Human monocytotropic ehrlichiosis
Human monocytotropic ehrlichiosis[1] (HME) is a form of ehrlichiosis associated with Ehrlichia chaffeensis.[2]
This bacteria is an obligate intracellular pathogen affecting monocytes and macrophages.
Ecology & Epidemiology
HME occurs across the south-central, southeastern, and mid-Atlantic states, regions where both the white-tailed deer (Odocoileus virginianus) and lone star ticks (Amblyomma americanum) thrive.
HME occurs in California in Ixodes pacificus ticks and in Dermacentor variabilis ticks.[3]
Nearly 600 cases were reported to the CDC in 2006. In 2001-2002, the incidence was highest in Missouri, Tennessee, and Oklahoma, as well as in people older than 60.[4]
Symptoms
The most common symptoms are fever, headache, malaise, and muscle aches (myalgia). Compared to Human Granulocytic Ehrlichiosis, rash is more common.[5] Laboratory abnormalities include thrombocytopenia, leukopenia, and elevated liver tests.
The severity of the illness can range from minor or asymptomatic to life-threatening. CNS involvement may occur. A serious septic or toxic shock-like picture can also develop, especially in patients with impaired immunity.[6]
Diagnosis
Tick exposure is often overlooked. For patients living in high-prevalence areas who spend time outdoors, a high degree of clinical suspicion should be employed.
Ehrlichia serologies can be negative in the acute period. PCR is therefore the laboratory diagnostic tool of choice.[7]
Treatment
If Ehrlichiosis is suspected, treatment should not be delayed while waiting for a definitive laboratory confirmation, as prompt doxycycline therapy has been associated with improved outcomes.[8] Doxycycline is the treatment of choice.
Presentation during early pregnancy can complicate treatment.[9]
Rifampin has been used in pregnancy and in patients allergic to doxycycline.[10]
References
- ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. pp. 1130. ISBN 1-4160-2999-0.
- ^ Schutze GE, Buckingham SC, Marshall GS, et al. (June 2007). "Human monocytic ehrlichiosis in children". Pediatr. Infect. Dis. J. 26 (6): 475–9. doi:10.1097/INF.0b013e318042b66c. PMID 17529862. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?an=00006454-200706000-00005.
- ^ Holden K, Boothby JT, Anand S, Massung RF (July 2003). "Detection of Borrelia burgdorferi, Ehrlichia chaffeensis, and Anaplasma phagocytophilum in ticks (Acari: Ixodidae) from a coastal region of California". J. Med. Entomol. 40 (4): 534–9. doi:10.1603/0022-2585-40.4.534. PMID 14680123.
- ^ CDC Ehrlichiosis statistics
- ^ Dumler JS, Choi KS, Garcia-Garcia JC, et al. (December 2005). "Human granulocytic anaplasmosis and Anaplasma phagocytophilum". Emerging infectious diseases 11 (12): 1828–34. PMID 16485466.
- ^ Paddock CD, Folk SM, Shore GM, et al. (November 2001). "Infections with Ehrlichia chaffeensis and Ehrlichia ewingii in persons coinfected with human immunodeficiency virus". Clinical Infectious Diseases 33 (9): 1586–94. doi:10.1086/323981. PMID 11568857.
- ^ Prince LK, Shah AA, Martinez LJ, Moran KA (August 2007). "Ehrlichiosis: making the diagnosis in the acute setting". Southern medical journal 100 (8): 825–8. PMID 17713310. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0038-4348&volume=100&issue=8&spage=825.
- ^ Hamburg BJ, Storch GA, Micek ST, Kollef MH (March 2008). "The importance of early treatment with doxycycline in human ehrlichiosis". Medicine 87 (2): 53–60. doi:10.1097/MD.0b013e318168da1d. PMID 18344803.
- ^ Muffly T, McCormick TC, Cook C, Wall J (2008). "Human granulocytic ehrlichiosis complicating early pregnancy". Infect Dis Obstet Gynecol 2008: 359172. doi:10.1155/2008/359172. PMC 2396214. PMID 18509484. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2396214.
- ^ Krause PJ, Corrow CL, Bakken JS (September 2003). "Successful treatment of human granulocytic ehrlichiosis in children using rifampin". Pediatrics 112 (3 Pt 1): e252–3. doi:10.1542/peds.112.3.e252. PMID 12949322. http://pediatrics.aappublications.org/cgi/pmidlookup?view=long&pmid=12949322.
See also
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