Lyme disease is caused by the bacterium Borrelia burgdorferi, which is spread to humans by tick bites. In the days or weeks after a tick bite, early Lyme disease typically causes a rash and flu-like symptoms. Left untreated, advanced or late-stage Lyme disease can lead to a number of symptoms months or even years after the initial tick bite. Complications of advanced Lyme disease commonly affect the joints, nervous system and heart.
The authors of an October 2007 article in "The New England Journal of Medicine" note that arthritic symptoms are the most common manifestations of late-stage Lyme disease. Joint pain and swelling due to advanced Lyme disease tend to affect large joints such as the knees and hips. Arthritis associated with late-stage Lyme disease is often debilitating and severe but can generally be treated with the appropriate antibiotics.
Up to 20 percent of people with Lyme disease experience neurological symptoms, according to a July 2008 review article in "Medicine and Health." People with advanced Lyme disease may develop chronic numbness and tingling in their hands and feet due to nerve damage, a condition known as peripheral neuropathy. In rare cases, late-stage Lyme disease can affect the brain itself and cause a disorder called Lyme encephalopathy. Symptoms include problems with concentration and short-term memory. Lyme encephalomyelitis is another rare complication. This progressive disorder involves the brain and spinal cord and may lead to impaired thinking and difficulty walking.
Cardiac or heart-related complications tend to occur early after infection. In people who do not receive Lyme disease treatment, however, symptoms may not become apparent for several months. About 5 percent of people with Lyme disease experience cardiac symptoms, reports the author of a November 2010 article in "Medicine and Health." Lyme disease can interfere with the electrical activity in the heart, leading to palpitations, lightheadedness and fainting. Inflammation of the heart muscle and the lining around it, known as myopericarditis, is also a potential complication. Lyme myopericarditis can cause chest discomfort and difficulty breathing.
Joint and heart-related complications of Lyme disease typically respond well to treatment with antibiotics. For people who have Lyme disease without neurological symptoms, antibiotic therapy with doxycycline (Doryx, Monodox), cefuroxime (Ceftin) or amoxicillin is recommended by the Infectious Diseases Society of America. Doxycycline, ceftriaxone (Rocephin), cefotaxime (Claforan) and penicillin are antibiotic options recommended for people with nervous system complications, according to IDSA and the American Academy of Neurology. When Lyme disease symptoms persist despite a full course of treatment, additional antibiotic therapy is not recommended, advises the IDSA.