Lyme disease is caused by infection with a bacterium transmitted to humans by a tick bite, usually in the late spring, summer or early fall. It can cause a number of problems, including rash, memory loss and heart problems. But keep in mind that each of these symptoms is common among people without Lyme disease. It is nearly unheard of in certain parts of the country, where the particular types of ticks associated with the Lyme disease bacterium (and the deer they feed upon) are not present — 90 percent of cases are confined to eight U.S. states, including Connecticut, Massachusetts, Minnesota, New Jersey, New York, Pennsylvania, Rhode Island and Wisconsin.

The features of Lyme disease tend to occur in a particular order.

• The rash occurs first and may be accompanied by fever, joint and muscle aches and fatigue; it tends to resolves over days.
• Days to months later, heart inflammation and/or nervous system problems may develop.
• Months to years after the tick bite, arthritis and additional neurological problems, including problems with brain function, may develop.

The particular features of each of these problems help to determine whether it is likely to be related to Lyme disease. For example, the rash tends to be a large, expanding red area, often with a central area that is spared; however, this rash does not typically persist or come and go for years. The heart disease of Lyme disease may cause palpitations, but usually only for days to weeks. Other symptoms related to heart inflammation from Lyme disease include fainting spells, difficulty breathing (due to congestive heart failure ) or chest pain. Nervous-system problems include stiff neck and fever (from meningitis), weakness of the facial muscles, or a burning pain or numbness in an extremity or the trunk. Forgetfulness may occur months to years after infection, but it is rarely the sole neurological problem (and the vast majority of forgetful people do not have Lyme disease as the cause). The arthritis is usually located in one joint, especially the knee.

Antibody tests for Lyme disease are quite useful in sorting out whether this infection is the likely cause of symptoms. When neurological problems are prominent, a can be helpful, since tests of the spinal fluid can provide valuable information about whether the Lyme bacterium is causing inflammation in the brain or other parts of the nervous system. These tests also can help to determine treatment, including whether it should be oral or intravenous and how long the therapy should last.

Additional testing, such as or an might shed light on the cause of your palpitations and memory problems.

To answer your question, more information is needed, including:

• Whether there was a tick bite at the beginning of symptoms and whether the tick was attached to the skin or engorged
• Details about your initial symptoms and how they changed over time
• The time of year and your geographic location when symptoms began
• What the rashes looked like at the beginning and what they look like now
• Whether the palpitations are accompanied by fainting or other symptoms
• The results of your physical examination, Lyme antibody tests and EKG (and, perhaps others tests as above)

In addition, it is important to rule out other explanations for your symptoms. For example, a dermatologist might determine a clear explanation or recommend a to determine whether another condition was responsible. In rare cases, a skin biopsy can reveal evidence of Lyme disease, but usually the appearance is so typical that a biopsy is not necessary. Similarly, an evaluation by a neurologist, including detailed testing of brain function, can be a useful way to determine the cause of your memory loss.

Finally, because Lyme disease is an infectious illness, infectious-disease specialists can help to integrate all of your symptoms into a "big picture" and suggest an effective approach for treatment.

It's never too late for antibiotic treatment for untreated Lyme disease, but there is evidence that prolonged antibiotic treatment (for several months or more) is not effective for any of its complications. And, of course, antibiotics for Lyme disease are unlikely to help if the symptoms are due to something else. I would recommend re-evaluation with your health-care providers to review the details of your symptoms, examine you and, perhaps, perform additional tests. Only then can you and your doctors embark on an optimal treatment program.

One final suggestion, especially now that spring is here: Do what you can to avoid Lyme disease in the future, because even people who have had it once can get it again.