Blackout Flashcards
Define syncope.
A form of loss of consciousness in which hypoperfusion of the brain is the cause
List the four main mechanisms of syncope.
Reflex – caused by a primitive reflex that leads mammals to play dead. It causes a temporary drop in blood pressure.
Cardiac
Orthostatic
Cerebrovascular – non-cardiac structural causes of reduced cerebral perfusion (RARE)
How can the cardiac causes of syncope be further divided?
Arrhythmia Outflow obstruction (e.g. aortic stenosis, HOCM)
What can cause orthostatic hypotension?
Blunting of the normal autonomic response to standing up (vasoconstriction + rise in heart rate)
DUE TO
- drugs or autonomic nephropathy (anti hypertensives, anti sympathetic)
- dehydration
-baro-receptor dysfunction
- autonomic instability
What are some of the causes of syncope (that fall under the four mechanisms)?
Reflex - Vasovagal syncope - Other: carotid sinus hypersensitivity Cardiac - Arrhythmias - Outflow obstruction Orthostatic/postural hypotension (delay in the autonomic reaction to standing up) - Drugs (anti hypertensive, anti sympathetic) - Dehydration - Autonomic instability - Baroreceptor dysfunction Cerebrovascular - Vertebrobasilar insufficiency - Subclavian steal syndrome - Aortic dissection
List some non-syncopal causes of blackout.
Intoxication (alcohol, sedatives) Head trauma Metabolic - (hypoglycaemia) Psychogenic (non-epileptic) Epileptic seizure
What is the most common cause of blackout in:
Young
Middle-aged
Elderly
The young -Vasovagal
The middle-aged- Vasovagal + arrhythmia
The elderly - Postural hypotension
Which classes of medications are commonly associated with orthostatic hypotension?
ACE inhibitors Diuretics Beta-blockers Alpha-blockers CCBs
List three questions that are important to ask about the event preceding the blackout.
Was there any WARNING?
Were there any PRECIPITATING FACTORS?
Was there any HEAD TRAUMA?
Which causes of collapse may be associated with symptoms preceding collapse?
Epileptic seizure – patients may experience a prodromal aura
Vasovagal – patients may experience vagal symptoms (e.g. sweating, pallor, nausea, dizziness)
Which causes of collapse tend to occur with no warning?
Cardiac causes
NOTE: arrhythmias may cause preceding palpitations
List some factors that may precipitate collapse and state the underlying cause of collapse that they are associated with.
Standing up – postural hypotension
Exercise – cardiac pathology (e.g. aortic stenosis, HOCM, long QT)
Head turning – carotid body hypersensitivity
Vigorous arm activity – subclavian steal syndrome
Vasovagal has many precipitants (e.g. fear, heat, standing for a long time)
List two questions that are important to ask about what happened during the collapse.
HOW LONG did the blackout last?
Was there any TONGUE-BITING, MOVEMENT OF LIMBS or INCONTINENCE of urine or faeces?
What feature of the collapse is pathognomonic with an epileptic seizure?
Tongue-biting
What question is important to ask about the state of the patient after the collapse?
Did the patient RECOVER SPONTANEOUSLY or were they CONFUSED afterwards?
List five key components that should be explored in the patient’s past medical history.
Previous episodes of collapse Diabetes Cardiac illness Peripheral vascular disease (ask about intermittent claudication because they may not have had a PVD diagnosis) Epilepsy Anaemia Psychiatric illness
List some important features of the drug history that help narrow the differential for collapse.
Insulin and other hypoglycaemics
Antihypertensives
Vasodilators
Anti-arrhythmics (paradoxically predisposes to arrhythmia)
Antidepressants (hypotension may be a side effect)
Warfarin and other anticoagulants
List some important features of the social history.
Alcohol
Use of stimulant recreational drugs (e.g. cocaine) – can cause tachyarrhythmia and drop cardiac output
What key question must be asked about the family history of the patient?
Have you had any close relatives who have died suddenly below the age of 65?
List some key features of general examination that allow narrowing of the differential diagnosis.
Tongue-biting
Dehydration
Head trauma
List some features of the cardiovascular examination that may indicate a cardiac cause of collapse.
Irregular pulse – AF
Ejection-systolic murmur – aortic stenosis
Carotid bruits – carotid artery stenosis
What test is important to perform in order to check for orthostatic hypotension?
Lying/standing blood pressure
How is orthostatic hypotension clinically defined?
Systolic drop > 20 mm Hg
Diastolic drop > 10 mm Hg
Why are focal neurological signs important to pick up?
Peripheral neuropathy may be caused by diabetes
Parkinson’s disease can lead to autonomic dysfunction
List three important blood investigations that should be performed in a patient with collapse and state the reasons for using them.
