Patient will present as → a 22-year-old female comes to the emergency department for a syncopal episode. Just prior to the syncopal episode, the patient experienced painful menstrual cramping. She experienced a cold sweat and palpitations with the cramping. The patient describes similar episodes to her menstrual cramps in the past. Her vital signs and physical examination are normal. ECG is unremarkable.
Vasovagal syncope (common faint, neurocardiogenic syncope, or reflex syncope) is characterized by an abrupt onset of hypotension followed by a syncopal episode often in reaction to a stressful trigger
- Caused by a paradoxical withdrawal of sympathetic stimulation and a replacement by enhanced parasympathetic (vagal) activity causing bradycardia, vasodilation, marked decrease in BP, and cerebral perfusion
- The most common cause of syncope. Most people have one episode, but for some, it is a recurrent problem
- Common triggers include strain, stress, extended periods of standing, heat exposure, or the sight of blood
- Symptoms include paleness, nausea, sweating, a rapid heartbeat, and fainting
In healthy patients with a classic history of vasovagal syncope, a normal exam, and a normal ECG, no further testing is indicated, and laboratory testing is low yield
- When a diagnosis is not certain, or when patients have multiple potential causes of syncope, serum electrolyte testing, complete blood count, and cardiac enzymes may be indicated
- Upright tilt-table study can reproduce the symptoms in susceptible people
- Can occur at any age, but if the first episode is after age 40, be reluctant to make this diagnosis
Can usually be reversed by assuming the supine posture and elevating the legs
- Treatment usually involves trigger avoidance, but may on rare occasions include β-blockers and disopyramide or a pacemaker
Question 1 |
Orthostatic hypotension Hint: Typically occurs upon standing up, not after prolonged standing. | |
Cardiac arrhythmia Hint: Can cause syncope but usually doesn't have a clear trigger like standing in a hot room. | |
Vasovagal syncope | |
Seizure disorder Hint: Presents differently and is not typically triggered by standing or emotional stress. | |
Hypoglycemia Hint: Can cause fainting but is usually associated with symptoms like shaking, sweating, and hunger. |
Question 2 |
Significant Aortic Valve Stenosis Hint: While aortic valve stenosis can cause syncope, it is not the mechanism underlying vasovagal syncope, which is a neurally mediated response. | |
Orthostatic Hypotension Due to Inadequate Peripheral Vasoconstriction Hint: Orthostatic hypotension is a different condition where blood pressure drops upon standing, not the primary mechanism of vasovagal syncope. | |
Pulmonary Artery Occlusion Causing Right Ventricular Dysfunction Hint: This describes a pulmonary embolism, not vasovagal syncope. | |
Intracranial Blood Pooling Causing Compression of Brain Structures Hint: This mechanism is not associated with vasovagal syncope, which is a transient and reversible condition without structural brain involvement. | |
Enhanced Parasympathetic Activity and Reduced Sympathetic Tone |
Question 3 |
Start beta-blocker therapy Hint: May be considered in some cases but is not the first-line preventive measure. | |
Begin antiepileptic drug therapy Hint: Not indicated for vasovagal syncope. | |
Wear compression stockings Hint: Helpful for orthostatic hypotension but less so for vasovagal syncope. | |
Increase fluid and salt intake | |
Avoid stressful situations Hint: While practical, it's not always feasible and does not address the underlying physiological response. |
List |
References: Merck Manual · UpToDate