PBL5

Question 1

what is amlodipine

Answer 1

 Ca2+ blocker.
 Acts on myocardial cells in smooth muscle.
 Causes vasodilation.

Question 2

what are the side effects of amlodipine

Answer 2

• abdominal pain
• palpitations
• nausea
• oedema
• headaches

Question 3

what is warfarin

Answer 3

 Vitamin K antagonist.
 Lowers the amount of vitamin K present in the body.
 Vitamin K is needed for blood to clot.
 Warfarin is monitored by INR.

Question 4

what monitors warfarin

Answer 4

INR

Question 5

how do you work out a pack year history

Answer 5

 Pack years = years smoked x packs smoked per day.
 15 pack year = 1 pack per day for 15 years.
 15 pack year = pack a day for 15 years / 2 packs a day for 7.5 years.

Question 6

what is the INR (international normalised ratio)

Answer 6

 Prothrombin time (PT) is the time taken for blood to clot.
 PT varies under different circumstances.
 INR is a standardized result available for comparison.
 A higher INR means the blood takes longer to clot.
 Normal physiological values = 0.8 – 1.2.

Question 7

what is global aphasia

Answer 7

 Complete loss of all aspects of spoken and written language.
 Associated with a lesion in Broca’s and Wernicke’s area.
 Broca’s and Wernicke’s area are connected by the arcuate fasciculus.

Question 8

what is a stroke

Answer 8

a lack of blood supply to the brain

Question 9

what is atrial fibrillation

Answer 9

• this is a cardia arrhythmia that is often associated with rapid heart rate and detected by abnormalities on an ECG

Question 10

what is the epidemiology of stroke

Answer 10

 200/100,000 per year.
 Rate o stroke dramatically increases between the ages of 75 and 84.
 70% strokes occur in >65s.
 Stroke causes 11% of deaths in the UK.
 Costs £7 billion / year.

Question 11

what are the two types of stroke

Answer 11

• ischaemic

- haemorrhage

Question 12

what are the risk factors to stroke

Answer 12

 Smoking.
 Atrial fibrillation.
 Hypertension.

Question 13

what is the physiology of stroke

Answer 13

 Hypertension and smoking increase atherosclerotic plaque formation.
 Plaques can then rupture and block vessels causing occlusion.
 AF can result in stagnant blood pooling in the atria.
 This block can be carried into the circulation (embolus) and block vessels in the
brain.

Question 14

describe the blood supply to the brain

Answer 14

Anterior Circulation:
 Blood reaches the brain from the internal carotid arteries.
 Internal carotid arteries divides at the optic chiasm into the anterior and middle
cerebral arteries.
 The ophthalmic artery branches off from the internal carotid artery proximally to
supply the eyes.
 Internal carotid arteries provide 80% of blood for the brain.

Posterior Circulation:
 Vertebral arteries supply the other 20% of blood to the brain.
 Basilar and posterior cerebral arteries make up posterior circulation.
 Posterior circulation supplies the hind brain and some aspects of the temporal lobe.

Question 15

what do the medial cerebral arteries give of

Answer 15

lateral and medial strait arteries

Question 16

what do the lateral and medial strait arteries supply

Answer 16

 These arteries supply the corpus striatum and internal capsule.
 This is where all axons going to or from the cortex pass.

Question 17

what do the MCA supply

Answer 17

• Primary motor cortex.
• Primary somatosensory cortex.
• Primary auditory cortex.
• Primary area for olfaction.
• Posterior parietal cortex.
• Broca’s and Wernicke’s language areas.

Question 18

what blood vessel is affected

Answer 18

left cerebral artery

Question 19

what is the cause of

• global pahasia
• right side facial drop
• lack of power on the right side
• equivocal plantar reflex
• lack of sensation

Answer 19

Global Aphasia:
 Broca’s and Wernicke’s areas are affected.
 The arcuate fasciculus is also affected.
 This leads to language and speech difficulties.

Right Sided Facial Droop:
 Corticobulbar tract damage.
 This innervates the facial motor nucleus.
 UMN lesion so contralateral impact.

Lack of Power on Right Side:
 Left primary motor cortex has been damaged.
 Works contralaterally.

Equivocal Plantar reflex:
 A Babinski sign indicates pyramidal (Corticospinal) damage.
 Too early to tell in acute stroke.
 Reflexes may become hyper-reflexic later.

Lack of Sensation:
 On right side of body.
 Damage to the somatosensory centre on the left.
 Contralateral.

Question 20

what is blood colour without contrast in a CT

Answer 20

white

Question 21

what is blood with contrast in a CT

Answer 21

black

Question 22

what does the CT show

Answer 22

 The CTs show no haemorrhage meaning the stroke was ischaemic. - blood would have shown up if it was haemorrhage
 As time goes on infarcted tissue becomes darker on a CT in an ischemica stroke, these only become visible at 3-6 hours
 As the CT scan was normal is shows the stroke was recent, 3-6 hours ago.

Question 23

what is the treatment for stroke

Answer 23

 First step for acute stroke without CT scan evidence is 300mg aspirin.
 Antiplatelet therapy can also be used to stop new cots forming.
 Aspirin should be continued for 2 weeks, after which Warfarin should be used.
 Surgery is an alternative procedure to treat stroke.
 Thrombolytics such as tPA should also be used.

Question 24

what does tPA do

Answer 24

• it activates actives which breaks down thrombosis
• tPA converts plasminogen to plasmin
   Plasmin promotes thrombolysis by cleaving fibrin.

 This results in clot degradation.
 Ischaemia is therefore reduced.
 tPA should only be used for up to 4.5 hours after stroke.
 After this their effectiveness diminishes heavily.
 Thrombolytics may increase the risk of intracranial haemorrhage.

Question 25

what is the prognosis

Answer 25

 If thrombolysis is performed within 5 (or 3-4.5) hours there is a good chance of recovery.  If intervention was not successful, then full recovery is unlikely. - some revascualrisaiton of the brain may occur - stroke rehabilitation - this is the process by which patients with disability strokes undergo treatment to help them return to normal life by regaining and relearning the skills

Question 26

what is bendroflumethazide

Answer 26

- this is a thiazide diuretic that is used to treat hypertension causing vasodilation of blood vessels thereby reducing blood pressure - it works by inhibiting sodium absorption in the kidney

Question 27

why is the stroke most likely ischemic

Answer 27

- Atrial fibrillation and high blood pressure are both risk factors for ishemica stroke - untreated hypertension can damage the blood vessel walls leading to thromboembolism - AF can result in stagnant blood int he left atrium which can lead to thrombus formation, if the clot becomes mobile it is called and embolus

Question 28

what is used to reduce the chance of a stroke

Answer 28

warfarin

Question 29

when is tTPA lienced

Answer 29

- only within 4.5 hours after onset after symptoms as after this they can become ineffective