Blackouts or Flashcards
acronym for causes of blackouts
CRASH Cardiac Reflexes Arterial Systemic Head
Cardiac causes of blackouts
Stokes-Adams Attacks
Brady - heart block, sick sinus, long-QT
Tachy - SVT, VT
Structural - weak hear (LVF, tamponade), block (AS, HCM, PE)
Reflex causes of blackouts
- Vagal overactivity
- vasovagal syncope
- situational (cough, effort, micturition) - sympathetic underactivity = postural hypotension
- Salt deficiency (hypovolaemia, Addisons)
- Toxins (Cardiac - ACEi, diuretics, nitrates) (Neuro - TCAs, benzos, antipsychotics, L-DOPA)
- Autonomic Neuropathy (DM, Parkinson’s, GBS)
- Dialysis
- Unwell (chronic bed rest)
- Pooling (venous, varicose veins, prolonged standing)
Acronym for sympathetic underactivity causes of blackouts
STANDUP
arterial causes of blackouts
- Vertebrobasilar insufficiency: migraine, TIA, CVA,
subclavian steal - Shock
- Hypertension: phaeochromocytoma
systemic causes of blackouts
- Metabolic: ↓glucose
- Resp: hypoxia, hypercapnoea (e.g. anxiety)
- Blood: anaemia, hyperviscosity
head causes of blackouts
- epilepsy
- drop attacks
general investigations for blackouts
- lying and standing BP (>20/10 difference after 3 min → postural hypotension)
- ECG ± 24hr ECG
- U+E, FBC, Glucose
- Tilt table
- EEG, sleep EEG
- Echo, CT, MRI brain
Triggers for cardiogenic syncope
exertion, drugs, unknown
symptoms before cardiogenic syncope
palpitations, chest pain, dyspnoea
symptoms during cardiogenic syncope
pale, slow/absent pulse, clonic jerks may occur
symptoms after cardiogenic syncope
rapid recovery
investigations for cardiogenic syncope
- ECG
- 24hr ECG
- Echo
triggers for vasovagal syncope
prolonged standing
heat
fatigue
stress
symptoms before vasovagal syncope or postural hypotension
- Gradual onset: secs→mins
- Nausea, pallor, sweating, tunnel vision, tinnitus
- Cannot occur lying down
symptoms during vasovagal syncope or postural hypotension
- Pale, grey, clammy, brady
- Clonic jerks and incontinence can occur, but no tongue biting
symptoms after vasovagal syncope or postural hypotension
rapid recovery
investigations for vasovagal syncope or postural hypotension
tilt-table testing
triggers for postural hypotension
standing up
triggers for arterial causes of blackout
- arm elevation (subclavian steal)
- migraine
symptoms of arterial blackout
same as vasovagal
+ diplopia, nausea, dysarthria
investigations for arterial blackout
- MRA
- duplex vertebrobasilar circulation
symptoms of hypoglycaemic syncope
tremor, hunger, sweating, lightheadedness
→ LOC
triggers for epileptic causes of blackout
flashing lights
fatigue
fasting