Neuro Review part 1

Question 1

What are the 2 “holes” in the skull?

Answer 1

transtentorial notch (small) and foramen magnum (large) through which the brain is attached to the spinal cord.

If brain swelling occurs, the brain has nowhere to expand but down towards the foramen magnum.

Question 2

Cranial Nerves to know

Answer 2

I Olfactory - smell, often affected with a basilar skull fracture

II optic - sight, NOT pupil reaction

III oculomotor - pupillary function, flows out of midbrain (in brainstem) and transverse the transtentorial notch; therefore, with an increase in intracranial pressure, parasympathetic stimulation is blocked, sympathetic stimulation predominates = dilated pupils on the side of the injury

V trigeminal - corneal reflex, chewing

VIII vestibulocochlear - intactness of this cranial nerve is tested by doll’s eyes and cold caloric exams

IX glossopharyngeal - swallow, gag

X vagus - pharyngeal/laryngeal movement

all cranial nerves arise from the brain stem except cranial nerves I and II, which arise from the cerebrum above the brain stem

Question 3

The basilar artery supplies blood to the ____

Answer 3

lower areas of the brain and the brain stem

2 vertebral arteries come together to form the basilar artery

Question 4

The carotids supply blood to the ___

Answer 4

upper areas of the brain.

The left internal carotid is dominant for most people.

Question 5

brain function based on anatomic location:

Answer 5

frontal lobe: personality, abstract thought, long-term memory

temporal lobe: hearing, sense of taste and smell, interpretations

occipital lobe: vision, visual recognition, reading comprehension

parietal love: object recognition by size, weight, shape; body part awareness

cerebellum: coordination, balance, gait

Question 6

Circle of Willis

Answer 6

A circulatory anastomosis comprised of various arteries that supply blood to the brain. A well-developed Circle of Willis allows collateral blood flow to one area from another area in the event of an occlusion.

Less than 50% of the population has a well-developed Circle of WIllis.

The following arteries compose the Circle:
anterior cerebral artery (L and R)
anterior communicating artery
internal carotid artery (L and R)
posterior cerebral artery (L and R)
posterior communicating artery (L and R)

The basilar and middle cerebral arteries (MCA) are NOT part of the circle.

Question 7

What is the first sign of a neurological problem?

Answer 7

a change in LOC (level of consciousness), except for an epidural hematoma which may cause pupillary changes first.

Question 8

Reticular Activating System (RAS)

Answer 8

a network of neurons that connects the brain stem (lower RAS) to the cortex (upper RAS).

Upper RAS is responsible for awareness and lower RAS is responsible for sleep-wake cycle.

If the lower RAS is damaged, a coma occurs; if only the upper portion of the RAS is damaged, the patient loses awareness but still wakes up and goes to sleep.

Question 9

Components of a Neuro exam

Answer 9

Mental status: LOC, speech/language, memory, attentions span/thought content/judgement, Personality

Motor function: strength/movement, pronator drift, flexion/distention, flaccid

Sensory function

Pupillary assessment: CN III

Reflexes: babinski, brain stem (Cough/Gag/Corneal), Doll’s eyes

Question 10

What is Cushing’s triad?

Answer 10

a sign of herniation of the brain.

1. Increase SBP (widening pulse pressure)
2. Decrease Heart Rate
3. Decrease Respiratory Rate

Question 11

Glascow Coma Scale (GCS)

Answer 11

15 (Best) to 3 (Worst).

If the score is 8 or less, the outcome is poor.

Question 12

What is homonymous hemianopsia?

Answer 12

loss of vision in half the field of each eye

Question 13

State whether each change is on the same side or opposite to the pathology in the brain.

Eyes deviate:
Pupillary changes:
Visual changes:
Motor changes:
Babinski:

Answer 13

Eyes deviate toward the pathology.

Pupil changes are on the same side (ipsilateral)

Visual changes are opposite side of the pathology (contralateral).

Motor changes are opposite the side of pathology (contralateral).

Babinski is opposite side of the pathology (contralateral).

Question 14

uncal herniation

Answer 14

Displacement of the the temporal lobe (uncus) against the brain stem and the third cranial nerve (oculomotor)

Lateral shift, NO initial change in LOC

Blown (dilated) pupil on the same side seen BEFORE change in LOC d/t compression of parasympathetic innervation to the affected side.

babinski on opposite side

Question 15

Central Herniation

Answer 15

Swelling on both sides, downward displacement of hemispheres usually d/t diffuse edema (slow development). May be caused by cerebral edema secondary to encephalopathy or stroke.

Slight change in LOC and then could lead to coma and then death.

