Makindo Medical Notes

🩺 Postural orthostatic tachycardia syndrome (POTS) is the final common pathway of a heterogeneous group of underlying disorders that share similar clinical features.

📖 About

• POTS is not a single disease but a syndrome – a collection of disorders leading to the same clinical picture.
• 🧠 Autonomic dysfunction is central to its pathophysiology.

🧬 Aetiology (Unclear cause)

• ⚖️ Neuroendocrine dysfunction
• 🦠 Small fibre neuropathy
• 🌡️ Mast cell activation
• ⬆️ High plasma norepinephrine levels

📏 Definition: Diagnostic Criteria

• ❤️ Heart rate increase ≥ +30 bpm on standing (within 10 min)
• 🧍 Symptoms worsen with standing, improve with lying down
• ⏳ Symptoms persist > 6 months
• 🚫 No other overt cause of orthostatic tachycardia (e.g. bleeding, dehydration, meds)

🩺 Clinical Features

• 👩 Female:Male ratio ≈ 5:1
• 🦠 Often triggered by viral illness, COVID, pregnancy, immunisation, sepsis, surgery, or trauma
• 💓 Orthostatic intolerance with palpitations, fatigue
• 😵 Frequent lightheadedness, presyncope
• 🏃 Exercise intolerance, dyspnoea on exertion
• 📉 Symptoms worse around menstruation
• 🛌 Fatigue, poor sleep, daytime somnolence
• 🌐 IBS, joint hypermobility, abnormal sweating
• 🦵 ~50% show dependent acrocyanosis (red-blue discolouration of legs, cold to touch)

🦵 Dependent Acrocyanosis

🔎 Investigations

• 🧪 Bloods: FBC, U&E, LFTs, CRP → typically normal
• 📈 ECG: usually normal at rest
• 🫀 Echo: normal
• 📊 24h Holter: episodic tachycardia
• 🪜 Tilt-table test: diagnostic, reproduces HR rise and symptoms

💊 Management

• 🚫 Stop contributing drugs: antidepressants, antihypertensives, alcohol, opiates, sildenafil
• 🏃‍♀️ Reconditioning: gradual aerobic exercise (20 min, 3×/week)
• 💧 IV saline (1L over 1–2h) for short-term/emergency benefit
• 🧦 Compression stockings (30–40 mmHg)
• 🥤 Hydration: 2 L/day
• 🧂 Salt loading: +2–4 g/day (monitor for oedema)
• 💊 Fludrocortisone 0.1–0.2 mg OD (risk: hypoK, hypoMg, oedema)
• 💊 Desmopressin (occasional use; risk: hyponatraemia)
• 💊 Midodrine 5–10 mg TDS (risk: nausea, scalp pruritus, supine HTN)
• 💊 Beta-blockers (metoprolol) in adolescents
• 💉 Erythropoietin in severe refractory cases (↑ blood volume & vascular tone)
• ✨ Management is trial and error – goal is symptom relief and quality of life.

📚 References

• BJMP – Evaluation & Management of POTS
• AHA Review of POTS