ELM 10.1

Question 1

Causes of stroke?

Answer 1

• Brain artery blocks
• Brain artery bleeds
• Poor general circulation
• Heart failure
• Drowning
• Low oxygen at birth

Question 2

What is transported inside the brain?

Answer 2

• O2
• Carbohydrates
• Amino acids
• Fats
• Hormones
• Vitamins

Question 3

What is transported outside the brain?

Answer 3

• Co2
• Ammonia
• Lactate
• Hormones

Question 4

What is F.A.S.T?

Answer 4

• Facial weaknes, arm and leg weakness, speech problems, test these signs

Question 5

Neurotransmitters in the brain

Answer 5

• Glutamate

Question 6

Ions in the brain

Answer 6

Calcium, sodium

Question 7

Free radicals in the brain

Answer 7

• Abnormal oxygen molecules, e.g. superoxide

Question 8

Reparative mechanisms

Answer 8

• Plasticity
• Neurogenesis
• Angiogenesis

Question 9

How can you cool a human using a catheter?

Answer 9

Insert into femoral vein and thread into vena cava

Question 10

Which of the following symptoms is commonly seen in a haemorrhagic stroke, but infrequently in an ischaemic stroke?

a.	 Facial weakness

b.	 Pain on the left side of the body

c.	 Severe headache

d.	 Slurred speech

Answer 10

c

A haemorrhagic stroke is due to the spontaneous rupture of a blood vessel within the brain. This leads to the build up of intracranial pressure, which frequently results in severe headache and vomiting. If untreated, raised intracranial pressure can lead to “coning”, where the cerebellar tonsils are forced through the foramen magnum at the base of the skull. This event frequently results in severe disability or death.

Pain on the left side of the body is characteristic of a heart attack. Facial weakness and slurred speech can occur in both types of stroke.

Question 11

Whilst talking to your grandmother she suddenly starts behaving as if she is drunk: her speech becomes slurred and she cannot stand up. After a few minutes, her behaviour starts to return to normal and there are no lasting effects. You take her to Accident and Emergency and are told by the doctor you see that she has had a(n):

a.	 haemorrhagic stroke

b.	 ischaemic stroke

c.	 silent stroke

d.	 transient ischaemic attack

Answer 11

d

She has had a transient ischaemic attack (TIA), which is also known as a mini-stroke. TIAs results from a brain blood vessel becoming blocked for a short period (during which time the patient experiences symptoms similar to a “proper” stroke). When the blockage clears from the blood vessel, the symptoms will resolve. A TIA can be regarded as a warning that the patient will eventually have a completed (full) stroke, so in this situation, it would be important for your grandmother to be treated with aspirin or statins to reduce that risk.

Question 12

Excitotoxicity following an ischaemic event happens largely because glutamate release becomes subject to:

a.	 feed-forward regulation

b.	 lack of feedback

c.	 negative feedback

d.	 positive feedback

Answer 12

d

Low oxygen levels mean that cells cannot maintain their resting membrane potential and become depolarized, losing control of their intracellular calcium concentration. Increased calcium in the cytoplasm triggers the release of glutamate, which can act upon, and depolarise neighbouring cells. These cells in turn, release their own glutamate and so on. Increased calcium also activates an array of enzymes such as phospholipases, which ultimately leads to the destruction of the cell.

Question 13

When the blood supply is restored following an ischaemic stroke, a second phase of brain damage can occur. This type of damage is termed:

a.	 energy failure

b.	 excitotoxicity

c.	 reperfusion injury

d.	 thrombolysis

Answer 13

c

When blood begins to flow back into ischaemic tissue (i.e. the tissue is reperfused), instead of normal function being restored, an inflammatory response is initiated via mediators such as interleukin-1. Oxidative stress can also occur. Oxidative stress refers to the uncontrolled production of reactive oxygen species (ROS) and can result in damage to many different cellular components.

Question 14

Animal studies demonstrate neuroprotection in ischaemic stroke if the brain is cooled. What is thought to be a good temperature to maintain animals at to achieve this effect?

a.	 4°C

b.	 12°C

c.	 24°C

d.	 32°C

Answer 14

d

If you go lower than 32°C it is difficult for the animals to tolerate the cooling for extended periods of time.

Question 15

In this question there are three correct options and one incorrect. Select the three correct answers.

Which of the following factors increase your risk of having a stroke?

[mark all correct answers]
a.
Northern European heritage

b.	 Obesity

c.	 Age

d.	 Atrial fibrillation

Answer 15

b, c, d

Question 16

In this type of question there are three correct and one incorrect options. Select the three correct options.

Which of the following are mediators of neuronal damage in ischaemic stroke?

[mark all correct answers]
a.
Calcium ions

b.	 Free radicals

c.	 Glutamate

d.	 Glutathione

Answer 16

a, b, c

Glutathione is actually protective in stroke: it is an antioxidant and scavenges reactive oxygen species.