FBC – anaemia can worsen oxygen starvation of the brain
U&Es – check for biochemical evidence of dehydration + electrolyte abnormalities
Capillary blood glucose – exclude hypoglycaemia + check for undiagnosed diabetes
What other investigation is important to perform in a patient with collapse?
ECG – check for arrhythmia
NOTE: a normal ECG does not exclude a cardiac cause because arrhythmia may be paroxysmal
List three causes of aortic stenosis.
Bicuspid aortic valve
Senile calcification
Rheumatic fever
Define status epilepticus.
Seizures lasting for > 30 mins or repeated seizures without regain of consciousness in between
Describe the treatment of status epilepticus.
IV benzodiazepines (e.g. lorazepam, buccal midazolam)
If still fitting after 10 mins, repeat IV benzo
If still fitting after 10 mins, consider phenytoin infusion
If still fitting after 10 mins, consider general anaesthesia (e.g. thiopentone)
List some potential causes of status epilepticus.
Poor compliance with anti-convulsant medications Metabolic (e.g. hypoglycaemia) Alcohol and other toxins Hypoxia Infection
What is a Stokes-Adams attack?
A sudden transient loss of consciousness induced by a slow or absent pulse and subsequent loss of cardiac output
What underlying problems can cause Stokes-Adams attacks?
Complete heart block
Sinoatrial disease
Define epilepsy.
A tendency to recurrent, unprovoked seizures
Define seizure.
A transient excessive electrical activity with motor, sensory and cognitive manifestations
What are the two different types of seizure?
Generalised – affecting the whole brain
Partial – affecting a part of the brain
What are the subdivisions of generalised seizures?
Tonic-clonic – patients are initially rigid and then convulse with rhythmical muscular contractions
Absence – patients loses consciousness and seems vacant and unresponsive (mainly in children)
Atonic – brief loss of muscle tone making the patient fall
Tonic – like the tonic phase of tonic-clonic
Clonic – like the clonic phase of tonic-clonic
Myoclonic – extremely brief muscle contraction seen as jerky movements
What are the two different types of partial seizure?
Simple Partial – consciousness is UNimpaired
Complex Partial – consciousness is impaired
What is the main side-effect of all anti-convulsants?
They are ALL TERATOGENIC
What birth defects are the following drugs associated with:
Sodium Valproate
Phenytoin
Sodium Valproate
Neural tube defects
Phenytoin
Cleft palate + congenital heart disease
Describe the effect of carbamazepine and phenytoin on drug metabolism.
They are CYP450 inducers
They cause increased metabolism and, hence, reduced effectiveness of OCP and warfarin
Which anti-convulsant is associated with Stevens-Johnson syndrome?
Lamotrigine
List four rare cardiac causes of collapse.
HOCM
Long QT Syndrome
Brugada Syndrome
Arrhythmogenic Right Ventricular Dysplasia
List two acquired causes of long QT syndrome.
Hypomagnesaemia
Hypokalaemia
Describe the inheritance pattern of Brugada syndrome.
Autosomal dominant
What ECG changes are associated with Brugada syndrome?
RBBB
Saddle-shaped ST elevation in V1-3
What is the main intervention used for patients with these rare causes of collapse?
Implantable cardioverter defibrillator (ICD)
How is a vaso-vagal syncope explained by a patient?
odd sensation in stomach
- pale and clammy
- knowing they are going to loose conscioussness
How is a cardiac arrhythmia syncope explained by a patient?
no obvious trigger (playing sport or sitting watching TV and pass out)
What causes cardiac arrhythmia?
In what age group does it present and why?
due to ischaemic heart disease- arthrosclerosis
-> if it is so bad that is causes arrhythmia - these people succumb from it before reaching old age
What causes orthostatic hypertension?
In what age group does it present and why?
DUE TO MEDICATIONs
- ACE inhibotors, beta blockers, CCB
patients get up but can’t compensate for the drop in BP
What is the most likely cause of this syncope?
no warning signs
cardiac - outflow obstruction or arrhythmia
OR
cerebro vascular - subclavian steal syndrome
CAN HAVE PALPITATIONS BEFORE
What is the most likely cause of this syncope?
aura
epileptic seizure
What is the most likely cause of this syncope?
dizziness
vasovagal
What is the most likely cause of this syncope?
head turning
carotid hypersensitivity syndrome
What is the most likely cause of this syncope?
when getting up, straining or exercising
orthostatic
What is the most likely cause of this syncope?
exercising
caridac
HOCM, aortic stenosis, cardiac channelopathy
What is the most likely cause of this syncope?
vigorous arm activity
subclavian steal syndrome
how would you structure you history?
