DEAR DR. DONOHUE: My son-in-law has had problems with kidney stones since the late 1970s. He is in his mid-50s. In the past, he has had the stones blasted and had a large stone removed with a basket. He is always asked if he eats lots of cheese and drinks lots of milk. He does not. Never has he been given a special diet. Should he be on one? – L.L.

ANSWER: What he needs to be on is fluids in abundance. He should drink eight to 10 8-ounce glasses of water a day, and lots of fluid in other forms such as juices. He’ll know he’s drinking enough fluid if his urine is colorless to pale yellow. Stones don’t form when urine is dilute.

Ask your son-in-law what kind of stones he has had. The most common is calcium citrate, and my answer presumes that was his kind of stone.

It sounds logical for someone with calcium stones to stay away from calcium-rich foods – cheese, milk and other dairy products. It turns out that isn’t necessary, and, in fact, it promotes stone formation. Your son-in-law can eat cheese and drink milk.

He should stay away from salt and salty foods. The sodium part of salt pushes calcium into the urine and increases the risk of developing stones. Potassium-rich foods have the opposite effect. Bananas, potatoes, orange juice, raisins, broccoli, corn, squash and Brussels sprouts are potassium-rich foods. Meat favors stone formation. He does not have to give up meat, but he should cut back his consumption of it. Sugar has the same effect, so he must go easy with sweets. That’s about all there is to a stone diet.

You might wonder about the oxalate component of calcium oxalate stones. Oxalate foods include nuts, chocolate, spinach, rhubarb and beets. He doesn’t have to abstain from these foods, but a slight lowering of them helps out.

DEAR DR. DONOHUE: I don’t seek a medical diagnosis, but I do seek a medical commentary. I am 94, and I don’t need mobility aids. Since 1989, I have had a hernia that does not bother me. Does it need to be taken care of?

I also have a “skipped beat.” What is the significance of that? I also would like to understand what a hydrocele is. – S.P.

ANSWER: A hernia that’s not causing trouble and has not done so for 18 years doesn’t require an operation. You can let it be.

A “skipped beat” most often means an extra heartbeat, and usually that beat is a premature ventricular beat. It’s a beat arising in the lower heart chambers – the ventricles. From time to time, everyone has a PVC. If there aren’t many PVCs and if a person’s EKG shows that they are not occurring at a dangerous time in the heart cycle, they can be ignored.

A hydrocele is an accumulation of clear fluid in the scrotum. If it’s large, painful or interferes with walking, then it can be removed surgically. Most of the time, it requires no treatment.

In rare instances, a hydrocele is a sign of testicular cancer, especially when it forms at young ages. Testicular cancer is unusual for someone of your age. If your doctor has examined it and found nothing suspicious, you can ignore it.

DEAR DR. DONOHUE: In regard to the young man who is 6 feet 1 inch tall and weighs 130 pounds, you mentioned family trait before listing possible diseases. At 21, I was an inch shorter and 5 pounds heavier than this young man. I was completely unlike my parents, uncles and aunts. I later discovered that I had a build identical to a great-grandfather who was unknown to me. I now have an oversize granddaughter who is a clone of my grandmother. The girl never knew her great-grandmother. So family trait doesn’t mean that every close relative looks the same. – W.G., M.D.

ANSWER: The writer of the letter and I both thank you. I’m sure your input will put him at greater ease.

DEAR DR. DONOHUE: I am a 71-year-old woman. I take medicine for high blood pressure and for cholesterol control. For a long time I’ve been having headaches, and sometimes I get a sharp pain on one side of my head. I think I’m going to have a stroke. I had an MRI of my brain and was told over the phone that I have small vessel disease of the brain. I was told not to worry, but the report really scares me. Would you explain what small vessel disease is? – D.A.

ANSWER: A good number of people over the age of 70 would have a similar report on their MRI brain scans. “Small vessels” are the tiniest branches of arteries. Each small vessel serves a very limited area of brain. Small vessels are places where plaque builds up. Plaque is a heap of cholesterol, fat, blood proteins and blood platelets that clings to an artery’s wall. In time, the buildup can block the flow of blood through the artery. Blocking blood flow in a few small vessels doesn’t generally create huge problems.

On the MRI report you sent me, the radiologist said that the changes seen “probably” represent small vessel disease. He isn’t sure, so the changes are not great and are not signs that a major stroke lies in your future.

Small vessel disease is not the cause of headaches or the sharp pain you sometimes get on the side of your head.

Continue doing exactly as you have been doing. Make sure your blood pressure stays in a controlled zone. High blood pressure accelerates plaque formation. The same goes for cholesterol.

High cholesterol adds to plaque growth. You should watch your diet, steering clear of fats and too much cholesterol. Try to get some exercise every day of the week. If you can work up to 30 minutes of exercise a day, you can completely forget about your MRI report. Worrying about it is more of a threat to your health than is the report itself.

The stroke booklet provides information on the causes and treatment of strokes in general. Readers can obtain a copy by writing: Dr. Donohue – No. 902, Box 536475, Orlando, FL 32854-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com