Lyme Disease ============ þ Co-infection - Babesia microti (babesiosis) - Anaplasma phagocytophilum (formerly Ehrlichia, ehrlichosis) þ Distribution - usually in CT, DE, ME, MD, MA, MI, NH, NJ, NY, PA, RI, WI - rarely in HI, MT, OK (2002) - usually between May and September - different clinical picture in Europe as different species þ Erythema Migrans Rash and Differential - 70-80% of those infected will get erythema migrans - Differential: Erythema Marginatum, Tinea Corpora, ... - 20-50% (MedLtr 2006 sayd 15%) will have multiple lesions from hematogenous spread. - Rash starts about 10 days after bite (range 1-30 days) þ Lyme Disease Differential - if high fever, suspect alternative diagnosis or coinfection with ehrlichosis or babesiosis þ Lyme Disease Epidemiology: - more common in children than adults - incidence increasing (1982-1995: 70,000 cases diagnosed); 11,000 cases reported in 1994, 40% increase from 1993 [Scientific American Medicine]. - only about 25% of those with Lyme disease remember a tick bite þ Lyme Disease Diagnostic Guidelines: [Gerber MA, Shapiro ED. Diagnosis of Lyme disease in children. J Ped 1992; 12(1):158-62.] - base diagnosis primarily on clinical grounds - serology is only to confirm clinical diagnosis - commercial kits are unreliable; use a reference lab - serology not needed for clinical diagnosis: tick bite followed by erythema migrans - for suspected early disseminated Lyme disease (Bell's palsy, meningitis), use serology to confirm; but, antibodies may be slow to develop, so may have false negative tests, so treat anyway - for suspected late disseminated disease (arthritis, neurological or psychiatric problems) use serological test - initial test should be ELISA (or immunofluoresecnt assay IFA); if equivocal, perform immunoblot (Western blot) - resist temptation to test patients with vague nonspecific symptoms such as fatigue, fever, myalgias, or transient arthralgias; ELISA remains positive for many years, even in treated patients; a false positive test in such a patient may lead to numerous courses of unneded antibiotics (sometimes with placebo effect) and failure to diagnose the true problem - " ...because the incidence of false positive test results far exceeds the true incidence of Lyme disease, the costs and risks of treating patients with chronic, nonspecific clinical ailments far outweight the benefits." [Scientific American Medicine, August 1995.] - Seroconversion may not occur until weeks after the development of symptoms. - IgG detectable 4-6 weeks after initial infection - Antibiotic therapy may blunt the serologic response leading to a false negative test. - Patients with a prior Lyme infection may remain persistently positive. þ Should those with tick bites be treated prophylactically? - No. [Shapiro ED, et al. A controlled trial of antimicrobial prophylaxis for Lyme Disease after deer tick bites. N Engl J Med 1992; 327(25):1769.] - Maybe. [Magid D, et al. Prevention of Lyme Disease after tick bites: a cost-effectiveness analysis. N Engl J Med 1992; 327(8):534.] - "Antimicrobial Prophylaxis Not Warrented in Lyme Disease: ... In one double-blind, placebo-controlled trial of amoxicillin conducted in southeastern Connecticut, where Lyme disease is endemic, only two of 387 persons who were bitten by deer ticks developed Erythema Migrans; both had received placebo. At one year of follow-up, no person in either group had an asymptomatic seroconversion or developed late disease. The results of this study, as well as the availability of effective treatment for early Lyme disease and the potential toxicity of antibiotics in general, suggest that routine antimicrobial prophylaxis of persons bitten by deer ticks is unwarranted." [Scientific American Medicine, August 1995; Shapiro ED, Gerber MA, Holabird NB, et al. A controlled trial of antimicrobial prophylaxis for Lyme disease after deer-tick bites. N Engl J Med 327:1769, 1992.] - Maybe (MedLtr 5/23/06) + best if endemic area, tick attached for >48 hours + study of 482 patients with tick bites, doxycycline 200 mg PO stat within 72 hours or tick removal 87% effective in preventing erythema migrans [Nadelman RB. Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite. N Engl J Med 2001:345:79.] + study of Amox x 10d effective but so little infection in placebo group can't really conclude anything. [Shapiro ED. A controlled trial of antimicrobial prophylaxis for Lyme disease after deer-tick bite. N Engl J Med 1992;327:1769.] þ Lyme Disease Complications: - Eye: Conjunctivitis is the most common manifestation, but keratitis and iritis can occur as well. In severe cases the patient can develop a panophthalmitis that can cause unilateral blindness. - Bannworth's Syndrome: Radicular pain (similar to that with an acute disc problem) with an associated lymphocytic pleocytosis, It is more commonly seen in European patients. - Bell's Palsy - Meningitis with waxing and waning headache. - Cardiac complications: + 10% of patients with Lyme disease have cardiac involvement, such as pericarditis, tamponade, myocarditis, and heart block. + Fifty percent of those with cardiac involvement will develop complete heart block. þ Lyme Disease Treatment: - Single isolated Erythema Chronica Migrans lesion: 10-30 days (the longer duration for those with large lesions). - carditis with block: treat with IV ceftriaxone and PO prednisone. [emedicine.com - http://www.emedicine.com/emerg/topic588.htm (Edlow [au], Danzl [ed]).] - Doxy the only usual agent also effective against Anaplasma phagocytophilum (formerly Ehrlichia, ehrlichosis) but not for kids or pregnant women. - Study of 180 patients with erythema migrans: [Wormser GP. Duration of antibiotic therapy for early Lyme disease. A ramdomized, double-blind placebo-controlled trial. Ann Intern Med 2003;138:697.]