ASK DR. BAUGHAN                                      November 20, 1997

BE KIND TO KIDNEYS

As the last leaves fall to earth and the first snow covers the ground, the cycle of beginning and ending is reflected in our neighbors’ health.  There are a flurry of births, and a cluster of elderly patients who brace for the rigors of another winter.  The delicate balance of health in the elderly often is revealed by how well the kidneys are working.  In those with several chronic conditions, usually on several medications, if the interplay of environment, disease and medications falls out of rhythm, the kidneys may signal the disharmony.  They usually do so subtly, though, with the person quietly declining.  This is one cause of the “dwindles.”

Think of the kidneys like a drip-irrigation garden.  Too much water flow and the garden drowns.  Too little steady flow and the garden shrivels.  Ensuring that the kidneys have a sufficient, consistent blood flow is the best protection against kidney failure.  This requires ensuring that the person has adequate fluid and water supply.  As impressed with ourselves as we may be, we are mostly water.  As the founder of cardiology, Sir William Harvey, once said, “Even the Archbishop of Canterbury is 60% water.”

As a natural consequence of aging, the 70 year old kidney functions only half as well as the 35 year old kidney.  Anything that affects the intake or retention of fluids can be devastating to the elderly kidney, since it does not have the degree of reserve function it used to have.  If someone “just doesn’t feel like eating” for a few days, particularly if they are on certain medicines, they can become dehydrated enough to affect their kidneys.  This is especially true since many elderly do not drink enough fluids even when they feel well.  Any additional loss of fluids through vomiting or diarrhea must be noted with concern.  The most reliable sign of dehydration in the elderly is a drop in blood pressure going from lying to standing.  If the pressure drops low enough, the person will feel light-headed or faint.

Infections can threaten the kidneys not only by decreasing fluid intake, but by making the body use fluids up more rapidly, particularly if there is a fever.  Infections can divert blood flow from the kidney to other parts of the body.  Any decreased flow to the kidney endangers the “drip-irrigation system.”  Bladder infections can ascend to the kidneys and cause direct damage.  The elderly are less likely to have the typical symptoms of burning on urination of a bladder infection.  They may simply notice a change in odor or concentration of the urine.

Medications must be suspect in any decline in kidney function.  Diuretics (“water pills”- Lasix, furosemide, HCTZ, Dyazide, etc.) are perhaps the most common culprits.  They may be necessary for heart and kidney function, but too little or too much can be dangerous.  If fluid intake decreases, but the diuretic dose does not change, the person can “dry up.”  Sedatives or tranquilizers (Valium, Xanax, Ativan, Halcion, Haldol, etc.) may make the person sleepy enough that they do not feel or respond to normal thirst signals.  If blood pressure medications lower the blood pressure too much (which can happen with decreased fluid intake), the kidneys do not get the steady drip they need.  A few types of medications, such as certain antibiotics or arthritis medicines, can have a direct toxic effect on the kidneys.  Use of them must always be balanced against their need for the other health problem.

We are creatures of water, sodium and potassium.  The most important treatment in the hospital for kidney failure is balancing the body fluids with intravenous (IV) fluids, drip by drip.  Hospitalizations can be prevented and kidneys protected if the same principle is used at home.  Keep the fluids going in, even if only sip by sip, drip by drip.  The garden may bloom for yet another Spring.