PRESENTING COMPLAINT:
ASK BEFORE
- precipitating factors (what were you doing)
- warning sign (How did you feel before it happened)
- recent head trauma
DURING
- how long unconscious for
- any tongue biting, incontinence, twitching
AFTER
- recover spontaneously
- feel drowsy afterwards
PAST MEDICAL HISTORY:
- happened beofre
- diabetes
- cardiac illness
- ask about leg claudication - indication of IHD
- previous stroke, MI
- epilepsy
- psychiatric issue- panic attack
DRUG HISTORY:
- insulin
- anti hypertensive
- vasodilator - GTN
- antiarrhytmic- can cause paroxysmal arrhythmias
- anti depressants - TCA
- Warfarin- subdural haemorrhages - CT Head!
SOCIAL:
- Alcohol
- recreational drugs
FAMILY HISTORY:
- anyone die spontaneously (HOCM)
What investigations would you do generally in a patient with collapse
BLOODS:
- FBC: anaemia
- BM- hypoglycaemia
- U & E- dehydration (raised urea disproportional to creatinine) OR Electrolyte abnormalities
ECG - arrhythmias
If you suspect the cause of the collapse is due to cardiac abnormality (such as valve lesions)
what is the appropriate inverstigation in addition to the others?
echocardiogram
If you suspect the cause of the collapse is due to carotid sinus hypersensitivity
what is the appropriate inverstigation in addition to the others?
carotid sinus massage
If you suspect the cause of the collapse is due to carotid epilepsy
what is the appropriate inverstigation in addition to the others?
CT or MRI of head
- look for tumour
Don’t do EEG - loads of false positives
what is a stroke adams attack?
What is the cause?
What is the treatment?
transient loss of cousciousness for 15-20 sec
-> may have twitching due to brain hypoxia
after comes round is flushes and good sats
Due to 3rd degree heart block or sinoatrial disease
Treatment is a pace maker
What is the tilt table test?
Why is it not used often?
TEST FOR VASOVAGAL SYNCOPE
patient lying down and then put upright
- see if they syncope
DON’t do on patients with:
- orthostatitc hypertension
Not very specific or sensitive
If someone is suffering from episodes of loss of consciousness- what do you need to advise them to do?
Inform the DVLA:
IF due to transient loss of blood to head
-> unlikely to recur can drive 4 weeks later
-> likely to recurr but identified and treated - 4 weeks later BUT if no identifiable cause 6months
IF unexplained but no seizure - 6 months
IF seizure - needs to be seizureless for 1 year and then can drive again
GUY looses consciousness when puts on tie before going to church
What does he have?
What is the investigation?
What is the treatment?
What does he have? - carotid sinus hypersensitivity
What is the investigation? carotid sinus massage - monitor with ECG and blood pressure (CHECK IF NO ARTHROSCLEROSIS OTHERWISE STROKE- check with doppler) - massage for 5 second carotid at angle of jaw - see if faint (always have atropine at hand if you cause acaridac arrest)
What is the treatment? can be due to low BP or bradycardia
IF DUE TO bradycardia - cardiac pacing might be good
What is HOCM - what are the symptoms?
What is the pathophysiology?
WHat is the inheritance pattern?
what are the symptoms? sudden collapse after exercise
What is the pathophysiology? no physiological left ventricular hypertrophy, outflow obstruction of aorta during systole
WHat is the inheritance pattern? autosomal dominant
What is Long QT symdrome - what are the symptoms?
What is the pathophysiology?
WHAT ARE the ECG changes
what are the symptoms? collapse particular dyrubg exertion associated with VT
What is the pathophysiology? potasium or sodium channel abnormality-
WHAT ARE the ECG changes? long QT interval and VT
What is Brugada symdrome - what are the symptoms?
What is the pathophysiology?
WHat is the inheritance pattern?
WHAT ARE the ECG changes
what are the symptoms? collapse
What is the pathophysiology?cardiac sodium channel dysfunction
WHat is the inheritance pattern? autosomal dominant
WHAT ARE the ECG changes? - RBB and V1-V3 saddle shaped ST elevation
What is arrhythmogenic right ventricular dysplasia- what are the symptoms?
What is the pathophysiology?
WHat is the inheritance pattern?
WHAT ARE the ECG changes
What is arrhythmogenic right ventricular dysplasia- what are the symptoms? collapse
What is the pathophysiology? myocardium replaced by fatty fibrotic tissue
WHat is the inheritance pattern?
WHAT ARE the ECG changes?RBB and V1-V3 T wave inversion and epsilon wave
