DEAR DR. DONOHUE: I am a 75-year-old woman who was treated for breast cancer in 2008. What I am concerned about is that my oncologist tells me I have Paget’s disease. I asked how he knows I have it. He said from my X-rays and bone scans. I went on my computer, and the information I got tells me to have an alkaline phosphatase test. Should I have this test? — N.R.

DEAR DR. DONOHUE: Will you write about Paget’s disease? My son-in-law has it, and it has brought pain in his left leg. He went from being an active roofer to now requiring a wheelchair. He is in great pain. Do you know anything that could help him? — P.C.

ANSWER: Bones are in a state of constant flux. From the day of birth to the day of death, they undergo continuous remodeling. That entails bone breakdown followed by bone buildup. In Paget’s disease, for reasons that are not clear, bone breakdown goes ballistic. Rebuilding tries to follow, but it does so with a result that leaves much to be desired. New bone is laid down with such haste that the job is done sloppily, and the new bone is often deformed and easily broken.

Quite often, the new, Pagetic bone is limited to a few small areas and causes no symptoms. It’s discovered when an X-ray or bone scan is done for an unrelated reason. Paget’s disease is found in 3 percent of those over 40, but nowhere near that number is treated nor needs treatment.

Alkaline phosphatase is an enzyme found in bones. In Paget’s disease, its blood level rises and is additional proof of disease activity. If N.R.’s oncologist thought he needed those results, he would have ordered the test.

The pelvis, the backbones, the skull, the femur (upper leg bone) and the tibia (lower leg bone) are the ones most often targeted in Paget’s disease.

When treatment is called for, the same drugs used for osteoporosis are used for Paget’s disease. Pain control might be difficult, but it should be achievable. Perhaps a consult with a pain clinic would help P.C.’s son-in-law.

The best friend that Paget’s disease patients have is The Paget Foundation. Contact the foundation at 800-23-PAGET or at www.paget.org. You’ll find it a rich source of information and help.

DEAR DR. DONOHUE: What is the difference between inflammation and infection? — B.M.

ANSWER: Inflammation is a body reaction that promotes health, but it’s a double-edged sword. For the most part, it keeps us healthy. It controls infections, heals wounds, gets rid of dead tissue and walls of foreign bodies. In some circumstances, inflammation works against us. When it doesn’t turn off when it should, or when it’s brought on by illnesses that keep it going, then it injures the body. Rheumatoid arthritis is an example of an illness where inflammation doesn’t know when to stop.

Infections are invasions of the body by germs — viruses, bacteria and parasites. Those infections alert the body to danger, and inflammation is one way the body has to combat them. This is good inflammation.

DEAR DR. DONOHUE: What is the difference between regular table salt and sea salt? I always thought salt was salt and used in excess is bad for your health. I understand regular table salt has a place in health because it provides iodine.

According to a Hollywood star, sea salt is supposed to be good for you. She claims it lowers blood pressure. What is your take on this? — S.S.

ANSWER: Salt is salt, sodium chloride, NaCl. Sea salt comes from evaporation of saltwater, like ocean water. It has trace amounts of magnesium, copper and iron, but not enough to be a health benefit. It can be considered the same as table salt without iodine.

If sea salt is the large-crystal variety such as kosher salt, less of it is contained in a teaspoon than is regular salt. You can pack more table salt, with its small crystals, into a teaspoon. The difference isn’t great. Sea salt isn’t better for you than regular salt. It doesn’t lower blood pressure.

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.