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Medicine Phase 2a Neuro > Transient ischaemic attack and amaurosis fugax > Flashcards

Transient ischaemic attack and amaurosis fugax Flashcards

1
Q

Define TIA

A

A brief episode of neurological dysfunction due to temporary focal cerebral ischaemia withOUT infarction

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2
Q

Generally how long does it take for symptoms of TIA to have resolved

A

24 hours
Very important to resolve quickly as without intervention, more than 1 in 12 patients will go on to have a stroke within a week, so prompt management is imperative

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3
Q

Epidemiology of TIA

A

Black ethnicity more at risk

More common in males

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4
Q

Pathophysiology of TIA

A

Commonest cause = Cerebral ischaemia, resulting in a lack of O2 and Nutrients to the brain resulting in cerebral dysfunction
In TIA, period of ischaemia is short lived - symptoms only last 5-15 mins usually after onset and then resolves before irreversible cell death occurs

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5
Q

If symptoms of TIA gradually progress and dont resolve, what pathology would this suggest

A

Demyelination
Tumour
Migraine

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6
Q

Causes of TIA

A

Atherothromboembolism from the carotid is chief cause
Cardioembolism resulting in Microemboli
Hyper-viscosity
Rare: Vasculitis or hypoperfusion

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7
Q

Causes of Microemboli by cardioembolism

A

Mural thrombus post-MI or in AF
Valve disease
Prosthetic valve

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8
Q

Examples of hyper-viscosity diseases that can result in TIA

A

Polycythaemia
Sickle cell anaemia
Extremely raised white cell count
Myeloma

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9
Q

Risk factors of TIA

A 
Age (increases with age)
Clotting disorder
Combined oral contraceptive pill (increases clot risk)
Diabetes
Excess alcohol
Heart disease - valvular, ischaemic or atrial fibrillation
Hyperlipidaemia
Hypertension
Past TIA
Peripheral arterial disease
Polycythaemia vera
Raised packed cell volume (PCV)
Smoking
Vasculitis (SLE, giant cell arthritis)
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10
Q

Long-term medical treatment of TIA

A

P2Y12 inhibitor e.g. Clopidogrel (antiplatelet drug)

Statin e.g. simvastatin

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11
Q

Describe ABCD2 score

A 
Calculates risk of stroke after TIA:
Age > 60yrs = 1
Blood pressure >140/90mmHg =  1
Clinical features:
-unilateral weakness = 2
-speech disturbance without weakness = 1
Duration of symptoms:
>1hr = 2
10-59mins = 1
Diabetes = 1
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12
Q

ABCD2 score:
What score strongly predicts a stroke and should be referred immediately to specialist?
What score predicts they should be referred to a specialist within 24 hours?
How quickly should a patient suspected of TIA be seen?

A

Score greater than 6 strongly predicts a stroke and should be referred to a specialist IMMEDIATELY

Score greater than 4 should be assessed by a specialist within 24hours

All patients with suspected TIA should be seen within 7 days

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13
Q

What other conditions (not in ABCD2 score) mean a person is at a high risk of a stroke

A

Atrial fibrillation
>1 TIA in one week
TIA whilst on anticoagulant

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14
Q

Pathophysiology of TIA

A

Most common cause of a TIA is cerebral ischaemia resulting in a lack of oxygen and nutrient to the brain
Results in cerebral dysfunction
HOWEVER
Period of ischaemia is short, with symptoms only lasting for 10-15 minutes after onset and then resolves before irreversible cell death occurs
Symptoms that gradually progress suggest a different pathology such as demyelination, tumour or migraine

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15
Q

General clinical presentation

A

SUDDEN loss of function, usually lasting for minutes only, with complete recovery and no evidence of infarction on imaging

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16
Q

What % of TIAs affect the anterior circulation (cartotid artery)

A

90%

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17
Q

What area of brain is supplied by anterior circulation

A

Frontal and medial part of cerebrum

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18
Q

Clinical presentation of TIA of anterior circulation

A 
Weak, numb CONTRALATERAL leg +/- similar, if milder, arm symptoms
Hemiparesis
Hemi sensory disturbance
Dysphasia
Amaurosis fugax
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19
Q

What are:
Hemiparesis
Dysphasia

A

Hemiparesis - weakness on an entire side of the body

Dysphasia - language impairment

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20
Q

**What is Amaurosis Fugax

A

Sudden transient loss of vision in one eye

21
Q

What causes amaurosis fugax

A

Temporary reduction in the retinal, opthalmic or ciliary blood flow leading to temporary retinal hypoxia

22
Q

What is amaurosis fugax a sign of?

