Stroke and Brain Haemorrhage Flashcards
Define stroke
Sudden onset of focal or global neurological symptoms due to disruption of blood supply (ischaemia or haemorrhage) and lasting more than 24 hours
List the causes of ischaemic stroke
Unexplained
Large artery athersclerosis (plaque/thrombus embolises to brain)
Cardioembolic (e.g. atrial fibrillation)
Small artery occlusion (lacune)
Rare causes e.g. arterial dissection or venous sinous thrombosis
What type of imaging can be used to prove a stroke?
Diffusion-weighted MRI
Stroke pathophysiology; describe the ischaemic cascade
Interruption of the blood supply to the brain
Ischaemia - failure of cerebral blood flow to part of the brain
Hypoxia
Anoxia
Infarction - stroke
Oedema and/or secondary haemorrhage
List the non-modifiable risk factors for stroke
Previous stroke
Old age
Male
Family history of stroke
List the modifiable risk factors fro stroke
Hypertension Smoking High cholesterol Poor diet Obesity
Describe how chronic hypertension and smoking increase the risk of stroke
Chronic hypertension worsens atheroma and affects small distal arteries
Smoking increases risk of cardiac problems which in turn increases risk of stroke
What is the main function of Broca’s area in the brain?
Speech (initiation)
What is the main function of Wernicke’s area in the brain?
Speech comprehension
Which part of the brain is responsible for general comprehension of language
Parietal lobe
Which arteries give rise to anterior circulation in the brain? What are the two major branches of these arteries?
Internal carotid arteries
Branch into anterior cerebral and middle cerebral arteries
Describe the anatomy of the arteries that for the posterior circulation in the brain
Vertebral arteries, become basilar artery, branches into cerebellar/pontine arteries and posterior cerebral artery
What symptoms might present if the anterior cerebral artery is occluded?
Contralateral:
paralysis of foot and leg
sensory loss over foot and leg
impairment of gait and stance
What is agnosia?
neglect syndromes, e.g.
- visual
- sensory
- anosagnosia
- prosopagnosia
Occlusion of which artery is most likely to cause agnosia?
Middle cerebral artery of the right (non-dominant) hemisphere
What symptoms might present if the middle cerebral artery is occluded on the left (dominant) side?
paralysis/sensory loss of right (contralateral)
homonymous hemianopia
dysphasia/aphasia
What type of stroke tends to occur in the basal ganglia?
Small vessel lacunar strokes
What happens over time to lacunar strokes?
Infarcts are replaced by CSF forming little “lakes”
What are the symptoms of lacunar strokes?
No cortical signs (dysphasia, neglect, hemianopia)
May be purely motor or purely sensory
Dysarthria - “clumsy hand syndrome”
Ataxic hemiparesis
Which parts of the brain would be affected by a posterior circulation stroke?
brainstem, cerebellum, thalamus, occipital lobe, medial temporal lobes
Describe the possible symptoms of brainstem dysfunction
coma vertigo nausea/vomiting cranial nerve palsy ataxia hemiparesis hemisensory loss visual field deficits crossed sensory-motor deficits
What are the aims of treatment for acute ischaemic stroke?
Restore blood supply
Prevent extension of ischaemic damage
Protect vulnerable brain tissue
What is t-PA?
tissue Plasminogen Activator
- given IV to teat acute ischaemic stroke
- works by dissolving the clot and therefore inproving blood flow to the ischaemic part of the brain
Describe the criteria for use of t-PA (there are 4)
Less than 45 hours from symptom onset
Disabling neurological deficit
Symptoms present for over 60 minutes
Consent obtained
Describe the exclusion criteria for use of t-PA
Anything that increaes the possibility of haemorrhage
- blood on CT
- recent surgery
- recent episodes of bleeding
- coagulopathies
BP greater than 185 systolic or 110 diastolic
Glucose less than 2.8
Describe how intracranial haemorrhages are classified (in general terms)
Traumatic - extradural haematoma - subdural haematoma - traumatic subarachnoid haemorrhage - intra-parenchymal contusions Non-traumatic (a form of stroke) - subarachnoid haemorrhage - intracerebral haemorrhage - vascular malformations
Where are brain aneurysms most likely to occur?
In the major blood vessels at the base of the skull
Give three conditions that are associated with a higher risk of subarachnoid haemorrhage
Polycystic kidney disease
Ehler’s-Danlos
Marfans
(the latter two are connective tissue disorders which cause blood vessels to be more fragile and therefore more likely to bleed)
Describe the presentation of subarachnoid haemorrhage
Severe headache, often “thunderclap”
May also experience a sentinel headache; a lesser “warning” headache a few hours/days before the SAH
Meningism (caused by irritation of the meninges because blood is an irritant)
Focal neurological deficits
Seizures
ECG changes (brain activity can caue changes in the heart)
Reduced level of consciousness, coma, death
When a patient’s conscious level decreases, at what point should they be intubated and why?
GCS of eight or less
At this point there is a risk that the patient will not be able to maintain their own airway
Why can SAH lead to hydrocephalus?
Damage caused by haemorrhage disrupts the production and/or drainage of CSF
Describe the complications of SAH
Rebleeding (if caused by aneurysm) Vasospasm Hydrocephalus Seizures Electrolyte abnormalities e.g. hypernoatraemia
When is the risk of aneurysmal rebleeding the highest after an SAH?
First day after the haemorrhage
What is vasospasm and why is it a problem?
Spasm of cerebral arteries (form of stroke)
- blood in SA space is an irritant
- this causes release of inflammatory cytokines
- results in smooth muscle contraction in vessel wall
- brain area supplied by spastic artery is starved of oxygen
- leads to permenant deficit/weakness if untreated
Which drug can be used to reduce the risk of vasospasm? How long should it be taken for?
Nimodipine
1-3 weeks
How is vasospasm diagnosed?
Clinical signs (i.e. neurological deficit)
Transcranial doppler
CT-Angiogram
Digital subtraction angiography (DSA)
How is vasospasm treated?
“triple H”: hypertension, hypervolaemia, haemodilution
- Admit to ICU; boost BP and give fluids
Endovascular techniques to dilate vessel if spasm is focal
Which type of stroke has the worst prognosis? What proportion of strokes are caused by this?
Intracerebral haemorrhage
15% of strokes are IH
- twice as common as SAH
What are the risk factors for intracerebral haemorrhage?
Hypertension
Increasing age
Substance abuse
Underlying lesion such as tumour or vascular lesion
Describe the clinical features associated with an intracerebral haemorrhage
Developing neurological deficit, often more gradual than embolic stroke
- contralateral weakness of face/arm/leg
- dysphasia is bleed is in the dominant hemisphere
Symptoms relating to raised intracranial pressure
- headache
- vomiting
- deteriorating consciousness level
- death
- herniation syndromes
What is an arteriovenous malformation?
An abnormal connection that develops between arteries and veins - no capillary bed
How can AVMs cause problems?
High flow and high pressure of blood
Veins are not designed to cope with this
Risk of haemorrhage 2-4% per year
What types of haemorrhage are most associated with AVMs?
Intraparenchymal (most common)
Subarachnoid
Which type of brain haemorrhage may present after trauma with an initial lucid period (where the patient recovers) followed by a decline in neurological function?
Subdural haemorrhage
