principles of neurosurgery 2

  1. coma
    unawareness of self and environment
  2. alpha coma
    apparent comatose state except exhibits EEG rhythm with alpha frequency
  3. alpha coma is observed in the following
    • global ischemic changes of brain following MI
    • focal brain stem lesion at or caudal to pontomesencphalic junction
    • metabolic or toxic encephalopathies
  4. persistent vegatative state
    state of wakefulness withou the ability to appreciate or respond to external stimuli
  5. brain death
    comatose state with irreversible total loss of cerebral and brain stem function preceding cessation of cardiac activity
  6. locked in state
    • unimpaired consciousness with tetraplegia and pseudobulbar paralysis
    • preserved vertical, absent horizontal eye movement
    • respond to verbal stimuli with coded eye movements
  7. lethargy
    • mild decrease in level of alertness
    • reponds but lacks concentration and attention span
  8. obtundation
    • moderate decrease in level of alertness
    • tend to sleep when undisturbed but arose with simple questions
  9. stupor
    • severe decrease in level of alertness
    • pt responds to continuous vigorous stimulation with unintelligible sounds. No verbal responce.
  10. confusion
    clouded slow thinking
  11. delirium
    • hyperactive
    • agitated
    • confused with hallucinations
    • paranoid ideation
    • signs of autonomic overactivity
  12. syncope
    transient loss of conciousness from reversible, temporary impairment of blood flow to brain
  13. sleep
    cyclic loss of consciousness reversible with stimulation
  14. clinical assesment of comatose pt
    • circumstances in which pt was found
    • PMH from family, friends, physician
    • Hx of fall assault, penetratnig wound, MVC, phychiatric illness, suicide attempt, epilepsy, illicit drug use, endocrine or metabolic disorders, cardiac irregularities, hpertension, vascular disease, coagulopathy
    • search pt for empty pill container
  15. first step in managing a comotose pt
    • inspect airway
    • if pt vomits place them on side
    • depending on circumstance use an
    • oral air way
    • nasal air way
    • endotracheal tube
    • cricothyrotomy
  16. whether a pt is placed an a ventilator depends on
    • blood gas
    • tidal volume
    • RR
    • oxygen saturation
    • LOC
  17. After assesment of airway and vital signs the next step is
    inspect head, neck, and extremities for trauma
  18. signs of head trauma
    • racoon eyes - periorbital echimosis
    • drainage of clear fluid or blood from nose or ears
    • battle signs
  19. odors to take note of in evaluation of coma
    • alcohol - inebriation
    • ammonia - uremia
    • musty - hepatic coma
    • spoiled fruit - diabetic coma
  20. After evaluating airway, vital signs, check for signs of trauma, noticing odors what next
    IV line with appropriate electrolyte solution
  21. hypotension in trauma is a sign of
  22. deviation of eye away from side of paralysis, looking toward the lesion in coma
    right frontal destructive lesion
  23. deviation of eye toward the side of paralysis, looking away from the lesion in coma
    deep seated thalamic lesions
  24. conjugate deviation toward side of paralysis in coma
    unilateral pontine lesions
  25. disconjugate gaze in coma
    • internuclear opthalmoplegia
    • paresis of individual muscles
    • peesixting tropia or phoria
  26. spontaneous slow horizontal roving eye movements in coma
    • imply intact brain stem
    • good prognostic indicator
  27. pupil evaluation first evaluate
    for orbital injury, prior cataract surgery as these cause dialation
  28. unilaterally dialated and fixed pupil
    • uncle herniation with compression of 3rd CN at tentorial edge resulting in
    • impairment of parasympathetic pupilloconstrictor fibers in nerve
  29. bilateral fixed and dialated pupils
    • bilateral midbrain lesions
    • anoxic encephalopathy
    • brain death
    • sudden expansion and rupture of an internal carotid artery anyeurism
    • extreme midbrain compression
  30. bilateral small pinpoint pupils
    pontine lesion
  31. unilateral horner's syndrome with miosis, ptosis, enophthalmos
    • medullary lesion
    • hypothalmic lesion
  32. no reaction to direct light
    reaction to consensual light
    optic nerve injury
  33. forced downward deviation of eyes
    may also be accompanied by
    • lesion of thalamus or tectum of the midbrain
    • may also be accompanied by a non-reactive pupil (parinaud's syndrome)
  34. vertical divergence
    • skew deviation
    • fallows lesions of cerebellum or brain stem
  35. ocular bobbing
    accompanied by
    • aka conjugate downward movements
    • follows lesions of pontine tementum
    • accompanied often by lateral gaze paralysis
  36. disconjugate movement seen in
    • cranial nerve paralysis
    • usually 6th due to genral increased ICP
    • usually 3rd due to uncle herniation
