Cerebral Infarction Flashcards Preview

Systems: Neurology AB > Cerebral Infarction > Flashcards

Flashcards in Cerebral Infarction Deck (77)
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1
Q

Define stroke

A

A sudden onset of focal or global neurological symptoms caused by ischemia or haemorrhage and lasting more than 24 hours.

2
Q

Define TIA

A

Term used to describe symptoms which resolve within 24 hours.

3
Q

How long do most TIAs last?

A

Most resolve within 1-60min

4
Q

What are the types of stroke cause?

A
  • Ischaemic 85%

- Haemorrhagic stroke 15%

5
Q

What can cause an ischaemic stroke?

A
  • Large artery atherosclerosis
  • Cardioembolic
  • Small artery occlusion
  • Undermined/cryptogenic
  • Rare causes such as arterial dissection or venous sinus thrombosis
6
Q

What can cause a haemorrhagic stroke?

A
  • Primary intracerebral haemorrhage

- Secondary haemorrhage such as subarachnoid haemorrhage or AVM

7
Q

What is the incidence and impact of stroke?

A
  • 2nd- 3rd cause of death in developed countries
  • # 1 cause of disability in adults.
  • 150,000 new strokes/year in UK.
  • 67,000 deaths/year in UK.
8
Q

What does the risk of stroke increase with?

A

Increases with age

9
Q

What public campaign is associated with stroke awareness?

A

FAST

10
Q

What is ischaemia?

A
  • Is the failure of cerebral blood flow to a part of the brain caused by an interruption of the blood supply to the brain.
  • It can be transient (as in TIA) and results in varying degrees of hypoxia (↓oxygen).
11
Q

What can hypoxia result in?

A
  • Hypoxia stresses the brain cell metabolism. This is especially important in the ischemic penumbra.
  • If prolonged, the hypoxia→anoxia (no oxygen).
  • Anoxia →infarction (complete cell death, leading to necrosis). This is a stroke.
12
Q

Apart from infarction what other damage can anoxia result in?

A

Oedema, depending on the size +location of the stroke or secondary haemorrhage into the stroke

13
Q

What is the ischaemic penumbra?

A

Area around the ischaemic core

14
Q

What is the pathogenesis of ischaemic stroke?

A
  • Disruption/injury to plaque surface
  • Platelet adhesion/aggregation and fibrin formation
  • Platelet-fibrin embolus
  • Total arterial occlusion due to thrombus
15
Q

What are the non-modifiable risk factors for strokes?

A
  • Previous stroke
  • Being old
  • Being male
  • Having a horrible family history
  • Impaired cardiac function (recent heart attack, atrial fibrillation).
16
Q

What modifiable risk factors for strokes?

A
  • Hypertension
  • Smoking
  • Cholesterol
  • Diet
  • High BMI
  • Sedentary life style
  • Alcohol
  • Oral contraceptives (+ HRT) with a high estrogen content. Progesterone-only OK
17
Q

What is the most important modifiable risk factor for stroke?

A

Hypertension

18
Q

Why is hypertension a risk factor for stroke?

A
  • Stroke risk is related to blood pressure level
  • Chronic hypertension worsens atheroma and affects small distal arteries.
  • Both stroke and hypertension reach major proportions in the elderly.
  • The majority of people with hypertension have it poorly treated.
  • Hypertension is a major risk factor for haemorrhagic strokes as well (~50% of cases).
19
Q

How does diabetes affect the risk of stroke?

A

Diabetes mellitus increases the incidence of strokes up to 3-fold in both sexes.

20
Q

How does smoking affect the risk of stroke?

A

Smokers have

  • a 2-fold ↑risk of cerebral infarction.
  • a 3-fold ↑risk of sub-arachnoid haemorrhage.

Some of the increased risk of stroke relates to the complications of cardiac problems.

21
Q

Why do increased serum lipids increase the risk of stroke?

A

↑serum lipids increase stroke risk due to blood vessel wall atheroma

22
Q

What increases the deposition on LDL-C in arterial walls?

