Kidney Disease

March is National Kidney Month.  This is an opportunity for us to raise awareness about kidney disease.  I thought we could start this week with an overview of how your kidneys work and why they are so important.  Then we can talk about the different kidney diseases and what we can do about them.

Lets start with the basics.

The kidneys are bean-shaped organs, about the size of your fist.  There is one on either side of your spine at the lowest level of your rib cage.  The basic function of the kidney is to filter your blood, but they do more than that.  

Why are your kidneys so important?

Your kidneys remove wastes, toxins, and extra fluid from your body.  They remove acid that is produced during normal function of the body at the cellular level.  They maintain a healthy balance of water, salts, and minerals in your blood, including sodium, calcium, potassium, and phosphorus.  This healthy balance allows your nerves, muscles, and other tissues in your body to function normally.  Your kidneys also make some of your body's hormones.  

Here is a list of the most important functions performed by your kidneys...

• Remove waste products from the body, including acid produced by cellular functions
• Remove drugs from the body
• Maintain the body's healthy fluid balance
• Make hormones that control your blood pressure
• Control the production of red blood cells (which carry the oxygen in your blood)
• Produce an active form of vitamin D, which helps maintain strong, healthy bones

How do your kidneys work?

Your kidneys are made up of filtering units called nephrons, with about a million nephrons in each kidney.  Blood circulates through your kidneys many times each day.  As blood moves through the nephron, waste products and extra fluid are removed from the blood through a very complex process.  This extra fluid and waste becomes urine, which is stored in the bladder until it is removed from the body through urination.  

Healthy kidneys filter about a half cup of blood every minute, adding up to about 150 quarts of blood filtered each day!  Most of what is filtered is returned to your body, with only about 1-2 quarts of urine being made each day.

Let's talk about kidney disease.

There are different types of kidney disease.  

• Acute kidney failure - This happens when your kidneys suddenly become unable to filter waste products from your blood.  This acute issue develops rapidly, usually within a few days.  It is most common in people who are already in the hospital, especially people who are critically ill.  Acute kidney failure can be fatal and requires intensive treatment, and sometimes temporary dialysis.  The good news is that acute kidney failure can be reversible.  If you are otherwise in good health, you may recover completely normal kidney function once your acute illness that caused the kidney failure improves.  

• Chronic kidney disease (CKD) - CKD is defined as having some type of kidney abnormality, or "marker" such as protein in the urine AND having decreased kidney function for three months or longer.  There are many possible causes of CKD.  These causes include chronic diseases such as diabetes and high blood pressure, acute inflammatory conditions, inherited conditions, and many others.

Next week we will talk more about the causes of CKD, how it is diagnosed, and more.

If you have any questions about kidney disease, please log into your account and send us your question. We are here to help.

Dr. Anita Bennett MD - Health Tip Content Editor