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{{Infobox Disease
{{Ehrlichiosis}}
| Name          = {{PAGENAME}}
'''This page is about clinical aspects of the disease. For microbiologic aspects of the causative organism(s):'''
  | Image          =
{{Seealso| Anaplasma phagocytophilum}}
| Caption        =
{{Seealso| Ehrlichia}}
| DiseasesDB    = 31663 |
| ICD10          = {{ICD10|A|79|8|a|75}} |
| ICD9          = {{ICD9|082.4}}
| ICDO          =
| OMIM          =
| MedlinePlus    = 001381 |
| eMedicineSubj  =
| eMedicineTopic =
| MeshID        = D016873
}}
{{SI}}
'''For patient information on this page, click [[Ehrlichiosis (patient information)|here]]'''  
'''For patient information on this page, click [[Ehrlichiosis (patient information)|here]]'''  


{{CMG}}; {{AE}} {{RT}}
{{CMG}} {{AE}} {{IMD}}; {{RT}}  


{{SK}}  Sennetsu fever; human granulocytic ehrlichiosis; Anaplasma phagocytophilum; Ehrlichia phagocytophila; human monocytic ehrlichiosis
{{SK}}  Sennetsu fever; human granulocytic ehrlichiosis; Anaplasma phagocytophilum; Ehrlichia phagocytophila; human monocytic ehrlichiosis


==Overview==
==[[Ehrlichiosis overview|Overview]]==
'''Ehrlichiosis''' is a [[Tick-borne disease|tickborne]]<ref>[http://www.cdc.gov/ticks/diseases/ehrlichiosis/faq.html#howget CDC "Questions and Answers" page for tickborne rickettsial diseases]</ref> bacterial infection,<ref>{{cite book |author=Dawson, Jacqueline E., Marty, Aileen M. |chapter=Ehrlichiosis |editor=Horsburgh CR, Nelson AM |title=Pathology of emerging Infections |publisher=American Society for Microbiology|year=1997 |volume=1 }}</ref> caused by bacteria of the family [[Anaplasmataceae]], genera ''[[Ehrlichia]]'' and ''[[Anaplasma]]''.  These [[Obligate intracellular parasite|obligate intracellular]] [[bacteria]] infect and kill the [[white blood cell]]s. Ehrlichiae are transmitted to humans by the bite of an infected tick. Usually, symptoms occur within 1-2 weeks following a tick bite. <ref> [http://www.cdc.gov/ehrlichiosis CDC Ehrlichiosis main information page] </ref>


==Historical Perspective==
==[[Ehrlichiosis historical perspective|Historical Perspective]]==
* In 2008, human infection by [[Panola Mountain]] (Georgia, USA) ''Ehrlichia'' species was reported.<ref>{{cite journal |author=Reeves WK, Loftis AD, Nicholson WL, Czarkowski AG |title=The first report of human illness associated with the Panola Mountain Ehrlichia species: a case report |journal=Journal of medical case reports |volume=2 |pages=139 |year=2008 |pmid=18447934 |pmc=2396651|doi=10.1186/1752-1947-2-139|url=http://www.jmedicalcasereports.com/content/2//139}}</ref>
* On August 3, 2011, infection by a yet-unnamed bacterium in the genus ''Ehrlichia'' carried by [[deer tick]]s that has caused [[flu-like]] symptoms in at least 25 people in [[Minnesota]] and [[Wisconsin]] was reported; human ehrlichiosis was thought to be very rare or absent in Minnesota and Wisconsin.<ref name="Steenhuysen, 2011">Julie Steenhuysen. 2011. ''New tick-borne bacterium found in upper Midwest''. Reuters, 8/3/2011, http://www.trust.org/alertnet/news/new-tick-borne-bacterium-found-in-upper-midwest/, accessed August 4, 2011.</ref>  The new species, which is very similar genetically to an ''Ehrlichia'' species found in [[Eastern Europe]] and [[Japan]] called ''E. muris'', was identified at [[Mayo Clinic]] Health System's [[Eau Claire]] hospital.<ref name="Steenhuysen, 2011" />
* In 1991 Dr. Aileen Marty of the [[AFIP]] was able to demonstrate the bacteria in human tissues using standard stains, and later proved that the organisms were indeed Ehrlichia using [[immunoperoxidase stain]]s.


