Dear Doctor: What’s going on with that outbreak of lung disease that’s hitting people who vape? Our 20-year-old son and a lot of his friends vape sometimes, and we’re getting worried.

Dear Reader: You’re not alone in your concerns. Federal health officials have said that close to 200 cases of a serious lung disease that appears to be associated with vaping have been reported. There now also appears to have been at least one death caused by this illness, an adult male in Illinois, according to officials in the state.

The Centers for Disease Control and Prevention is investigating reports from 22 states to date. Most cases involve males ranging in age from 17 to 38. The U.S. Food and Drug Administration is continuing to investigate a potential link between the use of e-cigarettes and serious neurological symptoms, including seizures, fainting and tremors.

Symptoms of the respiratory illness include pressure or tightness in the chest, shortness of breath and difficulty breathing that becomes progressively worse. Some patients also have experienced fever, weight loss, nausea, fatigue and diarrhea. Imaging tests of the patients’ lungs have all revealed abnormalities, including areas of increased density, known as opacities.

In some cases, patients have required mechanical ventilation to aid in breathing and have improved after treatment with corticosteroids. An 18-year-old man in Florida who vaped went to a hospital emergency room and learned he had a hole in his right lung, which had caused it to collapse. Tests for infectious agents have been largely negative, which has added to the mystery of what is causing the disease. One behavior all patients have had in common is recent vaping.

The challenge is that the similarities end there. The patients had inhaled a variety of products, including cannabis-based products, nicotine and homemade substances. They had used a number of different vaping devices. They had purchased the products in a variety of stores and via several different online retailers. This has led investigators to turn their attention to the delivery system of vaping devices.

E-cigarettes work by using a coil to super-heat a liquid and turn it into an aerosol, which is then inhaled. These super-fine particles can then be drawn deep into the lungs. Vaping liquids contain numerous volatile organic chemicals and other substances, not all of which are identified on the packaging. Some of them are known to be potentially harmful. The flavorings used in vaping liquids also contain numerous compounds whose long-term health effects are unknown.

As federal and state health officials continue to investigate, medical professionals and the public have been asked to report any vaping-related symptoms or illnesses, along with specifics about the products that were used, to state health authorities.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I feel like I’ve tried every diet, and no matter what, I just can’t seem to lose weight. A friend who had a surgery that removed part of her stomach was finally able to lose 65 pounds. I wonder if that’s safe?

Dear Reader: You’re referring to a sleeve gastrectomy, a laparoscopic surgery that promotes weight loss by changing the digestive system. In a sleeve gastrectomy, the surgeon removes about three-fourths of the stomach, then uses the remaining tissue to create a pouch shaped somewhat like a banana. The new stomach is significantly smaller, which restricts the amount of food that it can hold. That means feeling satiated faster and with a smaller volume of food. This change in stomach size also results in a reduction of ghrelin, the so-called “hunger hormone,” which is produced primarily by the stomach. A decrease in ghrelin causes a decrease in feelings of hunger.

Sleeve gastrectomy, which is not reversible, is an increasingly popular procedure that began in the early 1990s. Originally introduced as part of a two-step weight-loss surgery, it has since become a stand-alone procedure. Unlike other bariatric procedures, such as gastric bypass surgery, the sleeve gastrectomy isn’t as strongly associated with malabsorption of nutrients, which can lead to malnutrition.

Patients who qualify for this surgery are typically between 18 and 75 years old, are morbidly obese, have a body mass index (BMI) of 40 or more and prior difficulty trying to lose weight. Although results vary, patients can lose 60% of their excess weight in the first two years after surgery.

As with any surgery, sleeve gastrectomy carries risks. Bleeding, infection, adverse reaction to anesthesia and blood clots are risks common to all surgeries. Although rare, it is possible for the newly formed “sleeve” to leak. Longer-term complications can include an increase in acid reflux, hypoglycemia, malnutrition, gastric obstruction and ulcers. Some researchers believe the drop in ghrelin may also have long-term effects that are not yet known. Ghrelin not only stimulates appetite, it aids in fat storage and plays a role in regulating blood sugar and in the release of growth hormones.

After the procedure, while the digestive tract is healing, patients must follow a structured eating plan that provides nutrients but doesn’t stretch the newly constructed stomach. The first stage restricts patients to a liquid diet. This is followed by a gradual switch to pureed foods, followed by soft foods. About three months after surgery, patients will have completed a highly controlled switch to solid foods. Life with a sleeve gastrectomy means small, nutrient-dense meals. Dehydration is a risk, so it’s important to drink plenty of water each day.

In our own practices, we continue to first recommend conservative lifestyle interventions for weight loss. These include following a regular exercise program, working on nutrition and sometimes talking with a therapist. However, we have had patients who do everything correctly and are unable to reach a safe and healthy weight. In those cases, we find that weight loss surgery can be effective.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I was recently diagnosed with irritable bowel syndrome and was told to follow something called the low-FODMAP diet. Honestly, this is all so new that it’s stressful and confusing. Can you explain what’s going on?

Dear Reader: First, you’re not alone in feeling overwhelmed by a new and unexpected diagnosis. Not only are you getting a crash course on an unfamiliar medical state or condition, you’re also being asked to master the details of a new treatment regimen. This can easily add to your stress.

Your diagnosis means that your medical history, along with the symptoms you’ve described to your health care provider, match those of a chronic disorder known as IBS, or irritable bowel syndrome. Symptoms typically include recurrent abdominal pain, which is accompanied by bloating, cramping, gas, constipation or diarrhea. Many people living with IBS find that episodes of diarrhea will alternate with periods of constipation. IBS is a chronic condition, which means that it is managed rather than cured. The cause is unknown. However, recent research points to a gut-brain connection.

Diet is a first line of defense in managing IBS. The FODMAP diet your doctor recommended is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. The “ODMAP” of the acronym are certain sugars, contained in some foods. (Not all carbohydrates are considered FODMAPs.)

For people with IBS, foods with these types of sugars are either not completely digested or are incompletely absorbed. The sugars also cause the foods that contain them to be osmotic, which means that they attract water. These factors can cause these foods to be fermented -- that’s the “F” in FODMAP -- by bacteria in the digestive tract, leading to the gastric symptoms of IBS.

Foods to avoid include those with fructose, which means fruit, honey and anything made with high-fructose corn syrup. Stone fruits like peaches, nectarines, plums, cherries and apricots also contain polyols, a carbohydrate known as a sugar alcohol, which is directly referenced in the FODMAP acronym. Also, avoid dairy products that contain lactose. Low-lactose milk products such as aged cheeses and lactose-free yogurt are usually OK. Other high-FODMAP foods include wheat products, onions, garlic, lentils, beans and legumes, including soy and soy products. Some artificial sweeteners also contain polyols, and should be avoided.

Because each person’s body responds differently to specific high-FODMAP foods, the diet is broken into two phases. The first phase asks patients to eliminate all high-FODMAP foods from their diet for a period of four to six weeks. In the second phase, the eliminated foods are gradually reintroduced. This allows problem foods to be identified.

Fine-tuning the FODMAP diet so that it is varied, interesting, nutritious and high in fiber is challenging. We suggest working with a registered dietitian nutritionist or certified nutritionist to craft a diet that is both effective and sustainable.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)