Cardiorenal syndrome.

The combination of decompensated heart failure and kidney failure is frequently referred to as the "cardiorenal syndrome." The cause and pathophysiology of this entity are complex and poorly understood, and treatment options are limited. This report describes 2 patients who were hospitalized for decompensated heart failure and developed diuretic resistance with rapidly worsening renal function. Understanding the underlying causes helped break the cardiorenal syndrome in the first patient but only had a transient beneficial effect in the second patient.