Stroke

Stroke is an Acquired brain injury (ABI)

Definition: Stroke or CVA “Cerebrovascular Accident” – a cardiovascular condition where blood supply to the brain is disrupted.

An infarction with brain cell death.

Types of strokes:

Transient ischaemic attacks (TIA). “Mini strokes”.

  • Ischaemic (occlusive) strokes – make up 70-80% of all strokes – thrombotic and embolic blockage strokes. (often smaller area of damage)

  • Haemorrhagic strokes. 20-30%. Cerebral & subarachnoid haemorrhages (often result of TBI) (often larger area of damage due to increased pressure in brain)

The most common type of stroke syndrome is caused by infarction around the middle cerebral artery, with contralateral weakness, sensory loss, hemianopia & either language disturbance (L hemisphere) or impaired spatial perception (R hemisphere).

Ischaemic strokes

  • Brain injury caused by inadequate blood supply resulting in decreased O2 & nutrients to brain tissue.

  • Within minutes to hours, an area of irreversible damage develops – infarct core.

Ischaemic penumbra – area that surrounds the infarct core but is potentially viable brain tissue if blood flow is restored quickly.

Management of Ischaemic strokes - Thrombolysis

  • Aims to re-establish blood supply to the ischaemic penumbra.

The thrombotic drug used in acute treatment of ischaemic strokes is the recombinant tissue-type plasminogen activator, PLAT or tPA (Alteplase), which breaks down the clot. (high risk of bleeding so NOT used in hemorrhagic strokes)

Haemorrhagic Strokes

Causes of Hemorrhagic Strokes:

  • Hypertension (80% due to HTN)

  • Cerebral amyloid angiopathy (neuro condition where amyloid protein builds up on the walls of the arteries in the brain and weakens them so burst).

  • Aneurysm

  • Arteriovenous Malformation (AVM) blood vessels tangled from birth.

  • Neoplasm (tumour)

  • Coagulation disorder e.g. haemophilia.

Intracerebral haemorrhage – deeper - occurs within the brain substance, but a rupture through the cortical surface may produce associated subarachnoid bleeding.

They increase pressure in the brain – which can cause hypoxia.

Subarachnoid haemorrhage – bleeding from the intracranial vessels into subarachnoid space. - increases pressure in brain

With both kinds of haemorrhage there is leakage from small intra-cerebral arteries into the brain parenchyma.

Most common sites for hemorrhagic stroke:

  • Thalamus *

  • Putamen *

  • Cerebellum * – ***all involved with voluntary movement and coordination.

  • Brainstem – controls respiration and heartbeat

Management of Haemorrhages

  • Conservative approach – anti-fibrinolitic agents (e.g. Factor 7A, Vit K) which delay clot dissolution around the ruptured aneurysm but outcomes may be poor.

  • Operative removal of intracerebral haematomas through a craniotomy flap.

  • Aneurysm clipping, trapping, coiling, balloon remodelling.

  • Medications: anti-convulsant (e.g. diazepam); anti-hypertensives (e.g. B-blockers); osmotic diuretics to reduce intracranial pressure (e.g. Mannitol)

General Stroke Symptoms

Acute onset of neurologic deficits, such as:

  • Memory loss

  • Hemiparesis (weakness) or hemiplegia (paralysis) AND Hemisensory loss

  • Monocular or binocular visual loss and other visual field deficits

  • Diplopia (Double vision)

  • Dysarthria - usually with bilateral lesions; the speech has a halting jerking quality (scanning speech or staccato speech).

  • Ataxia - an ataxic gait with a broad base, uncoordinated movement; the patient falters to the side of the lesion; also slurred, uncoordinated speech

  • Vertigo

  • Aphasia (expressive or receptive) – not able to express self with words correctly, struggle with communication

Accompanied by sudden and severe headache, nausea and vomiting.

Results of stroke:

  • Physical problems

  • Cognitive problems: nice to violent behaviour, lack of attentions/ arousal, memory issues

  • Behavioural problems

Common problems

  • UMN motor deficits e.g. Hemiparesis or hemiplegia (cerebral hemisphere & lacunar infarct)

  • Bilateral and asymmetric deficits (brain stem infarct)

  • Spasticity & increased muscle tone e.g. bilateral “scissoring”

  • Clonus

  • Contractures.

  • Ataxia.

  • Pathological reflexes

  • Poor motor control.

  • Chronic balance & gait deficits, increased falls risk

Affected side neglect:

• Affected side neglect – also called hemiagnosia, hemineglect, unilateral neglect, spatial neglect or neglect syndrome.

• Loss of sense of position, attention to or awareness of the affected side.

• Visual symptoms:

The stroke injures the optic nerve, (information from eyes to the brain). Called a "visual field deficit" or "hemianopsia," - the person only sees out of a part of each

eye, instead of the whole eye.

• Sensory symptoms: Loss of sensation in the face, arm or leg. May be temporary, or more severe.

• Perceptual symptoms: The inability to take in information & make sense of the surrounding world. Inability to sense the position of the affected side.

Spasticity

  • Combination of paralysis, increased tendon reflex activity and hypertonia.

  • Loss of inhibition of motor neurons, causing excessive velocity-dependant muscle contraction. This leads to hyperreflexia, an exaggerated deep tendon reflex.

Signs of spasticity: flexed elbow, bent wrist, pronated forearm, clenched fist, thumb in palm.

Strengthen muscles across the joint from spastic muscles:

  • elbow extensors,

  • forearm supinators,

  • wrist extensors,

  • hip extensors and abductors,

  • knee extensors,

  • ankle dorsiflexors.

Stroke Effects on Exercise Responses

  • ↓ functional & aerobic capacity (65 – 74%).

  • ↓ VO2peak (up to 50%) & ↑ sub-maximal VO2.

  • Only 20 – 35% of patients can achieve 85% age-predicted max HR. Higher submax HR.

  • ↓ exercise efficiency.

  • Ventilation / respiratory problems.

  • ↑ fatigue @ lower workloads.

  • Balance, posture, gait, motor skill, muscle recruitment problems.

Exercise Assessments

High CVD risk? Initial test with 12 lead ECG if possible

  • Low intensity exercise may not require formal ex testing but will require medical clearance.

Contraindications? Resting BP must be below 200/110mmHg.

  • Unstable angina & other CVD contraindications.

Aerobic testing modes: 6MWT, TM (should be client-specific), cycle (5-10 or 15 w/ stage), Shuttle walk test, arm ergo; 2 min Step Test.

Considerations: self-paced walk speed; TM support (harness or handrail); cycle support& foot/ hand straps; arm ergo; cognitive issues – understanding instructions; supervision (safety).

PRT: MMT; machine weights, isokinetic dynamometers (may be unable to isolate joint), TheraBand’s, free weight (for clients with adequate control)

Functional: Sit to stand; TUG; muscle endurance tests; balance, agility, and gait tests; functional ability tools.

Flexibility: goniometer, standard tests.

Recommended outcome measurements for EP’s:

Balance: Functional reach test, lateral reach test, step test (tapping in front of step), four square step tests.

Exercise capacity and Mobility: 6MWT, timed up and go, the high-level mobility assessment tool (HiMAT) or Tinetti tool.

Exercise: focus on the 4 R’s: Reactivity, …

There is a long answer Q in exam requiring clinical reasoning – maybe ex prescription for certain issue. E.g. stroke