Lyme Disease: From Ticks to Aches

By: Martin Bergman, MD
Last Reviewed on: August 11, 2005
Discovery

Since its first description in 1977, Lyme disease has captured the attention of both the medical community and the public. The investigation that determined the cause and ultimately the treatment of Lyme disease is a classic case of medical research.

In Old Lyme, Connecticut, during the fall of 1975, two concerned mothers began a search for a cause of an unusual number of cases of what appeared to be juvenile rheumatoid arthritis (JRA). Drs. Allen Steere and Stephen Malawista at Yale University joined the quest, and their initial survey found a cluster of 51 cases of apparent JRA in three communities along the Connecticut River. They also noted some interesting connections among the cases; the disease seemed to limited to one side of the river, and was more common in the warmer months of the year. But the most striking clue was the peculiar ?bull?s eye? rash that many of the patients had. A few years later the final piece of the Lyme disease puzzle came when the bacterium Borrelia burgdorferi was located in a deer tick. Researchers now know that Lyme disease is transmitted to people by deer ticks infected with B. burgdorferi. More importantly, they understand how to treat and prevent the disease.

Although originally seen in New England, cases have been reported in all 50 states and in most countries around the world. More than 20,000 cases have been reported to the Centers for Disease Control and Prevention (CDC), with the bulk of them being found in either the northeast/greater Atlantic region, or in the Great Lakes region.


How the Disease is Spread
Understanding and treating Lyme disease requires some knowledge about the life cycle of the deer tick, Ixodes dammini. The tick hatches from eggs in the early spring and sets out looking for food. At this point, it is not yet infected and lives off of the blood of the white-footed mouse, which is often infected with Borrelia burgdoreri. The mouse and tick are not affected by the harmful bacterium, but the tick does become a carrier and can transmit it to animals and people.

After "molting" over the winter, the tick reappears the following spring as a nymph. This is bad news for people and pets because the nymph requires a lot of food and consequently infects many more ?hosts,? like dogs, horses and humans. In the fall, the tick will molt into an adult to feed and reproduce. Ixodes dammini?s common name is the deer tick because it prefers to mate on deer Most Lyme disease cases occur in the late spring through fall, when the tick is actively feeding.

Luckily, a tick bite usually doesn?t result in Lyme disease. First, not all deer ticks are infected with the harmful bacterium. Next, the deer tick has to be attached to your skin and feeding for at least 24 hours before it transmits the disease. Finally, even when you or your pet is bitten by an infected tick, there is only a 1 to 3 percent chance of getting Lyme disease.

Signs and Symptoms
You will usually notice a large round or oval rash with a pale center within a week to a month after a bite. This is an erythema chronicum migrans (ECM) rash but is commonly called a "bull?s eye" rash. It is large and spreads quickly, getting as big as 8 to 10 inches wide. One way to test whether a rash is ECM is to draw a circle around it. By the next day, a Lyme disease rash should have spread outside of the circle. Sixty to 70 percent of Lyme disease patients will recall having an ECM rash, but often don?t remember a tick bite. On the other hand, more than 90 percent of patients who actually know they have been bitten will be actively looking for an EMC rash and promptly seek medical attention if it appears. Without treatment, the rash will fade on its own, giving the false impression that everything is OK. Additional rashes may appear but they are generally smaller and do not last as long.

ECM rashes are not the only sign of Lyme disease. Other symptoms include fatigue, headache, muscle aches, fever and swollen glands. Lyme disease does mimic the flu but doesn?t typically involve a stuffed or runny nose or sore throat.

If untreated at this point (or if no signs have yet appeared), the bacterium can spread through the body and infect other sites. One serious complication is meningitis, an infection of the membranes that surround the brain and spinal cord. Meningitis symptoms, including severe headache, stiff neck and sensitivity to bright lights, require immediate medical attention. Also, some patients may have mood swings, memory difficulties or weakness from inflammation in the brain. Fortunately, this is not a common problem. A doctor may perform an MRI to show any abnormalities in the brain and rule out any other possible conditions.


