Lyme disease, caused by the spirochete Borrelia burgdorferi, remains a significant public health concern in the United States, particularly in certain geographic clusters. As the most commonly reported vector-borne illness in the U.S., with an estimated 30,000 confirmed cases annually, it is imperative for pediatricians to stay updated on the latest guidelines and recommendations for its diagnosis and treatment.
This blog delves into the intricacies of Lyme disease—from early localized manifestations to late disseminated complications—ensuring that you have the most up-to-date information to support your clinical decisions and provide optimal care for your patients. All of the content below is excerpted from MedStudy's Pediatrics Core books to provide pediatricians with a comprehensive overview of the current best practices for diagnosing and treating Lyme disease.
The content below is excerpted from the 11th Edition Pediatrics Core > Emergency Medicine and Maltreatment > Submersion Injury. This MedStudy Core content was medically reviewed by Lynn Bullock, MD.
In the U.S., the spirochete B. burgdorferi causes Lyme disease. Transmission occurs by the Ixodes scapularis tick in the eastern and midwestern states and by the Ixodes pacificus tick in northern California. (The protozoa Babesia is also transmitted by I. scapularis.) There is geographic clustering, with most cases occurring in New England, the mid-Atlantic states, Wisconsin, Minnesota, and, less frequently, northern California (Figure 17-30). Lyme disease is the most commonly reported vector-borne illness in the U.S. In the Centers for Disease Control and Prevention (CDC) 2019 Annual Tables of Nationally Notifiable Infectious Diseases and Conditions, Lyme disease ranked number 6. There are ~ 30,000 confirmed and ~ 10,000 probable cases per year reported to the CDC. However, its true incidence is likely to be higher. It is estimated that only 1 in 10 cases are reported.
Figure 17-30: Reported cases of Lyme disease—U.S., 2019
There is no clear evidence that Lyme disease causes a congenital infection syndrome.
Lyme disease is usually transmitted during the ticks’ nymph stage due to its small size (< 2 mm), thereby going unnoticed during feeding. Ticks are most likely to transmit infection after ~ 2 or more days of feeding. If a person reports having had a tick on them for a few hours the previous day, provide reassurance that no treatment is necessary.
Lyme disease is divided into 3 stages (see Table 17-6 for key manifestations):
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- Early localized (Stage 1)—diagnosis is clinical in this stage. Erythema migrans is the characteristic skin lesion of early localized disease; it typically appears 1–2 weeks after the tick bite. The lesion starts at the site of the bite and is a slowly spreading (usually > 5 cm in diameter), irregular erythematous lesion with either a bull’s eye or a clear center (Figure 17-31). Other early symptoms include myalgias, arthralgias, fever, headache, and lymphadenopathy. Serology is negative in 90% of early localized disease; therefore, base the diagnosis on clinical findings.
- Early disseminated (Stage 2)—this stage occurs weeks to months later in untreated patients, with recurring erythema migrans (usually multiple smaller lesions),neurologic problems (e.g., lymphocytic meningitis, neuritis), and heart problems (e.g., myocarditis, which can cause a rapidly alternating 1st, 2nd, or 3rd degree atrioventricular block). The neuritis often presents as a peripheral neuropathy, a cranial nerve (CN) palsy, or both; consider it in a patient with a suggestive history and facial nerve (CN 7) palsy (a.k.a. Bell’s palsy), foot drop, or both. Serologic tests are usually positive for IgG and IgM antibodies.
- Late disseminated (Stage 3)—months to years later, late disseminated disease occurs in untreated patients, most commonly with arthritis (oligoarthritis or migratory—large joints, mostly knees). Swelling is often out of proportion to pain, and white blood cell count and erythrocyte sedimentation rate are lower in comparison to pyogenic arthritis. There also can be chronic neurologic syndromes, but these are rare in children. As with Stage 2, serologic tests are usually positive for IgG and IgM antibodies.
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Figure 17-31: Erythema migrans
Do you need to check Lyme serology on a patient with erythema migrans? No! Just treat based on your clinical diagnosis. Again, erythema migrans is pathognomonic for Lyme disease.
A 2-tier approach is recommended for the serologic diagnosis of Lyme disease. Follow a positive enzyme-linked immunosorbent assay or immunofluorescent antibody assay with a Western blot (a.k.a. immunoblot). If the acute-phase serum testing is negative, convalescent-phase testing is recommended 2–3 weeks after the initial test. Antibody testing for Lyme disease is preferred over use of polymerase chain reaction or culture methods. Treat only symptomatic patients with positive results on the 2-tier antibody testing, according to the 2020 Clinical Practice Guidelines for Prevention, Diagnosis and Treatment of Lyme Disease by the Infectious Disease Society of America, American Academy of Neurology, and American College of Rheumatology.
