Q: What is chronic Lyme disease?
A: Lyme disease is due to tick bite transmission of the bacteria Borrelia burgdorferi. Although the very small deer ticks are the most common culprits, any tick may transmit the disease.
Early localized Lyme disease occurs days to a month or so after the tick bite, sometimes manifested by a rash at the site of the bite which is red and then clears in the middle (so it looks like a bull’s eye ‘target’). This lasts 2-3 weeks in untreated patients, and about 20% will have this rash recur. After this initial rash about 40% of untreated patients get similar looking rashes at other locations around their body. About one-third of patients will not develop any symptoms other than the rash. Most develop flu-like symptoms possibly including a headache, fever, chills, a stiff neck, muscle and/or joint aches and fatigue. Some people get swollen glands, sore throat or a cough.
The diagnosis of early localized Lyme disease is made clinically based on the symptoms, rash and risk for, or known, tick bite. Blood tests are not very useful in early Lyme disease. Treatment of early localized disease is usually quite effective, and typically consists of three to four weeks of antibiotics by mouth.
Early disseminated Lyme disease may occur weeks to months after the tick bite, and is manifested by malaise and fatigue. In addition:
Most patients will also have intermittent transient bouts of arthritis (usually mild arthritis of several joints) which ‘settles’ into a single joint over a day or two (with the knee, ankle and wrist as the most common locations, in that order). Untreated, the arthritis will usually last a week or so and then resolve on its own, with most patients having recurrent bouts every two to three months. Subsequent bouts of arthritis are usually less severe than the initial bout, but can involve multiple joints.
Neurologic symptoms manifest in about 15% of patients, and can include chorea (irregular spasmodic movement of the muscles), meningitis-like symptoms, Bell’s palsy (drooping of one side of the face) or other neurologic symptoms.
About 8 percent of patients will develop heart problems including changes in the electrical conduction of the signals that make the heartbeat, inflammation of the heart muscle or even decreased function of the left ventricle.
Diagnosis of early disseminated disease is based on the clinical picture; however antibody blood tests are usually done to help confirm the diagnosis (although false positive tests and false negative tests not uncommon). Treatment is once again antibiotics; the specific length of treatment and route of administration (by mouth or intravenous) depends on the specific symptoms the patient has, and whether the patient has previously been treated with antibiotics.
The symptoms of chronic Lyme disease (now termed post-treatment Lyme disease syndrome or PTLDS) occur in as many as 10 to 20 percent of patients, and may manifest many months after the initial tick bite, and despite previous treatment with antibiotics.
Symptoms include fatigue/malaise (which can be severely debilitating), joint or muscle pain/stiffness and/or neurocognitive/psychiatric symptoms. Many other symptoms may occur as well.
The diagnosis of PTLDS is based on the clinical picture, although blood tests for Lyme antibodies are also done. Patients treated with antibiotics early in the course of their disease may not build levels of certain antibodies, and so may ‘test negative’. In addition, for unknown reasons, other patients may not build measurable antibody levels.
This means that patients with a documented history of Lyme disease can develop PTLDS and still have ‘negative’ blood tests.
Early stage Lyme disease is felt to be due to the initial infection, and early disseminated disease thought to be due to a more generalized systemic infection. The cause of the symptoms in PTLDS is not understood, although there are many theories:
An autoimmune or inflammatory response to the infection, with the assumption that the infection itself has cleared
Infection with another organism in addition to Borrelia burgdorferi (ticks may transmit other infectious agents)
Damage to the immune system, body tissue and/or body organs from the earlier infection
PTLDS is still not very well understood. Studies of PTLDS response to aggressive, long duration antibiotic therapy have yielded inconsistent results. This makes it impossible to give any generalized evidence-based advice to PTLDS patients, so treatment must be decided on a case by case basis; many patients have their symptoms spontaneously improve over time. The hope is that future research will shed light on this disease, and that successful treatments that speed recovery will be developed.