In February, 2007, a 32-year-old man presented with a 3-week history of shortness of breath on exertion. He had no important medical history and was not taking any medication. His blood pressure was 100/80 mm Hg, he had a sinus tachycardia of 110 beats per min, and a respiratory rate of 18 breaths per min. His neck veins were distended and more pronounced on inspiration. On examination, his pulse was rapid and weak in character but did not alter with respiration. Heart sounds were quiet on auscultation of the praecordium. On the basis of these findings, a clinical diagnosis of cardiac tamponade was suspected.
A chest radiograph demonstrated an enlarged heart, and echocardiography showed a large pericardial effusion with a mediastinal mass compressing the left atrium (figure A), associated diastolic collapse, and severely impaired left ventricular function (ejection fraction 33%). Emergency pericardiocentesis was done and 1700 mL of blood-stained fluid was drained; microscopy showed red blood cells and macrophages, but cytology and tumour markers were negative.
CT of the chest and abdomen (figure B) showed a 6·4×7·5×7·5 cm vascular mediastinal mass with central necrosis and numerous feeding vessels. Subsequent cardiac catheterisation showed multiple feeding branches from the coronary arteries and a large bronchial vessel supplying part of the tumour
The combination of a pericardial effusion, vascular mediastinal mass, and unexplained left ventricular dysfunction raised the differential diagnoses of arteriovenous malformation, haemangioma, thymoma, lymphoma, and phaeochromocytoma. Measurement of urinary catecholamines showed elevated levels of dopamine (12 674 nmol/24 h; normal range 70–1900) and noradrenaline (3281 nmol/24 h; 63–471) with normal adrenaline levels. A 123I-metaiodobenzylguanidine (MIBG) scan showed uptake in the region of the mass, confirming that the lesion was an extra-adrenal phaeochromocytoma, also known as a paraganglioma.
Embolisation was done to de-vascularise the tumour before surgery; prior blockade with phenoxybenzamine and propranolol was done to control blood pressure and prevent tachyarrhythmias. During surgical excision a magnesium sulphate infusion achieved stable intra-operative haemodynamics. The tumour was successfully excised from the left atrial roof. The patient made an unremarkable post-operative recovery. Histology confirmed the diagnosis of a paraganglioma. Within 6 weeks of surgery his left ventricular function had substantially improved (ejection fraction 54%). When last seen in June, 2007, the patient was asymptomatic.
Cardiac tamponade is a life-threatening clinical syndrome requiring prompt recognition and management. The diagnosis is made clinically by raised jugular venous pressure or neck vein distension (Kussmaul's sign if more pronounced on inspiration1), hypotension, and muffled heart sounds. This combination is known as Beck's triad and is observed in 10–40% of cases.2 Pulsus paradoxus may also be seen. Tamponade occurs when fluid accumulation in the pericardial cavity causes a substantial rise in intra-pericardial pressure. At least 200 mL of fluid must accumulate before the cardiac silhouette is affected on chest radiography.3
Echocardiography is a readily available, inexpensive, and easy to use tool to investigate cardiac tamponade and possible causes, for example mass infiltration, as in our case.
Extra-adrenal phaeochromocytomas are rare vascular tumours; it is useful to remember the rule of 10s: 10% of phaeochromocytomas are extra-adrenal, 10% are malignant, 10% are familial, and 10% are bilateral.
MIBG scanning is a valuable technique for identifying tumour deposits4 in conjunction with CT and MRI. Features suggestive of malignancy include very high dopamine levels and vascular invasion. Close liaison between radiologists, oncologists, endocrinologists, geneticists, cardiologists, anaesthetists, and cardiothoracic surgeons is required to ensure optimum management. Underlying paraganglioma should be considered as a differential diagnosis in cases of cardiac tamponade, particularly in the young.
References
1 KC Bilchick and RA Wise, Paradoxical physical findings described by Kussmaul: pulsus paradoxus and Kussmaul's sign, Lancet 359 (2002), pp. 1940–1942.
2 C Beck, Two cardiac compression triads, JAMA 104 (1935), pp. 714–716.
3 DH Spodick, Acute cardiac tamponade, N Engl J Med 349 (2003), pp. 684–690.
4 B Shapiro, J Sisson and V Kalff et al., The location of middle mediastinal phaeochromocytomas, J Thorac Cardiovasc Surg 87 (1984), pp. 814–820.
The Lancet Volume 371, Issue 9626, 24 May 2008-30 May 2008, Page 1810
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