DEAR DR. DONOHUE: I would like to see a column on arthritis. Thank you. — M.D.

ANSWER: “Arthro” means joint; “itis,” inflammation. A large number of illnesses fall into the arthritis category — gout, joint infections, ankylosing spondylitis (spine arthritis) and psoriasis. When most people say “arthritis,” they are speaking of osteoarthritis or rheumatoid arthritis.

Osteoarthritis is the most common kind. Almost all humans will have at least a touch of it if they live long enough. Joints are the place where two bone ends meet. The ends of the bones are covered with protective and cushioning cartilage. In osteoarthritis, the cartilage wears thin and frays. The two bone ends rub against each other — bone on bone — and that creates pain and stiffness. Aging is the major factor in producing osteoarthritis. Involved joints include the knees, hips, neck, lower back, fingers and feet. Tylenol, aspirin and the nonsteroidal anti-inflammatory medicines (Aleve, Advil, Motrin) often are the first medicines suggested as treatment. Osteoarthritis induces people not to use affected joints in order to avoid pain. Rest compounds the problem; it weakens muscles that protect the joints. A supervised exercise program and the application of heat or cold can reduce pain and keep joints mobile. Severely affected joints immobilize people, and joint replacement is the approach that restores mobility.

Rheumatoid arthritis affects not only joints, it also affects other body organs and tissues. Joint inflammation, swelling, pain, stiffness and deformity are its hallmarks. Since the entire body is involved, fatigue is a prominent symptom. The heart, the lung coverings and blood vessels can become inflamed. More-powerful medicines come into play in rheumatoid arthritis, drugs like methotrexate, cortisone (for short periods only) and newer medicines that fight inflammation-causing chemicals. The latter medicines include drugs like etanercept (Enbrel) and infliximab (Remicade). Physical therapy is an important treatment. Joint replacement is an option for severely affected joints.

DEAR DR. DONOHUE: I have two questions. Three years ago, I could swim 25 lengths of the pool. Now swimming one length leaves me gasping for breath. The same thing happens to me when climbing stairs. My doctor thinks there is water in my chest cavity that needs to be removed. How is that done? Secondly, my ankles and legs swell during the day. I take a water pill, but it’s not helping. My doctor says nothing can be done for it. Thank you for any advice. — J.K.

ANSWER: Both questions can be handled in a single answer. You describe heart failure. Fluid in the chest cavity is a pleural effusion. Heart failure is one cause. Cancer, liver failure, kidney failure and infections are other causes. Both heart failure and a pleural effusion lead to breathlessness. The fluid can be removed with a needle and syringe or a drainage tube. However, if the cause is heart failure, medicines can mobilize the fluid. Swelling of the ankles and legs is another sign of heart failure.

Press your doctor to address the issue of congestive heart failure. Many treatments are available. Medicines is the first step to take.

 DEAR DR. DONOHUE: I am a 75-year-old male. I have a home blood pressure machine. How often and at what time of day should I take my blood pressure to give the most accurate reading? — J.C.

 ANSWER: Blood pressure fluctuates throughout the day. It’s higher in the early-morning hours after waking. It’s lower in the evening and during sleep. You can take your blood pressure at any other time of day, but be consistent with the time.

 It’s important to follow these rules to get an accurate reading. Don’t drink any caffeinated beverages or smoke for at least 30 minutes before taking your pressure. Sit quietly in a chair for five minutes with your feet flat on the floor. You can read or listen to music. The arm on which you take your pressure should be supported and be at heart level. You can rest it on a table or some other piece of furniture. Take two recordings, with a slight break between the two. Average the two readings. Taking your pressure once a day is enough.

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