Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 22-10: Cardiorenal Syndrome + Key Features Download Section PDF Listen +++ ++ Defined as a pathophysiologic disorder of the heart and kidneys wherein the acute or chronic deterioration of one organ results in the acute or chronic deterioration of the other Classified into five types Type 1 consists of acute kidney injury (AKI) stemming from acute cardiac disease Type 2 is chronic kidney disease (CKD) due to chronic cardiac disease Type 3 is acute cardiac disease as a result of AKI Type 4 is chronic cardiac decompensation from CKD Type 5 consists of heart and kidney dysfunction due to other acute or chronic systemic disorders (such as sepsis) + Clinical Findings Download Section PDF Listen +++ ++ Cardiac dysfunction: acute or chronic heart failure, ischemic injury, or arrhythmias Kidney disease: acute or chronic, depending on the type of cardiorenal syndrome + Diagnosis Download Section PDF Listen +++ ++ Evaluate cardiac status with applicable studies, such as BNP, ECG, and echocardiogram Evaluate kidney status with applicable studies, such as BUN; serum creatinine, serum electrolytes, serum bicarbonate Complete blood count Urine microscopy Fractional excretion of sodium or FENa = (urineNa/serumNa)/(urineCr/serumCr) × 100% FENa is high (> 1%) in acute tubular necrosis Renal ultrasound + Treatment Download Section PDF Listen +++ ++ Treat primary underlying cardiac or renal dysfunction