Date Published: April 24, 2007
Publisher: Public Library of Science
Author(s): Ronald C. W Ma, Kwok Hing Yiu, Edward H. C Wong, Kin Hung Liu, Joseph Y. S Chan, Chun Chung Chow, Clive S Cockram
Abstract: Ronald Ma and colleagues discuss the differential diagnosis and management of a patient who presented with recurrent episodes of chest discomfort, palpitations, and labile blood pressure.
Partial Text: A 53-year-old man was admitted to hospital in September 2005 with chest pain. He had a history of nasopharyngeal carcinoma in 1986, for which he was treated with fractionated radiotherapy (62.5 Gy total). His blood pressure (BP) was 100/70 mmHg at the time of diagnosis. He was in remission following radical radiotherapy, but had partial hypopituitarism for which he required thyroxine replacement. Six months prior to admission, he complained of chest discomfort, was noted to be hypertensive in clinic with BP 156/93 mmHg and pulse rate of 107 bpm, and was started on atenolol. Renal function tests, electrolytes, fasting lipids, thyroid-stimulating hormone, and free T4 (thyroxine) were normal. Baseline electrocardiogram (ECG) was unremarkable. An exercise tolerance test was negative. On the day of admission, the patient described retrosternal chest tightness lasting 10 minutes. This was associated with palpitations and nausea. His medications were felodipine, propranolol, alprazolam, and thyroxine. On admission, he was markedly hypertensive (BP 182/123 mmHg). On examination, the patient was afebrile. His BP was persistently elevated. His pulse rate was 80 bpm. Cardiovascular examination was otherwise unremarkable. He had no audible carotid or abdominal bruits. Neurological examination was unremarkable. Fundoscopy was normal. Bedside urine analysis was normal. Plasma electrolytes, renal function, liver function, and amylase were all normal. Fasting glucose was 6.3 mmol/l. Heart size was normal on chest X-ray. ECG showed sinus rhythm (90 bpm) and incomplete right bundle branch block. The patient was initially treated for suspected acute coronary syndrome and was started on an intravenous nitrate infusion. Shortly afterwards, his BP abruptly dropped to 97/62 mmHg and the nitrate infusion was discontinued. Repeat ECG with right-sided chest leads did not show any evidence of right ventricular infarct. Serial troponin T tests were negative. On further questioning, he described a 6-month history of episodic chest discomfort, palpitations, and sweating. He also described marked fluctuation in blood pressure with home readings around 80/40 mmHg and markedly elevated readings in clinic. During admission, frequent fluctuation in BP with a systolic BP (SBP) between 106–226 mmHg and a diastolic BP (DBP) between 62–114 mmHg was noted. This was accompanied by a resting tachycardia with frequent fluctuation of heart rate.
The presence of paroxysmal hypertension should always alert health-care providers to the possibility of a catecholamine-secreting phaeochromocytoma. The diagnosis is supported by the demonstration of elevated plasma or urine catecholamines or metanephrines . However, if this diagnosis is not confirmed, an alternative explanation needs to be sought. Other causes of paroxysmal hypertension include labile hypertension, hyperthyroidism, renovascular hypertension, seizure disorder, migraine, alcohol withdrawal, drugs such as cocaine, amphetamines, or clozapine , carcinoid syndrome, panic disorder, and baroreflex failure . In some cases of paroxysmal hypertension, no obvious cause could be identified, though it has been suggested that careful psychosocial interviewing may uncover repressed emotional distress that patients may not be aware of .