Blood supply and stroke Flashcards
What do the internal carotid arteries supply?
- Anterior 3/5 of cerebrum
* Diencephalon
What are the main branches of the internal carotid arteries?
- middle cerebral artery (MCA)
- Anterior cerebral artery (ACA)
- Perforating branches (striate, lenticulochoroidal arteries etc.)
What do the vertebrobasilar arteries supply?
- Brainstem
- Cerebellum
- Posterior 2/3 cerebrum
What are the main branches of the vertebrobasilar arteries?
- Cerebellar (PICA, AICA, SCA)
- Pontine
- Posterior cerebral arteries
- Striate and thalamic branches
What supplies the brainstem?
- posterior circulation:
- Posterior cerebral
- SCA (superior cerebellar)
- Basilar
- AICA
- PICA
What are the main signs of stroke?
- Sudden onset
- Facial asymmetry
- Speech disturbance (dysphasia)
- Asymmetrical weakness in muscles
What is a stroke?
- Interruption of the blood supply to a focal part of the brain causing loss of neurological function
- Symptoms last over 24 hours or lead to death with no apparent cause other than that of vascular origin
What is a transient ischaemic attack?
- Same cause as stroke
* Symptoms lasting less than 24 hours
3 types of stroke
- Haemorrhagic
- Ischaemic
- Subarachnoid haemorrhage
What are the causes of haemorrhage stroke?
- Hypertension
- Tumour
- Bleeding disorders
- Vascular malformation
- Amyloid pathology
What are the causes of ischaemic stroke?
• Small vessel disease
- lacunar stroke (smokers)
• Hypoperfusion - blood flow related
• Large vessel atheroma/thrombosis - plaques in vessels
• Cardio-embolism - myocardial infarct affecting the endocardium/atrial fibrillation can cause ischaemic stroke
What is a lacunar stroke?
- Type of ischaemic stroke in deep areas when small perforating vessels get blocked (usually basal nuclei or internal capsule)
- Gaps/cavities are left in the brain when necrotic tissue is resorbed
Describe the progression of ischaemic stroke
- Core is where the permanent damage is
* Penumbra surrounds the core, neurones in the penumbra can be saved
What is the watershed area?
- The most vulnerable area, if blood flow is reduced, theses areas will die first:
- Cortical border zone
- Internal border zone
- Cortical border zone
What does FAST stand for?
• Face - has it fallen on one side?
• Arms - can they raise both arms and keep them there?
• Speech - is it slurred?
• Time - call 99
(• check their glucose - can mimic a stroke)
Describe examination in vascular neurology
- BP and pulse measurement in 2 arms
- Level of consciousness
- Cardiac and carotid bruits
- Blood glucose level
- Neck stiffness/meningism
- Abnormal or involuntary movements
- Any seizure like activity
- Skin rash/infarcts e.g. vasculitis, papular rash
- Specific neurological - eye movements, speech, visual fields, inattention, motor and sensory, gait assessment
What are the different types of stroke classfications?
- Oxford community stroke project: clinical symptoms
- TOAST classification: mechanism
- Carotid and vertebrobasilar territory
For OCSP classification what do you need to check and when?
- Pattern at the time of maximum deficit
- Motor/sensory pathways (muscle power, sensation)
- Visual pathways (field of vision)
- Higher cortical functions (speech, spatial awareness)
- Brainstem funcitons (swallowing, eye movement)
What are the classifications of the OCSP classification?
- Total anterior circulation syndrome (TACS)
- Parietal Anterior Circualtion Syndrome (PACS)
- Lacunar syndrome (LACS)
- Posterior circulaitokn syndrome (POCS)
Lacunar syndrome
- Pure motor
- Pure sensory
- Sensorimotor
- Ataxic hemiparesis
Posterior circulation syndrome
- Brainstem
- Cerebellar
- Isolated homonymous hemianopia
Total Anterior Circulation Syndrome
• Triad of:
- hemiparesis
- Dysphasia
- Homonymous hemianopia
Partial anterior Circulation syndrome
- 2 of the features of TACS or:
- Dysphasia
- Parietal lobe signs (e.g. inattention, agnosia, apraxia, agraphaesthesia, Alexia)
Describe the ABCD^2 assessment
- 7 point to predict early stroke post TIA
- Age >/60 =1
- Blood pressure: systolic >140 and/or diastolic >/90 =1
- clinical features: unilateral weakness= 2; speech disturbance w/o weakness = 1
- Duration of symptoms in minutes: >/60=2, 10-59= 1
- Diabetes = 1
What can mimic a stroke?
- Seizure
- Syncope
- Sepsis
- Space occupying lesion
- Somatisation
- hypoglycaemia
What are the red flags?
- No history
- No risk factors
- Young age
- Seizure
- Unusual headaches
What are the common risk factors of stroke?
- Hypertension
- Ischaemic heart disease
- Peripheral vascular disease
- Transient ischaemic attack
- Diabetes mellitus
What investigations should be carried out if there is a suspected stroke?
- Good history and examination
- ECG/Holter
- Cholesterol/autoimmune and thrombophilia screen
- Carotid doppler
- CT brain/MRI brain
- Cerebral angiography
What are the indications for an urgent head scan?
- Depressed level of consciousness
- Unexplained, progressive or fluctuating symptoms
- Papilloedema, neck stiffness or fever
- Severe headaches at onset
- History of trauma prior to onset
- Indication of thrombolysis or anticoagulation
- History of anticoagulant treatment or known bleeding tendency
In which type of stroke can mass effect be seen
Ischaemic stroke, after 4 hours
Secondary prevention drug treatment
- Antithrombolytics: clopidogrel or Aspirin and Dipyridamole (in atrial fib. Warfarin or NOAC)
- Anti lipids if total cholesterol is >4.0mmol/l, treat with a statin
- Target BP< 130/80 with a calcium channel blocker or thiazide diuretic or an ACE inhibitor
Describe the management of a subarachnoid haemorrhage
• CT brain/ lumbar puncture if CT normal, look for bilirubin and xanthochromia, cerebral angiogram • Management: - intubate if severe hypoxaemia - 3l of NaCl per 24 hours 0.9% - Keep MAP<130mmHg - Nimodipine - Codeine or tramadol for pain - Phenytoin if seizures have occurred - Antiemetics
Describe the blood supply of the medulla
- Medial: Anterior spinal
- Lateral posterior: vertebral artery
- Lateral anterior: Posterior inferior cerebellar
Describe the blood supply of the pons
- Medial: Basilar
- Lateral posterior: branches of the basilar
- Lateral anterior: Branches from the basilar and anterior inferior cerebellar
Midbrain blood supply
- Medial: Basilar, posterior cerebral, posterior communicating
- Anterior lateral: Branched from the posterior cerebral
- Posterior lateral: posterior cerebral, superior cerebellar
