On the first Friday of every month I give a lecture to the residents at St. John Hospital and Medical Center. I like to do an electrolyte lecture but for March the chief resident asked me to talk about cardiorenal syndrome. In researching the lecture I came across this article by Claudio Ronco.
The article defines cardiorenal syndrome as any condition with simultaneous kidney and heart failure. He then goes on to subdivide cardiorenal syndrome into 5 types:
- Acute heart failure causing acute renal failure
- Chronic heart failure causing chronic kidney disease
- Acute kidney injury causing any type of acute cardiac dysfunction (including arrhythmia)
- Chronic kidney disease causing any chronic cardiac disease
- Any systemic condition that causes renal and cardiac dysfuction (e.g. sepsis)
It doesn’t have to be this way look at the example of hepatorenal syndrome. The syndrome does not refere to just any situation with simultaneous renal and liver dysfunction. It is a very specific diagnosis that only occurs with chronic liver disease and ascites. The patients must be oliguric, there is no non-oliguric HRS. Patients must be sodium avid and unresponsive to fluids and albumin. Additionally the patients cannot have laboratory or imaging evidence for an alternative cause of renal failure. Because of this definition hepatorenal syndrome identifies a very specific disorder, with a specific pathophysiology and unique prognosis and treatment options.
Ronco takes the beautiful and evocative name cardiorenal syndrome, strips it of all specificity and then tries to restore it by tacking on five different types. The fifth type 5 is the one that makes my brain explode. Sepsis, really? Acute kidney injury from sepsis that happens in the same patient who also suffers from sepsis induced cardiomyopathy should now be considered to have cardiorenal syndrome? Ronco is a man who has spent his life studying sepsis and acute renal failure, I can’t believe he is actually referring to that condition as CRS type 5.
I’m not buying what Ronco’s selling. Cardiorenal syndrome begins and ends with type 1 for me.