Enquiry 5, Stroke Part 1

Question 1

Why are some parts of the body depicted larger then others in the motor and sensory homunculus?

Answer 1

For both the motor and sensory cortex the neurons are laid out in a specific way and is generally depicted as a homunculus, with more neurons present in the areas appeared larger . For example in the motor cortex the face and hands have a larger depiction indicating there are more neurons travelling to these areas of the body as compared to the elbow.

Question 2

what are the primary functions of the meninges and where are they found?

Answer 2

the meninges are found below the skull. their primary functions are to provide stabilisation of the brain within the skull, shock absorption and to carry the blood supply to the entire brain

Question 3

what are the primary functions of the meninges?

Answer 3

their primary functions are to provide stabilisation of the brain within the skull, shock absorption and to carry the blood supply to the entire brain

Question 4

what are the meninges made up of and where are they found?

Answer 4

the meninges are found below the skull. there are three layers of meninges working together: - the dura mater - arachnoid mater - pia mater

Question 5

describe the dura mater and its function

Answer 5

is a tough fibres covering with one layer attached to the periosteum of the skull. there are spaces throughout the dura where it extends deep into the cranial cavities creating dural folds and helping to secure the brain within the skull.

Question 6

describe the arachnoid mater and its function

Answer 6

is below the dura. this layer contains lymphatic fluid helping to decrease friction and below this is the sub arachnoid space, which contains a web like collection of collegen and elastin. in the space you will also find cerebral spinal fluid CFS.

Question 7

describe the pia mater and its function

Answer 7

is the inner most layer. it is a delicately thin layer attached to the brain and spinal cord. the layer is highly vascularised and the blood supply to the brain runs along the top of this layer.

Question 8

where and what are the sinuses within the skull?

Answer 8

sinuses are areas within the dura folds where large veins can be found which collect blood and circulate it back to the heart e.g. the superior sagittal sinus.

Question 9

what is the function of CSF?

Answer 9

the cerebral spinal fluid plays a key role for shock absorption and is a transport system for dissolved gases, nutrients, chemicals and waste. the brain and spinal cord have numerous cavities (sinuses, sub arachnoid space) that are filled with csf.

Question 10

In the brain the cavities, filled with csf, are interconnected and create a passage way for the csf to circulate. this passage way branches into four chambers, known as the ventricles. Explain how each ventricle is connected and their structures within the brain.

Answer 10

Each cerebral hemisphere has a large lateral ventricle which are connected via the third ventricle in the diencephalon (near the thalamus and hypothalamus). the third ventricle is connected to the fourth ventricle, located in the pons and medulla oblongata, via a cerebral aquaduct. these structures can be impacted by stroke. *picture

Question 11

where in the brain is the blood supply found?

Answer 11

found along the top of the pia mater

Question 12

what causes a stroke?

Answer 12

happens when blood flow to the brain is cut off. when brain cells are staved of oxygen they become damaged causing a stroke. (Insult within the brain).

Question 13

symptoms following a stroke?

Answer 13

Face Arms Speech Time - drooping face - weakness in arms or legs - difficulty speaking - confusion - changes to vision - loss of balance - memory loss

Question 14

what is an ischaemic stroke?

Answer 14

make up about 85% of all stokres. caused by a blockage in one or more of the arteries that supply blood to the brain.

Question 15

how can the circle of willis help to prevent a stroke?

Answer 15

the circle of willis may provide collateral circulation and may help to prevent cell death (from lack of o2 in blood).

Question 16

what causes an ischaemic cascade? and what damage does this cause?

Answer 16

as cell death occurs the ischaemic cascade begins and the amount of cell death and damage becomes evident. as cascade develops, significant swelling develops in brain causing compression to near by areas in brain like the ventricles.

Question 17

what does an ischaemic stroke and lateral ventricles look like in a CT scan?

Answer 17

in ct scan darkened area shows the ischaemic stroke. left and right of midline is a black linear structure which is a lateral ventricle. healthy brain should present both symmetrical ventricles (looks like a butterfly). compression to the lateral ventricle (in an ischaemic stroke) causes csf to move out of the space and increases inter cranial pressure.

Question 18

what causes an embolic stroke?

Answer 18

embolic stroke occurs when a clot is formed in another area of the body and travels to the brain. they occur in the heart or arteries of the chest and neck. they break free and travel throughout blood stream into the brain. when they reach a blood vessel they cant pass through and the clot is stuck which stops the blood flow. this blockage is called an embolus.

Question 19

how to treat an embolus?

Answer 19

when these clots occur the use of clot busting drugs (e.g TPA), or neuro surgery (e.g Thrombectomy) can help minimise the effects.

Question 20

describe the removal of an embolus through a thrombectomy.

Answer 20

Thrombectomy - mechanical removal of a clot. done by inserting a catheter into the femoral artery. when the clot is found it is entrapped by the catheter and then removed.

Question 21

what are the negative effects of TPA

Answer 21

TPA can result in significant bleeding and the selection criteria to use this drug is very specific.

Question 22

what is a haemorrhagic stroke?

Answer 22

Is when bleeding occurs within the brain. Causes lots of tissue damage as the area surrounding the bleed/haematoma have diminished blood flow and oxygen. there is an increased pressure from the haematoma itself to the local brain tissue resulting in infarction (tissue death).

Question 23

what is the survival rate of an haemorrhagic stroke compared to an ischaemic stroke? How common is it?

Answer 23

around 1 in 10 patients who have a haemorrhagic stroke die before reaching hospital. the risk of death in the first 3 months is much higher than that of an ischaemic stroke. about 15% of all strokes are haemorrhagic.

