CCRN: Neuro

Cranial nerves

1. olfactory

2. optic

3. oculomotor

4. trochlear

5. trigeminal

6. abducens

7. facial

8. vestibulocochlear

9. glossopharyngeal

10. vagus

11. spinal accessory

12. hypoglossal

what is olfactory nerve disfunction associated with?

basilar skull fracture

why is oculomotor nerve disfunction associated with brain injury

flows out of midbrain/brain stem and traverses transtentorial notch, so increase in ICP blocks parasympathetic stimulation and causes pupil dilation on same side as brain injury

trigeminal nerve functions

• corneal reflex

• chewing

how to test vestibulocochlear nerve function

doll’s eyes reflex

cold caloric exams

glossopharyngeal nerve function

swallow and gag reflexes

vagus nerve function

pharyngeal/laryngeal movement

frontal lobe functions

• personality

• abstract thought

• long-term memory

temporal lobe functions

• hearing

• sense of taste and smell

• interpretations

occipital lobe functions

• vision

• visual recognition

• reading comprehension

parietal lobe functions

• object recognition by size, weight, and shape

• body part awareness

cerebellum functions

• coordination

• balance

• gait

arteries within the circle of willis

• anterior cerebral arteries (L and R)

• anterior communicating artery

• internal carotid arteries (L and R)

• posterior cerebral arteries (L and R)

• posterior communicating arteries (L and R)

what does consciousness depend on?

• intact cerebral cortex

• reticular activating system

  • neurons that connect brain stem to cortex

  • upper part responsible for awareness

  • lower part responsible for sleep-wake cycle

expressive (Broca’s) aphasia affected lobe

dysfunction of dominant frontal lobe

receptive (Wernicke’s) aphasia affected lobe

dysfunction of dominant temporal lobe

Doll’s eyes reflex interpretations

• normal (positive): eyes turn to opposite side that the head is turned

• abnormal: eyes stay at midpoint

• abnormal: eyes turn to same side as head is turned

types of respiratory changes seen in neurologic injury and areas of brain associated with them

• hyperventilation: midbrain

• apneustic breathing: pontine

• ataxic (leads to resp arrest): medulla

obtunded meaning

patient can speak but mumbles words

stuporous meaning

patient cannot speak but can moan/grimace

anopsia

loss of entire visual field of one eye

homonymous hemianopsia

loss of vision in half of the field of each eye

bitemporal hemianopsia

loss of outer half of visual field in each eye

left/right homonymous hemianopsia

loss of left or right half of visual field of both eyes (same field in both eyes)

what kind of injury does hemianopsia correspond to

• optic nerve damage

• side of brain opposite of affected field

  • eyes deviate towards injury side

• neglect of affected side

is a positive babinski reflex happen on the same or opposite side of injury?

contralateral

what is uncal herniation?

displacement of temporal lobe against brain stem and third cranial nerve causing lateral shift

exam changes seen with uncal herniation

• blown pupil seen before LOC change

  • parasympathetic innervation to affected side blocked

• contralateral babinski reflex

• slight weakness and pronator drift

what is the most common cause of uncal herniation

epidural hematoma

what is central herniation

• swelling on both sides of brain that causes downward displacement of hemispheres

• usually due to diffuse edema and has slower development

central herniation exam changes

• slight LOC change and then could lead to coma

• pupils both small initially but then both dilate

• bilateral babinski

encephalopathy etiology

• hypoxic

• metabolic

• hepatic

• drugs

• infection

when to treat BP during ischemic stroke

• systolic over 220

• diastolic over 120

inclusion criteria for tpa use (ischemic stroke)

