ESSENTIALS OF DIAGNOSIS
Cardiac dysfunction: acute or chronic heart failure, ischemic injury, or arrhythmias.
Kidney disease: acute or chronic, depending on the type of cardiorenal syndrome.
Cardiorenal syndrome is 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. This syndrome is classified into five types as a matter of convention. Achieving euvolemia is the overarching therapeutic goal regardless of type (see Heart Failure section in Chapter 10).
Type 1 consists of AKI stemming from acute cardiac disease. Type 2 is 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). Identifying and defining this common syndrome may assist in the future with treatments to improve its morbidity and mortality. Although novel agents are being examined for future therapies, the mainstay of treatment is to address the primary underlying heart or kidney dysfunction.
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