An adult case of nephrotic syndrome presenting with pulmonary artery thrombosis: a case report

INTRODUCTION: Pulmonary artery thrombosis is one of the most important complications in patients with nephrotic syndrome. It is well known among nephrologists, however, that this possibly lethal complication very rarely occurs before the diagnosis of nephrotic syndrome. CASE PRESENTATION: A 21-year-old Japanese woman who had no specific medical history consulted a primary care clinic. Although she had been aware of the edema of her lower extremities for 2 weeks, her chief complaints were palpitations and chest pain, which had started the day before. An electrocardiogram and chest radiograph did not reveal any specific abnormalities. Because her etiology was not clear, she was referred to an emergency division in a hospital 2 days later. Although arterial blood gas analysis did not reveal hypoxemia, computed tomography revealed thrombi of the bilateral pulmonary arteries and left iliac vein. At this point, a laboratory examination confirmed the diagnosis of nephrotic syndrome. Subsequently, she was admitted, and anticoagulant therapy was initiated immediately. The next day, oral corticosteroid therapy was initiated, and an inferior vena cava filter was placed internally. Her proteinuria resolved after 3 weeks of treatment. The prompt and complete response to corticosteroid therapy suggested that minimal change disease was the etiology of the nephrotic syndrome and pulmonary artery thrombosis. CONCLUSIONS: An awareness regarding the complication of pulmonary artery thrombosis in nephrotic syndrome is important not only for nephrologists but for all clinicians. Contrast-enhanced computed tomography is crucial to detect pulmonary artery thrombosis.