Diuretic resistant oedema: nailing the diagnosis.

Peripheral oedema is a commonly encountered clinical problem. Although it has many causes, its pathophysiology ultimately involves two processes: altered capillary haemodynamics and renal salt and water retention. A minority of cases are resistant to diuretic treatment; causes of such resistance include excessive sodium intake, poor diuretic drug absorption, reduced secretion of free diuretic into urine (for example, in nephrotic syndrome, renal failure, and heart failure), and lymphatic obstruction. We present a case of diuretic-resistant oedema associated with pleural and pericardial effusions. Only after extensive ‘negative’ investigations and subsequent careful clinical examination was the diagnosis of Yellow Nail Syndrome (YNS) made. This case highlights the importance of considering a broad differential diagnosis when managing peripheral oedema, particularly in the setting of diuretic resistance.