A
  • ↑plasma level of low density lipoprotein (LDL) results in excessive amounts of LDL within the arterial wall.
  • Hypertension, cigarette smoke, and diabetes contribute to LDL-C deposition in arterial walls.
23
Q

How does alcohol affect stroke risk?

A
  • Small amounts of alcohol ↓stroke risk .

- Heavy drinking ↑risk 2.5 fold.

24
Q

How does obesity (especially abdominal) affect stroke risk?

A

Recently identified as an independent risk factor for vascular disease including stroke.

25
Q

Why may someone be in a hyper-coaguable state?

A
  • Malignancy

- Genetics

26
Q

What is Broca’s area responsible for?

A

Speech

27
Q

What is the frontal lobe responsible for?

A

Smell

28
Q

What is the temporal lobe responsible for?

A
  • Intellectual and emotional functions

- Hearing

29
Q

What is the brainstem responsible for?

A
  • Swallowing
  • Breathing
  • Heartbeat
  • Wakefulness center
  • Other involuntary functions
30
Q

What is the cerebellum responsible for?

A

Coordination

31
Q

What is Wernicke’s responsible for?

A

Speech comprehension

32
Q

What is the occipital lobe responsible for?

A

Primary visual area

33
Q

What is the parietal lobe responsible for?

A

Comprehension of language

34
Q

What is the anterior circulation to the brain?

A
  • 2 x Internal carotid arteries
  • 2 x Anterior Cerebral Artery (ACA)
  • 2 x Middle Cerebral Artery (MCA)
35
Q

What is the posterior circulation to the brain?

A
  • 2 Vertebral arteries →1 basilar
  • 3 pairs of cerebellar arteries
  • 2 Posterior cerebral artery (PCA)
36
Q

What anastomoses exist in the brain?

A
  • Circle of Willis: via anterior and posterior communicating arteries
  • Borderzone anastomoses: between peripheral branches of anterior, middle and posterior cerebral arteries
37
Q

Where does the anterior circulation arise from?

A

Internal carotid arteries

38
Q

What are the symptoms of ACA occlusion?

A

Contra-lateral

  • Paralysis of foot and leg
  • Sensory loss over foot and leg
  • Impairment of gait and stance.
39
Q

What are the symptoms of MCA occlusion?

A

Contra-lateral

  • 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 (usually right side).
40
Q

What triad can occur with disruption of MCA territory?

A
  • Hemiplegia
  • Homonymous hemianopia
  • Dysphasia
41
Q

What can disruption of the right hemisphere result in?

A
Left hemiplegia, homonymous hemianopia
Neglect syndromes agnosias)
-Visual agnosia
-Sensory agnosia
-Anosagnosia (denial of hemiplegia)
-Prosopagnosia (failure to recognise faces)
42
Q

What is the circulation to the basal ganglia?

A

Medial and lateral lenticulostriate arteries from the middle cerebral artery

43
Q

What is absent in a lacunar stroke?

A

Devoid of cortical signs

E.G. no dysphasia, neglect, hemianopia

44
Q

How can a lacunar stroke present?

A
  • Pure motor stroke
  • Pure sensory stroke
  • Dysarthria - clumsy hand syndrome
  • Ataxic hemiparesis
45
Q

What anatomical structures are involved with the posterior circulation?

A
  • Brain stem
  • Cerebellum
  • Thalamus
  • Occipital and medial temporal lobes
46
Q

What are the symptoms of brainstem dysfunction?

A
  • Coma, vertigo, nausea,vomiting, cranial nerve palsies, ataxia.
  • Hemiparesis, hemisensory loss
  • Crossed sensori-motor deficits
  • Visual field deficits
47
Q

Acute ischaemic stroke therapies should…

A
  • Restore blood supply.
  • Prevent extension of ischemic damage.
  • Protect vulnerable brain tissue.
48
Q

What are the treatment options for stroke?

A
  • IV TPA
  • Stroke unit
  • Aspirin
  • Thrombectomy
49
Q

What are the components of a stroke unit?

A
  • Clinical staff
  • Stroke nurses
  • Physiotherapists
  • Speech and Language therapists
  • Occupational therapists
  • Dietitian
  • Psychologist
  • Orthoptist
50
Q

What are the 4 OCSP stroke classifications?

