Cerebral Infarction Flashcards Preview

S2.3 Neurology > Cerebral Infarction > Flashcards

Flashcards in Cerebral Infarction Deck (23)
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1
Q

What is the definition of a stroke?

A

Focal neurological deficit due to disruption of blood supply lasting more than 24 hours.

2
Q

What percentage of strokes are ischaemic vs haemorrhagic?

A

85% Ischaemic

3
Q

What are the physical causes of stroke?

A

Ischaemic

  • large artery atherosclerosis
  • cardioembolic e.g. AF
  • small artery occlusion
  • undetermined
  • rare (arterial dissection, venous sinus thrombosis)

Haemorrhagic

  • primary intracerebral haemorrhage (70%)
  • secondary e.g. SAH, arteriovenous malformation
4
Q

What are the risk factors for stroke (modifiable/non-modifiable)?

A

Modifiable

  • hypertension (most important)
  • diabetes (3x stroke incidence)
  • smoking (2-3x stroke incidence)
  • heavy drinking (2.5x)
  • obesity

Non-modifiable

  • previous stroke
  • old
  • male
  • family history
  • recent MI, AF
  • OCP with high oestrogen content
  • malignancy
5
Q

In practice, what are the three main causes of localised interrupted blood supply?

A

Atheroma + arterial thrombosis causing ischaemia
Thromboembolism e.g. from left atrium causing ischaemia
Ruptured aneurysm of a cerebral vessel causing haemorrhage

6
Q

Generally, changes in what three aspects of vasculature can cause disturbances?

A
Vessel wall
Blood flow (including pressure)
Blood constituents
7
Q

What are two common sites of vessels rupturing causing haemorrhagic stroke?

A

Basal ganglia - microaneurysms form in hypertension

Circle of Willis - Berry aneurysms form in hypertension

8
Q

What is a common cause of thromboembolism-stroke (excluding atheroma)?

A

Arrhythmias such as AF, thrombus in left atrial appendage breaks off and can embolise to aorta/carotid/further

9
Q

In ICA thrombosis, where would you typically get ischaemia?

A

MCA territory

10
Q

What can cause generalised infarctions? (not due to thrombus/embolism/haemorrhage)

A

Hypoxia

  • flow but low O2: CO2 poisoning, near drowning, respiratory arrest
  • inadequate supply - cardiac arrest, hypotension, brain swelling
  • cyanide poisoning - can’t use O2
11
Q

What pattern of infarction might be seen in hypotension induced infarction vs cardiac arrest?

A

Hypotension
- watershed infarct - central territories remain perfused, watershed zones poorly perfused - borders between main artery supply areas

Cardiac arrest
- largescale infarction due to complete perfusion loss - cortical infarction

Complex
- mix of various types - complex pattern

12
Q

What might be some symptoms of ACA stroke?

A

Contralateral paralysis of face/arm/leg
Contralateral sensory loss over foot/leg
Contralateral impairment of gait/stance

13
Q

What might be some symptoms of MCA stroke?

A

Contralateral paralysis of face/arm/leg
Contralateral sensory loss of face/arm/leg
Contralateral homonymous hemianopia

14
Q

What might be some symptoms of right hemisphere stroke?

A
Left hemiplegia, homonymous hemianopia
Neglect syndromes (agnosia)
- Visual agnosia
- Sensory agnosia
- anoagnosia - denial of hemiplegia
- prosopagnosia - failure to recognise faces
15
Q

What are lacunar stroke symptoms?

A
Devoid of cortical signs
- e.g. no dysphasia/neglect/hemianopia
Pure motor stroke
Pure sensory stroke
Dysarthria - clumsy hand syndrome
Ataxic hemiparesis
16
Q

What are symptoms of posterior circulation stroke?

A

Involved anatomy

  • brainstem/cerebellum/thalamus
  • occipital and medial temporal lobes

Brainstem dysfunction

  • coma, vertigo, nausea, vomiting, cranial nerve palsies, ataxia
  • hemiparesis, hemisensory loss
  • crossed sensori-motor deficits
  • visual field deficits
17
Q

What investigations might be done in suspected stroke?

A

Routine bloods - FBC, glucose, lipids, ESR
CT/MRI - infarct vs haemorrhage
ECG - ?AF, LVH
Echo - valves, ASD, VSD, PFO
Carotid Doppler - ?Stenosis
Cerebral angiogram/venogram - ?vasculitis
Hypercoagulable blood screen

Must search for aetiology in TIA (10% recurrence within 2 weeks)

18
Q

What are some differential diagnoses for stroke?

A
Post-ictal states e.g. Todd's paralysis
Hypoglycaemia
Intracranial mass
Vestibular disease
Bell's palsy
Functional hemiparesis
Migraine
Demented patients with UTIs
19
Q

What are the usual terms used to describe different types of stroke?

A

TACS - Total anterior circulation
PACS - Partial anterior circulation
LACS - Lacunar stroke
POCS - Posterior circulation

20
Q

What are the three aims of initial treatment in stroke? What are example treatments that help with this?

A

Restore blood supply
Prevent extension of ischaemic damage
Protect vulnerable brain tissue

E.g.

  • aspirin
  • stroke unit
  • thrombolysis
  • thrombectomy

Carotid endarterectomy is effective treatment in symptomatic ICA stenosis

21
Q

What is the usage and exclusion criteria for use of TPA?

A

<4.5 hours of symptom onset
Disabling neurological deficit
Symptoms present >60 minutes
Consent obtained

Exclusion

  • anything increasing haemorrhage probability e.g. blood on CT, recent surgery, recent bleeding episodes, coagulation problems
  • BP >165 systolic or 110 diastolic
  • glucose <2.8 or >22
22
Q

What treatment is given for secondary prevention of stroke?

A
Anti-hypertensives - RRR >25%
Antiplatelets - RRR 25%
Lipid lowering agents - RRR 25%
Warfarin for AF - RRR 66%
Carotid endarterectomy
23
Q

What is the prognosis of different stroke types, in terms of death/dependence at 6 months?

A

TACS - 96%
PACS - 45%
LACS - 39%
POCS - 38%