loss of consciousness Flashcards
neurological causes of LOC
- epileptic seizures
- raised ICP - tumour, post fossa lesions, hydrocephalus is colloic cyst
- SAH
- Sleep disorders (narcolepsy, cataplexy)
- basilar artery migraine
- cerebrovascular disease
types of neurally mediated syncope
- neurocardiogenic syncope
- carotid sinus syncope
- situation syncope (cough,micturution)
define syncope
transient loss of consciousness
classification of syncope
1) neurological
2) metabolic
3) psychiatric
4) cardiac
clinical signs and symptoms of neurocardiogenic syncope
may be preceded by prodromata such as nausea, diaphoresis, lightheadedness, blurred vision, headaches, palpitations, paraesthesia, and pallor
after recovery - washed out and tired feeling
carotid sinus syncope signs and symptoms
rotation or turning of the head or pressure on the carotid sinus (for example, carotid massage, shaving, tight collars or neckwear, or tumour compression)
cardiac syncope causes
cardiac arrhytmias
structural cardiopulmonary disease
- AS
- HOCM
- PE
causes if orthosatic/postural hypotension
drugs - vasodialtors, antidepressants, L-dopa preparations
autonomic neuropathy
- GBS
- Diabetes
- amyloid
neurodegenerative diseases
- MSA, PD
hypovolaemia - loss of blood, diuretic therapy, Addison’s disease
causes of LOC from metabolic disorders
hypoglycaemia
hyperventilation induced alkalosis
what is consciousness
wakefullness and awareness
depends on the sesnory input into the brain and the intrinsic activity of the reticular activating system, ascending reticular formation in the brainstem and its rostral connections, which maintain the cerebral cortex in an alter state
causes of short lived LOC
Seizure Vaso-vagal syncope Neurocardiogenic syncope Cardiac syncope Hypoglycaemia Dissociative or functional Cataplexy Head injury
typical pre-syncopal Sx
faint, hot, sweaty, muffled hearing, blurred vision, tinnitus, dizziness
temporal lobe epilepsy aura
déjà vu, jamais vu, olfactory and gustatory hallucinations
DD for seizures
Generalised tonic-clonic seizure with minor head injury
Generalised tonic-clonic seizure with significant head injury
Syncope with head injury and subsequent seizure with post ictal confusion caused by either the fit and/ or concussion
Acute intracranial event causing collapse or fit with head injury
Intracranial abnormality leading to seizure
what is narcolepsy
rare - tetrad of clinical features
-> daytime sleep attacks (10-20mins), irresistible, inappropriate
- > cataplexy - loss of postural control and limb weakness w preserved consciousness provoked by emotional events
- > sleep paralysis
- > hypnagogic hallucinations - frightening visual hallucinations on falling asleep
Mx of narcolepsy
amphetamines but careful
modafinil
clomipramine relieves cataplexy no effect on narcoleptic attacks
what is obstructive sleep apnoea
excessive daytime somnolence w partial upper airway obstruction - nocturnal apnoeic attacks
heavy snoring
Ix - pulse oximetry overnight
central sleep apnoea - apnoeic episodes occur without continuing respiratory effort
Mx CPAP
most common/uncommon causes of transient LOC
syncope
seizures
UNCOMMON hypoglycaemia narcolepsy/cataplexy hyperventilation vertebrobasilar ischaemia vertebrobasilar migraine psychogenic or 'non-epileptic attacks'
what is vasovagal syncope
fainting - caused by a sudden drop in BP resulting from peripheral vasodilation
reduction in CO -> vagal stimulation -> bradycardia
triggers - strong emotion, sudden intense pain, prolonged standing
Prodromal Sx of vasovagal syncope
Sx
prodromal
light headed, gradual dimming of vision, ringing in the ears, salivation, sweating, N/V
Sx
pale, clammy
what is situational syncope (micturition/cough)
micturtion -> men who get up during the night to pass urine -> vasodialtion, postural hypotension, bradycardia
