Background information on Acute Stroke

Background information on Acute Stroke

What is a stroke?

A stroke is similar to how a heart attack stops the blood going to the heart -but for the brain. So like a ‘brain attack’ or a sudden ‘strike’ to the brain. Depending where the blood is stopped from getting to in the brain, depends on what effect it’ll have on the person. Once deprived of blood and therefore oxygen, parts of the brain begin to die after only a few minutes and so a stroke  is classed as a medical emergency.

Otter hospital

Causes of stroke

Ischaemic– blood vessel blocked by clot, stopping flow. Most common 85% cases. Clot could be due to narrow arteries, clot in artery, or clot travelling from somewhere else to the brain. Brain area that dies is called an infarct‘the naughty clot “schemes” to injure the brain’

OR

Haemorrhagic-blood vessel ruptures and blood leaks out. 15% cases. The leaking blood building up also causes extra pressure inside the skull. Leak could be due to high blood pressure or a weakened/bulging blood vessel wall (‘aneurysm’)…‘haemorrhage of blood’

 

Brain anatomy

Where the brain dies dictates which abilities will be lost. The right side of the brain controls the left side of the body, and vice versa.This means an injury to the left side will affect movement in the right side of the body.

Areas of the brain

The different areas of the brain control different tasks:

Frontal lobe (front)

  • planning
  • initiation and motivation
  • problem-solving
  • voluntary movement
  • appropriate socialising & interactions with others
  • personality/emotions/behaviour
  • Broca’s area -produce spoken language

Parietal lobe (top middle strip: like saddle on a horse on the prairies, you experience a lot of unusual sensations as you ride through the desert like heat, smells, sore bum etc!)

  • perception: processing sensation from touch/pressure/temp/pain
  • Wernicke’s area-understand received language: spoken & written

Occipital lobe (back: why a blow to back of the head often affects vision)

  • processing visual input from eyes

Temporal lobes (front either side:where your temples are located, a lot of old artefacts are stored (memory) and labelled (different things identified) in an old temple)

  • distinguishing different smells & sounds apart
  • visual & verbal memory (for words & names)
  • attention

Cerebellum (bottom underneath, Latin for ‘little brain’)

  • controls smooth (involuntary) muscles like gut or maintaining balance

Brain stem (stick at bottom, joining onto spinal cord)

  • basic life support functions eg breathing, heart

Diagnosis of stroke

  • Medical history
  • Physical examination of symptoms, eg:
    • asking patient to show their teeth (checking for asymmetric facial droop)
    • asking patient to raise feet or arms (checking for asymmetric motor control to lower or upper limbs)
    • asking patient if they can feel touch on one/both limbs that they cannot see (checking for reduced sensation or bilateral extinction)
    • asking patient to name items nearby (checking for slurred speech, vision loss, memory impairment or perceptual deficits eg visual agnosia or apraxia)
    • asking patient what the date/time is, and where they are (orientation)
  • Brain scan=CT or MRI scan (only way to identify if damage caused by blockage or bleed)

 

On a CT scan, denser structures = whiter (like bone) and less dense areas = darker (blood, tissues or air). An ischaemic clot itself can sometimes be seen as a bright white speck, whereas the spongy dead brain tissue (infarct) is less dense than healthy brain so  = darker patch around the clot site, appearing 3-12 hours after the stroke.

The blood leak from a haemorrhage coagulates (liquid blood becomes solid) and so shows up immediately on a scan as whiter. As the clotted blood breaks down, after 1 week it darkens to the same grey shade as the healthy brain, and after 2-3 weeks it appears as darker grey patch than the brain (as the space occupied by dead brain tissue is replaced by cerebrospinal fluid).

CT scans- ischaemic and haemorrhagic strokes
Images from STARS training at http://www.strokecompetencies.org

Symptoms of a stroke occurring may include arm/leg feeling weak or heavy, tripping over/collapsing, facial weakness, drooping mouth/slurred speech. FAST helps you to remember what to look out for. These symptoms are a medical emergency and attention should be sought immediately. Don’t give them anything to eat or drink as their swallowing may be impaired.Don’t give anyone with a suspected stroke aspirin as you don’t know which type of stroke has happened- if it is a haemorrhagic then preventing clotting with aspirin will actually make it worse.

Early treatment is crucial in limiting the extend of permanent/severe disability. Treatment drugs (differ according to blockage/bleed causation) are ideally given within 3 hours. In the days following a stroke there are additional risks from another stroke, chest infections (due to swallowing difficulties) or epileptic seizures.

Different types of stroke

There are Ischaemic (clot) or Haemorrhaghic (leak) caused strokes. A TIA or Transient Ischaemic Attack is a ‘mini stroke’ where stroke symptoms are seen but they resolve themselves straight away, because the blood flow to the brain was only interrupted temporarily. There is a high risk someone will go onto have a full stroke after having a TIA so they must seek medical attention immediately.

Oxford/Bamford Classification describes the different types of stroke (using visible symptoms to  work out the brain area affected):

  • Total anterior circulation stroke (TAC)
  • Partial anterior circulation stroke (PAC)
  • Lacunar stroke (LAC)
  • Posterior circulation stroke (POC)

The type of stroke is then coded by adding a final letter to the above:

  • I – for infarct (e.g. TACI)
  • H – for haemorrhage (e.g. TACH)

 

NIHSS  (National Institute for Health Stroke Scale) describes the severity of stroke symptoms:

Score Stroke severity
0 No stroke symptoms
1-4 Minor stroke
5-15 Moderate stroke
16-20 Moderate to severe stroke
21-42 Severe stroke

Risk factors for stroke

  • + smoker  (doubles the risk)
  • + diabetes  (doubles the risk)
  • + over 55
  • + lack of exercise
  • + excess alcohol
  • + cocaine use
  • + obesity/diet high in cholesterol fat causing weight increase
  • + HTN/hypertension (high blood pressure)
  • + high cholesterol level
  • + diet high in salt & fat causing high BP/blood lipids
  • + previous TIA or stroke
  • + heart attack or irregular heart beat (AF/atrial fibrillation)
  • – vigorous exercise
  • – healthy diet, fruits etc
  • – moderate/low alcohol

 

Effects of stroke

Stroke is the biggest cause of adult disability, and third common cause of death.

