Pulmonary embolism as a cause of pulmonary oedema

Abstract

Acute pulmonary oedema is a well-described complication of pulmonary embolism. However, the relationship between these two conditions is not widely appreciated by physicians and the diagnosis of an underlying pulmonary embolism in patients with pulmonary oedema may well be missed. We describe two cases in which pulmonary oedema complicated pulmonary embolism, and discuss the possible factors involved in the development of oedema. These include altered left ventricular (LV) function, increased lung microvascular permeability, overperfusion and reperfusion injury. We also emphasise the importance of considering the possibility of an underlying pulmonary embolism in patients with pulmonary oedema so that appropriate thrombolytic therapy can be given early. Case histories Case oneA 78-year-old male ex-smoker with no previous history of cardiorespiratory symptoms presented with a 10-day history of dyspnoea. This had begun six days after a transurethral resection of a bladder tumour when he was awoken by fleeting sharp chest pain, and breathlessness which persisted until admission. On examination he was in sinus rhythm (80 bpm), with an audible third heart sound, a blood pressure of 145/80 mmHg, a jugular venous waveform visible 3 cm above the sternal angle and bilateral pitting oedema up to the lower thigh. Electrocardiography (ECG) showed occasional runs of 10 beats of atrial fibrillation (160 bpm). Arterial blood gases breathing room air were: pH 7.49, PaO 2 10.7 kPa, PaCO 2 4.3 kPa. Plain posteroanterior chest radiography (CXR) showed upper lobe blood diversion and interstitial shadowing. Routine haematology and biochemistry were normal.Left ventricular failure and paroxysmal atrial fibrillation were diagnosed by the admitting junior doctor, and treated with intravenous heparin, diuretics, and amiodarone. Twentyfour hours later the PaO 2 fell to 4.8 kPa (on room air), and the