What Causes Kidney Disease? A Painless Overview

At ComposeMD, I cover a broad range of topics, doing my best to focus on issues that should garner at least a bit of interest. So how, of all topics, did I choose the kidneys? Well, let’s just say that I might have a little bit of insight into this arena.  As such, here is a painless overview of what causes kidney disease.

 

The Kidneys

Starting with the basics, what are the kidneys anyway? The kidneys are two bean-shaped organs whose main function is to filter the blood and remove unnecessary waste products and fluid.  The resultant waste flows from the kidneys to the bladder and is eliminated in the form of urine.  Other important kidney functions include a role in red blood cell production (red blood cells carry oxygen) and the production of active vitamin D which is important for bone health.

On average, each kidney is comprised of about one million nephrons, which can be thought of as the key filtering units of the kidney.  If the number or function of nephrons decreases over time, the ability of the kidneys to carry out their above functions also diminishes.  All causes of kidney disease share the common reality of adversely affecting nephron number or function.

 

What Causes Kidney Disease?

Kidney disease can occur acutely (within hours to days), often referred to as acute kidney injury.  Alternatively, it can occur over a long period of time (months to years), often referred to as chronic kidney disease.  As is true for most disciplines, terminology can vary and become a source of confusion.

Acute Kidney Injury

Examples of causes of acute kidney injury include severe dehydration, severe trauma, and blockage (or obstruction) of the outflow of the kidneys by things such as stones or tumors.  Other causes include certain medications, the dye used for particular imaging tests, blood clots that impair blood flow to the kidneys (preventing appropriate blood filtering), severe autoimmune disease, and severe infection (called sepsis).  This list is not comprehensive.

Chronic Kidney Disease

Examples of causes of chronic kidney disease include lifestyle factors such as uncontrolled diabetes, uncontrolled high blood pressure, obesity, and smoking-related disease of the blood vessels that feed the kidneys.  Other potential causes include genetic factors, medications, chronic infections, slower moving autoimmune disease, environmental insults, and less severe obstruction of kidney outflow.  As above, this list is not comprehensive.

While one kidney can be sufficient in many cases, that only holds true if the nephrons in the one kidney are healthy.  If such a requirement is not met, one kidney will not be sufficient.

 

How Is Kidney Disease Discovered?

Abnormalities in kidney function are discovered by simple blood tests that detect the accumulation of waste products that are not being eliminated adequately.  In terms of identifying why the kidney disease has occurred, basic urine tests and imaging tests (such as ultrasound) can often answer the question.  On occasion, a kidney biopsy could be necessary.

Many with kidney disease often have no obvious symptoms directly attributable to the loss of kidney function.  Knowing this fact, monitoring of blood tests over time can be very important.  In more advanced stages of kidney disease, patients can notice fluid retention/high blood pressure as well as symptoms such as nausea, drowsiness, and itching related to waste product accumulation.  Furthermore, disturbances in other blood tests such as potassium and phosphorous (both removed by the kidneys) can become apparent.

 

Treatment

If kidney disease is severe enough, a treatment called dialysis could become necessary.  Dialysis essentially entails a way of filtering the blood and removing excess fluid.  In other words, it performs the functions that the kidneys are no longer able to perform.  Medications may be required to mimic the effect of kidneys on red blood cell and active vitamin D production.  If recovery of kidney function is not expected (a condition called end-stage kidney disease), kidney transplant could be an option for some.

Although dialysis and transplant have revolutionized the care of kidney disease, avoidance of kidney disease, if at all possible, is a much more desirable pathway.

 

Given the preventability of at least some types of kidney conditions, particularly certain forms of chronic kidney disease, implementing healthy lifestyle choices can go a long way in avoiding undesired outcomes.  So go ahead, put down that cookie, and grab a bag of lettuce.  And don’t forget the treadmill.