralysis
    • may affect spinal and cranial nerves
    • preceded by viral infection
    • characterized by segmental demyelination