• symptom onset under 4.5 hours ago

• negative CT scan

• no contraindications

contraindications for tpa

• hemorrhage or any history of ICH

• major surgery in last 2 weeks

• active bleeding in last 3 weeks

• stroke/head trauma in last 3 months

• MI in past 3 months

• seizure at onset of stroke

• platelets under 100k

• blood sugar under 50

• INR over 1.7

• spontaneous clearing of symptoms or only minor NIHSS symptoms

• persistent elevated BP

BP goals after tpa administration

• systolic under 180

• diastolic under 105

Hunt and Hess scale for SAH

1. asymptomatic or mild headache, slight nuchal rigidity

2. awake/alert, severe headache, stiff neck, cranial nerve palsy

3. drowsy or confused, stiff neck, mild focal neuro deficit

4. stuporous, moderate-severe hemiparesis, maybe mild posturing

5. coma, posturing

triad of symptoms for ruptured aneurysm

1. sudden explosive headache

2. decreased LOC

3. nuchal rigidity, positive Kernig’s sign

positive Kernig’s sign

patient's hip and knee flexed to a 90-degree angle; positive if patient has pain in the lower back or posterior thigh, or if they reflexively resist the extension of the leg

vasospasm treatment

• transluminal balloon angioplasty

• prevention:

  • nimodipine (CCB)

  • maintain CPP 60-70, avoid hypotension

  • monitor and treat hyponatremia

CPP equation

CPP= MAP - ICP

pharmacological part of treatment plan for brain tumors

steroid therapy (dexamethasone) to prevent elevated ICP

ICP numbers/categories

• normal: 0-10

• moderately high: 11-20

• increased: over 20

CPP average and minimums

• average: 80-100

• minimum: 50

• death: under 30

• if ICP elevated: keep around 70

S/S of increased ICP

• Altered LOC

• Restlessness/agitation

• Headache

• N/V

• Seizures

• Cranial nerve palsies (most commonly III, VI–X)

• Visual dysfunction

• Papilledema

• Pupillary changes

• Motor dysfunction (weakness, flexor and/or extensor posturing, flaccidity)

• Cushing’s triad

ICP waves

• A (plateau): awful

  • always pathological

• B: bad

  • usually pathological

• C: common

  • can be benign or pathological

what are A waves (ICP)

• sharp, massive spikes (50-100) that last for 5-20 min before abruptly falling

• can indicate severely reduced intracranial compliance (ex: vasospasm)

• risk of herniation or ischemia

what are B waves (ICP)

• sharp, rhythmic oscillations that occur more frequently (every 30 sec-2 min) that raise ICP by 20-30

• indicate unstable intracranial dynamics

what are C waves (ICP)

small, rhythmic fluctuations that occur 4-8 times/min that stay well below 20 mmhg

ways to reduce ICP

• decrease volume

  • mannitol, furosomide, hypertonics

  • upright patient position

• prevent dilation of cerebral vessels

  • prevent acidosis, keep pH normal

• reduce CSF volume

  • ventriculostomy

• prevent secondary brain injury

  • control breathing/pH, prevent hypoxemia and hypotension

• propofol

what imbalances should you avoid in elevated ICP?

• acidosis: causes vasodilation

• alkalosis: causes vasoconstriction, blood flow to head is reduced

• hyperextension, flexion of neck: prevents optimal jugular venous outflow

• PEEP: increases thoracic pressure and prevents optimal jugular venous outflow

• low protein: decreases serum oncotic pressure

• fever: cerebral hypermetabolism

• restraints, agitation, noxious stimuli

TBI severities based on GCS (first 48 hours)

• mild: 13-15

• moderate: 9-12

• severe: 3-8

what artery usually causes an epidural bleed?

middle meningeal artery

what type of herniation can result from an epidural hematoma?

uncal

epidural bleed symptoms

rapidly develop

• headache

• irritability and confusion

• vomiting

• pupil dilation (before LOC change)

• hemiparesis/hemiplegia

• decreasing LOC

classifications of subdural hematomas

• acute (s/s within 24 hours)

• subacute (s/s within 2 weeks)

• chronic (s/s more than 2 weeks after)

subdural hematoma clinical presentation

• similar to epidural, but less vomiting

• pupil change usually does not precede LOC change

• develops slower than epidural

what type of skull fracture doesn’t require surgery?

linear

when do surgeons operate to elevate depressed skull fractures?

