What is the treatment for vasovagal syncope triggered by coughing and feeling sick?

Treatment of Vasovagal Syncope Triggered by Coughing

For cough-induced vasovagal syncope, the most critical intervention is identifying and suppressing the underlying cause of the cough itself, combined with patient education about trigger avoidance and physical counterpressure maneuvers. 1

Understanding Cough Syncope

Cough syncope is classified as "situational syncope," a specific subtype of neurally-mediated reflex syncope that occurs during or immediately after coughing. 1 This is a reflex response triggered by the mechanical act of coughing that leads to vasodilation and/or bradycardia, resulting in systemic hypotension and cerebral hypoperfusion. 1

Primary Treatment Strategy: Address the Cough

The cornerstone of treating cough syncope is directly addressing the trigger factor—suppressing the cause of the cough. 1 This distinguishes cough syncope from other forms of vasovagal syncope where trigger elimination may not be as straightforward. Before implementing any other interventions, evaluate and treat:

• Chronic bronchitis or COPD exacerbations
• Asthma
• Post-nasal drip or upper airway cough syndrome
• Gastroesophageal reflux disease
• Medication-induced cough (ACE inhibitors)
• Pertussis or other respiratory infections 1

Essential Non-Pharmacological Interventions

Patient Education (Mandatory for All Patients)

• Explain that vasovagal syncope is not life-threatening and has a benign prognosis 2, 3
• Teach recognition of premonitory symptoms (lightheadedness, nausea, warmth, visual changes) to identify impending episodes 1, 2
• Instruct on immediate supine positioning when prodromal symptoms occur 1

Physical Counterpressure Maneuvers (Second-Line)

All patients with adequate prodromal warning should be taught physical counterpressure maneuvers: 3

• Leg crossing with muscle tensing
• Squatting
• Isometric arm contraction or handgrip
• These maneuvers can abort an episode if performed during the prodrome 2, 3

Volume Expansion Strategies (Third-Line)

Increase dietary salt and fluid intake (2-2.5 liters per day) unless contraindicated by hypertension, heart failure, or renal disease: 2, 3

• Use salt tablets or sport drinks as volume expanders 1, 2
• Consider head-up tilt sleeping (>10°) 2
• Compression garments or abdominal binders to reduce venous pooling 2
• Moderate exercise training, particularly swimming 2

Pharmacological Treatment (Fourth-Line)

Midodrine is the only medication with consistent evidence of efficacy and should be the first-line pharmacological agent if non-pharmacological measures fail. 3, 4 Meta-analysis of 5 randomized controlled trials shows midodrine reduces syncope recurrence by 43%. 3 It is contraindicated in patients with hypertension, heart failure, or urinary retention. 3, 4

Fludrocortisone (0.1-0.2 mg daily) may be considered only after midodrine fails, particularly in young patients with low-normal blood pressure. 2, 3 However, evidence supporting its use is limited and the POST II trial is still investigating its benefits. 5

Beta-blockers are NOT recommended as evidence fails to support their efficacy and they may worsen bradycardia in cardioinhibitory cases. 2, 3, 4

When Treatment Is Actually Necessary

Treatment is NOT required for patients who have experienced only a single syncope episode and are not in high-risk settings. 2, 3

Aggressive treatment is warranted when: 3

• Syncope is recurrent and unpredictable with minimal prodromal symptoms
• Patient works in high-risk occupations (commercial drivers, pilots, machine operators, competitive athletes)
• Frequency exceeds 5 attacks per year with severe physical injury 3

Cardiac Pacing (Last Resort)

Dual-chamber pacing should be reserved only for highly selected patients meeting ALL of the following criteria: 3

• Age >40 years
• Documented cardioinhibitory response
• Frequency >5 attacks per year with severe physical injury
• All other therapies have failed 2, 3

Critical Pitfalls to Avoid

• Do not overtreat patients with infrequent episodes 2
• Review and discontinue or reduce chronic vasodilator therapy (antihypertensives, nitrates) that may enhance susceptibility to vasovagal syncope 1
• Avoid routine neurological investigations unless loss of consciousness cannot be attributed to syncope or autonomic failure is suspected 1
• Monitor for supine/nocturnal hypertension when implementing volume expansion strategies 2