1 / 14

Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever. Pat Barrett Morning Report July 2, 2010. Rickettsia rickettsii (facts you probably know). Tick borne, though 1/3 to 1/2 do not recall a tick bite Dermacentor variabilis tick Incidence 15/100,000 persons at the most endemic areas

ezekiel-phelps
Download Presentation

Rocky Mountain Spotted Fever

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Rocky Mountain Spotted Fever Pat Barrett Morning Report July 2, 2010

  2. Rickettsiarickettsii(facts you probably know) • Tick borne, though 1/3 to 1/2 do not recall a tick bite • Dermacentor variabilis tick • Incidence 15/100,000 persons at the most endemic areas • 1-3% ticks infected in endemic areas MMWR: 2006: 55RR04: 1

  3. Pathophysiology • Gram negative intracellular • Virulence depends on the status of the vector • Trophic for endothelial cells • Transits rapidly by activating actin within host’s cells • No exotoxins, will cause necrosis, lymphohistiocyticvasculitis

  4. Incidence of RMSF CDC /epidemiology

  5. Tick Born Illness in NC

  6. Symptoms Usually develop 5-7 days after tick exposure Fever, headache, myalgia, arthralgia, nausea, vomiting Spotless RMSF occurs approx 10% of the time

  7. RMSF Rash • Typically at 5-7 days • Begins on wrists, ankles, palms and soles, then spreads centripetally • Often macularpapular then petechial • Rarely pruritic

  8. Spotless RMSF • Case Series from Duke (1) • 61% male • 66% African American • 53% mortality in the case series • 22.9% mortality in separate case series (2) where treatment was delayed past 5 days • 6.5% mortality if treated w/in 5 days 1: Clin Infect Dis 1992: 15:439 2: Clin Infect Dis 1995: 20:1118

  9. Laboratory Data • Clinical impression followed by acute and convalescent sera • Typically the latex agglutination has the fastest turn around time • IFA test for IgG and IgM, felt to be the standard, used by CDC. • False positives w/ other rickettsial exposures • PCR not widely available • Also hyponat, elevated transaminases, prolonged PT, aPTT

  10. Is There a Best Test? Am J Trop Med Hyg: 1986: 35: 840 Gold Standard: 4 fold increase from acute to convalescent, convalescent IFA > 1:64, isolation of Rickettsiae, fluorescent ab of specimen from bx or autopsy Indirect hemagglutination 94% sens Indirect fluorescent antibody 96% sens Latex agglutination 71% sens

  11. Is There A Best Therapy? J Clin Microbiol 1978;8:102 Doxycycline 7 days, 10-14 in severe cases 2nd Line Chloramphenicol No preventive therapy recommended for tick bites w/o illness – shown to delay symptom onset but not prevent infection.

  12. Conclusions • Ticks are awful • RMSF and Ehrlichia should be considered during any FUO work-up while a resident at UNC • There is some variability in when serology is positive • Rashless and rashalittle RMSF does exist • The benefits of not treating empirically must be carefully weighed against the risks

  13. The Solution

  14. References • NC DHHS: http://www.epi.state.nc.us/epi/gcdc/pdf/cdtable2009.pdf • CDC/epidemiology: http://www.cdc.gov/ncidod/dvrd/rmsf/epidemiology.htm • Chapman, AS et. MMWR: 2006: 55RR04: 1 • Up To Date: RMSF • Sexton, DJ, et al. Clin Infect Dis 1992: 15:439 • Kirkland, KB, et al. Clin Infect Dis 1995: 20:1118 • Kaplan, JB, et al. Am J Trop Med Hyg: 1986: 35: 840 • Kenyon RH, Williams RG, Oster CN, Pedersen CE Jr. Prophylactic treatment of Rocky Mountain spotted fever. J ClinMicrobiol 1978;8:102--4.

More Related