principles of neurosurgery 2

unawareness of self and environment

apparent comatose state except exhibits EEG rhythm with alpha frequency

• global ischemic changes of brain following MI
• focal brain stem lesion at or caudal to pontomesencphalic junction
• metabolic or toxic encephalopathies

state of wakefulness withou the ability to appreciate or respond to external stimuli

comatose state with irreversible total loss of cerebral and brain stem function preceding cessation of cardiac activity

• unimpaired consciousness with tetraplegia and pseudobulbar paralysis
• preserved vertical, absent horizontal eye movement
• respond to verbal stimuli with coded eye movements

• mild decrease in level of alertness
• reponds but lacks concentration and attention span

• moderate decrease in level of alertness
• tend to sleep when undisturbed but arose with simple questions

• severe decrease in level of alertness
• pt responds to continuous vigorous stimulation with unintelligible sounds. No verbal responce.

clouded slow thinking

• hyperactive
• agitated
• confused with hallucinations
• paranoid ideation
• signs of autonomic overactivity

transient loss of conciousness from reversible, temporary impairment of blood flow to brain

cyclic loss of consciousness reversible with stimulation

• 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

• inspect airway
• if pt vomits place them on side
• depending on circumstance use an
• oral air way
• nasal air way
• endotracheal tube
• cricothyrotomy

• blood gas
• tidal volume
• RR
• oxygen saturation
• LOC

inspect head, neck, and extremities for trauma

• racoon eyes - periorbital echimosis
• drainage of clear fluid or blood from nose or ears
• battle signs

• alcohol - inebriation
• ammonia - uremia
• musty - hepatic coma
• spoiled fruit - diabetic coma

IV line with appropriate electrolyte solution

bleeding

right frontal destructive lesion

deep seated thalamic lesions

unilateral pontine lesions

• internuclear opthalmoplegia
• paresis of individual muscles
• peesixting tropia or phoria

• imply intact brain stem
• good prognostic indicator

for orbital injury, prior cataract surgery as these cause dialation

• uncle herniation with compression of 3rd CN at tentorial edge resulting in
• impairment of parasympathetic pupilloconstrictor fibers in nerve

• bilateral midbrain lesions
• anoxic encephalopathy
• brain death
• sudden expansion and rupture of an internal carotid artery anyeurism
• extreme midbrain compression

pontine lesion

• medullary lesion
• hypothalmic lesion

optic nerve injury

• lesion of thalamus or tectum of the midbrain
• may also be accompanied by a non-reactive pupil (parinaud's syndrome)

• skew deviation
• fallows lesions of cerebellum or brain stem

• aka conjugate downward movements
• follows lesions of pontine tementum
• accompanied often by lateral gaze paralysis

• cranial nerve paralysis
• usually 6th due to genral increased ICP
• usually 3rd due to uncle herniation

positive is normal - eye work as a dolls

• head flexed at 30 degrees
• make sure tympanic membrane is intact
• 30mL of cold water into external auditory canal

• 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

• diffuse forebrain lesions
• sensitive to normal pCO2 causing a longer hyperventilatory phase followed by a shorter apnea
• results in alkolosis

• pO2 high, pCO2 low
• rare, but seen in head injury with severe midbrain lesion

• pO2 < normal then pulmonary edema or aspiration pneumonitis
• pO2 > normal then concider central neurogenic hyperventilation

• prolonged pause at full inspiration
• reflects lesion of mid to caudal pons
• seen in brain stem stroke from ba

• medullary lesions in respiratory center
• irrugular random deep and shallow breathing

• lower medullary lesions
• irregular sequence with varying paauses between clusters

• flexion of arms and wrist and extension of lower extremities
• cerebral white matter, internal capsule, or thalamus

• upper and lower extremity complete extension
• slightly more caudle in upper brain stem

• no response to any noxious stimuli
• medullary failure

• facial nerve intact
• first division of trigeminal nerve intact

reticular activating system in rostral pons, midbrain and thalamus

• Diffuse cortical lesions
• supratentorial mass lesions
• Direct lesions
• Infratentorial lesions

• diffusely affected neurons of cerebral cortex due to
• hypoxia
• hypoglycemia
• hyperosmolar coma
• acid base imbalance
• uremia
• hepatic coma

extrinsic or intrinsic in either cerebral hemisphere causes compression and uncal herniation resulting in compression of rostral brain stem and impairment of RAS

• in rostral brain stem itself
• acute hemorrhage or trauma

secondary compression oof brain stem caused by large cerebellar tumors, hemorrhage or infarction.

• 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

positron emision tomographic scan will show low cerebral metabolic rate for glucose

• decline from chronic nervous disorder
• acute brain insult

• pseudo coma
• ventral pontine syndrome
• de-efferent state
• cerebromedullospinal disconnection

• 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

total irreversible loss of functino of cerebral hemispheres and brain stem

• 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

isoelectric tracing in spite of high gain setting

• intoxicated with sedative or hypnotic drugs
• hypothermic

disconnecting the pt from respirator to allow PCO2 to rise to 60mmHg to initiate spontaneous repiratory effort

twice 6 hours apart

cardiac death will follow within days to weeks.