DEAR DR. DONOHUE: Would you please tell me what Berger’s disease is? What are its symptoms? My wife has it. What are the chances that our 10-year-old daughter will get it? – D.J.

ANSWER: Berger’s disease is now more commonly called IgA nephropathy. “Ig” is an abbreviation for immunoglobulin, an antibody. Antibodies are made by the immune system and are rocket-propelled grenades thrown at incoming germs or any foreign material to immobilize and destroy it. “A” is one class of antibodies.

In IgA nephropathy, the immune system has mistakenly identified the kidneys as foreign invaders, and it has attacked them with antibodies.

The signs and symptoms of IgA nephropathy vary considerably. One common manifestation is bloody urine that appears after a throat or intestinal infection or after strenuous exercise. The urine clears on its own, but repeat episodes of bloody urine are the rule. Some with IgA nephropathy have blood in the urine that is detectable only with a microscope. There can also be protein in the urine.

There is a genetic influence in some instances of this illness, but not all. That should not be interpreted as meaning your daughter is destined to have it.

Often, doctors prescribe ACE inhibitors for people with this illness. ACE inhibitors are blood pressure medicines. They are used here not to lower blood pressure but to protect the kidneys. Blood pressure might rise as a consequence of the illness, and then ACE inhibitors serve a dual purpose.

IgA nephropathy can smolder for years and years without impairing a person’s ability to function normally. Some eventually face kidney failure. If and when that happens, kidney dialysis or kidney transplantation is available.

DEAR DR. DONOHUE: My granddaughter, age 8, suffered from bouts of strep infections. My daughter took her to an ear, nose and throat doctor to find out why. The doctor asked if there was a dog in the house. Much to our amazement, they had obtained a Jack Russell terrier just before all this started. The doctor treated my granddaughter with antibiotics and suggested taking the dog to the vet for the same treatment. The vet confirmed that the dog had strep and prescribed antibiotics. Perhaps some of your readers will be interested in this story when they face a similar situation. – S.H.

ANSWER: “Strep” is short for streptococci (STREP-toe-KOK-sigh), a huge family of bacteria whose many members cause a variety of infections.

The most widely known strep infection is strep throat. It spreads from person to person in droplets of saliva or nasal secretions. It can spread quickly in close quarters like schools or Army barracks. Water and food have also been implicated in the spread of strep sore throats. Animals are not believed to be involved in the transmission of strep sore throat. They can be involved in other strep infections, however.

Your story is interesting. I don’t know what kind of strep infection your daughter had. I look forward to hearing from other doctors and veterinarians about their experiences and will pass them along to you and other readers.

DEAR DR. DONOHUE: About nine years ago, my doctor said my blood pressure was high and gave me a pill. After I took the pill, I got dizzy. My sister and her husband took me to the hospital, where I passed out. When I woke up, there were several cute nurses standing around my bed. I asked if I was in heaven. My doctor thought this was a big joke. I didn’t think it was so funny. What kind of pill would cause me to pass out? – C.O.

ANSWER: Some blood pressure medicines, especially when taken for the first time, can cause a profound drop in the pressure, so much so that the brain doesn’t get enough blood. That causes a person to faint.

This doesn’t happen all that frequently. It’s a reaction that occurs only in a few users. You were one of the unlucky few.

I hope you got the name of the pill. Avoid it, but don’t be afraid to take blood pressure medicines in the future if you need them.

DEAR DR. DONOHUE: What exactly are narcotics? Do they have a legitimate place in medicine? I ask because my mother suffered from cancer, and her last days were filled with pain. I pleaded with her doctors to give her narcotics, but they said they couldn’t use them. It was against the law. Is that the case? – M.N.

ANSWER: “Narcotics” is an umbrella designation for any drug that produces numbness or sleepiness. That’s the meaning of the Greek word “narcosis.” In a more restricted sense, it refers to drugs that come from the juice of the opium poppy or synthetic drugs that have chemical structures similar to drugs derived from the opium poppy.

Morphine, methadone, meperidine (Demerol) and fentanyl are examples of these drugs.

Use of these drugs in medicine is not illegal. When did your mother die? She might have died in an era when doctors were afraid to use these medicines because of their addicting properties. That is regarded as foolish today. Long-term use of these painkilling medicines for pain control has little addiction potential.

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.