Jarisch-Herxheimer Reaction (Last Updated - 5/17/2005)

-a usually mild & transient reaction which follows the initial anti-microbial tx. for spirochetal infex.:

     -Syphilis:
          -occurs in 50% w/ primary syphilis
          -occurs in 90% w/ 2nd-ary syphilis
          -occurs in 25% w/ early latent syphilis
     -Relapsing Fever:
          -esp. w/ louse-borne relapsing fever (LBRF)
     -Leptospirosis
     -Lyme Disease --> occurs in 15%

Clinical / Laboratory S/S's:
     -fevers
     -chills
     -myalgias
     -HA's
     -tachycardia
     -increased resp. rate (RR)
     -increased peripheral neutrophil count
     -vasodilation
     -mild hypotension

-onset of s/s's occurs w/in 2 hrs. of initiation of tx.
-fevers peak @ ~7 hrs. post-initiation of tx. and defervescence occurs w/in 12-24 hrs.

-recent research suggests the cause as inflammatory mediators (esp. TNF-alpha)
-assoc. w/ increased cytokine release into plasma:
     1) TNF-alpha --> enormous amounts
     2) IL-6
     3) IL-8
     4) CRP (C-Reactive Protein)

Treatment:
     -supportive --> bed rest & ASA
     -monitor fluid balance, BP and myocardial function
     -steroids & NSAID's --> NOT required

     -new research suggests that pts. undergoing anti-microbial tx. for spirochetal infex. may benefit from pre-tx. w/ Ab's to TNF-alpha
          -suppresses most s/s's
          -NOT recommended tx. yet

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References:

Harrison's Principles Of Internal Medicine: 15th Edition. 2001: pg. 1052,1056-1057,1059,1061,1064