{
  "abstract": "A 35 year old lady was initially referred for investigation of an irregular pulse noted during an antenatal visit. She was 37 weeks pregnant with a history of mild asthma (on inhalers). She reported intermittent palpitations sometimes coinciding with diarrhoea and recurrent syncope on standing with no clear prodrome. On one occasion blood pressure (BP) was 60/40 mmHg and heart rate (HR) 140 bpm. A 12 lead ECG showed sinus rhythm, incomplete right bundle branch block with supraventricular and ventricular ectopy. Echocardiography, ambulatory ECG and tilt table test were normal. She had an implantable loop recorder (ILR) for 3 years which ruled out arrhythmia. She was treated for orthostatic intolerance and lifestyle measures were advised (i.e. fluid and salt intake). Her palpitations were ongoing and coincided with sinus tachycardia on the ILR. Further tests were normal including thyroid function, 24hr ambulatory BP monitoring, 24hr urinary catecholamines and 5- hydroxyindoleacetic acid. She had ongoing syncope on standing refractory to midodrine and a lying standing BP/HR assessment in clinic was almost diagnostic for postural orthostatic tachycardia syndrome (POTS) phenotype ( table 1). She had developed intermittent facial swelling raising the suspicion of mast cell activation syndrome (MCAS) associated with POTS, and she was referred to Haematology. A diagnosis of indolent mastocytosis was made based on persistently markedly raised mast cell tryptase 21.2 ug/L (normal 0–12.9 ug/L), bone marrow biopsy findings and a KITD816V genetic mutation resistant to Imatinib. She was treated with Fexofenadine, emergency adrenaline Epipen and intermittent prednisolone. Repeat tilt table testing was suggestive of mixed phenotype POTS and reflex syncope (table 2). At 9 years follow up she reported ongoing palpitations and twice monthly unpredictable syncope refractory to midodrine and propranolol.Systemic mastocytosis is a rare haematological condition resulting in increased mast cell activity affecting the skin and other organs, usually due to sporadic genetic mutations involving the KITD816V gene. Episodic release of vasoactive mediators from mast cells results in intermittent symptoms of pruritis, flushing, itching, diarrhoea, syncope and anaphylaxis. Mastocytosis can progress from an indolent to aggressive form with guarded prognosis, and should be distinguished from MCAS. MCAS results in increased and inappropriate release of mast cells however in contrast to mastocytosis there is no increased proliferation or organ infiltration of mast cells. MCAS is known to be associated with POTS and Ehler’s syndrome, has a good long-term prognosis and symptoms often respond to anti-histamines. To our knowledge this is the first reported case of mastocytosis and POTS. Mast cell disorders should be considered in recurrent syncope and referral to Haematology can confirm the diagnosis aiding prognosis and management of refractory syncope.Abstract 4-008 Table 1Clinic lying and standing BP and HR Phase BP (mmHg) HR (bpm) Supine Baseline 110/65 64 Standing 3 min 118/75 92 5 min 105/80 88 A rise in HR of 28 bpm with no significant drop in BP was suggestive of POTS phenotype. BP blood pressure, HR heart rate, POTS postural orthostatic tachycardia syndrome.Abstract 4-008 Table 2Tilt table test Phase BP (mmHg) HR (bpm) Supine baseline 102/75 64 Immediate tilt 107/93 87 End of tilt 80/67 60 Supine recovery 106/65 65 On tilting, HR rose by 23 bpm with no significant drop in BP suggesting a POTS phenotype. The test was subsequently stopped due to symptoms of dizziness and feeling hot during which time there was a 22 mmHg drop in blood pressure while HR was normal. The tilt table findings were non diagnostic but suggestive of a mixed phenotype response (POTS and vasodepressor reflex syncope). BP blood pressure, HR heart rate, POTS postural orthostatic intolerance.",
  "authors": [
    {
      "affiliations": [
        "Department of Cardiology, North Manchester General Hospital, Manchester University NHS Foundation Trust"
      ],
      "name": "MRCP Jack Crispin"
    },
    {
      "affiliations": [
        "Department of Cardiology, North Manchester General Hospital, Manchester University NHS Foundation Trust",
        "Division of Cardiovascular Sciences, Faculty of Biology, University of Manchester"
      ],
      "name": "Ahmed Adlan"
    },
    {
      "affiliations": [
        "Department of Cardiology, North Manchester General Hospital, Manchester University NHS Foundation Trust",
        "Division of Cardiovascular Sciences, Faculty of Biology, University of Manchester"
      ],
      "name": "Nicholas Jenkins"
    }
  ],
  "title": "4-008 Rare case of mastocystosis and postural orthostatic tachycardia syndrome",
  "uid": "8fb68db5-a6f6-5cde-9bce-f1ca27375fe2"
}