Postural orthostatic tachycardia syndrome — formative SAQs

SAQ 1 — The adolescent girl with chronic daily orthostatic symptoms (10 marks)

Stem. A 15-year-old girl presents with four months of daily lightheadedness, palpitations, fatigue and difficulty concentrating that come on within minutes of standing and ease when she lies down. She felt well before this and recalls a viral illness at the onset. She has missed several weeks of school. On a supervised 10-minute active stand test her heart rate rises from 76 supine to 124 bpm upright, and her blood pressure stays at 108/68 mmHg throughout. Examination is normal and she has no family history of sudden death. [1]

Task. (a) State the diagnosis and the specific criteria that confirm it. (b) List the cardiac red-flag features that must be excluded before settling on this diagnosis. (c) Outline the stepwise management. [3]

Model answer

(a) Diagnosis and criteria (3 marks). The diagnosis is postural orthostatic tachycardia syndrome (POTS). The criteria are: chronic orthostatic intolerance on most days for ≥3 months; symptoms provoked by standing and eased by lying down; a heart-rate rise of ≥40 bpm in adolescents (≥30 bpm in adults, or an upright rate ≥120 bpm) within 10 minutes of standing or head-up tilt; and no orthostatic hypotension (no systolic fall ≥20 mmHg or diastolic fall ≥10 mmHg). This child meets all four. [1] [2]

(b) Cardiac red flags to exclude (3 marks). POTS does not cause collapse, so before settling on it you exclude: exertional syncope; syncope while supine or swimming; syncope provoked by a loud noise or fright; syncope with no prodrome; palpitations at the moment of collapse; chest pain or dyspnoea; and a family history of sudden death before about 50 years of age or a known inherited arrhythmia. A 12-lead ECG is obtained on every child. [3] [1]

(c) Stepwise management (4 marks). Step 1: educate, validate and reassure (POTS is real and treatable), keep a symptom and standing diary, and put a school plan in place. Step 2: hydration and salt — around 2–3 L of fluid and titrated sodium chloride per day, avoiding excess salt in hypertension or renal disease. Step 3: physical counter-pressure manoeuvres and compression garments. Step 4: structured recumbent or sub-threshold exercise to reverse the deconditioning spiral — the most evidence-based component. Step 5: phenotype-guided pharmacotherapy (midodrine, fludrocortisone, beta-blocker or ivabradine) only if non-drug measures are insufficient. Treat sleep, mood and school return in parallel. [5] [10]