Cerebral Infarction (clinical) Flashcards
Define stroke
Is a sudden onset of focal or global neurological symptoms caused by ischema or haemorrhage and lasting more than 24 hours
What is the two many causes of strokes
Ischaemic 85%
Haemorrhage 15%
Define Transient ischaemic attack
Term used when stroke symptoms resolve within 24 hours
Most TIAs last within 1-6mis
What is the causes of ischaemic stroke
Large artery atherosclerosis (e.g. Carotid)
Cardioembolic (e.g. atrial fibrillation)
Small artery occlusion (Lacune)
Undetermined/Cryptogenic
Rare causes:
-Arterial dissection
-Venous sinus thrombosis
What is the causes of haemorrhage stroke
Primary intracerebral hemorrhage
Secondary hemorrhage
- Subarachnoid hemorrhage
- Arteriovenous malformation
What is the cause of a primary intracerebral haemorrhage
Hypertension
What is the pathophysiology of stroke
Failure of cerebral blood flow to a part of the brain due ti interruption of the blood supply to the brain resulting in various degrees of hypoxia
Prolonged hypoxia becomes anoxia (no oxygen)
Anoxia then causes infarction leading to complete cell death and necrosis
This is a stroke
What further damage can result from a stroke
Oedema
Secondary haemorrhage
What affect does hypoxia have on the brain
Stresses the brains cell metabolism
Define ischemic penumbra
the penumbra is the area surrounding an ischemic event “ischaemic core” such as thrombotic or embolic stroke
What is the non modifiable risk factors for a stroke
Previous stroke
Being old
Being male
Family history
What is the modifiable risk factors for a stroke
Hypertension
Smoking
Cholesterol (diet)
High BMI/obesity
Alcohol
Diabetes
Impaired cardiac function
Oral contraceptive
Hyper-coagulable states
What is the most important modifiable risk factor for stroke
Hypertension
as stroke risk is directly related to your blood pressure levels
How does hypertension increases your stroke risk
Chronic hypertension worsens atheroma and affects small distal arteries
What contributes to the LDL- Cholesterol deposition in the arterial wall
Hypertension
Smoking
Diabetes
What is involved in the anterior circulation
From: 2 x Internal carotid arteries
2 x Anterior Cerebral Artery (ACA)
2 x Middle Cerebral Artery (MCA)
What is involved in the posterior circulation
From: 2 Vertebral arteries
1 Basilar
3 pairs of cerebellar arteries
2 Posterior cerebral artery (PCA)
How does the arterial blood supply anastomose in the brain
Through the circle of willis via anterior and posterior communicating arteries
Where does the borderzone anastomoses occur
between peripheral branches of
anterior, middle and posterior
cerebral arteries
What is symptoms of arterial cerebral artery
Contra-lateral:
paralysis of foot and leg
sensory loss over foot and leg
impairment of gait and stance
What is potential symptoms of middle cerebral artery occlusion
Contralateral:
- paralysis of face/arm/leg
- sensory loss face/arm/leg
- homonymous hemianopia
Gaze paralysis to the opposite side
Aphasia if stroke on dominant left side
Unilateral neglect and agnosia for half of external space if non dominant stroke
What side of the brain is usually a dominant stroke
Left - as most people usually right handed
Would be right dominance if patient is left handed
What is the specific symptom of middle cerebral occlusion on the dominant (left) side -patient is right handed
hemiplegia - paralysis on one side of the body
homonymous hemianopia,
dysphasia - language disorder
What is the specific symptom of middle cerebral occlusion on non dominant stroke (right side)
- the patient is right handed
Left Hemiplegia
Homonymous hemianopia
Agnosia - neglect syndrome
- Visual agnosia
- sensory agnosia
- Anosagnosia (denial of hemiplegia)
- Prosopanosia (failure to recognise faces)
Where is Broccas area and wernickes area both located if patient is right handed
On left side - both found on dominant side of the brain
If patient is left handed and presents with a stroke with speech difficulties, what hemisphere is affected
Right hemisphere (as presents with right sided dominance due to left handedness)
What supplies blood supply to the basal ganglia
Middle cerebral artery with branches to smaller arteries
medial and lateral lenticulostriate
Where does a lacunar ischaemic stroke occur
In the small arteries suppling the basal ganglia
What is symptoms of lacunar stroke
Pure motor stroke
Pure sensory stroke
Dysarthria - clumsy hand syndrome
Ataxic hemiparesis
What is a lacunar stroke devoid of
Cortical signs
What does the posterior circulation supply
Brain stem
Cerebellum
Thalamus
Occipital and medial temporal lobes
What is the symptoms of brain stem dysfunction
Coma,
vertigo,
nausea/vomiting,
cranial nerve palsies, ataxia - loss of full body movement
Hemiparesis, hemisensory loss
Crossed sensori-motor deficits
Visual field deficits
What is the purpose of ischaemic stroke therapies
Restore blood supply.