A
  • Total Anterior Circulation Stroke (TACS)
  • Partial Anterior Circulation Stroke (PACS)
  • Lacunar Stroke (LACS)
  • Posterior Circulation Stroke (POCS)
51
Q

LACS: Motor (≥2/3 face arm leg)

A

+ or -

52
Q

LACS: Sensory loss(≥2/3 face arm leg)

A

+ or -

53
Q

LACS: Hemianopia or Dysphasia or Neglect

A

N/A

54
Q

LACS: Brainstem + or cerebellar signs

A

N/A

55
Q

PACS: Motor (≥2/3 face arm leg)

A

+ or -

56
Q

PACS: Sensory loss (≥2/3 face arm leg)

A

+ or -

57
Q

PACS: Hemianopia or Dysphasia or Neglect

A

1

58
Q

PACS: Brainstem + or cerebellar signs

A

N/A

59
Q

TACS: Motor (≥2/3 face arm leg)

A

+ or -

60
Q

TACS: Sensory loss (≥2/3 face arm leg)

A

+ or -

61
Q

TACS: Hemianopia or Dysphasia or Neglect

A

2 (must have hemianopia)

62
Q

TACS: Brainstem + or cerebellar signs

A

N/A

63
Q

POCS: Motor (≥2/3 face arm leg)

A

+ or -

64
Q

POCS: Sensory loss (≥2/3 face arm leg)

A

+ or -

65
Q

POCS: Hemianopia or Dysphasia or Neglect

A

+ or -

66
Q

POCS: Brainstem + or cerebellar signs

A

+

67
Q

How do death or dependence rates vary depending on type of stroke?

A
  • TACS 96%
  • PACS 45%
  • LACS 39%
  • POCS 38%
68
Q

What is the strict criteria for TPA use?

A
  • < 4.5 hours from symptom onset.
  • Disabling neurological deficit.
  • Symptoms present > 60 minutes.
  • Consent obtained
69
Q

What is the exclusion criteria for IV TPA?

A

Anything that increases the possibility of hemorrhage:

  • Blood on CT scan
  • Recent surgery
  • Recent episodes of bleeding
  • Coagulation problems
  • BP >185 systolic or >110 diastolic
  • Glucose <2.8 or > 22mmol/L
70
Q

What does benefit of TPA decline with?

A

Time

71
Q

What is an effective treatment in symptomatic internal carotid artery stenosis?

A

Carotid endarterectomy

72
Q

What is the aetiology of stroke?

A
  • Atherosclerotic narrowing
  • Embolic - cardiac source (atrial fibrillation, recent MI)
  • Artery to artery embolism
  • Hypercoaguable state
  • Arterial dissection
  • Venous sinus thrombosis
73
Q

How should stroke be investigated?

A
  • Routine blood tests (FBC, glucose, lipids, ESR…)
  • CT or MRI head scan (infarct vs. hemorrhage)
  • ECG (?AF, LVH)
  • Echocardiogram (valves, ASD, VSD, PFO)
  • Carotid doppler ultrasound (?stenosis)
  • Cerebral angiogram/venogram (vasculitis?)
  • Hyper-coagulable blood screen
74
Q

What secondary prevention is there for stroke?

A
  • Anti-hypertensive
  • Anti-platelets
  • Lipid lowering agents
  • Warfarin for AF
  • Carotid endarterectomy
75
Q

What is the differential diagnosis for stroke?

A
  • Post-ictal states (e.g. Todd’s paralysis)
  • Hypoglycemia
  • Intracranial masses
  • Vestibular disease
  • Bell’s palsy
  • Functional hemiparesis
  • Migraine
  • Demented patients with UTIs
76
Q

What is the management post-stroke?

A
  • Prevention of stroke recurrence.
  • Prevention of complications related to stroke.
  • Rehabilitation.
  • Re-integration into the community.
77
Q

What are the objectives of stroke care?

A
  • Reduce mortality.
  • Reduce residual disability amongst survivors.
  • Improve psychological status of patients and care-givers.
  • Improve patient / care giver knowledge.
  • Maximize quality of life.