Exam 2: Stroke Clinical Exam and Imaging

Question 1

Stroke Facts

Answer 1

• Annual incidence ~795,000
• 610,000 - first time strokes
• 185,000 - previous stroke
• 5th leading cause of death in the
  US (decrease from 3rd)
• Leading cause of
  PREVENTABLE disability
• Costs the U.S an estimated $34
  billion annually
• Services, medicines, missed
  days of work

Question 2

What is a Stroke?

Answer 2

• Sudden interruption of blood supply
  to the brain causing neurological
  deficit
• Can be either ischemic (blockage) or
  hemorrhagic ( burst vessel)
• Effects of stroke depend on which
  part of the brain is injured.
  – Sudden weakness
  – Sudden loss of sensation
  – Sudden difficulty speaking
  – Sudden gait disturbance

Question 3

Time of Onset or Last Known Well

Answer 3

• If witnessed symptom onset: Time of onset
• If not witnessed symptom onset: Last seen at baseline
  health/function
• Woke up with symptoms: Last seen at baseline – usually when pt
  went to bed, or in middle of night if patient witnessed to be normal
• Times of reference
  – Television
  – The time the basketball game started

Question 4

Stroke Assessment

Answer 4

• ABC – BP, HR, O2 sats
• Finger stick for blood glucose – hypoglycemia symptoms can mimic
  stroke
• Focused history
  – Recent events – stroke, MI, trauma, surgery, bleeding
  – List of patient meds
  – Look specifically for anticoagulants (warfarin, dabigatran,
  apixaban, rivaroxaban, etc) , antiplatelet (aspirin, Plavix,
  Aggrenox) , insulin and antihypertensive use
  – Comorbid conditions – HTN, DM, Afib, CAD
• Neurological examination

Question 5

NIHSS Neurological Exam

Answer 5

• 1: LOC questions
• 2: Best Gaze
• 3: Visual fields
• 4: Facial palsy
• 5/6: Motor arm & leg
• 7: Limb ataxia
• 8: Sensory loss
• 9: Language (aphasia)
• 10: Speech (dysarthria)
• 11: Extinction/Inattention

Question 6

Cranial Nerve I

Answer 6

• Olfactory Nerve
• Major Function: Smell

Question 7

Cranial Nerve II

Answer 7

• Optic Nerve
• Major Function: Visual acuity
  and Visual Fields

Question 8

Cranial Nerve III,IV,VI

Answer 8

• III: Oculomotor: pupils, raises
  upper eyelid
• IV: Trochlear : depresses eye when
  adducted
• VI: Abducens: lateral eye
  movements

Question 9

Cranial Nerve V

Answer 9

• Trigeminal Nerve
• Major Function: Face and mouth
  touch/pain. Chewing

Question 10

Cranial Nerve VII

Answer 10

• Facial nerve
• Major Function: facial expression

Question 11

Cranial Nerve VIII

Answer 11

• Vestibulocochlear nerve
• Major Function: Hearing and balance

Question 12

Cranial Nerve IX, X

Answer 12

• Glossopharyngeal nerve
• Major Function: Taste (posterior 1/3
  tongue), Sensation to pharynx
• Vagus nerve
• Major Function: palate movements
  and vocal cords

Question 13

Cranial Nerve XI

Answer 13

• Spinal Accessory nerve
• Major function: raises shoulder and
  rotates and tilts head

Question 14

Cranial Nerve XII

Answer 14

• Hypoglossal nerve
• Major function: tongue movements

Question 15

CT Scan

Answer 15

• Developed directly
  from conventional xray technology
  – Measures DENSITY of tissues
  – Structures are described in terms of
  their density i.e hyperdense
• Differences
  – X-ray beam is rotated around patient
  – Xray data are reconstructed by CPU to
  obtain detail
• As Xray passes through the patient
  it is partially absorbed by tissues it
• Hyperdense: White: Bone, Calcifcation, Hemorrhage, Contrast
• Hyodense: Dark/Black: Air, CSF
• Isodense: Brain parenchyma

