Caring for Your Kidneys

Don’t Tell the Cardiologist, but the Kidney Rules


In the first year of medical school, we learned how the human body works. All the anatomy and physiology was focused on the healthy, well-working human body. We learned what goes on at the molecular stage on to the macro-biologic. Second year we learned pathology—disease states, infections, when things even at the molecular stage (or especially at the molecular stage) goes awry. There was some snootiness between professors during the first year, but when the specialists came to speak to us in lectures, this is where it got a bit more heated.

It was a standing joke that the cardiologists (heart doctors) made fun of the nephrologists (kidney doctors), and the nephrologists made fun of the cardiologists.  “All the kidney does is go ‘drip, drip, drip” the cardiologists would laugh.

“All the heart does is pump. How hard is that?” the nephrologists would retort.

Meanwhile, the neurosurgeons (brain surgeons) rolled their eyes (and they knew which cranial nerves controlled the roll!)

The heart IS a pump, albeit an electrical pump. If something goes wrong with the electrical wiring, the heart is in trouble. If the heart muscle is starved of “food” (oxygen) it will die off downstream of where the food supply is halted. If the doors are stiff and creaky and don’t close like they should the pump may back up depending on the severity of the hinge problem. And if the pressure is too high for the pump to pump against, the heart muscle has to work harder. This pump is pretty important because the brain really needs the oxygen that the heart pumps to it.  It is a beautiful design and works great, pumping blood to the brain and the rest of the body about 70 times per minute, 4,200 times per hour, 100,800 times per day. The heart tolerates a lot of abuse, from cigarette smoking to drinking energy drinks to high cholesterol diets.

The kidneys, on the other hand, filter the blood. I liken them to an automatic drip coffeemaker. The water is the blood coming in to be filtered. The brewed coffee in the carafe is like the blood as it exits the kidney. If the filter clogs up, or if the water goes through too slowly, the quality of the coffee is not as divine as it is when the filter works nicely and the water is forced through quickly. But, filtering the blood is not all that the kidneys do; they tightly regulate electrolytes. Sodium, potassium, even glucose are all very tightly regulated.  The kidneys also regulate blood pressure. This is why so many medications for blood pressure work in the kidneys. The kidneys even make hormones that do important things like stimulate the manufacture of blood cells and bring calcium into the bones. They do so much that most people have a pair of them—though you only really need one.

When the kidney(s) don’t work like they should, and it gets so bad that the toxins are not filtered out, a patient is put on dialysis. Kidney dialysis was first discovered by Dr. Willem Kolff and is the process by which one bypasses the diseased kidneys and uses a machine to filter the blood.

When the kidney(s) fail, and one requires dialysis, unless you qualify for a kidney transplant, you are looking at usually only 5-10 years of surviving on dialysis (though some folks manage to live a lot longer).

Take care of your kidneys! Don’t smoke – remember that smoking affects the blood vessels and contributes to plaque formation in important arteries. Nicotine can also cause contraction of the smooth muscle in the arteries. There is an important artery that runs to the kidneys; so, let’s not put a crimp in that hose.

Drink enough water to stay well hydrated, but not too much.  4-6 glasses (3-4 pints, or 1.5 liters) a day is good. Eat fresh food—avoiding processed foods helps you avoid the sodium (salt) that is used for preserving the food. Keep active—walk, swim, cycle.  Watch your blood pressure.  Every household should have a reliable blood pressure cuff, and know how to use it. Take your home blood pressure cuff into your primary care doctor and have it checked for accuracy.  Then make sure your kidney function (the blood work) is checked periodically. Some people are very susceptible to over the counter arthritis medicines (Non-Steroidal Anti-inflammatories or NSAIDs) such as Ibuprofen and Naproxen. Even if you don’t have high blood pressure, but DO take these medications on a regular basis, your kidney function should be checked to make sure the medications are not having an ill effect on the kidneys. And, try your darnedest to avoid diabetes. Not only diabetes but also the medications for diabetes are exceptionally hard on the kidneys.

So, don’t tell the cardiologist, but the kidneys rule, and the heart would be nowhere without one.