Dear Doctor: I have been diagnosed with chronic inflammatory demyelinating polyneuropathy, and am being treated with immunoglobulin infusions every three weeks. My questions are: Can this be cured, and are there any clinical trials for this?

Dear Reader: You have both my sympathy and my encouragement to seek the best treatment options for you. Chronic inflammatory demyelinating polyneuropathy (CIDP) was first named as a disease in 1975. Caused by the immune system's attack -- for unknown reasons -- on nerve fibers, CIDP affects between one and eight people out of 100,000. The attack upon the muscle nerves in the arms and legs leads to symmetrical weakness throughout the body.

The symptoms of CIDP can progress, or come and go, for more than eight weeks, which differentiates the disease from the more short-lived type of polyneuropathy seen in Guillain-Barre syndrome. About 30 percent of people with CIDP recover fully; but for some, symptoms can progress for years and lead to significant disability, such as an inability to walk.

The treatment that you are getting for CIDP, intravenous immunoglobulin (IVIG), is a concentrate of donor antibodies infused every three weeks after the initial dose. Not only do these antibodies have an anti-inflammatory effect, they neutralize the autoimmune antibodies so they don't attack the nerve cells. Although an estimated 54 percent to 75 percent of patients respond to IVIG, the majority must continue to receive the therapy indefinitely. This can be difficult, causing headaches, nausea, fever and rash, and increasing the risk of meningitis and blood clots.

On the plus side, newer formulations of immunoglobulin -- given subcutaneously -- are showing similar benefit as the intravenous form and can help patients avoid hospital-based infusions.

Some patients fare better on older therapies. One of the first treatments for the symptoms of CIDP were anti-inflammatory steroids, used even before the disease was an official diagnosis. The steroids are administered first at high doses and tapered to lower doses. However, during the tapering, many patients have a return of symptoms and thus must continue the therapy for many months. The problem with chronic steroid use is that it can cause weight gain, diabetes, cataracts, osteoporosis and high blood pressure.

Plasma exchange is another option. This therapy removes fluid containing harmful antibodies from the blood and replaces it with a substitute. The results of plasma exchange appear similar to those of IVIG. Although symptoms return when therapy is stopped, plasma exchange can be a good short-term treatment.

As for immunosuppressant drugs like azathioprine, mycophenolate, cyclophosphamide and methotrexate, these are used more rarely for CIDP. They appear to improve symptoms, but more data are needed on effectiveness, balanced against their possible side effects. Cyclophosphamide may be a good option for people for whom IVIG, steroids and plasma exchange have not helped. But because cyclophosphamide may induce life-threatening side effects, such as bone marrow failure, kidney failure and congestive heart failure, it's not to be taken lightly.

A newer CIDP drug, Natalizumab, which suppresses the immune response against the nervous system, could yet offer hope, but it's still under investigation in Europe.

I would assume that the immunoglobulin therapy is helping you currently, so consider asking your doctor about a clinical trial of the subcutaneous version. This may add convenience for you, without a reduction in benefit.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I recently read that blocking follicle-stimulating hormone can combat post-menopausal bone loss and weight gain in women. Please tell me how to go about blocking that hormone!

Dear Reader: Talk to women who have hit the age of 45 and beyond, and they pretty much agree that maintaining their weight, let alone losing weight, seems much harder than when they were younger. Now a series of studies have put follicle-stimulating hormone, or FSH, into the spotlight.

Produced by the pituitary gland, FSH plays a role in the release of eggs in women and the production of sperm in men. When a woman approaches menopause, the time at which her ovaries cease functioning, her blood levels of estrogen drop and FSH spikes. At this same stage of life, women begin to experience bone loss.

A professor at a medical school in New York City was intrigued by the fact that, even when estrogen levels held steady, bone loss continued to occur. As a result, he began to wonder whether FSH levels might play a role in the effects of menopause. Although he was studying the role of FSH in bone loss, he was startled when fat levels and weight gain were affected as well.

