Stroke

Stroke

1. Causes

   • Atherothrombosis (23%)
     • 30 to 50% are preceded by a TIA
     • Preferential location for atheromas
       • Aortic arch
       • Bifurcation of the carotid artery
         • Easily picked by doppler US
           • For the other vessels you can do CT angiography or MRI angiography
       • Carotid syphon
       • Bifurcation of the middle cerebral artery and the anterior communicating artery
   • Cardioembolic stroke (15%)
   • Pathologies of small vessels (lacunar stroke) (18%)
     • Basal ganglia and thalamus
     • Brainstem (particularly the pons)
   • Cryptogenic stroke (27%)
   • Haemorrhagic stroke (15%)
   • Causes of hemorrhagic stroke
     • Atherothromboembolism
       • Embolus
       • Occlusion
       • Reduced perfusion
       • Dolicoectasy
     • Inflammatory cerebrovascular pathologies
       • Vasculitis-arteritis
         • Major causes
           • In old people giant cell arteritis
           • Takayasu arteritis
         • Minor causes
       • Secondary vasculitis associated to other pathologies
     • Congenital
     • Arterial dissection
     • Traumatic injuries
     • Metabolic diseases
     • Coagulopathies
     • Cerebral hypoperfusion
   • The major origins of embolism are
     • Arterial atherothrombosis
     • Cardiogenic sources
     • Paradoxical embolism from DVT
   • Conditions affecting small vessels
     • Major
       • Simple diseases of the small vessels (hyaline atherosclerosis)
       • Complex diseases of the small vessels
     • Minor
       • Cerebral amyloid angiopathy
       • CADASIL

2. Dissection

   • 2 major consequences
     • Intramural hematoma
     • The wall may break and the blood may go internally or externally
   • Natural history
     • If risk of an aneurism (sub-adventitial dissection), better not to give anticoagulants
     • If risk of subintimal dissection, better to give anticoagulants
   • Epidemiology
     • ICA dissection: 2.5-3/100000
     • Vertebral A. dissection: 1.4/100000
   • Classification
   • Risk factors
     • Intrinsic
       • Fibromuscular dysplasia, Marfan’s S
       • Associated to other pathologies
       • Connective tissue pathologies
       • Arterits
     • Extrinsic
       • Minor traumatic injuries
       • Recent upper airways infection that produce some local inflammatory reaction
   • Local clinical manifestations
     • ICA
       • Headache
       • Partial Horner's syndrome
       • IX, X, XI e XII cranial nerves involvement by compression
     • Vertebral artery
       • Headache and cervical pain
     • The main symptom that informs you that you are facing a dissection is pain: headache
   • Ischemic clinical manifestations
     • ICA (49-84%)
     • Vertebral artery (77-96%)
   • Classification
     • Traumatic/spontaneous
       • Sudden turning of the head
       • Strong neck massage
       • Hyperextension of the head
       • Helmet closure
     • Symptomatic/Asymptomatic
     • Single/Multiple
     • Intracranial/Extracranial

3. Warning signs that a stroke is taking place

   • Sudden weakness
     • But not all strokes produce weakness
     • It is contralateral
   • Contralateral hemiparesis and contralateral hemiplegia
   • Hemianesthesia
   • Aphasia or neglect, plus decrease in speech production or dysarthria
   • Loss of vision
     • If the whole MCA is affected
     • If only a part is affected, we have quadrantanopsia
   • Unexplained dizziness, unsteadiness or sudden fall
     • The cerebellum or cerebello-vestibular system are involved

4. Diagnosis

   • Imaging
     • Not possible (with few exceptions) to perform an angiography because by injecting contrast in a stroke patient you will further damage the site of the lesion due to the breakdown of the BBB in stroke
   • Other exams
     • EEG
       • Distinguish between a real phenomenon and a hysteric seizure
     • Electrocardiogram
     • Chest x-ray
     • Hematological studies
     • Serum electrolytes, blood glucose, renal and hepatic chemical analysis

