Picture quiz: Pitting oedema and recurrent pulmonary embolism

A 37 year old man presented with sudden onset, sharp pain across the left side of his chest. The pain was worse on deep inspiration and associated with shortness of breath. He had no history of recent surgery, no long journeys, and he had not been immobile. He reported a previous pulmonary embolism, two years ago. Examination findings include pitting oedema of the ankles and ascites.

He said that his parents noticed he looked “puffy” at the age of 4. This problem worsened, until his face became swollen, and resolved after a course of prednisolone. The swelling returned months later. Further steroids were prescribed, and the problem abated. The patient had experienced relapse throughout his life, each one characterised by generalised oedema, lethargy, and frothy urine.

Routine investigations (box 1) showed that he was hypoproteinaemic, with raised D-dimers. Computed tomography angiography showed a large filling defect in the left lower lobe pulmonary artery—that is, pulmonary embolism (fig 1). Could this man's pulmonary embolism be related to his protein status?