16. Loss of consciousness

Question 1

define syncope

Answer 1

transient loss of consciousness due to global cerebral hypoperfusion with rapid onset, short duration and spontaneous complete recovery.

Question 2

causes of syncope broad categories

Answer 2

reflex/neurogenic syncope
- vasovagal
- situational
- carotid sinus

orthostatic syncope

cardiogenic syncope

Question 3

causes of vasovagal syncope

Answer 3

triggered by emotion, pain or stress

Question 4

causes of situational syncope

Answer 4

cough, micturition, gastrointestinal

Question 5

what is carotid sinus syncope

Answer 5

CSS is a type of reflex syncope or near-syncope with symptoms (eg, syncope, lightheadedness) caused by CSH manifesting during activities of daily life that put pressure on the carotid sinus (eg, turning the neck, looking upward).

Question 6

pathophysiology reflex syncope

Answer 6

transient failure of autoregualrion of BP –> leads to cerebral hypoperfusion and LOC

often has a trigger but sometimes this isnt obvious

reflex response characterised by vasodialtion and/or bradycardia leading to systemic hypotension adn cerebral hypoperfusion

Question 7

define postural hypotension

Answer 7

A drop in systolic BP of ≥ 20mmHg

A drop in systolic BP to below 90mmHg on standing

A drop in diastolic BP of 10mmHg with symptoms (this is less clinically significant)

Question 8

causes of postural hypotension menumonic

Answer 8

HANDI

H - hypovolemia, hypopituitarism

A - addisons disease

N - neuropathies autonomic NS (DM, amyloidosis, shy-drager syndrome)

D - drugs - D and 6 aNTIS
Diuretics
anti-hypertensives
anti-angina
anti-parkinsons
anti-depressants
anti-psychotics
anti-BPH (alpha blockers)

I - idiopatjic

Question 9

plan ?postural hypotension

Answer 9

If cause known treat cause

Investigate their pharmacology for causes

Conservative whilst investigating eg adequate hydration, Standing slowly, dorsiflexing the feet and even crossing the legs on standing upright, prevents excessive diuresis and fluid shifts that can lead to a sudden drop in blood pressure. Compression stockings

Fludrocortisone (steroid) (note: poor evidence base) or Midodrine

Question 10

define coma

Answer 10

a score of ≤ 8 on the Glasgow Coma Scale (GCS) lasting ≥ 6 hours.

an inability to maintain wakefulness and awareness

Question 11

some causes of cardiogenic syncope?

Answer 11

arrhythmias: bradycardias (sinus node dysfunction, AV conduction disorders) or tachycardias (supraventricular, ventricular)

structural: valvular, myocardial infarction, hypertrophic obstructive cardiomyopathy

get ecg and echo if indicated

Question 12

causes of coma

Answer 12

Primary cerebral
- hemorrahge
- infections
- trauma
- tumours

• metabolic/hypoxia
• drugs and alcohol

Question 13

DVLA syncope

Answer 13

simple faint: no restriction
single episode, explained and treated: 4 weeks off
single episode, unexplained: 6 months off
two or more episodes: 12 months off