  37. oculocephalic reflex
    positive is normal - eye work as a dolls
  38. oculovestibular reflex procedure
    • head flexed at 30 degrees
    • make sure tympanic membrane is intact
    • 30mL of cold water into external auditory canal
  39. oculovestibular reflex - findings
    • normal - nystagmus with fast component away from stimulated side
    • coma - slow deviation of eyes toward stimulation, with 2 to 3 minutes before neutral position is again gained
    • brain stem damage - no reaction eye remain fixed forward
  40. cheyne stokes respirations
    • diffuse forebrain lesions
    • sensitive to normal pCO2 causing a longer hyperventilatory phase followed by a shorter apnea
    • results in alkolosis
  41. central neurogenic hyperventilation
    • pO2 high, pCO2 low
    • rare, but seen in head injury with severe midbrain lesion
  42. differentiating central neurogenic hyperventilation vs pulmonary edema or aspiration pneumonitis
    • pO2 < normal then pulmonary edema or aspiration pneumonitis
    • pO2 > normal then concider central neurogenic hyperventilation
  43. apneustic breathing
    • prolonged pause at full inspiration
    • reflects lesion of mid to caudal pons
    • seen in brain stem stroke from ba
  44. Ataxic breathing
    • medullary lesions in respiratory center
    • irrugular random deep and shallow breathing
  45. cluster pattern
    • lower medullary lesions
    • irregular sequence with varying paauses between clusters
  46. decorticate posturing indicates
    • flexion of arms and wrist and extension of lower extremities
    • cerebral white matter, internal capsule, or thalamus
  47. decerebrate rigidity indicates lesion
    • upper and lower extremity complete extension
    • slightly more caudle in upper brain stem
  48. flaccidity is an indication of
    • no response to any noxious stimuli
    • medullary failure
  49. intact corneal reflex indicates
    • facial nerve intact
    • first division of trigeminal nerve intact
  50. consiousness relies on what
    reticular activating system in rostral pons, midbrain and thalamus
  51. four catagories of impaired consciousness
    • Diffuse cortical lesions
    • supratentorial mass lesions
    • Direct lesions
    • Infratentorial lesions
  52. diffuse cortical lesions result from
    • diffusely affected neurons of cerebral cortex due to
    • hypoxia
    • hypoglycemia
    • hyperosmolar coma
    • acid base imbalance
    • uremia
    • hepatic coma
  53. supratentoral mass lesions
    extrinsic or intrinsic in either cerebral hemisphere causes compression and uncal herniation resulting in compression of rostral brain stem and impairment of RAS
  54. Direct lesions
    • in rostral brain stem itself
    • acute hemorrhage or trauma
  55. infratentorial lesions
    secondary compression oof brain stem caused by large cerebellar tumors, hemorrhage or infarction.
  56. Persistent vegatative state presentation
    • pts appear wakeful but there is no cognitive function. Eyes may be open
    • but do not track or explore surroundings and do not move
    • purposefully or in response to commands.
    • No vocalization or verbalization
    • Faces are expressionless
    • May assume fetal position with limbs flexed with no responce to noxious stimuli and no purposeful movements
  57. persistant vegatative state tests
    positron emision tomographic scan will show low cerebral metabolic rate for glucose
  58. persistant vegatative states occurs due to
    • decline from chronic nervous disorder
    • acute brain insult
  59. locked in syndrome
    • pseudo coma
    • ventral pontine syndrome
    • de-efferent state
    • cerebromedullospinal disconnection
  60. locked in syndrome
    • tetra plegia, pseudobulbar paralysis
    • unable to communicate except by blinking
    • horizontal eye motions are affected
    • RAS is intact thus there is full consiousness
    • blood flow studies are normal
  61. brain death
    total irreversible loss of functino of cerebral hemispheres and brain stem
  62. brain death presentation
    • brain stem reflexes absent
    • pupils are fixed and maximally dilated
    • corneal, cough, and gag reflexes are absent
    • no responce to doll eyes or cold caloric stimulation
    • no spontaneous respiration
    • flacid with no responce to painful stimuli
    • DTR absent
  63. in brain death an EEG with show
    isoelectric tracing in spite of high gain setting
  64. before declairing brain death it must be ascertained that the pt is not
    • intoxicated with sedative or hypnotic drugs
    • hypothermic
  65. apnea can be tested by
    disconnecting the pt from respirator to allow PCO2 to rise to 60mmHg to initiate spontaneous repiratory effort
  66. brain death text administration usually occurs
    twice 6 hours apart
  67. after brain death occured it is inevitable that
    cardiac death will follow within days to weeks.
Card Set
principles of neurosurgery 2
principles of neurosurgery chapter 3