Approach to Syncope

 Syncope

An abrupt loss of consciousness or loss of postural tone which is of short duration and is followed by spontaneous recovery is known as syncope. 

There are four components of syncope

1. An abrupt and transient loss of consciousness 
2. Loss of postural tone
3. Short Duration
4. Spontaneous recovery

Prodrome

A constellation of symptoms like lightheadedness, diaphoresis, visual distrubances that can  precede the loss of consciousness. Prodrome can last for several seconds to minutes.

    Chest pain, palpitations or dyspnea point to cardiac cause

    Aura , Headache, Dysarthia, and limb weakness point to CNS causes

Pre-syncope

Occurance of prodromal symptoms of syncope without the subsequent loss of consciousness is known as pre-syncope.

During Attack

Is there a pulse?

Limb jerking, Tongue biting, Urinary Incontinence? Hypoxic Seizures

After Attack

Rapid recovery: Arrythmia, VAsovagal syncope

Prolonged, with drowsiness: Seizures

Questions to Ask of a Patient presenting with syncope

What was the patient doing immediately before ?

Were there any symptoms immediately before the attack? lightheadedness, diaphoresis, visual distrubances, etc

Are there any injuries?

For how long was the patient unconscious?

How long did it take to recover?

Was the event witnessed? 

Duration of Syncope:

    >5min: Unlikely syncope, Consider: Medications, Alcohol Blackout, Drug intoxication, Concussion, Nacrolepsy, OSA-related hypersomnolence

    <= 5 min:

        Were the following features present?

        Tonic Clonic movements during LOC , Bladder and bowel incontinence, longer period of confusion after the attack: Likely a Seizure

        No above-mentioned features: Most likely syncope

 

Driving and Syncope

Simple Faint: No Restriction

Unexplained syncope

    With Probable Cardiac Etiology: 4 weeks off driving if cause is identified and can be treated, otherwise 6 months off driving

    Loss of Consciousness with altered awareness with signs of seizures: 6months off

    Known epileptic, or has similar episode in past 5yr: 1year off

    Single episode of LOC with no cardiac and neuro cause found: 6 months off

Aeitology

Different causes of syncope can be divided into different types: Reflex syncope, Cardiogenic syncope, Orthostatic Hypotension, and Syncope mimics.

Reflex Syncope: 

    Dysfunctional autonomic response to normal stimuli

    Vasovagal syncope: Prolonged standing, Emotional stress, Blood draw, Severe pain

    Situational syncope: Coughing, sneezing, Micturition, Defecation, Post-exercise

    Carotid sinus hypersensitivity

Reflex syncope is usually precipitated by a clearly identifiable trigger, prodromal symptoms are present, and typically occurs in a younger patient.

Reflex syncope is relatively benign. Usually no further investigations are necessary. Ambulatory ECG monitoring can be considered. Carotid hypersensitivity is confirmed by carotid sinus massage test.

Cardiogenic Syncope:

    Bardyarrhythmias: Sinus Bradycardia, Sinus Pauses, AV Block

    Tachyarrhythmias: VT

    Mechanical: Aortic Stenosis, HOCM, Massive PE

Usually there are no precipitants of cardiogenic syncope. Sometimes it may be precipitated by exertion. Prodormal symptoms can be absent, injuries during fall are common and it typically occurs in older patients with notable risk factors.

Cardiogenic Syncope is relatively dangerous and thus requires complete cardiovascular exam, Echocardiography, and ambulatory EKG monitoring.

Orthostatic Hypotension: 

    Systolic drop >= 20 or Diastolic drop>=10

    Volume Depletion

    Medications: alpha-blockers, antidepressants, antipsychotic

    Autonomic Failure: Parkinson, Diabetes, Alcoholism

Orthostatic Syncope is relatively benign, is precipitated by movement from sitting/lying position to an upright position, and typically occurs in older patients. 

There are no relevant EKG findings in orthostatic hypotension. Trial of IV fluids can be given to correct dehydration. The medicines can be adjusted if feasible. If neither IV fluids or stopping/ adjusting dose of medications improves the symptoms, consider autonomic  dysfunction.

Syncope Mimics

    Seizures

    Cerebrovascular Syncope 

         Vertebrobasilar Insufficiency

          Subclavian Steal syndrome

    Alcohol Withdrawl

    Medication Side Effect (e.g. sedation)

    Psychogenic Pseudo-syncope

 

Most common specific etiology of syncope is vasovagal syncope.

Most dangerous general category of syncope is cardiogenic syncope.