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Z Year3 Clinical Presentations > Blackout > Flashcards

Blackout Flashcards

1
Q

What is the difference between syncope and loss of conciousness?

A

loss of conciousness can be due to syncopal and non-syncopal causes

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2
Q

What is syncope?

A

form of loss of conciousness with the cause being hypoperfusion

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3
Q

What are the syncopal causes of blackout?

A
  1. Reflex
  2. Cardiac
  3. orthostatic
  4. cerebrovascular
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4
Q

What is the reflex cause of syncope?

A
  1. Activation of primitive reflex that leads to mammals play dead when faced with danger (different people have different threshold)
  2. Heart rate slows, BP drops, reducing cerebral perfusion leading to syncope
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5
Q

What are examples of reflex syncope?

A
  1. Vasovagal syncope
  2. Carotid sinus hypersensitivity
  3. Situational syncope (e.g. micturition)
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6
Q

What is the cardiac mechanism for syncope?

A

Pathologies causing a reduction in cardiac output (arrhythmias or outlet obstruction) can also lead to syncope

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7
Q

What are cardiac syncope examples?

A
  1. Arrhythmias
  2. Structural cardiac pathology causing outflow obstruction (e.g. aortic stenosis, hypertrophic obstructive cardiomyopathy)
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8
Q

What is the orthostatic mechanism for syncope?

A
  1. Low BP on sitting or standing
  2. When stand up vasconstriction happens to compensate for loss of BP, takes a few secs so heart rate increases temporaily
  3. If reduced intravascular volume (e.g. dehydration) and/or normal autonomic response (transient tachycardia and peripheral vasoconstriction) to standing is blunted (e.g. due to drugs or autonomic neuropathy) are vulnerable to blackouts
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9
Q

What are examples of orthostatic syncope?

A
  1. Drugs (anti-hypertensive, anti-sympathetic)
  2. Dehydration
  3. Autonomic instability
  4. Baroreceptor dysfunction (in hypertensive patients)
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10
Q

What is the cerebrovascular mechanism for syncope?

A

Non cardiac structural causes of reduced cerebral perfusion e.g. obstructions to the blood flow between heart and brain

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11
Q

What are example of cerebrovascular syncope?

A
  1. Verterbrobasilar insufficiency
  2. Subclavian steal
  3. aortic dissection
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12
Q

What are non-syncopal causes of transient loss of conciousness?

A
  1. Intoxication (e.g. alcohol, sedatives)
  2. Head trauma
  3. Metabolic (mainly hypoglycaemia)
  4. Psychogenic (non-epileptic) seizure
  5. Epileptic seizure
  6. Narcolepsy
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13
Q

What are differentials for loss of consciousness with a young patient?

A

vasovagal syncope (presyncopal sensation)

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14
Q

What are differentials for loss of consciousness with a middle aged patient?

A
  1. Vasovagal syncope

2. Cardiac arrhythmias (no warning)

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15
Q

What are differentials for loss of consciousness with a old patient?

A

Orthostatic hypotension

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16
Q

Which medications can cause orthostatic hypotension?

A
  • diuretics
  • ACE inhibitors
  • beta blockers
  • alpha blockers
  • CCBs
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17
Q

What do you ask about the incident of loss of conciousness?

A
  • any warning

- any precipitating factors

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18
Q

What can you suggest if there was no warning?

A
  • cardiac cause (cardiac arrythmias)

- cerebrovascular cause (e.g. subclavican steal syndrome)

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19
Q

What differentials would you think if there was warning?

A

other cause e.g. aura before epileptic seizure, dizziness preceding a vasovagal episode

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20
Q

What are examples of precipitating factors?

A

exercise, standing up, fear, pain

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21
Q

What would a postural trigger suggest?

A

orthostatic hypotension

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22
Q

What would loss of consciousness caused by head turning suggest?

A

carotid sinus hypersensitivty

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23
Q

What would blackout while sitting or lying down suggest?

A

cardiac arrythmias

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24
Q

what would passing out with exercise suggest?

A

primary cardiac pathology

  • aortic stenosis
  • cardiomyopathy
  • cardiac channelopathy (long QT syndrome)
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25
Q

What would symptoms immediately following vigorous arm activity suggest?

A

subclavian steal

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26
Q

What would recent head trauma and blackouts maybe suggest?

A

Subdural Haemarrohage in elderly and alcoholic which may be precipitated by head trauma days or weeks earlier and may be associated with subsequent seizures

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27
Q

What would a short lived episode suggest?

A
  • vasovagal

- arrythmias

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28
Q

What would biting their tongue down during the episode suggest?

A

epileptic seizure

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29
Q

What would moving their limbs or were they incontinent of urine or faeces during the episode suggest?

A

vasovagak

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30
Q

What would a spontaneous recovery suggest?

A

not neurological or metabolic (unless epilepsy)

31
Q

What would a slow recovery with confusion suggest?

A

epileptic seizure

32
Q

What are the before symptoms of epilepsy?

A
  • stereotypes aura (partial seizure)

- no warning (general seizure)

33
Q

What are the during symptoms of epilepsy?

A
  • can last minutes
  • stereotypes episodes, same every time
  • tongue biting pathognomonic
  • twitching and incontinence may occur but not specific
34
Q

What are the after symptoms of epilepsy?

A

slow recovery, confused for 5-30 mins

35
Q

What are the before symptoms for vasovagal?

A
  • vagal symptoms (sweating, pallor, nausea)

- may have been precipitant (e.g. fear)

36
Q

What are the during symptoms for vasovagal?

