From the Guidelines
The differential diagnosis for a 17-year-old female with lightheaded spells should prioritize vasovagal syncope, orthostatic hypotension, and postural orthostatic tachycardia syndrome (POTS) as the most likely causes, based on the definitions and guidelines provided by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. The initial workup should begin with a thorough history focusing on the circumstances of the episodes, associated symptoms, medication use, and menstrual history. A complete physical examination should include orthostatic vital signs, cardiovascular assessment, and neurological evaluation.
- Key components of the history include:
- Circumstances of the episodes (e.g., triggers, position, activity)
- Associated symptoms (e.g., palpitations, tremulousness, generalized weakness, blurred vision)
- Medication use
- Menstrual history
- Laboratory tests should include:
- Complete blood count to assess for anemia
- Basic metabolic panel to check electrolytes and glucose
- Thyroid function tests
- Pregnancy test An electrocardiogram is essential to rule out cardiac causes such as long QT syndrome or arrhythmias, as defined in the guideline 1.
- If episodes are frequent or concerning, consider:
- 24-hour Holter monitoring or event recorder
- Tilt-table testing to assess for orthostatic intolerance or POTS
- Echocardiogram to rule out cardiac structural abnormalities For persistent symptoms, further evaluation may include neurology referral or other specialist consultations.
- Management depends on the underlying cause but may include:
- Increased fluid and salt intake for orthostatic hypotension
- Iron supplementation for anemia
- Beta-blockers for vasovagal syncope
- Patient education about recognizing prodromal symptoms and avoiding triggers is important for prevention, as emphasized in the guideline 1.
From the Research
Differential Diagnosis
- Reflex syncope
- Orthostatic hypotension (OH)
- Postural orthostatic tachycardia syndrome
- Psychogenic pseudosyncope
- Anemia and iron deficiency
Workup
- Tilt table testing (TTT) may be indicated when the initial syncope evaluation does not yield a certain, highly likely, or possible diagnosis, but raises clinical suspicion of reflex syncope, OH, postural orthostatic tachycardia syndrome, or psychogenic pseudosyncope 2
- Echocardiography to evaluate for ventricular and atrial remodeling, decrease in ventricular contractility, and alteration of ventricular relaxation, which can be associated with anemia and iron deficiency 3
- Laboratory tests to evaluate for anemia and iron deficiency, which can contribute to symptoms of lightheadedness and syncope 3
- Minimum requirements for TTT include a tilt table with an appropriate tilt-down time, a continuous beat-to-beat BP monitor with at least three electrocardiogram leads, and trained staff 2
Diagnostic Considerations
- Acknowledgement by the patient/eyewitness of the reproducibility of the induced attack is mandatory in concluding a diagnosis of reflex syncope 2
- TTT may be therapeutic in patients with reflex syncope to educate patients on prodromes and recognize hypotensive symptoms causing near-syncope to perform physical countermanoeuvres for syncope prevention (biofeedback) 2
- Detection of hypotensive susceptibility requiring therapy is of special value in patients with reflex syncope and OH 2