==Pathophysiology==
==[[Ehrlichiosis classification|Classification]]==
* ''Ehrlichia'' are transported between cells through the host cell [[filopodia]] during initial stages of infection, whereas, in the final stages of infection the pathogen ruptures the host cell membrane.<ref>{{cite journal |author=Thomas S, Popov VL, Walker DH |title=Exit Mechanisms of the Intracellular ''Bacterium Ehrlichia'' |journal=PLoS ONE |volume=5 |issue=12 |pages=e15775|year=2010|url=http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0015775 |doi=10.1371/journal.pone.0015775 |pmid=21187937|pmc=3004962|editor1-last=Kaushal |editor1-first=Deepak}}</ref>
* Most of the symptoms of Ehrlichiosis can likely be ascribed to the immune dysregulation that it causes.
* Early in infection, production of [[TNF-alpha]], a cellular product that promotes [[inflammation]] and immune response, is suppressed.  Experiments in mouse models further supports this hypothesis, as mice lacking TNF-alpha I/II receptors are resistant to liver injury caused by ehrlichia infection.<ref>{{cite journal|last=McBride|first=Jere W.|coauthors=Walker, David H.|title=Molecular and cellular pathobiology of Ehrlichia infection: targets for new therapeutics and immunomodulation strategies|journal=Expert Reviews in Molecular Medicine|date=31 January 2011|volume=13|doi=10.1017/S1462399410001730}}</ref>
* Late in infection, however, production of this substance can be upregulated by 30 fold, which is likely responsible for the "[[toxic shock]]-like" syndrome seen in some severe cases of ehrlichiosis.


==Causes==
==[[Ehrlichiosis pathophysiology|Pathophysiology]]==
Five species of the genus Ehrlichia have been shown to cause human infection:<ref>{{cite journal |author=Dumler JS, Madigan JE, Pusterla N, Bakken JS |title=Ehrlichioses in humans: epidemiology, clinical presentation, diagnosis, and treatment |journal=Clin. Infect. Dis. |volume=45|issue=Suppl 1 |pages=S45–51 |year=2007 |month=July |pmid=17582569 |doi=10.1086/518146|url=http://www.cid.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17582569}}</ref>
* ''[[Anaplasma phagocytophilum]]'' (which causes [[human granulocytic anaplasmosis]], formerly known as human granulocytic ehrlichiosis).
* ''[[Ehrlichia ewingii]]'' (which causes [[human ewingii ehrlichiosis]]). ''E. ewingii'' primarily infects deer and dogs (see [[Ehrlichiosis (canine)]]).<ref name="Goddard"/>
* ''[[Ehrlichia chaffeensis]]'' (which causes [[human monocytic ehrlichiosis]]).
* ''[[Ehrlichia canis]]''
* ''[[Neorickettsia sennetsu]]''


The latter two infections are not well studied.
==[[Ehrlichiosis causes|Causes]]==


==Epidemiology and Demographics==
==[[Ehrlichiosis differential diagnosis|Differentiating Ehrlichiosis from other Diseases]]==
* The average reported annual [[incidence]] is 0.7 cases per million population.<ref name="Goddard">{{cite journal |author=Goddard J |title=What Is New With Ehrlichiosis?|journal=Infections in Medicine|date=September 1, 2008|url=http://www.consultantlive.com/headache/article/1145625/1405478}}</ref>
* ''A. phagocytophilium'' is endemic to New England and the north central and Pacific regions of the United States.
* ''E. chaffeensis'' is most common in the south central and southeastern states.
* ''E. ewingii'' is most common in the south central and southeastern states.


