Tick-borne Illnesses: The Risks of a Missed Diagnosis

For a patient with a tick-borne illness, early diagnosis matters. Luckily, according to Robert Jones, MD, Medical Director for Infectious Diseases at Quest Diagnostics, physicians are much more aware of Lyme disease and other tick-borne infections than in the early days of the epidemic. “It’s a much more ‘Lyme-literate’ population these days,” he says.But the risks of missing the diagnosis are still there, especially when a patient has a non-standard presentation, such as lack of a rash for Lyme disease. Once thought to be required for the diagnosis, it is now clear that up to 30% of patients never develop a rash.“As with most diseases, the earlier you catch it the better,” Dr. Jones says. Early treatment requires a short course of antibiotics, usually oral doxycycline, which is not only effective against infection by the Borrelia burgdorferi bacterium that causes Lyme disease, but also Anaplasma and Ehrlichia, two other tick-borne bacteria that can cause infection instead of or along with Borrelia.

Untreated, the infection can spread to the joints, the heart, and the central nervous system, days to months after the initial infection. “Acutely, the symptoms are tied to site of infection—fluid in the joints, inflammation of the heart, or invasion into the meninges,” notes Dr. Jones. In the joints, it can cause arthritis, severe joint pain, and swelling, especially in the knees. In the heart (called Lyme carditis), it can cause palpitations, shortness of breath, and chest pain. In the CNS, it can cause severe neck pain, headache, neuropathy, Bell’s palsy, and cognitive symptoms. “Not everyone follows the same course, and there is no linear progression of symptom development,” he says. After rash, arthritis is the most common symptom, followed by carditis (affecting approximately 1% of patients), and then meningitis.When the infection has progressed, more invasive treatment may be required. “If there is a concern for central nervous system Lyme disease, we will typically use intravenous antibiotics, usually a third-generation cephalosporin such as ceftriaxone,” says Dr. Jones. Mild heart block can be treated with oral antibiotics, but more significant heart block may also require IV antibiotics. “Generally speaking, doxycycline will treat Ehrlichia, Anaplasma, and Lyme disease,” but not Babesiosis. Amoxicillin can treat Lyme disease, but not the others, so that if doxycycline is contraindicated, it may be valuable to rule out their presence through testing.Treatment is still effective after a delayed diagnosis, Dr. Jones adds, “although the symptoms may take longer to dissipate,” even after successful eradication of the infection. The persistence of symptoms after treatment, called post-treatment Lyme disease syndrome (PTLDS), is not the same as “chronic Lyme disease,” defined as a persistent infection after antibiotic treatment, he emphasizes. There is no clinical evidence that the latter condition exists, he says, as the Infectious Disease Society of America has emphasized in their guidelines.While not every patient with a suspected tick-borne illness needs to be tested, it can provide important information. “From an epidemiological standpoint it is always nice to know what is in your community,” Dr. Jones says. “If I recognize Babesiosis is in my community, for example, then I know to look for it, and to test for it.” It may help guide the choice of treatment as well, especially if the patient is not responding to an initial round of oral doxycycline, which is often the first agent given. “And it is useful to be able to tell the patient exactly what they have,” he added.

This information is provided for informational purposes only and is not intended as medical advice. A physician’s test selection and interpretation, diagnosis, and patient management decisions should be based on his/her education, clinical expertise, and assessment of the patient.