BY KEITH ROACH, M.D.

Learning the available options for dealing with a kidney stone DEAR DR. ROACH: I just found out that I have a kidney stone. I’m 77 years old, and I don’t want to deal with it. I’ve heard of potassium citrate and pulverizing it with sound waves. Are these options? — J.M.

ANSWER: When a person gets a kidney stone, the goals are to manage any symptoms, determine if a person’s health is at risk (especially from infection or kidney damage), and decide which treatment might be necessary to prevent any new stones.

Extracorporeal sound wave lithotripsy is one way of removing symptomatic stones, as is ureteroscopy with laser lithotripsy. The decision of whether intervention needs to be done is made by a urologist with expertise in stone management, and treatment depends on the size, type and location of your stone(s).

Prevention of a recurrent stone depends on the specific stone type and any metabolic issue the person has. Nearly everyone with stones is recommended to increase their water intake (adequate enough to make at least 2 liters of urine a day — and yes, we measure it) and decrease their salt intake (less than 2,300 mg of sodium a day). My former professor at the University of Chicago, Dr. Fred Coe, told me that he has seen people with sodium levels in their urine exceeding 25,000 mg a day. A high sodium level strongly favors stone formation.

Potassium citrate is a good choice for people who have calcium oxalate stones (60% to 80% of stones) and low measured citrate in their 24-hour urine tests. A low-oxalate diet may also be appropriate, but you can’t make an informed decision without knowing which kind of stone you have and what your metabolism is like.

If you do pass a stone, save it; it will be useful for your doctor. There are several different types of less-common stones, and management can’t be tailored for you without this information.

DEAR DR. ROACH: I read that fluoride might no longer be put into drinking water. Is fluoride dangerous? — V.A.M.

ANSWER: As with all substances (even a naturally occurring mineral like fluoride), the dose is what makes fluoride either a useful way of reducing tooth decay or a risk for side effects. This especially includes fluorosis, which is tooth damage due to excess fluoride during tooth development (up to age 4).

At extremely high levels, far above what is put into the water supply, there is the potential for adverse effects on brain development, which were generally found in geographic areas where naturally occurring fluoride levels are very high. This risk can be avoided by carefully regulating the amount of fluoride in the water supply as most communities in North America have been doing for decades.

At the low levels used for supplementation of water, there does not seem to be any increased risk of brain injury, but the risk of tooth decay is substantially less. Communities that stopped water fluoridation found worsening of people’s dental health community-wide. They also noted a large increase in dental visits for cavities, a greater incidence of anesthesia used for dental treatments, and an increased need for antibiotics due to tooth infections.

My review indicates that the benefit in prevention of dental problems greatly outweighs the potential harms, which can be avoided by careful attention to community fluoride water levels. For people in communities that have stopped the fluoridation of water, alternatives include daily fluoride supplements, fluoridated toothpastes, and fluoride varnish that gets provided by dentists at regular dental visits.