Syncope

Question 1

What is the definition of syncope?

Answer 1

Transient loss of consciousness due to inadequate cerebral blood flow.

Question 2

What are common mimics of syncope that are not true syncope?

Answer 2

Seizures, pseudoseizures, sleep issues, and mechanical falls with subsequent loss of consciousness from head trauma.

Question 3

What is helpful for ruling out seizure as an etiology for loss of consciousness?

Answer 3

Seizures have a gradual, prolonged period of recovery (with the exception being absence seizure) due to the postical stage.

Question 4

What are the typical clinical features of syncope?

Answer 4

Transient loss of consciousness lasting ~10 seconds, potentially resulting in a fall or accident. May be preceded by prodromal symptoms specific to the etiology.

Question 5

What is the key component of the workup for syncope?

Answer 5

Detailed history and physical exam, ECG/telemetry, orthostatics, labs for metabolic disturbances, and transthoracic echocardiogram (TTE) if structural heart disease is suspected.

Question 6

Why is it important to determine if the syncopal event was sudden or gradual?

Answer 6

• Sudden onset points to cardiac or neurological
• Gradual onset points to toxins or metabolic problems
• Vasovagal can be sudden or gradual

Question 7

How is low-risk syncope managed?

Answer 7

Patients with clear vasovagal syncope and no red flags can be discharged home.

Question 8

A 22-year-old woman is brought to the office by her mother because “she has been passing out.” The patient’s first episode occurred about a year ago when she split up with her boyfriend. A more recent episode was also provoked by strong emotion. Both episodes were preceded by nausea, light-headedness, weakness, and blurred vision, lasted about a minute, and ended with rapid recovery of consciousness. The patient sustained no significant injuries in either episode. She is concerned because one of her childhood friends passed out and died while playing football. Medical history is otherwise insignificant. The patient takes no medications and does not use alcohol or illicit drugs. She has no family history of early coronary artery disease, cardiomyopathy, or sudden cardiac death. Blood pressure is 110/70 mm Hg while supine and 108/70 mm Hg while standing. Physical examination findings are within normal limits. ECG reveals no abnormalities. Complete blood count and serum chemistries are within normal limits. Which of the following is the best next step in management of this patient?

Answer 8

This patient has experienced recurrent vasovagal syncope, a type of reflex syncope. It is typically triggered by emotional distress, prolonged standing, or painful stimuli, and patients usually experience an autonomic prodrome with nausea, pallor, diaphoresis, or generalized warmth. Spontaneous resolution of the episode occurs within seconds to a few minutes. Patients with vasovagal syncope have an excellent prognosis, and the initial approach is aimed at providing education and reassurance. Patients are advised to avoid triggers and to assume a supine position with raised legs at the onset of prodromal symptoms. In addition, patients may be taught physical counterpressure maneuvers (eg, leg crossing with tensing of muscles, tensing of arm muscles with clenched fists) to improve venous return and cardiac output, and abort an episode of vasovagal syncope during the prodromal phase.

Question 9

What is the most common cause of syncope?

Answer 9

vasovagal syncope

Question 10

What causes vasovagal syncope?

Answer 10

Increased parasympathetic outflow leading to transient bradycardia and hypotension, often triggered by emotional stress, pain, fear, or prolonged standing.

Question 11

What are the prodromal symptoms of vasovagal syncope?

Answer 11

Nausea, diaphoresis, pallor, and a general feeling of unwellness before syncope.

Question 12

What is a clear-cut indication of vasovagal syncope?

Answer 12

Rapid onset and return to consciousness with no other major red flag symptoms.

Question 13

How is vasovagal syncope diagnosed?

Answer 13

Diagnosis is clinical.

Question 14

What is the purpose of tilt-table testing?

Answer 14

Tilt-table testing is reserved for special cases of vasovagal syncope.

Question 15

How is vasovagal syncope managed?

Answer 15

Management includes reassurance and counterpressure maneuvers when prodromal symptoms occur. The initial management of vasovagal syncope is aimed at providing education and reassurance about its benign nature and prognosis and advising patients to avoid potential triggers of syncope. In patients with recurrent episodes, physical counterpressure maneuvers can abort or delay an episode of syncope and are recommended during the prodromal phase.

Question 16

What are the physical physical counterpressure maneuvers used to abort an episode of vasovagal syncope?

Answer 16

Patients should be taught physical counterpressure maneuvers that includes leg crossing with tensing of muscles, tensing of arm muscles with clenched fists, to improve venous return and cardiac output, and abort an episode of vasovagal syncope.

Question 17

Physical counterpressure maneuvers used to abort an episode of vasovagal syncope are used during which phase?

Answer 17

during the prodromal phase

Question 18

Can beta-blockers be helpful in vasovagal syncope?

Answer 18

Beta blockers were once thought to interfere with the neurologic pathways responsible for vasovagal syncope; however, these drugs have shown no benefit in preventing vasovagal syncope in randomized trials and are not recommended.