5. Prevention

   • Anticoagulation
     • Heparin (initially) + oral anticoagulants (chronic therapy)
     • When we believe the stroke is of embolic origin
       • We know patient is in AF or evidence from CT studies
       • If not, don't do it
     • Usually we wait 7 -10 days after the acute event before starting a secondary prevention with anticoagulants
     • The risk of transformation is extremely high in the first 36 hours and then it gradually decreases
   • 3 strategies
     • Mass strategy to try to prevent it in all those who are at risk
     • High risk strategy to prevent stroke only in the patients who are at a very high risk of an event
     • Concentrate instead on those who already had a primary event thus to prevent recurrences (form of secondary prevention)
   • Control the risk factors
     • Apply an antiplatelet or anticoagulant treatment
       • Antiplatelet drugs are to be used only in case of atherothrombotic stroke (no effect on hemorrhagic or lacunar stroke)
     • In case of hypertension, secondary prevention by ACE-I therapy
     • Modify life style risk factors
   • Carotid stenosis treatment
     • If the stenosis is >70%
       • Not indicated if <50%
     • If the patient has a symptomatic stenosis
     • Either surgically or by stenting
   • Patent foramen ovale
     • in selected cases when there is clear evidence that its patency may be a source of emboli, the closure of the foramen is absolutely indicated
   • Aspirin (antiplatelet) therapy
     • Antiplatelet drugs
       • Dipiridamol + aspirin
         • Treatment of choice
       • Clopidogrel
     • Reasonable if we cannot perform fibrinolysis because it is too late
     • Better not to perform it immediately except if the stroke was of a huge entity
   • Antihypertensive secondary prophylaxis
     • No evidence that it is beneficial in patients with stroke
     • Indicated in patients with stroke who have aortic dissection, acute myocardial infarction, heart failure, ARF, hypertensive encephalopathy
     • ACE-I therapy
   • Anticoagulation in stroke is mandatory only when we have a TIA
     • Prevent second wave of embolization
     • Mandatory, start as soon as possible when: TIA or ischemic stroke with complete recovery within 1-2 days due to atrial fibrillation
     • Mandatory, best time to start unclear: Non-disabling ischemic stroke due to atrial fibrillation, non hemorrhagic transformation
   • Emergency administration of Abciximab

6. Treatment

   • Acute stroke treatment
     • 1 - Draw blood
     • 2 - Perform EKG
     • 3 - Head CT
     • If it is more than 6 hours before then you cannot do any appropriate intervention because it becomes too dangerous
     • If it is less than 4.5 hours, we can do something
     • The main factors determining the risk of hemorrhagic transformation upon reperfusion are
       • Time
       • Extension
       • Blood pressure
     • Perform thrombolysis
   • Stem cell therapy
   • Rehabilitation
     • 25% of patients die, but 40% remain alive with disabilities
   • Thrombolysis
     • Pharmacological
       • recombinant tissue plasminogen activator
         • The injected amount has to be 0.9 mg/kg but we cannot exceed 90 mg as a global dose
       • They digest fibrinogen, so less fibrin is available to form the fibrin component of the thrombus
     • Mechanical
     • Mandatory when major vessels are hit
     • To be effective it has to be performed within 3 hours from beginning of stroke, but about 25% of strokes happen during night
       • Possible to understand when it happened with MRI diffusion technique
     • If we do nothing, ~40% of the vessels will reopen spontaneously
     • Easier to destroy an embolus than a thrombus
     • Must be avoided when the patient is under anticoagulation therapy or had recent surgery
     • Better if it is intravenous (but if you are in a good center, also intra-arterial
       • Disadvantages of arterial
         • More time consuming
         • More invasive (->more risk)
       • Intra-arterial is indicated in case of vertebra-basilar artery occlusion
     • Ultrasound thrombolysis is last strategy
   • Reduce the amount of edema
     • Steroids
     • Osmotic treatment (the most important one)
     • Decrease in blood pressure
     • Opening the brain
     • Immediate carotid endoartectomy or int.radiology
   • Mandatory to perform CXR, because pulmonary infection is very frequent