DEAR DR. DONOHUE: Please address in your column thoracic aortic aneurysms, and the pros and cons of inserting a stent. – C.J.

ANSWER: Aneurysms are bulges on artery walls. They’re weak spots, and the danger of their bursting depends on their size.

The aorta – the body’s largest artery – is attached to the heart and receives blood pumped from the heart. From the heart, it runs downward in the chest (the thoracic aorta) and then through the abdomen (the abdominal aorta) to its bottom, where it divides into two arteries for the legs. Most aortic aneurysms are in its abdominal portion. Yours is in the chest part, and what I am about to say applies only to chest aneurysms.

Many aneurysms are silent, producing no symptoms, and often are discovered on a routine chest X-ray. When a chest aneurysm produces symptoms, the most prominent one is chest pain similar to angina pain.

Chest aneurysms whose diameter is less than 5 cm (about 2 inches) expand slowly and can be watched safely. Larger aneurysms call for treatment, and the standard treatment is surgically inserting a graft to shore up the weakened wall. An endovascular graft stent is a new procedure where the graft is inched into place through a soft, pliable tube that reaches the aorta from a surface vessel. It’s a less-traumatic procedure, so recovery is quicker. Success in patching the aneurysm with a graft stent is in the 90 percent range. The mortality rate in the 30 days following the procedure hovers around 9 percent, the same as it is with surgery. A small percentage of graft stents have to be reattached at a later date.

Most patients would opt for the graft stent method because of its relative ease. However, age, general health and aneurysm size are factors that must be considered in judging whether open surgery or the graft stent maneuver is the better choice for a particular patient.

READERS: Many women have written to ask for information on endometriosis. The booklet on that topic covers it in depth. To obtain a copy, write: Dr. Donohue – No. 1105, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: Relatives have told me that a condition called porphyria affects some of our family members. They say it causes uncontrollable anger, which I have long seen in my older brother and mother. Can you tell me more about it? I find myself losing it all too often over things an otherwise kind and caring man should take in stride. – M.H.

ANSWER: The porphyrias are a group of eight illnesses that result from a deficiency of one of the many enzymes needed to construct the heme part of hemoglobin. Enzymes are proteins that oversee and speed up all the chemical and construction processes that take place in the body. Hemoglobin is a giant molecule inside red blood cells that grabs onto oxygen as blood courses through the lungs and releases it when blood arrives at sites where oxygen is needed.

Stomach pain, skin eruptions, psychiatric disorders (such as paranoia, anxiety, depression and hallucinations) and nerve problems are examples of some of the disturbances that are found in one or other of the porphyrias.

Porphyrias are rare illnesses. Anger outbursts alone are insufficient to suggest them. You can talk to your doctor about testing for them, but I believe you’re barking up the wrong tree.

DEAR DR. DONOHUE: My son is 11 and overweight. He is 5 feet ¾ inches tall and weighs 165 pounds. He has lost about 20 pounds. He has to lose four more pounds to play football. He doesn’t eat after 5 p.m., but I feed him watermelon. His doctor says it has too much sugar in it. Is that true? – Anon.

ANSWER: A large slice of watermelon (a 16th of the melon) has 41 grams of sugar. That’s 164 calories. It takes a good amount of exercise to burn that many calories. I’d stop the watermelon snacking.

DEAR DR. DONOHUE: As a practicing gynecologist, I encourage your readers to learn about certain diseases that go undiagnosed for years. One is interstitial cystitis, which affects approximately 2 million Americans, and whose features are pelvic pain with urgent and frequent urination. It may be misdiagnosed as recurrent infections or as an overactive bladder. I encourage women (and men) who have IC symptoms to visit www.AllAboutIC.com for information. – J.M.

ANSWER: Certainly, Doctor, I pass your word on to readers. Interstitial cystitis is a disorder that merits coverage, since it’s not a rarity and since, as you point out, it often is misdiagnosed. In addition to your figures, a Canadian survey of patients seeing urologists puts the percentage of their female patients suffering from interstitial cystitis at 8 percent and their male patients suffering the same at 0.4 percent. It often takes an interstitial cystitis patient seven years before the correct diagnosis is made.

Pain in the lower pelvis in the area of the bladder and frequent, agonizing urinations are two prominent symptoms. “Frequent urination” can be as many as 60 bathroom trips during the day and nearly as many nighttime trips. A special coating protects the bladder lining. In interstitial cystitis, it’s believed that this coat has been damaged and urine is able to contact the bladder lining and irritate it.

The diagnosis is based on the patient’s symptoms. Some ancillary tests, like a scope inspection of the bladder, are sometimes done.

Elmiron is an oral medicine often prescribed for this condition. It works for some, but not all. Other treatments include bathing the bladder with special solutions.

The Interstitial Cystitis Association stands ready to help people obtain a diagnosis and to provide them with information on this misunderstood illness. The association’s toll-free number is 800-435-7422 and its Web site is www.ichelp.org.

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