Common symptoms while a stroke is occurring are slurred speech, disturbed vision in one/both eyes, feeling weak/numb/pins&needles on one side of the body, or a drooping mouth.

Common effects after a stroke are:

  • altered level of consciousness
  • loss of motor coordination (ataxia)
  • inability to sequence muscles correctly (apraxia)
  • limb weakness
  • paralysis down one side of the body (hemiplegia)
  • pain
  • abnormally floppy or tense muscle tone affecting movement
    • spascity- v.high muscle tone tightness & stiffness limiting movement
    • clonus- rapid involuntary leg movement esp calf
    • contractures- stiff arm joints, painful to move
    • subluxation- joint dislocation esp shoulder due to weak muscle tone
  • loss of sensation (agnosia)
  • vision changes eg loss of each L/R half of vision fields (homogynous hemianopia)
  • skin integrity changes
  • odema- swelling when weak limb is left dangling
  • speech changes eg slurred speech (dysARthria), problems producing or understanding speech (dysphaSia)
  • mouth problems
    • difficulty swallowing (dysphaGia)
    • drooling
    • loose fitting dentures due to lack muscle control
    • food stuck/left in cheeks on affected side
  • incontinence
  • asymmetrical face, altered self-body image
  • behavioural/personality changes
  • altered thinking processes, eg inability to recognise objects (agnosia), attention, memory, problem-solving or perception
  • feeling emotional and unable to control (emotionally labile)
  • increased risk of thrombosis (clotting)
  • difficulties in moving and impaired insight into own safety
  • difficulties carrying our ADLs

 

Rehabilitation following a stroke

A stroke can affect ADLs such as washing, dressing, grooming, driving, work, or leisure/socialising. In order to overcome challenges in carrying out these activities, the OT will need to explore which aspects the patient finds are causing difficulty, establish what a reasonable achievement for their current/predicted level of recovery will be, and break down the goal into small, manageable steps.

Indicators for good recovery include being younger, continence, mild symptoms, rapid improvement after stroke. Signs indicative of a poor recovery are a pre-morbid disability, incontinence, dysphagia, aphasia, or cognitive problems.

Assessments used for stroke patients include BADS, MOCA, Frenchay orientation test, Rivermead Perceptual Assessment Battery, Berg Balance…

Normal movement patterns 

The Bobath concept is an approach to neurological rehabilitation that is applied in patient assessment and treatment (eg stroke or cerebral palsy). The goal is to promote motor learning to achieve efficient motor control in various environments, thereby improving participation and function in ADLs. This is done through specific patient handling skills to guide patients through the initiation and completion of intended tasks.

Bobath techniques used by OTs in stroke rehabilitation include therapeutic handling, facilitation and inhibition.

 

Moving & Handling of stroke & neuro patients

Stroke patients can be unaware of their limitations in moving themselves after a stroke, due to changes in their vision, limb weakness, cognitive perception etc. They can believe they are more able than they are which could cause them to injure themselves when moving about.

  • If a patient says they are able to do something, it is best to establish their ability yourself first- this could be through their Care Plan/medical records, other staff, or their carer.
  • Don’t pull by the arm, as weak shoulder muscles can let the shoulder partially pop out of the socket & cause injury (called subluxation of the shoulder). For this reason the stroke-affected arm should always be propped up by pillows and not left to hang.

 

Guidelines & policies influencing acute Stroke care

  • BASP- British Association of Stroke Physicians
    • produce national stroke standards for all stroke teams to achieve consistency of care
  • RCP- Royal College of Physicians
    • stroke guidelines (used in creating NICE guidelines)
  • NICE- National Institute for Clinical Excellence
    • guidelines based on evidence that outline the most effective interventions for particular medical problems
  • SSNAP – Sentinel Stroke National Audit Programme– this records data on key clinical requirements for patients who have been admitted at A&E with a stroke. There are requirements for lots of different departments; the ones that apply to OT are below (the department it’s relevant to is in brackets):
    • Proportion of patients who spent at least 90% of their stay on stroke unit (whole stoke unit/MDT)
    • Proportion of patients reported as requiring occupational therapy (OT)
    • Median number of minutes per day on which occupational therapy is received (OT)
    • Median % of days as an inpatient on which occupational therapy is received (OT)
    • Compliance % against the therapy target of an average of 25.7 minutes of occupational therapy for all patients [Target = 45 mins of occupational therapy + 5/7 days per week + 80% of patients] (OT)
    • Proportion of applicable patients who were assessed by an occupational therapist within 72h of clock start (OT/MDT)
    • Median time between clock start and being assessed by occupational therapist (hours:mins) (OT)
    • Proportion of applicable patients receiving a joint health and social care plan on discharge (whole stroke unit/MDT)

[NOTE: median is the middle number in set of data, used to remove effect of any high or low outliers which would skew the data]

Recent articles on acute Stroke

  • AVERT phase II and III trial

+++++++++++++++++++++

Sources:

STARS training at http://www.strokecompetencies.org

Advertisements