Question 24

how is a haemorrhagic stroke seen in a CT scan?

Answer 24

The CT scan for an intrecerebral (within brain) hemorrhage - areas in white indicate blood or fluid leaking from haemorrhagic stroke, - darkened areas indicate ishaemia or cell death as said before. Haemorrhagic stroke can also compress the lateral ventricles and increases the inter cranial pressure, limiting the flow of csf to the brain and spinal cord.

Question 25

what is a sub dural haemorrhage/haematoma?

Answer 25

is bleeding within brain in the sub dura space and normally occurs from traumatic brain injury.

Question 26

there are two types of haemorrhages, inter cranial (bleeding within skull) and subarachnoid haemorrhage. What is a subarachnoid haemorrhage?

Answer 26

remember the subarachnoid space is below the arachnoid mater and above the highly vascularised pia mater. Most common causes of this haemorrhage is from aneurysm rupture, arterial venus malformation or head injury.

Question 27

how to treat a subarachnoid haemorrhage?

Answer 27

life threatening and neuro surgery needed to stop bleeding. If bleeding and pressure is too intense then craniotomy (drilling of hole into skull to relieve pressure) or craniectomy (removal of part of skull) will be required to manage this.

Question 28

what are the symptoms of a subarachnoid haemorrhage?

Answer 28

generally no warning signs but can occur during physical exertion and symptoms can come on suddenly which need to taken care of immediately. these include severe headache, light sensitivity, blurred or double vision, loss of consciousness and neck stiffness.

Question 29

what are aneurysms?

Answer 29

are a bulge in a blood vessel due to a weakened vessel wall. as blood passes through the weakened vessel, the wall bulges outward like a ballon, due to the increased blood pressure on the inside of vessel.

Question 30

where do aneurysms occur?

Answer 30

occur in the brain and in arteries that transport blood away from the heart, like the abdominal aorta.

Question 31

how to identify an aneurysm?

Answer 31

No signs or symptoms unless it bursts. if they burst it results in a sub arachnoid haemorrhage, and the person will present with the symptoms of that haemorrhage (said already).

Question 32

How to treat an aneurysm if discovered before a rupture?

Answer 32

If aneurysm is discovered prior to rupture neurosurgery can be performed and a coil or clip is placed to correct the aneurysm. - Coil Platinum coils are placed in aneurysm via a catheter, to create a blockage in the artery, preventing rupture. - Clipping A metal clip is attached to the walls of the aneurysm, bringing them closer together, allowing vessels to heal and wall to strengthen over time.

Question 33

how to identify an aneurysm.

Answer 33

aneurysms can be seen on an angiogram as a saccular/berry (most common type of brain aneurysm) or a fusiform

Question 34

what is an arteriovenous malformation (AVM)?

Answer 34

is an abnormal connection of the arteries and veins where the vessels by pass normal brain tissue and diverts blood from the artery directly to the veins. this means that the brain tissue does not get the oxygenated blood that it should be getting as the arteries travel through. Most AVMs are congenital (present from birth) and can occur anywhere in the brain.

Question 35

effects of an AVM on patients?

Answer 35

more than 50% of patients with an avm will have an inter cranial haemorrhage at some point. 20-25% will have focal seizures And 15% will have headaches. 1/3 of patients who have a bleed that developed from an AVM will develop permanent brain damage. if avms rupture they are extremely life threatening depending on the location of the avm.

Question 36

what does an AVM look like?

Answer 36

*picture

Question 37

As physios it is important to know what medical management patients have gone through following stroke. What medical management is needed for Ischaemic and Haemorrhage stroke?

Answer 37

Ischaemic stroke: 1. thrombolysis is the use of blood thinning or clot busting drugs for clots in the brain e.g. TPA tissue plasminogen activator (CT scan initially to rule out haemorrhage before providing treatment for ischaemic stroke with the use of TPA because of the risk of bleeding being so high. - most beneficial in the first 3 hours 2. Thrombectomy - mechanical removal of thrombis or embolis 3. Blood thinning medication - aspirin High blood pressure and cholesterol management medication - to decrease the risk of having another stroke - can be taken for life Haemorrhage stroke: 1. strict blood pressure management - <140 systolic BP , required to prevent worsening bleeding. Need to know patients BP before session, during and after, do we need to stop the session? - Craniotomy/craniectomy perfromed. may need a helmet to protect brain if had a craniotomy when the patient is standing up/working on balance etc, to decrease risk of falling and further damage. - sometimes skull can be put back in, depending on BP management but it is a risky procedure and need evaluation by neuro surgeon before and need physio therapy following that procedure.

Question 38

What are some common motor impairments post stroke?

Answer 38

It does depend on type of stroke or which artery has been affected but some examples: - Ataxia (incoordination of movement - caused by impairment to cerebellum) - Impaired selective control (inability to isolate 1 or two muscle groups from activating) - Poor knee extension and proximal hip control - Inability to dissociate upper and lower trunk - Inability to hold/find midline - Shuffled gait pattern - Decreased proximal trunk control (less stability in upper part of trunk) - Increased tone in upper/lower limb - Increased extensor tone in neck - Scapular instability, can cause scapular winging. (because trunk and abdominals are weak due to stroke can cause winging)

Question 39

What are some non motor impairments following stroke?

Answer 39

• Neglect (visual or spacial). Generally occurs along side a right mca stroke (unaware of left side so treatment on left side) - Apraxia (inability to plan through a task) - Visuo-spatial disorders (controversive pushing) - Impulsivity - Lack of insight (unaware on what can and cant do due to sudden stroke, so need to educate) - Impaired sensation