Transient LOC and Persistent LOC (Coma) Flashcards
Causes LOC
Toxic/Metabolic
- Hypoxia, hypercapnia, sepsis, hypotension
- Drug intoxication, poisoning (CO)
- Renal or liver failure
- Hypoglycaemia, DKA
Neurological
- Trauma
- Epilespy (seizures)
- Infection (meningitis, encephalitis)
- Tropical (malaria, typhoid, rabies)
- Tumour
- Vascular (stroke, SAH, SDH)
What would you ask someone about when trying to determine a cause of transient LOC?
Individual account
- History preceding events - Context/timing, posture
- Event itself
- What happened afterwards
Witness account
- What happened before
- What happened during
- What happened after
What are the main groupings of precipitants to syncopal events?
- Reflex - Neurocardiogenic - micturition, cough
- Orthostatic - dehydration, medication related, endocrine, autonomic nervous system
- Cardiogenic - arrhythmias, AS
Why can proping someone up who is having a syncopal event cause the event to prolong?
Decreased cerebral perfusion which is corrected by lying flat. If propped up, this prolongs the cerebral hypoperfusion
What are causes of a provoked seizure?
- Alcohol withdrawal
- Drug withdrawal
- Within a few days of head injury
- Within 24 hours of stroke
- Within 24 hrs neurosurgery
- Severe electrolyte disturbances
- Eclampsia
What are causes of sudden LOC?
- Epilepsy
- Syncope
- Non-epileptic attacks (pseudoseizures)
- Panic attacks and hyperventilation
- Hypoglycaemia
- Drop attacks
- Hydrocephalic attacks
- Basilar migraine
- Severe vertigo
- Cataplexy, narcolepsy, sleep paralysis
How woud you distinguish syncope from a seizure?
Syncope often presents with LOC + sympatoms and signs of sympathetic overdrive e.g. gradual pallor, cold sweat, feeling nauseous, tachycardia etc. Those who experience syncope (for whatever cause) can be incontinent, and recover quite quickly
Seizures lack features of sympathetic overdrive, and can be incontinent, can frequently suffer some sort of injury, and recovery is slow.
What are causes of syncope?
- Neurocardiogenic syncope (vasovagal)
- Cardiac syncope (Stokes–Adams attacks)
- Situation syncope - Micturition syncope, Cough syncope
- Postural hypotension
- Carotid sinus syncope
What is vasovagal syncope?
Syncope due to sudden reflex bradycardia with vasodilatation of both peripheral and splanchnic vasculature (neurocardiogenic or vasovagal syncope).
What are precipitants vasovagal syncope?
- Emotion
- Prolonged standing
- Pain
- Fear
- Venesetion
What are prodromal features of a vasovagal syncope?
Brief episode of:
- Dizziness
- Light-headedness
- Pallor
- Nausea
- Sweating
- Feeling of heat
- Visual grey-out
What are features of the blackout seen in vasovagal syncope?
-
Usually lie still
- Can have jerking/twitching movments
- Pallor
- Can be incontinent
- No tongue biting
How long do vasovagal attacks last?
Approximately 2 minutes
Why can brief clonic jerks occur in vasovagal syncope?
Cerebral hypoperfusion
What are features following a vasovagal attack?
Tiredness - differentiated from post-ictal by lack of drowsiness/confusion
What are cardiogenic causes of syncope?
- Cardiac arrhythmias
- Aortic stenosis
- Hypertrophic cardiomyopathy
What are Stoke-Adams attacks?
Transient arrhythmias causing decreased CO and LOC. Patient falls to the ground with no warning, is pale, with a slow or absent pulse. Recovery occurs in seconds - patient fluses, pulse speeds up, and consciousness is regained
Anoxic clonic jerks can occur
What is micturation syncope?
Syncope that occurs during or after urination - usually in men at night
What is cough syncope?
Occurs when venous return to the heart is obstructed by bouts of severe coughing
What is effort syncope?
Syncope brought on by exercise - often cardiac cause underlying e.g. aortic stenosis, HOCM
What is carotid sinus syncope?
Syncope due to vagal response caused by pressure over the carotid sinus baroreceptor in the neck e.g. due to tight collar
What are pseudoseizures?
Usually there are bizarre thrashing, non-synchronous limb movements, but there can be extreme difficulty in separating these attacks from seizures. EEG videotelemetry is valuable.
What types of migraine can cause loss of consciousness?
- Basilar migraine
- Familial hemiplegic migraine
What might suggest that someone has lost consciousness due to hypoglycaemia?
Prior seconds/minutes of hunger, shaking, sweating and darkening of visual fields. Following confusion, loss of consciousness +/- convulsions or hemiparesis can occur
What might indicate that syncope has been caused by a panic attack?
- Hyperventilation
- Dizziness
- Chest pains/tightness
- Feeling like your choking
- Tingling in face/extremities
- Palpitations
- Trembling
- Feeling of dissociation
What can cause drop attacks?
Mostly benign, but can be caused by:
- Hydrocephalus
- Cataplexy
- Narcolepsy
What might a single, fixed dilated pupil indicate in a comatose patient?
Coning/Uncal herniation
What might bilateral pinpoint pupils indicate in a comatose patient?
- Opiate overdose
- Pontine lesion/stroke
What might a loss of Doll’s eye reflex indicate?
- Deep coma
- Brainstem lesions
- Brain death
What might the following indicate in a comatose patient?
Dysgonjugate gaze - usually indicates brainstem lesion, can also be mildly dysgonjugate in metabolic coma
What can small, reactive pupils indicate in someone who is comatose indicate as a potential cause?
Metabolic/toxic causes
What is the cause of a vegetative state?
Extensive cortical damage with intact brainstem
How would GCS (eyes, verbal and motor scores) differ between a vegetative state and a coma?
Eye score is the main difference
- Vegetative - E4, M1-4, V1-2
- Coma - E1-2, M1-4, V1-2
What is the cause of locked-in syndrome?
Occlusion/haemorrhage leading to Ventral pontine infarct with preserved ARAS (ascending Reticular Activating System) that extends from the thalamus and influences the state of arousal