Other, less severe nerve damage, signaled by weakness or burning pain in a body area, can also occur. One of the most common nerve "palsies" associated with Lyme disease is a drooping of one side of the face, with difficulty closing the eye or chewing and keeping food in the mouth.

At this point, the heart can be infected by the bacterium, causing shortness of breath and an abnormal heart rhythm.

The joints are also at risk of being affected, with typically one or two larger joints, such as the knee, feeling stiff and achy. Some people, though, may suffer from widespread joint pain.
Over time, the infection will become more chronic and can eventually lead to more permanent damage. Sometimes, even after a patient has been diagnosed and treated for Lyme disease, a feeling of fatigue, muscle aches and difficulty sleeping may continue. Called post-Lyme fibromyalgia, it is thought to be caused by the body?s reaction to Lyme disease, and not to persistent infection. This may last for more than six months, but does not require further antibiotic treatment. Generally it will clear up by itself over time, although sometimes medications to control sleep disturbance and pain may help. Lyme fibromyalgia is, however, controversial, and not all physicians agree that these symptoms are related to Lyme disease.

Tests and Treatments
Lyme disease is usually easy to diagnose and treat. If a person has a classic bull?s eye rash, no blood tests are needed or even recommended. Appropriate antibiotic therapy (usually oral doxycycline) provides a cure. In less clear cases doctors will perform blood tests. These tests are usually very accurate. Rarely, false negative tests occur (meaning the person has Lyme disease, but the test is "negative"). Usually this happens after a person has been given antibiotics too early, or if he or she didn?t complete the prescription. Just as often, a patient may have a false positive test (the person does not have Lyme disease, but the test is "positive"). There are many possible causes for the positive result, including something as simple as a mild gum disease.

When a physician is concerned about either an infection in the joints or central nervous system it may be necessary to drain the joint (by arthrocentesis) or perform a "spinal tap" (a lumbar puncture) to be certain. Then these fluids can be sent for PCR (polymerase chain reaction) testing, which is very specific for Lyme disease.

In the right setting, with the right symptoms, testing can be extremely helpful. However, the symptoms of Lyme disease are often attributed to other diseases. Misdiagnosis of rheumatoid arthritis, systemic lupus erythematosus (SLE, or lupus) and even depression can happen because of the similar signs and symptoms. It is crucial that physicians not rush into treating Lyme disease without ruling out any other possible causes.


Once Lyme disease is correctly diagnosed, the vast majority of patients can be cured, despite what you may have read in some media sources. It is important to stress that regardless of the "stage" of the Lyme disease, most patients can be cured with proper antibiotics, and rarely require more than one to two months of treatment. Fortunately, true treatment failures are extremely rare and can be fixed by changing the medication regimen.

Also, experts recommend "careful watching" to see whether symptoms are due to slow recovery or from active infection. Over-treatment puts patients at risk of dangerous gastrointestinal diseases or "super-infections" that can form from other bacteria and fungi.

While Lyme disease is generally very easily treated the best course of action is to avoid infection in the first place. When going into tall grass or wooded areas, wear long sleeves and long pants tucked into the socks. Light-colored clothing will make the dark deer tick easier to spot and remove before it gets close to the skin for its meal. DEET, a common insect repellant, is also very helpful. Upon returning from a wooded area, perform a simple but thorough "tick check" to identify "freckles" that don?t belong. If an imbedded tick is found, there is no need to panic. Simply grasp the head of the tick with a tweezers and gently remove it; lit matches, cigarettes and petroleum jelly do not help. The bite site should then be watched carefully for the signs of any spreading rash. If this appears, or any of the other Lyme symptoms occur, see a health professional immediately.

As people continue to expand into the wilderness and forests there is a greater chance of exposure to Lyme disease. Much has been made of this disease, often playing on people?s fears and anxieties of this illness. Fortunately, we now know much about the disease, and can take appropriate measures toprevent and cure it.