Lyme Disease

Microbiology

• Infection with spirochete Borrelia burgdorferi (consider coinfection w/ Ehrlichio. Babesia)

• Transmitted by ticks (Ixodes); animal hosts include deer and mice

• Infection usually requires tick attachment >36-48 h

Epidemiology

• Lyme disease most common vector-borne illness

• Peak incidence is in the summer months (May-Aug)

• Majority of cases in NY. NJ. CT. RI.WI. PA. MA. ME. NH. Ml. MD. DE

• Humans contact ticks usually in fields with low brush near wooded areas

Clinical Manifestations

Stage

Manifestations

Stage 1 (early localized)

wks after infection

Due to local effects of spirochete General: flu-like illness

Dermatology ( 80%): erythema chronicum migrans (ECM) -macular, erythematous lesion with central clearing, ranging in size from 6-38 cm; lymphocytomas: regional LAN

Stage 2 (early dissem.)

wks to mos after infection

Due to spirochetemia and immune response General: fatigue, malaise. LAN. HA; fever uncommon Derm: multiple (1-100) annular lesions ECM Rheumatology ( 10%): migratory arthralgias (knee & hip) &

myalgias, oligoarthritis Neurologic (-15%): Bell's palsy (or other cranial neuropathies), aseptic meningitis, mononeuritis multiplex (may be painful), transverse myelitis

Cardioc ( 8%): heart block, myocarditis

Stage 3 (late persistent)

mos to y after infection

Due to chronic infection or autoimmune response Derm: acrodermatitis chronica atrophicans, panniculitis Rheumatology ( 60%): joint pain, recurrent mono- or oligoarthritis of large joints, synovitis Neurologic subacute encephalomyelitis, polyneuropathy, dementia

(NEJM 2001:345:115: Loncet 2003:362:1639)

(NEJM 2001:345:115: Loncet 2003:362:1639)

Diagnostic studies

• In general, a clinical diagnosis

• Serology (in right clinical setting)

screen with ELISA, but false © due to other spirochetal diseases. SLE. RA. EBV. HIV. etc. false © due to early antibiotic therapy confirm © ELISA results with Western blot (1 Sp)

• CSF examination in Pts with suspected neurologic disease

© intrathecal Ab production if (CSF IgG/serum lgG)/(CSF albumin/serum albumin) >1

Treatment (ne)m 2006:354:2794)

• Prophylaxis protective clothing, tick ✓ q24h. DEET (all help prevent tick-borne diseases) doxycycline 200 mg po x 1 w/in 72 h of finding partially engorged, nymphal Ixodes tick attached 1 risk of Lyme from 3.2 to 0.4%. Even in hyperendemic area, would need to treat 40-150 people to prevent 1 case of Lyme (nejm 2001:345 79)

• Antibiotics: if din. manifestations and * serology (? and h/o tick bite if nonendemic area)

local or early dissem. w/o neuro or cardiac involvement: doxycycline 100 mg PO bid (standard duration rec. has been 3-4 wks. but recent studies suggest 10 d to 3 wks may be just as effective) neuro (other than Bell's palsy), cardiac, chronic arthritis, pregnancy: ceftriaxone 2 g IV qd x 2-4 wks (nejm 1997.337:289)

• Vacdne: 78% . in occurrence of Lyme disease in Pts in endemic areas at risk for exposure

(nejm 1998339:209); currently unavailable because of concerns re: joint & neuro toxicity

Was this article helpful?

0 0

Post a comment