Lyme Disease
Lyme disease is a tick-borne illness caused by the bacteria Borrelia burgdorferi and, less commonly, Borrelia mayonii. It’s transmitted to humans through the bite of infected blacklegged ticks (deer tick, lxodes scapularis).
Lyme disease has 3 stages:
- Stage 1: Early localized Lyme Disease most commonly manifested by Erythema migrans characterized by spreading erythema with central clearing giving the appearance of "Bull's eye". Associated symptoms are mainly lethargy and body aches.
- Stage 2: Early Disseminated Lyme Disease characterized by multiple erythema migrans spots. Might involve the heart with AV block and myocarditis. May cause neurologic issues like meningitis, facial nerve palsy and pain syndromes.
- Stage 3: Late Disseminated Lyme Disease characterized by marked arthritis mainly the knees, usually monoarthritic, cognitive impairment and muscle weakness.
Diagnosis: Classic acute stage 1 needs no work up rather prompt empiric treatment especially in endemic states. If confirmation is needed then a 2 step approach is done per guidelines. The Centers for Disease Control and Prevention (CDC) recommends a two-step testing process, where the second step is performed only if the first step is positive or indeterminate. It’s important to note that antibodies can take several weeks to develop, so patients may test negative if infected only recently.
- Enzyme-linked immunosorbent assay (ELISA): This test detects antibodies to Borrelia burgdorferi in the blood. It’s usually the first test done and, if positive, is followed by a confirmatory test.
- Western Blot: This test confirms the ELISA diagnosis by detecting antibodies to several proteins of Borrelia burgdorferi.
If thrombocytopenia present, then think about co-infection with HGA (human granulocytic anaplasmosis).
If high grade fever present, consider co-infection with Babesiosis and/or HGA.
Prevention is important in this disease. When hiking in endemic area, skin spray applications like N,N-diethyl- m-toluamide (DEET), picaridin and oil of lemon eucalyptus are helpful in keeping the tick away.
Prophylaxis: If a tick gets attached for at least 36 hours, then prophylaxis with antibiotics within 72 hours of tick removal might be indicated. Doxycycline 200 mg once.
Treatment:
Treatment of Erythema migrans includes one of these:
- Doxycycline 100 mg twice daily for 10 days (1st line of treatment)
- Amoxicillin 500 mg three times a day for 14 day
- Cefuroxime 500 mg twice daily for 14 days
- Azithromycin 500 mg daily for 7 days (last if above contraindicated)
Treatment of Lyme arthritis: Start with oral medications as above but for 28 days, if no significant response then start with IV ceftriaxone for 2 to 4 weeks.
Treatment of Lyme neurological manifestations: Start with IV ceftriaxone (Cefotaxime or Penicillin G are alternatives) then switch to PO doxycycline for total treatment of 14-21 days.
Treatment of Lyme carditis: Start with IV ceftriaxone then switch to PO doxycycline (amoxicillin and cefuroxime axetil are alternatives) for total treatment of 14-21 days.
Treatment of Lyme borrelial lymphocytoma is PO doxycycline (amoxicillin and cefuroxime axetil are alternatives) for total treatment of 14 days.
Treatment of Lyme acrodermatitis chronica atrophicans is PO doxycycline (amoxicillin and cefuroxime axetil are alternatives) for total treatment of 21-28 days.
This post covers the points you need to know for your board exams as well as for teaching residents on the daily rounds. Medical professionals can't use the information here to treat their patients nor people can use the information her to treat themselves. If you are having any medical issues, contact your local emergency services. Please refer to your doctor for medical advice.