A

First clinical evidence of an ICA stenosis - warning sign of an imminent ICA territory stroke

23
Q

What % of TIAs affect the posterior circulation (vertebrobasilar artery)

A

10%

24
Q

Clinical presentation of TIA of posterior circulation

A 
Diplopia
Vertigo
Vomiting
Choking and dysarthria
Ataxia
Hemisensory loss
Hemianopia vision loss
Loss of consciousness (rare)
Transient global amnesia
Tetraparesis
25
Q

What is ataxia

A

No control over body movement

26
Q

What is diplopia

A

double vision

27
Q

What is vertigo

A

feeling that your surroundings are moving

28
Q

What is dysarthria

A

Unclear articulation of speech but understandable

29
Q

What is transient global amnesia

A

episode of confusion/amnesia lasting several hours, followed by complete recovery

30
Q

What is tetraparesis

A

muscle weakness affecting all 4 extremities

31
Q

Is it possible to differentiate TIA from stroke

A

Impossible to differentiate until there is a full recovery (TIA)

32
Q

Describe giant cell arteritis presentation

A

Monocular, temporary visual impairment normally presents

Raised ESR, thickening and tenderness of temporal artery

33
Q

*Differential diagnosis

A

Hypoglycaemia
Migraine aura (symptoms spread and intensify over minutes, often with visual scintillations (sparkling/blinking))
Focal epilepsy (since limb shaking can occur in a TIA)
Intracranial lesion - tumour or subdural haemotoma
Syncope due to arrhythmia
Transient weakness of arm, hand or leg after a seizure
Retinal or vitreous haemorrhage
Giant cell arteritis

34
Q

What is Todd’s paralysis

A

transient weakness of arm, hand or leg after a seizure

35
Q

Diagnosis

A

Based on description
Bloods (FBC, ESR, Glucose, Creatinine, electrolytes, Cholesterol)
Carotid artery doppler ultrasound to look for stenosis/atheroma
ECG
CT or diffusion weighted MRI
Echocardiogram/cardiac monitoring to assess for a cardiac cause

36
Q

What would you do to determine extent of stenosis

A

MR/CT angiography

37
Q

Why is an ECG part of the diagnosis

A

Look for AF or evidence of MI ischaemia

38
Q

What is the purpose of these blood tests in diagnosis of TIA:
FBC
ESR
Glucose

A

FBC - look for polycythaemia
ESR - will be raised in vasculitis
Glucose - to see if hypoglycaemic

39
Q

How would you calculate risk of stroke after TIA

A

ABCD2 score

40
Q

Describe ABCD2 score

A

Age > 60yrs = 1
Blood pressure > 140/90mmHg = 1
Clinical features:
Unilateral weakness = 2
Speech disturbance without weakness = 1 Duration of symptoms:
Symptoms lasting more than 1hr = 2 Symptoms lasting 10-59mins = 1
Diabetes = 1

Score greater than 6 strongly predicts a stroke and should be referred to a specialist IMMEDIATELY
Score greater than 4 should be assessed by a specialist within 24hours
All patients with suspected TIA should be seen within 7 days

41
Q

How long until all patients with a suspected TIA should be seen

A

Within 7 days

42
Q

What is the minimum score on ABCD2 that strongly predicts a stroke and what would you do?

A

Score greater than 6 strongly predicts a stroke and should be referred to a specialist IMMEDIATELY

43
Q

What would happen is ABCD2 score is greater than 4 (but not over 6)

A

Score greater than 4 should be assessed by a specialist within 24hours

44
Q

What other factors put patient at high risk of stroke, that are not in ABCD2 score

A

Atrial fibrillation
More than 1 TIA in one week
TIA whilst on an anticoagulant

45
Q

Treatment

A

Control CVS risk factors
Antiplatelet drugs
Cardiac endarterectomy

ABCD2 score (and possible referral)
(Anticoagulant if they have AF, mitral stenosis or recent big septal MI e.g. WARFARIN)
Statin longterm e.g. SIMVASTATIN
Control cardiovascular risk factors
Do NOT DRIVE for at least 1 month following TIA

46
Q

How long can a person not drive for following a TIA

A

At least 1 month

47
Q

Treatment - Antiplatelet drug

A

ASPIRIN IMMEDIATELY
Then switch to Clopidogrel
If this is contraindicated, given aspirin with DIPYRIDAMOLE (↑cAMP and ↓ thromboxane A2)

P2Y12 inhibitor longterm e.g. CLOPIDOGREL

48
Q

When would you give an anticoagulant like warfarin in treatment of TIA

A

If they have AF, mitral stenosis or recent big septal MI

49
Q

Treatment - control of CVS risk factors

A

Antihypertensives such as ACE-inhibitor e.g. RAMIPRIL or angiotensin receptor blocker e.g. CANDESARTAN
Improve diet, stop smoking

Medicine Phase 2a Neuro (28 decks)

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