Treat erythema migrans in children of any age with 10 days of oral doxycycline or 14 days of either amoxicillin or cefuroxime. Azithromycin is an alternative option used for 5–10 days (7 days in the U.S.; less studied for this indication).
Isolated facial nerve palsy due to Lyme disease should be treated with antibiotics. Oral doxycycline (100 mg bid) for 14 days is recommended, and no lumbar puncture is usually necessary. Amoxicillin has not been studied for this indication or other neurologic Lyme disease. Intravenous ceftriaxone (alternatives: cefotaxime or penicillin G) is recommended for any parenchymal brain or spinal cord involvement and most other forms of neuroborreliosis (i.e., meningitis, radiculoneuropathy, cranial neuropathies, or peripheral nervous system manifestations). Treatment is usually for 14–21 days, and switching from intravenous (IV) to oral agents may be appropriate in select patients.
Initial treatment of uncomplicated Lyme arthritis with an oral antibiotic agent for 28 days (doxycycline is the drug of choice for those ≥ 8 years of age while amoxicillin is preferred for those < 8 years of age because of the long duration [i.e., exceeding 21 days]) should prove effective. If there is partial response or relapse, repeat treatment with the same oral agent. Parenteral ceftriaxone should be used if there is no response or worsening Lyme arthritis on oral treatment. Up to 1/3 of patients have residual synovitis or joint swelling following arthritis treatment. Manage these with supportive therapy—not antibiotics. Nonresponders frequently are human leukocyte antigen (HLA)-DR4 allele positive. Treat cardiac Lyme disease with IV ceftriaxone for 14–21 days.
No preexposure prophylaxis is indicated (i.e., do not give medications prior to outdoor activity to defend against tick bites). If a patient has an attached tick, it should be removed as soon as possible. Use fine-tipped tweezers to grab the tick as close to the skin surface as possible. Pull the tick straight up, without twisting, to avoid crushing the tick in the skin; this also helps prevent the tick from regurgitating, defecating, or urinating into the bite wound. Afterwards, clean the skin site with soap and water or alcohol. Diagnostic testing of the tick to confirm the Ixodes species (available from commercial labs and some local health departments) is recommended to provide anticipatory guidance to determine whether the patient needs chemoprophylaxis. Otherwise, dispose of the tick by flushing it down the toilet or throwing it out in a sealed container with alcohol. Testing the tick for Borrelia is not helpful, as it has been shown to poorly predict the risk of infection. Amoxicillin has not been studied sufficiently as prophylaxis against Lyme disease. Instead, the CDC recommends using oral doxycycline as chemoprophylaxis if all the following conditions are met:
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- Doxycycline is not contraindicated.
- The attached tick can be identified as an adult or nymphal I. scapularis tick (preferably in a diagnostic lab).
- The tick has been attached ≥ 36 hours based on the degree of engorgement with blood or likely time of exposure to the tick.
- Prophylaxis can be started within 72 hours of tick removal.
- The patient lives or has recently traveled to a hyperendemic area for Lyme disease (at least 20% of nymphal ticks and > 50% of adult ticks are infected with B. burgdorferi).
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Some patients with Lyme disease may have persistent posttreatment symptoms of fatigue, joint pain, myalgia, and/or cognitive impairment for weeks to months after successful treatment. This has been called “chronic Lyme disease,” which is a misnomer because there is no scientific evidence of persistent infection. Several studies have shown that prolonged antibiotic treatment for these symptoms does not offer any benefit and may be harmful.
Note: In an exam scenario, if a patient has only fatigue, joint stiffness (not arthritis), muscular aches, and/or tenderness—do not check Lyme titers and do not treat for Lyme disease based on these nonspecific findings.
Staying on top of the latest guidelines for Lyme disease is essential for pediatricians to provide the best care for their patients. By understanding the disease stages, recognizing key symptoms, and using the right treatment protocols, pediatricians can manage Lyme disease effectively and prevent complications. This blog, featuring excerpts from MedStudy's Pediatrics Core books, offers a comprehensive overview of the current best practices. Our goal is to equip you with the knowledge you need to confidently take on the boards, plus diagnose and treat this common vector-borne illness.