In a series of experiments using mice whose ovaries had been removed, researchers administered an antibody to block FSH. Without ovaries to produce estrogen, which prevents bone loss, the mice should have experienced a drop in bone mass. Researchers were surprised to find that not only did the bone mass of the mice hold steady, they also began to lose fat.

A colleague at another medical center was persuaded to try the same experiment and got the same results. They also advanced their understanding of how and why the mice, despite being forced into menopause, experienced weight loss.

To get into the details, we first need to talk about two types of adipose tissue -- white and brown fat. Unlike white fat, whose job is to store energy for future use, brown fat is loaded with mitochondria, tiny structures within our cells that burn energy and give off heat.

As babies and children, we have plenty of brown fat. By the time we hit adulthood, only small amounts of brown fat remain. In the case of the FSH-deprived mice, their levels of brown fat rose. This caused their metabolism to rev up, burn calories and lose weight.

Considering that women typically gain anywhere from 5 to 15 pounds or more as a result of menopause, with much of it around the abdomen, it's easy to see why these results have sparked widespread interest. But as the researchers themselves point out, it can be a long leap to translate results from mice to human beings. Only time and further studies will tell.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Are some people just not meant to fly? I get severe ear pain when my plane is descending. I've tried chewing gum and repeated swallowing, and I never fly with a sinus condition. Unfortunately, I have clogged-up ears for several weeks afterward. Any suggestions?

Dear Reader: First, let's look at the cause of ear pain when we fly. Initially, we experience a decrease in outside pressure as we ascend into the sky. This decrease causes less external pressure upon the eardrums. Thus, the air behind the eardrums (in the middle ear) pushes them outward.

Airplane cabins are pressurized to minimize this decrease in pressure, and the body does its part as well. For starters, the middle ear equilibrates some of the pressure difference within it by removing the air through the Eustachian tubes, where it is released into the back of the nose and expelled into the environment. Part of that excess air in the middle ear is absorbed by its mucous membranes.

But, as we descend, the external pressure on our ears begins to increase again to that of the landing altitude. This pressure pushes the eardrums inward. Again, the Eustachian tubes are important because they allow the external air to enter through the back of the nose and balance the pressure between both sides of the eardrums.

If a person has significant nasal congestion, the Eustachian tubes can be blocked, meaning the middle ear can't equilibrate on descent. Thus, the outside pressure pushes in on the eardrums, stretching them inward. As you know, this causes significant pain and, in some people, a swelling of the middle ear and a rupture of the eardrum. Infants and toddlers, whose Eustachian tubes are more susceptible to closure, will let you know how these changes in pressure affect them.

Chewing gum and swallowing can help some people by opening up the Eustachian tubes; so too can closing off the nose with the fingers and exhaling forcefully to help bring air into the middle ear. You can even purchase devices that help place air into the nose while swallowing, so as to open the Eustachian tubes.

This advice doesn't pertain to you, of course. It's possible you have chronic nasal congestion caused by allergies or environmental irritants. If that's the case, you have several straightforward options.

Nasal steroids, for starters, can decrease the nasal swelling and increase the ability of the Eustachian tubes to stay open. Because it may take five to six days before you notice an improvement in swelling, I would recommend that you take one of these drugs for three weeks prior to flying. The allergy and asthma drug Montelukast -- taken for a week before flying -- also may help reduce nasal congestion from allergies, benefitting the Eustachian tubes. Then there are over-the-counter nasal decongestants like Afrin, which also can be used to decrease nasal swelling and keep the Eustachian tubes open. There are no good studies on their use for this purpose, but I often recommend using them two hours prior to landing. You can also try -- and this is my recommendation -- a combination of all three.

Before you do, however, my suggestion is for you to ask your doctor why your Eustachian tubes become blocked with air travel. He or she can best guide your next steps. It's unlikely that you simply "weren't meant to fly."

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)