Collapse, Syncope and Episodic Syncope

Question 1

What are differential diagnoses for “collapsing” patients?

Answer 1

Collapse, weakness, syncope, fainting, fits, seizures, funny turns

Question 2

What questions should be asked when taking a history for collapsing patients?

Answer 2

• Number of events
• Age of onset
• Duration
• Time of day
• Association with exercise/excitement, feeding, rest/waking
• Prodrome/post-ictal behaviour
• Tonic/clonic or flaccid
• Autonomic signs
• Consciousness lost
• MM pallor/cyanosis?
• Heart rate
• Normal between episodes
• Exercise intolerance?
• Medication
• Toxin/ drug access

Question 3

What is syncope?

Answer 3

Sudden, short-lived loss of consciousness

Temporary failure of delivery of energy substrate to CNS

Typically failure of perfusion

Question 4

What are the clinical signs of syncope?

Answer 4

• Sudden onset
• Generalised weakness/ ataxia
• Flaccid collapse- motionless
• Consciousness lost
• Maybe autonomic signs
• Maybe generalised mm activity –> might have seizure-like activity occasionally

Question 5

What are the differentials for syncope?

Answer 5

Inappropriate vascular reflexes:
o Vasovagal 
o Carotid sinus 
o Situational (e.g. tussive) 
o BP falls- perfusion fails 
o Clinically normal? 
o Excited when someone arrives, vasodilation quickly then syncope for a few seconds 

Cardiac: 
o Dysrhythmia 
o Flow obstruction 
o Pump failure 
o Tamponade (fluid in pericardium)/ preload failure 
o Perfusion fails 
o Clinical abnormality likely – makes easier to diagnose 
o Exertional? 

Non-cardiac:
o Metabolic
o Central neurological
o Clinical abnormality?

Question 6

What is episodic weakness?

Answer 6

• Intermittent/ persistent exercise intolerance
• Worsens with exercise
• Improves with rest

Question 7

What body systems could be involved with weakness?

Answer 7

Muscular 
Neuromuscular 
Neurological 
Orthopaedic
Respiratory
Cardiac
Metabolic 
Haematological

Question 8

What diagnostic tests can be used to identify the body system involved?

Answer 8

Metabolic:
ACTH/ TSH/ insulin levels, etc.

Neuromuscular:
Edrophonium response test/ anti-ACh Ab

Muscular:
EMG, mm biopsy

Cardiorespiratory:
Blood gases, ECG, echo, radiography

Question 9

Often collapse/ syncope/ weakness is NAD. What can you tell the owner to do to monitor?

Answer 9

Heart rate
MM
Video when episodes occur

Can attempt to induce an episode with exercise

As the number of negative tests goes up then the likelihood of diagnosis goes down