Blackouts Flashcards
What is the main differentials for ‘blackouts’?
vasovagal syncope, situational syncope (cough, effort, micturition), carotid sinus syncope, epilepsy, Stokes-Adams attacks, drop attacks, hypoglycaemia, orthostatic hypotension, anxiety, factitious blackouts
What are the key questions to ask in a history of blackouts?
Any witnesses/during: any LOC? Any injury? Did the pt move, stiff or floppy? Incontinence? Complexion changed? Bite their tongue? Associated symptoms? How long? Before the attack: any warning? What circumstances? Preventable? After the attack: how much do you remember? muscle ache after? anyone in family getting them/Sudden arrhythmic death syndrome?
What is the pathology behind vasovagal (neurocardiogenic) syncope?
reflex bradycardia +/- peripheral vasodilatation provoked by emotion, pain, fear or standing too long.
What is the typical history of vasovagal syncope?
Onset over seconds (not instantaneous) and often preceded by nausea, pallor, sweating and closing in of visual fields. It cannot occur if lying down. Falls to the ground, unconscious for approx 2 min. Brief clonic jerking of the limbs may occur (reflex anoxic convulsion due to cerebral hypoperfusion. No stiffening or tonic/clonic sequence. Urinary incontinence is uncommon and no tongue biting. Recovery is rapid
What are the types of situational syncope and an explanation of each?
cough syncope: syncope after a paroxysm of coughing. Effort syncope: syncope on exercise; cardiac origin eg aortic stenosis, HCM. Micturition syncope: syncope during or after micturition. Mostly men at night
What is the pathology of carotid sinus syncope?
hypersensitive baroreceptors cause excessive reflex bradycardia +/- vasodilatation on minimal stimulation eg head-turning, shaving
What features of blackouts are suggestive of epilepsy?
attacks when asleep or lying down; aura; identifiable triggers such as TV; altered breathing; cyanosis; typical tonic-clonic movements; incontinence of urine; tongue-biting; prolonged post-ictal drowsiness, confusion, amnesia and transient focal paralysis (Todd’s palsy)
What is a Stokes-Adams attack? What is the typical history?
Transient arrhythmias (such as bradycardia due to complete heart block) causing decreased cardiac output and LOC. Patient falls to the ground with no warning (except palpitations), pale, with a slow or absent pulse. Recovery in seconds, patient flushes, pulse speeds up and consciousness regainedl. A few clonic/tonic jerks may occur if attack is prolonged (cerebral hypoperfusion). Attacks may happen several times a day and in any posture.
What are ‘drop attacks’ and what is the typical history? What are some of the other causes of drop attack blackouts?
sudden weakness of the legs causes the patient to collapse. Usually an older woman, no warning, no LOC and no confusion afterwards. Condition is benign, resolving spontaneously after a number of attacks. Other causes: hydrocephalus (pt may not be able to get up for hours); cataplexy - triggered by emotion, associated with narcolepsy
What are some of the other causes of blackouts?
hypoglycaemia - tremor, hunger and perspiration herald light-headedness or LOC. Orthostatic hypotension: unsteadiness or LOC on standing from lying in those with inadequate vasomotor reflexes; eledrly, autonomic neuropathy, antihypertensive medication, overdiuresis, multisystem atrophy. Anxiety: hyperventilation, tremor, sweating, tachycardia, paraesthesia, light-headedness and no LOC suggest panic attack. Factitious blackouts: pseudoseizures, Munchausen’s. Choking: if airway occluded by food, pt may collapse, become cyanotic and unable to speak