Pupils small initially and then blow.

bilateral babinski

Question 16

What is encephalopathy?

Answer 16

nonspecific term for any diffuse disease of the brain that alters brain function or structure.

minor to major, can result in swelling, increased intracranial pressure (ICP)

Treatment:
1. identify etiology and treat
2. Keep patient safe.
3. avoid conditions that increase ICP

Question 17

Right sided vs. Left sided stroke

Answer 17

Right sided: eyes deviate right, left muscle weakness, left homonymous hemianopsia, left babinski, EMOTIONAL lability

Left sided: eyes deviate left, right muscle weakness, right homonymous hemianopsia, right babinski, APHASIA

Question 18

Treatment for Acute Ischemic stroke

Answer 18

1. Rule out hypoglycemia (mimics a stroke)
2. ABCs
3. assess BP: do not treat unless SBP>220 or DBP>120. A sudden decrease will decrease perfusion
4. IV, O2, cardiac monitoring
5. baseline labs
6. CT scan within 25 mins

Decide if thrombolytics are needed.

Question 19

tPA inclusion and exclusion criteria:

Answer 19

Inclusion: onset s/s <4.5 hours, CT negative, No contraindications

Exclusion:
evidence of hemorrhage,
stroke or head trauma <3 months,
history of ICH,
major surgery in past 14 days,
active bleeding within 21 days,
MI within past 3 months,
seizure at stroke onset (history of seizure ok),
platelets < 100,
blood sugar <50,
INR >1.7 if on warfarin,
spontaneous clearing of symptoms or only minor symptoms,
persistent high BP (SBP>185, DBP>110)

Administration:
bolus (10%), IV infusion over 1 hour (remainder)

Post tPA
1. frequent neuro checks
2. BP management: SBP<180, DBP<105
3. Bleeding precautions

Question 20

Pontine infarct stroke characteristics include: (think P)

Answer 20

1. aPneustic breathing pattern
2. Pinpoint Pupils
3. Parasympathetic innervation (loses sympathetic nervous system innervation)

Question 21

Subarachnoid Hemorrhage

Answer 21

caused by trauma, a rupture of an aneurysm, or a tumor; 5% of all strokes

usually aneurysmal is the middle cerebral artery (MCA) and is seen in those 50-70 yrs old

symptoms of a ruptured aneurysm:
1. sudden explosive headache
2. decreased LOC
3. nuchal rigidity, positive Kernig’s sign

Complications of a SAH:
hydrocephalus (villi which reabsorb CSF are blocked), rebleed, vasospasm

Question 22

treatment of a vasospasm

Answer 22

1. angioplasty (select cases)
2. prevention includes:
   CCB (nimodipine),
   maintain cerebral perfusion pressure (60-70) with fluids, pressors, and inotropes (avoid hypotension!);
   monitor and treat hyponatremia which may precede a vasospasm

Question 23

brain tumors

Answer 23

s/s like a stroke, also seizures.

mortality remains high

usually includes steroid therapy (decadron) to prevent elevated ICP

Question 24

Intracranial pressure (ICP) and Cerebral Perfusion Pressure (CPP)

Answer 24

normal is 0-10 mmHg
moderately high is 11-20 mmHg
increased >20 mmHg

CPP is more important than ICP alone.

CPP = MAP-ICP
normal 80-100 mmHg
minimum for perfusion is 50 mmHg
brain death < 30 mmHg

with elevated ICP, keep CPP around 70 mmHg (hypotension in the presence of elevated ICP can be devastating)

Question 25

Strategies to lower ICP

Answer 25

1. decrease volume: mannitol/furosemide/3% saline, position patient upright
2. prevent dilation of cerebral vessels (ie prevent acidosis)
3. ventriculostomy (reduce CSF)
4. ABC’s to prevent secondary brain injury: Airway - control pH, Breathing - prevent hypoxia, Circulation - prevent hypotension
5. prevent pain/agitation (propofol)
6. avoid 0.45NS or D5W - why? these are hypotonic and would increase brain swelling

should hyperventilation be used to decrease ICP? No, will cause alkalosis resulting in vasoconstriction and will lower ICP and blood flow! Keep pH normal!

AVOID:
1. acidosis and alkalosis - these cause vasodilation and vasoconstriction.
2. hypotonic solutions - cause cerebral edema
3. hyperextension/flexion of the neck - prevents optimal jugular venous outflow
4. PEEP - increases thoracic pressure and prevents jugular venous flow
5. Low protein - decreases oncotic pressure
6. restraints or agitation
7. fever - leads to cerebral hypermetabolism