Question 16

CT Scan Advantages and Disadvantages

Answer 16

• Advantages
  – Rapid Acquisition – 5 minutes!
  – Highly Sensitive for Hemorrhage
  – Cost Effective
• Disadvantages
  – Radiation
  – Not very sensitive for acute
  infarction
  – Susceptible to bone artifact
  – Difficult to identify small infarcts

Question 17

More about CT Scans

Answer 17

• Normal CBF threshold 20-30
  ml/100g/minv
• Acute brain ischemia below this 
  cellular edema (cytoxic edema)
• Acute brain ischemia < 10
  ml/100h/min  immediate net water
  intake into gray matter
• Net uptake of water  decrease
  XRAY attenuation on CT
• 1% increase in tissue water causes a
  decrease of HU
• Specific for depicting IRREVERSIBLE
  BRAIN INFARCTION
• The goal is to open up the vessel as soon as possible to minimize IRREVERSIBLE damage!
• By understanding the various imaging modalities, we can identify what is already damaged, where it is damaged, and what we can save

Question 18

CT Angiogram

Answer 18

• Requires less than 5 minutes
• Uses a bolus of about 80 -
  100mL of iodinated non ionic
  contrast agent
• Clots causes “filling defects”
  – Sensitivity 92-100%
  – Specificty 82-100%
• Better for larger vessels
• Good for calcified plaques

Question 19

MRI Brain

Answer 19

• Developed from nuclear
  magenetic resonance
• Magnetic field is applied to cause
  protons in the specimen to align
  their intrinsic spins in parallel with
  the magnetic field.
• Protons = Hydrogen nuclei
• Intensity of MRI signal is based on
  proton density and relaxation time
  (T1, T2)

Question 20

MRI Brain and Stroke

Answer 20

• DWI – based on the capacity of the MRI to detect signal related to movement of water molecules
• Can detect ischemia within 3 to 30 minutes ; 90% sensitivity

Question 21

MRI Brain Advantages and Disadvantages

Answer 21

• Advantages
  – High contrast and resolution
  – Sensitive for small lesions
  – Good for posterior fossa
  – No Radiation
• Disadvantages
  – Takes long ~ 30-45 min
  – Costly
  – Not ideal for bone

Question 22

Cerebral Hemorrhage

Answer 22

• CT is sensitive tool to identify
  hemorrhage
• Imaging is important to understand
  location/volume, risk of further injury,
  guide treatment
• Types of Hemorrhages
• Epidural
• Subdural
• Subarachnoid
• Intraparenchymal

Question 23

Epidural Hematoma

Answer 23

• Present with trauma with LOC 
  lucid interval
• Hyperdense collection in epidural
  space between skull and dura
  mater
• Extent of hemorrhage is LIMITED
  BY SUTURES
• Crescentic or Biconvex appearance
• Often accompanied by skull
  fracture

Question 24

Subdural Hematoma

Answer 24

• Less likely to be acutely
  symptomatic
• Hyperdense collection in
  subdural space between
  arachnoid mater and pia mater
• CROSSES SUTURE LINES
• Caused by injury to venous
  structures;
• Less likely associated with skull
  fracture
• May cause mass effect

Question 25

Subarachnoid Hemorrhage

Answer 25

• Can be traumatic or secondary to aneurysm rupture
• “Worst headache of my life”
• Aneurysmal rupture typically involves basal cisterns where majority of aneurysms are located and can extend diffusely throughout SA space

Question 26

Intraparenchymal Hemorrhage

Answer 26

• Commonly caused by hypertension
• Commonly presents with acute onset
  of headache
• Hyperdense collection in the
  parenchyma
• HTN related bleeds more commonly
  located in basal ganglia, cerebellum
• Other important causes of bleeding:
  amyloid angiopathy (lobar), AVM,
  neoplasms