A
  • lasts seconds

- may twitch or be incontinent

37
Q

What are the after symptoms of vasovagal?

A

rapid recovery on sitting or lying

38
Q

What are the before symptoms of an arrythmia?

A

no warning

39
Q

What are the during symptoms of arrhythmia?

A
  • Last seconds

- May be twitch or incontinent

40
Q

What are the after symptoms of arrythmia?

A

rapid spontaneous recovery

41
Q

When someone blackout what are important question to ask about PMHx?

A
  1. Has it happened before?
  2. Diabetes?
  3. Cardiac illness?
  4. Peripheral vascular disease?
  5. Epilepsy
  6. Anaemia?
  7. Psychiatric illness
42
Q

What drug Hx is important to ask with blackout?

A
  1. Insulin
  2. Antihypertensives
  3. Vasodilators
  4. Antiarrhythmics
  5. Antidepressants
  6. Warfarin / other anticoagulants
43
Q

What social Hx do you ask about with blackout?

A
  1. Alcohol?
  2. Stimulant recreational drugs? cocaine and amphetamine stimulate the heart causing tachyarrythmias and potentially drop in cardiac output
44
Q

What family Hx do you ask about with blackout?

A
  • Sudden death in relations <65 years?
  • significant in all cases of unexplained syncope esp if exercise induced syncope as some cardiomyopathies and arrhythmias are hereditary
45
Q

Why do you ask about alcohol in SHx in blackout?

A

may not be true loss of conciousness just loss of upright posture

46
Q

Why do you ask about stimulant recereational drugs in SHx in blackout?

A

cocaine and amphetamine stimulate the heart causing tachyarrythmias and potentially drop in cardiac output

47
Q

Why do you ask about diabetes in PMHx?

A 
predispose to 
-vascular disease
-hypoglycaemia
-polyuria
-dehydration
-autonomic dysfunction
Can cause orthostatic hypotension
48
Q

Why do you ask about cardiac illness in PMHx?

A

heart disease is a strong predictor of a cardiac cause of syncope

49
Q

Why do you as about peripheral vascular causes in PMHx with blackout?

A
  • predispose to cerebrovascular events (TIA, stokes)

- rarely cause of transient loss of consciousness

50
Q

Why do you ask about epilepsy in PMHx of blackout?

A

If patient has was this episode similar to normal episodes

51
Q

Why do you ask about anaemia in PMHx in blackout?

A

contribute to hypoxia

52
Q

What conditions may suggest anaemia?

A
  • myelodysplastic syndrome
  • frequent blood transfusions
  • melaena
53
Q

Why do you ask about pyschiatric illness in PMHx in blackout?

A

panic attacks and hyperventilation and loss of consciousness

54
Q

Why do you ask about insulin in DHx in blackout?

A

hypoglycaemia

55
Q

Why do you ask about antihypertensives in blackout?

A

ACE inhibitors, CCBS, diuretics , beta blockers can cause hypotension

56
Q

Why do you ask about vasodilators in blackout?

A

(e.g. GTN, isosorbide mononitrate) - can cause hypotension esp in elderly

57
Q

Why do you ask about antiarrhythmics in blackout?

A

paradoxically predispose to arrhythmias

58
Q

Why do you ask about antidepressants in blackout?

A

hypotension can be side effect of Tricyclic antidepressants

59
Q

Why do you ask about warfarin and other anticoagulants in blackout?

A

vulnerable to subdural haemorrahage and your threshold for CT is lower if on these medications

60
Q

What signs do you look for in examination of after blackout?

A
  1. Bitten tongue
  2. Dehydration
  3. Head trauma
  4. Heart
  5. Carotid bruits
  6. BP
  7. Focal neurological signs
61
Q

What are signs of dehydration and why do you look for them esp in blackout?

A
  • dry mucous membrane
  • tachycardia
  • hypotension
    1. contribute to hypovoleamia
    2. predispose to cerebral hypoperfusion
62
Q

What would a slow or irregular pulse suggest?

A
  1. heart block

2. A fib

63
Q

Why do you check for heart murmur with blackout?

A

aortic stenosis can cause outflow obstructions and cerebral hypoperfusion

64
Q

What would carotid bruits suggest?

A

carotid artery stenosis

65
Q

What are you looking for in BP?

A

orthostatic hypotension

66
Q

What is orthostatic hypotension?

A

drop in >20mmHg in systolic BP or >10mmHg on standing

67
Q

What are first line investigations for blackout?

A
  1. Bloods

2. ECG

68
Q

What bloods do you do?

A
  1. Cap blood glucose
  2. FBC
  3. U+Es
69
Q

What do you look for in cap blood glucose?

A
  1. exclude hypoglycaemia

2. undiagnosed diabetes (polyuria and dehydration)

70
Q

What do you look for in fbc?

A

check for anaemia

71
Q

How would dehydration show in U+Es?

A

rasied urea, out of proportion to creatinine

72
Q

What do you look for U+Es?

A
  1. dehydration

2. exclude electrolyte imbalance (predispose arrythmia)

73
Q

Why do you do an ECG?

A

show abnormality but if normal does not exclude a cardiac cause as arrythmias can be intermittent

74
Q

What other tests may you do if the history suggests it in blackout?

A
  1. For a structural cardiac abnormality such as valve lesion, consider echo
  2. For carotid sinus sensitivity consider carotid sinus massage
  3. For epilepsy consider brain scan (CT or MRI)

Z Year3 Clinical Presentations (37 decks)

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