• if depressed segment is greater than 5 mm below inner table of adjacent bone

• gross contamination

• dural tear with pneumocephalus

• underlying hemaoma

what is a communicated skull fracture?

fracture with bone fragmentation, usually depressed

what is a basilar skull fracture

a linear fracture that occurs in the floor of the cranial vault (skull base) resulting in a meningeal tear

• requires more force than other areas of neurocranium

• rare

s/s of basilar skull fracture

• raccoon eyes (periorbital edema and ecchymosis)

• Battle’s sign: discoloration at back of ear

• rhinorrhea containing CSF

  • no nose blowing

• otorrhea (fluid from ear)

• often damage to cranial nerve I (lose sense of smell)

nursing actions for suspected basilar skull fracture

• determine if drainage has CSF

  • check for sugar- halo sign

  • cover ear/nose with gauze- don’t pack it in

• don’t place NG tube

• monitor for meningitis

Status Epilepticus definition

seizure activity of 5 minutes or more with no return to consciousness between seizures

early pathophysiology of Status Epilepticus

• increased cerebral blood flow

• tachycardia and HTN

• increased CO2 and decreased O2

• increased glucose from stress response

• increased K+ (from destruction of skeletal muscle cells, under stress from seizure activity)

late pathophysiology of Status Epilepticus

• cerebral blood flow unable to meet demands

• arrhythmias from hyperkalemia; V-Fib

• hypoglycemia

• highly elevated K+ and CKs (rhabdomyolysis)

causes of status epilepticus

• withdrawal from anticonvulsant meds

• acute alcohol withdrawal

• toxic levels of drugs

• CNS infections

• brain tumors or CNS trauma

• metabolic disorders (hypoglycemia, hepatic failure, electrolyte imbalances, hypoxic encephalopathy)

• stroke

CSF characteristics of bacterial meningitis

• opening pressure above 180

• purulent

• elevated glucose

• highly elevated protein

• highly elevated WBC

CSF characteristics of viral meningitis

• normal opening pressure

• clear

• normal glucose

• elevated protein

• elevated WBC

signs of meningeal irritation

• headache

• nuchal rigidity

• Brudzinski’s sign

  • move chin to chest, positive if legs come up

• Kernig’s sign

  • move leg up and out, positive if causes neck and leg pain

brain death definition

complete, irreversible cessation of function of cerebrum, cerebellum, and brain stem

apnea tests prerequisites

• core temp over 36.5

• systolic greater than 90

• PaCO2 over 35 mmHg

• absence of drugs that cause respiratory depression

steps of an apnea test

• preoxygenation with 100% O2

  • draw baseline ABG for PaCO2

  • PaO2 may be normal or supranormal after

• disconnected from ventilator for 8-12 min (while O2 still being delivered)

• draw final ABG after

when to terminate apnea test early

• spontaneous respiratory movements noted

• BP instability: systolic falls under 90

• SpO2 falls under 85%

• unstable cardiac arrhythmias

positive apnea test results

• no respiratory movements

• PaCO2 greater than or equal to 60 mmHg or 20 mmHg over baseline

supports brain death diagnosis

what is Guillain-Barré Syndrome

• demyelination of lower motor neurons

• results in ascending paralysis, usually symmetrical

• return of motor movement occurs proximally

• protein may be found in CSF

  • due to inflammation and damage at blood-nerve barrier

what can cause Guillian-Barre Syndrome

• autoimmune response to viral infection (most common)

• recent vaccination (flu shot)

• recent surgical procedure

GBS treatment

• monitor for respiratory failure, urine retention, and dysphagia

• vent if needed

• IVIG over 2-5 days

• if not IVIG, do plasma exchange or plasmapheresis for 5 treatments

MG characteristics

• progressive skeletal muscle weakness that starts with fatigue early on and can later result in paralysis

• ocular dysfunction common

myasthenic crisis pathology

• deficiency of acetylcholine

• due to being undiagnosed/undertreated or due to an acute exacerbation

cholinergic crisis cause (for MG patient)

• due to excess of acetylcholine

• due to overtreatment with Mestinon (pyridostigmine)

tensilon test for MG

• if myasthenic crisis: Tensilon will improve symptoms

• if cholinergic crisis: will see increased muscle weakness and SLUDGE symptoms

  • have patient hold arms out to sides to detect weakness

what is Tensilon?

edrophonium: a short-acting cholinesterase inhibitor used to diagnose MG

What do each of the ICP waveform peaks mean?

• P1: percussion wave– arterial pulsation

• P2: tidal wave– brain tissue compliance

• P3: dicrotic wave– aortic valve closure at end of systole