Q3 Urgent Caring- Tick-Borne Illness: A Diagnostic Approach for the Urgent Care Clinician

KidBits: Tick-borne Illnesses in Children

Due to the nonspecific nature of tick-related illness, combined with decreased body awareness, tick bites and their associated symptoms can often be less conspicuous in children, and easier to overlook or attribute to an alternative diagnosis. This is important to remember, especially with rickettsial disease, because while children represent 6% of all reported cases of RMSF, they account for 22% of fatalities.98 Children’s style of play (outdoors, with pets, etc.) may place them at increased risk for tick exposure. Because of this, familiarity with the pathophysiology of tick-borne disease is essential to making an accurate diagnosis and treatment plan. Preferred pediatric treatment regimens for Lyme disease include doxycycline, amoxicillin, or cefuroxime. Doxycycline is especially indicated if neurological symptoms are present. The preferred agent for treatment of RMSF, ehrlichiosis, and anaplasmosis in pediatric patients is also doxycycline. As with pregnancy, the adverse effects of doxycycline in children (in particular, teeth staining) have been largely disproved in recent studies.99,100

5 Things That Will Change Your Practice

  1. Many patients with tick-borne illness never report finding a tick. 
  2. Do not rely on serological tests to make a clinical decision or to initiate antibiotic treatment.
  3. Doxycycline is the first-line antibiotic treatment for Lyme disease, RMSF, ehrlichiosis, and anaplasmosis in patients of all ages. Recent research shows no evidence of tooth staining when doxycycline is used in short courses in pediatric patients. 
  4. Prophylactic treatment is not needed for tick bites, except for prevention of Lyme disease transmission when the recommended criteria are met. 
  5. The presence of an erythema migrans rash in a patient at risk for Lyme disease is diagnostic and treatment should be initiated without testing.

Risk Management Pitfalls for Tick-Borne Illness in Urgent Care

  1. “My practice is not located in a Lyme disease-endemic area, so there’s no way this patient has Lyme disease.” Although 95% of Lyme disease cases are reported in 14 states in the Northeast and upper Midwest regions of the US, the geographic footprint of Lyme disease is expanding. In states where Lyme disease is not endemic, positive cases are usually attributed to patient travel (e.g. a backpacker in the Adirondack Mountains who returns home to San Diego after vacation). Clinicians should always obtain a complete travel history.
  2. “My patient told me she didn’t have any tick bites, so I didn’t consider tick-borne illness.”
    A significant number of patients do not recall a tick bite. Patients also may have the misperception that tick bites only occur in the woods and therefore overlook potential exposures in backyards, developed areas, etc. 
  3. “I didn’t start doxycycline in my 8-year-old patient because I was concerned about the effects on his teeth and bones.” Doxycycline is the first-line treatment for all suspected rickettsial infections in the pediatric population. Recent studies have shown no adverse effects when the antibiotic is used in short courses. Children are at higher risk for serious disease and death from tick-borne illnesses and prompt treatment is critical to minimize this risk. 
  4. “My patient was diagnosed with babesiosis, but I didn’t realize he also had Lyme disease.” Coinfections should always be considered, as tick species often can carry and transmit multiple diseases. Ixodes ticks are vectors for anaplasmosis, Lyme disease, babesiosis, Powassan disease, and B miyamotoi disease. Rash is infrequently seen with babesiosis, so if rash is also present, coinfection should strongly be considered.
  5. “I clinically diagnosed my patient with influenza. RMSF wasn’t in my differential diagnosis.” The initial symptoms of spotted fever rickettsiosis are nonspecific and cannot be easily differentiated from viral illnesses such as influenza and COVID-19. Clinicians must maintain a high index of suspicion, especially if a patient presents with “flu-like” symptoms during the spring and summer months. 
  6. “The tick serology test was negative, so I ruled out tick-borne illness.” Serology testing measures antibodies produced by the body in response to an illness, a process that takes a few days. If testing was performed too early in the disease course, antibodies would not be detectable. For this reason, a 4-fold increase in antibody titers is needed two to four weeks apart for laboratory confirmation of disease. In RMSF or ehrlichiosis, the disease can be fatal before laboratory confirmation is finalized.

Time-and Cost-Effective Strategies

  • Among patients who present to Urgent Care with concern for tick-borne illness, Lyme disease is a frequent concern. Patients may request diagnostic testing for reassurance of the absence of disease. It is important to keep in mind that in most cases of Lyme disease, test results should not and ultimately do not change management. False-positive results can lead to undue stress and unnecessary treatment. Avoiding over-ordering of tests reduces costs, but also improves quality of management and prevents false alarm or false reassurance. 
  • Rather than ordering tests for all possible tick-borne diseases, the prevalence of local tick-borne illnesses should always be considered, and testing for specific tick-borne illnesses should be selected based on geographic considerations and patient risk. 
  • Though patients often bring ticks into the clinic, the tick should not be sent for testing but should only be used for visual identification of the tick species.
  • The persistent duration of antibodies makes follow-up testing unnecessary to confirm resolution of illness. Rather, clinicians and patients can be assured if appropriate treatment was initiated in a timely manner. 

References

  1. Dalton MJ, Clarke MJ, Holman RC, et al. National surveillance for Rocky Mountain spotted fever, 1981-1992: epidemiologic summary and evaluation of risk factors for fatal outcome. Am J Trop Med Hyg. 1995;52(5):405-413. (Review of epidemiological data)
  2. Volovitz B, Shkap R, Amir J, et al. Absence of tooth staining with doxycycline treatment in young children. Clin Pediatr (Phila). 2007;46(2):121-126. (Retrospective study; 61 patients)
  3. Casey Barton Behravesh, Schutze GE. Doxycycline can be used in young children without staining teeth. AAP News. 2015;26(5):16. (Expert opinion)

Excerpted from: Chao C, Decker KW. Tick-borne illness: a diagnostic approach for the Urgent Care clinician. Evidence-Based Urgent Care. 2023 June;2(6):1-30. Reprinted with permission of EB Medicine. Learn more about Evidence-Based Urgent Care and get a free sample issue at https://www.ebmedicine.net/urgent-care-info 

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