Question 19

What is situational syncope, and how is it managed?

Answer 19

Syncope triggered by specific situations (e.g., cough, urination, swallowing). Management includes reassurance; pacing may be required for carotid sinus syncope (stimulation of the carotid sinus from events like putting on a helmet, shaving, or tying a necktie).

Question 20

What is the pathophysiology of carotid sinus hypersensitivity?

Answer 20

Syncope while shaving most likely has carotid sinus hypersensitivity (CSH). When carotid sinus baroreceptors detect increased blood pressure, the brainstem responds by increasing parasympathetic tone (slows the heart rate) and reducing sympathetic tone (induces vasodilation). In some individuals, especially elderly men, the carotid sinus baroreceptors become overly sensitive to tactile stimulation, triggering an exaggerated vasovagal response with marked peripheral vasodilation (ie, decreased systemic vascular resistance). This can cause a transient reduction in cerebral perfusion that manifests as presyncope (eg, faintness, lightheadedness or syncope. As with other etiologies of syncope, cerebral perfusion quickly returns and symptoms resolve within 1-2 minutes. In addition to shaving, rubbing of a shirt collar while dressing or turning the head is another common cause of syncope due to CSH.

Question 21

A patient has a significant drop in blood pressure after pressing on the carotid sinus, what is the likely underlying cause?

Answer 21

• Carotid sinus syncope (a subtype of situational syncope) is commonly seen in patients with atherosclerosis.
• This is managed with a pacemaker or alpha agonist like midodrine.

Question 22

What causes orthostatic syncope?

Answer 22

Caused by hypovolemia, autonomic failure (e.g., diabetes, Parkinson’s), or medications (e.g., alpha or beta blockers).

Question 23

What are the clinical features of orthostatic syncope?

Answer 23

Lightheadedness, dizziness upon standing, and syncope after prolonged standing.

Question 24

How is orthostatic syncope treated?

Answer 24

Fluids for hypovolemia, and fludrocortisone or midodrine for neurogenic orthostatic hypotension.

Question 25

What are examples of high-risk features in syncope requiring admission?

Answer 25

Syncope during exercise, palpitations, abnormal ECG findings (e.g., VTach, bradycardia, prolonged QT, heart block, bifascicular block).

Question 26

What causes cardiogenic syncope?

Answer 26

Bradyarrhythmias (e.g., sinus bradycardia, heart block, sick sinus syndrome) or ventricular arrhythmias (e.g., VTach).

Question 27

How does onset help to distinguish a cardiogenic syncopal event, warranting a cardiac exam?

Answer 27

• Syncope often occurs suddenly without prodrome.
• Patients will regain consciousness quickly.

Question 28

What are the initial clinically relevant diagnostic steps for cardiogenic syncope?

Answer 28

1) Auscultation of the heart
2) ECG

Question 29

When a patient presents with syncope, what would prompt evaluation of the patient with a a transthoracic echocardiography?

Answer 29

Evaluation of the patient with a a transthoracic echocardiography should be performed in patients with syncope and clinical features such as exertional syncope or abnormal cardiac murmurs that are suggestive of structural heart disease.

Question 30

What are the structural heart diseases can cause syncope?

Answer 30

Aortic stenosis, Mitral stenosis, hypertrophic cardiomyopathy, Arrhythmogenic Right Ventricular Cardiomyopathy, Anomalous Coronary Artery.

Question 31

When does syncope typically occur in structural heart disease?

Answer 31

Usually during exertion.

Question 32

What are the nonstructural causes of cardiogenic syncope?

Answer 32

Brugada, Congenital long QT, WPW.

Question 33

How is cardiogenic syncope diagnosed when the index of suspicion is high for an underlying cardiogenic cause but there are equivocal findings on initial workup?

Answer 33

Cardiogenic syncope requires diagnosis with ECG or long term cardiac monitoring. A holter monitor is used when the diagnosis has not been specified. 24-hour Holter monitoring may be indicated to assess for cardiac syncope in patients who have clinical features (eg, syncope without autonomic prodrome) or ECG findings suggesting cardiac arrhythmia.

Question 34

How is syncope from structural heart disease diagnosed?

Answer 34

• ECG.
• Transthoracic echocardiogram (TTE).
• Cardiac enzymes (Troponin or CKMB).
• Put the patient on telemetry if inpatient or Holter monitor or implantable loop recorder if discharging.

Question 35

If a patient had gradual loss of consciousness, what is the likely underlying cause of the syncopal event?

Answer 35

• Toxin or metabolic derangement.
• The workup includes glucose level checks, oxygen saturation, urine drug screen, and a CBC.

Question 36

What are other potential causes of syncope?

Answer 36

Heat syncope, Pulmonary embolism, or subarachnoid hemorrhage.

Question 37

If the patient had a sudden onset of loss of consciousness, followed by a gradual return to consciousness, what is most likely etiology for their syncopal event?

Answer 37

Neurogenic, the workup will require a head CT with EEG to evaluate for seizure.