Chapter 13- Horses

Tim Yau takes a shot at Chapter 13.


In the medical world, doctors often talk about diagnoses being “horses” or “zebras.”  Zebras are the very uncommon diseases that are talked about ad nauseum in textbooks, case reports, and are seen over and over again in exams.  Yet in real life, a clinician may practice for years and not see the zebras they have studied so hard to learn about.  This chapter in Dr. Vanessa Grubbs’ book focuses on the common “horse” diagnosis of chronic kidney disease (CKD) and delves into the unfortunate truth that not all diseases can be cured with medication.

CKD is a “horse” diagnosis as it affects about 14% of the US population, with about 600,000 people with such advanced kidney failure that they require dialysis or a kidney transplant.  As the kidney’s capacity to filter blood decreases due to diabetes, hypertension, or other “zebra” diseases, their stage of CKD worsens.  Patients typically don’t develop symptoms of kidney failure until they have reached very low levels of function (often even less than 10%).  Despite the kidney’s remarkable adaptive capabilities, the inevitable progression of kidney disease and function is that of gradual loss.  Even without symptoms, it can be scary to be told the news that “your kidneys are only working at 30%.”

One of the ways I explain CKD to my patients is to state that you lose about 1% of your kidney function/year after age 40 simply because of normal aging.  Although the exact truth to this statement is debatable, I find that it helps many patients understand that the kidneys they were born with are subject to wear and tear just like their hips and knees. Diabetes and hypertension accelerate this loss of function – if neither of these are controlled, they can lose 10% function/year (or more), which leads to the need for dialysis or transplant in a short time.  These are the two most common causes of CKD and unfortunately there is no cure for either of them (the best we can do is control them).  Delaying or slowing down the inevitable progress of declining kidney function becomes considered by many a success.  Stable function, as mentioned in this chapter, is reassuring because it means things have not gotten worse since the last time we looked at it.  Neither myself or my patients know how long they are going to live, but if they die with enough kidney function to avoid dialysis, then it’s considered a success.

If the expectation is that the kidneys are not going to last the patient’s lifetime, then a discussion about their individual goals comes next.  This doesn’t always mean dialysis and transplant; sometimes patients don’t want either.  The truth is nobody ever WANTS dialysis or a transplant.  They want healthy kidneys, and to not have developed CKD in the first place.  Some patients aren’t good candidates for dialysis or transplant.  Others feel like they’ve lived a good life, and don’t want to spend their last years on a machine, or feel that the organ should go to somebody younger.  Finding out where each individual patient stands on this issue is so important.  The question is rarely answered after one discussion, but should happen “eventually.”  To end with the closing paragraph of this chapter:

“The hope is that our efforts will make eventually as far away as possible.  Because once eventually comes, all that is left to do is to try to replace the kidneys with a transplant or dialysis, because we can’t live without Her.”