Nejm 2006;354:2794; 2001;345:115; Ann IM 2002;136:421 (Rob Smith)

Cause:Borrelia burgdorferispread by Ixodes damminitick bite (same tick also spreads babesiosis and patients may get both—Ann IM 1985;103:374)

Pathophys:Sometimes an immune complex disease, but organisms now identified in joints most of the time (Nejm 1994;330:229). Clinical syndromes very much like primary, secondary, and tertiary syphilis; but much overlap between stage 1 and 2 sx complexes

Deer tick, also infests white-footed deer mice. Northeastern and northwestern US. HLA-DR4 and -DR_w2 B-cell allotypes associated with increased CNS, cardiac, and arthritic involvement (Nejm 1990;323:219). Most common tickborne spirochetal disease in US; attack rates up to 66% of people living in a highly endemic area over 7 yr (Nejm 1989;320:133); annual incidence = 20-80/100 000/yr; also common in N. Europe (Nejm 1995;333:1319)

Sx:

(Nejm 1991;325:159) Tick bite (should remove w tweezers) hx in 80% (Nejm 1995;333:1319); disease rare if tick on <24 h, usually takes 36-72 hr,and most ticks associated w disease have stayed on a week (Nejm 1992;327:543)

Stage 1: Arthralgias (98%), malaise (80%), headache (64%), fever (60%), stiff neck (aseptic meningitis); ringworm-like, nontender rash erythema chronicum migrans (ECM) in 77% (Nejm 1995;333:1319) to 90% (Rob Smith 5/06) within 7-14 d

Stage 2: Neurologic and cardiac

Stage 3: Arthritis; chronic neurologic changes

Si:

Stage 1: Fever, lymphadenopathy; and erythema chronicum migrans, a warm "ringworm" around bite (ECM), median diam = 15 cm (pictures—Ann IM 1991;114:490) and most >5 cm present in 90%

Stage 2: Neurologic: lymphocytic meningitis (15%) and meningoencephalitis, peripheral motor or sensory neuropathies, facial nerve palsies including Bell's palsy. And/or cardiac: myocarditis (8%), like rheumatic fever with heart block but valve disease rare or never; sometimes heart block is only sx, no fever or even malaise; usually transient, ~6 wk after primary infection

Stage 3: Recurrent polyarthritis at 1st, then 1-2 large joints; onset up to 4-6 mo after skin rash with decreasing recurrences over years. Late keratitis (Nejm 1991;325:159)

Ixodes scapularis Ticks. Panel A (left to right) shows an I. scapularis larva, nymph, and adult female. Panel B shows nymphal I. scapularis ticks in various stages of engorgement with blood according to the hours of attachment to humans. The ticks at 0 hour correspond in size to the middle (nymphal) tick in Panel A. Photographs courtesy of Dr. Richard Falco and James Vellozzi. Reprinted from Wormser and Fish with the permission of the publisher.

Fig 9.0

Maine CDC Wallet Card; March 2008

Adult deer ticks lack the white “racing stripes” on the dorsal carapace of dog ticks. Nymphs are infectious in the summer. Adults are the size of an apple seed; nymphs the size of poppy seeds.

Stage 1 lasts 3-4 wk, 50% don't develop subsequent stages (R. Smith 5/06). Sx and si of stages 2 and 3 may be chronic and recurrent over mo-yr. Even after rx, espif if given >3 mo after sx, residual arthralgias, fatigue, memory problems may persist (Nejm 2007;357:1422; Ann IM 1994;121:560). Abx tx in these cases is not helpful and carries substantial risk (Nejm 2001;345:85; Neurol 2003;60:1916). “Chronic Lyme” is not thought to be due to ongoing infection or any other measurable process. Very benign crs in children (Nejm 1996;335;1270)

Chronic myocardiopathy (Nejm 1990;322:249). Neurologic (Nejm 1990;323:1438): chronic encephalopathy in 90% of those who have stage 2 neurologic sx; also chronic polyneuropathy and leukoencephalitis

r/o ehrlichiosis (Ehrlichiosis), babesiosis (Babesiosis), anaplasmosis as separate or concomitant infection (Nejm 1997;337:27; Jama 1996;275:1657; Vector Borne Zoonotic Dis 2002;2:255)

Lab:

Hem:ESR >20 mm/h (53%), crit >37% (88%), wbc <10 000 (92%)

Path:Pos silver stain or culture of rash edge for organisms in 86% (Jama 1992;268:1311)

Serol:(Jama 1999;282:62; Ann IM 1997;127:1109) Need reliable lab; IgM and IgG ELISA titer increased (Nejm 1983;308:733) and pos Western blot; rare false positives, most in low-prevalence populations, in syphilis, and SBE (Ann IM 1993;119:1079); 5% false neg, esp in late stages (Ann IM 1987;107:730), seen if early po antibiotic rx or early in crs, or w some labs, which run 10-50% false neg and up to 25% false pos (Jama 1992;268:891). Immune complex measurement (Jama 1999;282:1942)

Synovial fluid:Organisms usually present by PCR (Nejm 1994;330:229); 20^±K WBCs, ie low end of septic/inflammatory arthritis

Rx:

(Med Let 2007;49:49)

Prevent w (Nejm 2003;348:2424):

• Permethrin (Nix) rx of clothing and DEET at 75+% concentration (Med Let 1989;31:46)
• Remove ticks within 24 h

Prophylactic rx after tick bite perhaps, doxycycline 200 mg po × 1, if engorged and/or on >36 h and in high-prevalence area (Nejm 2001;345:79 vs. 133); reduces risk from 3% to <0.6%

of stage 1: To decrease post-rash arthritis and illness:

• 1st: Tetracycline 250 mg qid or doxycycline 100 mg bid × 14-21 d; × 10 d (DBCT—Ann IM 2003;138:697) if erythema migrans alone; or, for children and pregnant women, amoxicillin 250-500 mg po tid × 21 d, but misses concomitant Ehrlichia infections; or
• 2nd: Cefuroxime 500 mg po bid × 21 d (Ann IM 1992;117:273), also misses Ehrlichia

of stages 2 and 3: Doxycycline 200 mg po bid or amoxicillin as above but for 4-6 wk (Nejm 1994;330:229) or ceftriaxone 2 gm iv/im × 14-21 d especially if bad arthritis or cardiac/neurologic findings, only 1/13 failures (Nejm 1988;319:1661); or penicillin G 20 million U qd iv × 10-21 d for cardiac, or neurologic abnormalities and/or meningitis (Ann IM 1983;99:767), cures 55% of arthritis. Avoid intraarticular steroids (Nejm 1985;312:869)

of acute nonmeningitis disseminated disease: Doxycycline 100 mg po bid × 21 d, equally effective as ceftriaxone 2 gm im qd × 14 d (Nejm 1997;337:289)

of heart block: Antibiotics and temporary pacer (Ann IM 1989;110:339) since usually transient

of chronic encephalopathy: 60-85% improve with ceftriaxone rx given even after several years

if pos titers or hx and chronic fatigue/fasciitis syndrome, antibiotic rx not helpful (DBCT—Nejm 2001;343:85; Ann IM 1993;119:503, 518)