DEAR DR. DONOHUE: Please tell us what the signs of multiple sclerosis are. Two years ago I woke up very dizzy. I went for an MRI, but everything was negative. I am 77, and I still cannot walk straight. What can be done for MS? I hope I don’t have it at my age. – Anon.

ANSWER: A few facts about multiple sclerosis ought to dispel your worries. The signs of multiple sclerosis are due to a disruption of the insulation of nerve cells (myelin) in the brain and spinal cord. It’s replaced by scar tissue, and that’s the “sclerosis” of multiple sclerosis. The “multiple” refers to “many scars.”

Without insulation, transmission of nerve signals fails. One early sign is vision disturbance in one eye. That eye, when it moves, frequently hurts. Muscles can become weak. People might feel peculiar sensations, or they might notice that areas of their body have become numb. A loss of balance is common. Hot baths or exercise often worsens signs or brings on new ones.

In the most common variety of MS, the relapsing-remitting form, signs appear, worsen and then usually disappear either completely or partially. However, as time goes by, new signs develop. Finally a stage is reached where they are permanent.

Multiple sclerosis commonly appears between the ages of 20 and 50, with most cases occurring in the 30s.

An MRI is a very good test for detecting the scars of MS.

There are medicines for MS. Cortisone drugs are used when it flares up. New medicines include interferons and glatiramer.

Your signs have stayed the same for two years – most unusual for MS. Furthermore, they are not typical of MS. It’s not likely that you have developed MS at your age. Your MRI was normal. The probability that you have it is all but nil.

I can’t tell you what’s making you walk with difficulty. A neurologist most likely can.

DEAR DR. DONOHUE: My husband has Parkinson’s disease. I would like to know if it is inherited. – J.J.

ANSWER: Parkinson’s comes from a depletion of the brain chemical dopamine, which transfers information to parts of the brain governing muscle movement. More than a million Americans have it.

Only about 5 percent of Parkinson’s patients have inherited it. The hereditary form begins in the 50s, 10 years younger than noninherited Parkinson’s begins.

DEAR DR. DONOHUE: My cardiologist ordered a blood test called creatine kinase for me. It was high. What problems could be causing this high reading? I work with weights and jog. – S.W.

ANSWER: Creatine kinase – CK – is an enzyme found in body muscle, heart muscle and the brain. Damage in any of those places raises its blood level. If the doctor asks the lab, it can distinguish between brain, body-muscle and heart-muscle CK.

Exercise can raise the CK reading. Even a slight bump to a muscle can cause a rise. Some medications elevate it. Low blood potassium and low amounts of thyroid hormone also increase the CK level.

I can’t speculate why your CK is on the high side. I would put money on your exercise as doing it, but your own doctor is going to have to give you the definite answer.

DEAR DR. DONOHUE: I was diagnosed with Wegener’s granulomatosis. My joints hurt, I had blood in my urine, and I coughed up blood from my lungs. After two years it is in remission, but I am still weak. What can you tell me about it? – W.M.

ANSWER: Wegener’s is a serious inflammation of blood vessels that serve the nose, the sinuses and the lungs. In addition, the kidneys are inflamed. It can also affect joints and skin. It most likely comes on from a response of the immune system to an unidentified trigger.

Your signs are graphic descriptions of the illness. Nasal discharge often contains pus and blood. Coughed-up mucus contains the same. Kidney inflammation produces urinary blood. Joints can hurt.

Formerly, Wegener’s was a fatal illness. Today, cyclophosphamide and cortisone can usually pull people through. It’s not unusual that you are still weak after having survived an illness that saps body strength. Your energy should come back.

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.