Prevent extension of ischemic damage.
Protect vulnerable brain tissue
What is the treatment administrated for ischaemic stroke
Aspirin
Heparin
Tissue Plasminogen
Activator (TPA)
Thrombectomy
Stroke unit
What is the most effective stroke treatment
Thromboectomy
What is the 8 different components of a stroke unit
Clinical staff Stroke nurses Physiotherapists Speech and Language therapists Occupational therapists Dietitian Psychologist Orthoptist
What is a tissue plasminogen activator
Enzyme that helps dissolve blood clots
What is the strict criteria for tissue plasminogen activator
< 4.5 hours from symptom onset.
Disabling neurological deficit.
Symptoms present > 60 minutes.
Consent obtained
What is the exclusion criteria for IV tissue plasminogen activator
Anything that increases the possibility go haemorrhage
BP >185 systolic or >110 diastolic
Glucose <2.8 or > 22mmol/L
What is the disadvantages of tissue plasminogen activator
Hard to find the balance and not cause an over bleed
Benefit from TPA declines with time
What is the four classifications of stroke
Total Anterior Circulation Stroke (TACS)
Partial Anterior Circulation Stroke (PACS)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
What is presentation of LACS
+/- Motor (2/3 face, arm leg)
+/- Sensory loss (2/3 face, arm, leg)
What is presentation of PACS
+/- Motor (2/3 face, arm leg)
+/- Sensory loss (2/3 face, arm, leg)
Will have 1 of:
- Hemianopia
- Dysphasia
- Neglect
What is the presentation of TACS
+/- Motor (2/3 face, arm leg)
+/- Sensory loss (2/3 face, arm, leg)
Will have Hemianopia
and Dysphasia or Neglect
What is presentation of POCS
+/- Motor (2/3 face, arm leg)
+/- Sensory loss (2/3 face, arm, leg)
+/- Hemianopia/Dysphasia /Neglect
Brain stem or cerebellar signs
What are TIAs
Warning sign of a stroke - with 10% stroke recurrence within the first 2 weeks
What is an effective treatment for carotid artery stenosis to prevent a stroke occurring
Carotid endarterectomy
What is preventative treatment to reduce the relative risk of a stroke
Antiplatelets Antihypertensives Statins Endarterectomy Warfarin - for AF
What investigations occur for a stroke
Routine blood test
CT/MRI head scan
EEG
ECHO
Carotid doppler ultrasound
Cerebral angiogram/venogram
Hyper-coagulable blood screen
What is the gold standard investigation for stroke and why
CT
- quick
- can determine if ischaemic or hemorrhagic
How is biopsy useful in stroke investigation
Temporal artery biopsy can show giant cell arthritis
What can be misdiagnosed as a stroke
Post-ictal states (e.g. Todd’s paralysis)
Hypoglycemia
Intracranial masses
Vestibular disease
Bell’s palsy
Functional hemiparesis
Migraine
Demented patients with UTIs
What is the management of an acute stroke
Prevention of stroke recurrence.
Prevention of complications related to stroke.
Rehabilitation.
Re-integration into the community
Define lipoyhallnosis
Small-vessel disease in the brain, that due to the sensitivity of hypertension results in lacuna stroke
