New research offers a possible way to tell apart two conditions with similar symptoms. One disorder is chronic fatigue syndrome. The other is neurologic post-treatment Lyme disease. This is a set of symptoms that linger after the infection that caused Lyme disease is treated. People with both conditions feel fatigue. Many also say they have problems with thinking. The new study included 43 people with chronic fatigue and 25 with lingering Lyme disease. They were compared with 11 healthy people. Researchers looked at spinal fluid from everyone. In people with chronic fatigue, they found 738 proteins in spinal fluid that were not found in the other groups. People with lingering Lyme disease had 692 proteins not found in the other groups. This is the first time that body substances have been found to distinguish between the two conditions. Researchers said it's also the first strong evidence that the central nervous system is involved in both. The jounal PLoS One published the study. HealthDay News wrote about it February 24.

By Diana Post, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

This is a very exciting article. It describes a new way for doctors to tell apart two disorders with similar symptoms.

Lyme disease is an infection caused by Borrelia burgdorferi bacteria. It is spread to people through tick bites. It is common in many areas of the United States.

Lyme disease is treated with antibiotics. Most people get better quickly. However, some people with proven Lyme disease who do not get well after treatment. They have no evidence of continued infection. But they still feel fatigue and have trouble thinking. They are said to have neurologic post-treatment Lyme disease.

Chronic fatigue syndrome is a poorly understood illness. The most common symptom is extreme fatigue that doesn't get better with rest. The symptoms last at least six months. Many people with chronic fatigue also complain about having trouble thinking.

Chronic fatigue syndrome often begins suddenly after an illness, trauma or the death of a loved one. It lasts for years. Often people never recover completely. The cause is unknown.

There has been much confusion about the relationship between chronic fatigue syndrome and Lyme disease, particularly neurologic post-treatment Lyme disease. Most doctors believe the two disorders are different, although they share many symptoms. Lyme is caused by an infection. Chronic fatigue syndrome is not. But people with both conditions have fatigue and problems with thinking. So it has been difficult for doctors to distinguish one from another.

Now there's a new study that may help. The researchers believe that these are separate and distinct disorders. They found that they could tell them apart by looking at proteins in the fluid that surrounds the brain and spine. This is called the cerebrospinal fluid. People with each condition seem to have distinct proteins in the fluid. These proteins are not found in people with the other condition. They also are not found in normal spinal fluid.

If this research is confirmed in the future, it may provide doctors with better ways to diagnose these two puzzling and difficult disorders.

Treatments for the two diseases are different. So a correct diagnosis will allow your doctor to give you the right treatment and better predict the course of your disease.

It is important to tell the two disorders apart for other reasons as well. We can't learn about possible causes and treatments if we lump them together. Researchers can get better results if they know they are studying people with each disorder separately.

What Changes Can I Make Now?

There is no way known to prevent chronic fatigue syndrome. However, there are things you can do to prevent Lyme disease.

Remember, Lyme disease is spread by the bite of a tick. So take these steps if you are in a region where Lyme disease is common.

• Avoid walking or working in areas where ticks tend to hide. These include wooded and grassy areas.
• Wear clothing that will prevent ticks from reaching your skin. Wear long pants, and tie them at the ankle or pull your socks over the pant legs. Wear shirts with long sleeves. Try to wear light colored clothing so you can better spot the ticks on your clothes.
• Consider using an insect repellant that is designed to repel ticks. Usually these contain DEET. There are repellants that can be sprayed onto clothing as well.
• Check your skin carefully after you have been outside in tick areas. Pull off any ticks that you find with tweezers.
• Call your doctor if you have been bitten by a tick to see if you should be given medicine. Also see your doctor if you develop a flu-like illness or a rash after a known tick bite or after you have been in area where ticks are common.

If you have been diagnosed with chronic fatigue syndrome, see a doctor who specializes in this difficult disorder. Remember, structured exercise is very important. Work with your doctor and physical therapist to design an exercise program for you.

What Can I Expect Looking to the Future?

This study should encourage more research on cerebrospinal fluid proteins in these two disorders. Telling them apart should allow better understanding of the causes of these diseases. It might also lead to new tests to diagnose them. Finally, I hope this type of research eventually will lead to new and better ways to treat these conditions.

Similar types of research also might be done on other poorly understood neurological illnesses. These studies could provide us with new insights.