==Risk Factors==
==[[Ehrlichiosis epidemiology and demographics|Epidemiology and Demographics]]==
Risk factors for ehrlichiosis include:


* Living near an area with a lot of ticks
==[[Ehrlichiosis risk factors|Risk Factors]]==
* Owning a pet that may bring a tick home
* Walking or playing in high grasses


==Natural History, Complications and Prognosis==
==[[Ehrlichiosis natural history, complications and prognosis|Natural History, Complications and Prognosis]]==
===Complications===
* [[Acute respiratory distress syndrome|Respiratory distress syndrome]]
* [[Hepatitis]]
* Kidney damage
* Lung damage
* Other organ damage
* [[Seizure]]
* [[Candidiasis]]
* Opportunistic [[nosocomial infection]]s<ref>{{cite journal|last=Thomas|first=Rachael J|coauthors=Dumler, J Stephen, Carlyon, Jason A|title=Current management of human granulocytic anaplasmosis, human monocytic ehrlichiosis and ehrlichiosis|journal=Expert Review of Anti-infective Therapy|date=1 August 2009|year=2009|month=August|volume=7|issue=6|pages=709–722|doi=10.1586/eri.09.44|pmid=19681699|pmc=2739015}}</ref>
* [[Death]]


==Diagnosis==
==Diagnosis==
===Symptoms===
[[Ehrlichiosis history and symptoms| History and Symptoms]] | [[Ehrlichiosis physical examination | Physical Examination]] | [[Ehrlichiosis laboratory findings|Laboratory Findings]] | [[Ehrlichiosis Chest X-ray| Chest X-ray]] | [[Ehrlichiosis other diagnostic studies|Other Diagnostic Studies]]
* [[Chills]]
* [[Fever]]
* [[Headache]]
* [[Nausea]]
* [[Muscle aches]] / [[myalgia]]s
* [[Fatigue]]
 
Other possible symptoms include:
* [[Diarrhea]]
* Fine pinhead-sized areas of bleeding in the skin ([[petechial rash]])
* Flat red rash ([[maculopapular rash]])
* General ill feeling ([[malaise]])
 
A [[rash]] appears in fewer than half of cases.
 
===Physical Examination===
====Vitals====
* [[Elevated body temperature]]
* [[Increased heart rate]]
* [[Blood pressure]]
 
====Skin====
* [[Rash]]
* [[Purpura]] - can be a presenting feature. <ref>{{cite journal |author=Marty AM, Dumler JS, Imes G, Brusman HP, Smrkovski LL, Frisman DM|title=Ehrlichiosis mimicking thrombotic thrombocytopenic purpura. Case report and pathological correlation |journal=Hum. Pathol. |volume=26|issue=8 |pages=920–5 |year=1995 |month=August |pmid=7635455 |url=http://www.humanpathol.com/article/0046-8177(95)90017-9/abstract|doi=10.1016/0046-8177(95)90017-9}}</ref>
 
====Head====
* [[Swollen lymph node]]s
 
===Laboratory Findings===
* [[Complete blood count]] ([[CBC]])
* Granulocyte stain
* Fluorescent antibody test


==Treatment==
==Treatment==
* [[Doxycycline]] is the drug of choice. 
[[Ehrlichiosis medical therapy|Medical Therapy]] | [[Ehrlichiosis primary prevention|Prevention]]
* For people allergic to drugs of the [[tetracycline]] class, [[rifampicin]] is an alternative.<ref name="Goddard"/> 
 
* Early clinical experience suggested that [[chloramphenicol]] may also be effective, however in vitro susceptibility testing revealed [[resistance]].


==References==
==Case Studies==
{{reflist|2}}
[[Ehrlichiosis case study one|Case#1]]


[[Category:Bacterium-related cutaneous conditions]]
[[Category:Bacterium-related cutaneous conditions]]
[[Category:Tick-borne diseases]]
[[Category:Tick-borne diseases]]
[[Category:Disease]]
[[Category:Disease]]
{{WH}}
{{WS}}

Latest revision as of 17:38, 18 September 2017

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This page is about clinical aspects of the disease. For microbiologic aspects of the causative organism(s): Template:Seealso Template:Seealso For patient information on this page, click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ilan Dock, B.S.; Raviteja Guddeti, M.B.B.S. [2]

Synonyms and keywords: Sennetsu fever; human granulocytic ehrlichiosis; Anaplasma phagocytophilum; Ehrlichia phagocytophila; human monocytic ehrlichiosis

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Ehrlichiosis from other Diseases

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms | Physical Examination | Laboratory Findings | Chest X-ray | Other Diagnostic Studies

Treatment

Medical Therapy | Prevention

Case Studies

Case#1