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bites . Whenever the patient is in a situation where risk of tick exposure is high , they should be encouraged to apply permethrin spray to their clothing or even do something as simple as tucking their pant legs into their footwear as both of these have been shown to be protective against tick-borne illnesses . 4
When evaluating a patient ( especially one who is immunocompromised ) with a febrile illness , flu like symptoms and the triad of anemia , thrombocytopenia , and elevated transaminases , one must always remember to include infections from Ehrlichia or other tick-borne pathogens in their differential diagnosis given their ability to act as opportunistic infections . Because a laboratory confirmation is required to meet the case definition , reporting may be influenced by a patient ' s access to health care .
It is likely that , given the prevalence of Ehrlichia chaffeensis in Arkansas and the relatively low socioeconomic status of many Arkansans , the actual incidence of infection is drastically underreported . Prospective seroepidemiology studies performed in Arkansas have demonstrated that the rate of asymptomatic infections could be as high as 2 / 3 total infections . 4 It stands to reason that an infection in an immunocompromised patient could result in severe pathology that otherwise would have been asymptomatic .
With patients in an immunocompromised state , early detection and treatment becomes all the more essential . Ideally , a patient with a clinical picture resembling HME should be started on empiric doxycycline within 24 hours of the onset of symptoms . Beginning treatment within 24 hours has been shown to have lower rates of being transferred to the ICU , decreased requirement for mechanical ventilation , and shorter hospital stay duration . 5
Our case demonstrates the nonspecific but severe presentation of HME in the immunocompromised patient . It also highlights the importance of early clinical suspension of HME gained by the history of tick exposure and triad of anemia , thrombocytopenia , and elevated transaminases in a febrile patient . Our case also emphasizes the rapid response of the disease to tetracyclines and the importance of early empiric therapy in highly endemic areas such as Arkansas .
References
1 . Ismail , Naheed ; McBride , Jerry . Tick- Borne Emerging Infections . Clinics in Laboratory Medicine 2017 ; 37 ( 2 ) 317-340
2 . Paddock CD , Childs JE . Ehrlichia chaffeensis : a prototypical emerging pathogen . Clin Microbiol Rev . 2003 ; 16 ( 1 ): 37 – 64 . doi : 10.1128 / cmr . 16.1.37-64.2003
3 . Centers for Disease Control and Prevention , National Center for Emerging and Zoonotic Infectious Diseases ( NCEZID ), Division of Vector-Borne Diseases ( DVBD ) https :// www . cdc . gov / ehrlichiosis / stats / index . html
4 . Steven J . Yevich , José L . Sánchez , Robert F . DeFraites , Cornelia C . Rives , Jackie E . Dawson , Iyorlumun J . Uhaa , Barbara J . B . Johnson , Daniel B . Fishbein , Seroepidemiology of Infections Due to Spotted Fever Group Rickettsiae and Ehrlichia Species in Military Personnel Exposed in Areas of the United States where Such Infections Are Endemic , The Journal of Infectious Diseases , Volume 171 , Issue 5 , May 1995 , Pages 1266 – 1273 , https :// doi . org / 10.1093 / infdis / 171.5.1266 Pavelites JJ , Prahlow JA ( 2011 ) Fatal human monocytic ehrlichiosis : a case study . Forensic Science Medicine and Pathology 7 : 287 – 293
Volume 117 • Number 4 october 2020 • 95