Anaplasma phagocytophilum: Difference between revisions

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Anaplasma phagocytophilum
(Created page with "* Cause of human granulocytotropic anaplasmosis = Microbiology = * Small, obligate intracellular Gram-negative bacterium * Related t...")
 
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* Cause of [[Human granulocytotropic anaplasmosis|human granulocytotropic anaplasmosis]]
 
 
 
= Microbiology =
 
= Microbiology =
   
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* Related to Ehrlichia and Rickettsiae
 
* Related to Ehrlichia and Rickettsiae
 
* Tropism for neutrophils
 
* Tropism for neutrophils
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= Clinical Presentation =
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* Incubation period of 1 to 2 weeks
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* Usually an acute undifferentiated fever
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* Can be mild or severe
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* Fever, headache, malaise, and myalgias are common
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* Can also cause nausea, vomiting, diarrhea, cough, arthralgias, nuchal rigidity, and confusion
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* Less than 10% have rash, most of which is concurrent Lyme disease
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* 36% of cases require hospitalization, and it is severe in 3 to 7%
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* Severe complications include respiratory failure, septic shock, rhabdomyolysis, hemorrhage, and opportunistic infections
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** Rare meningoencephalitis
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* Higher case-fatality rate in Shandong Province in China, for no clear reason (16% versus 2.6%)
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* Thrombocytopenia, lerkopenia, and mild anemia are common
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** Return to normal range within 14 days, but with persistent left shift
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* Abnormal liver enzymes are common in the first 7 days
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= Diagnosis =
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* 20-80% of patients will have circulating neutrophils with detectable '''morulae''' on blood film (in neutrophils/granulocytes)
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* Serology used to diagnose, by measuring IgG levels ≥1:64 or a fourfold rise
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** IgM testing less sensitive and specific
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* Culture not done routinely
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* PCR possible
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= Management =
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* Doxycycline 100 mg po bid
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[[Category:Parasites]]
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{{DISPLAYTITLE:''Anaplasma phagocytophilum''}}

Revision as of 13:41, 13 August 2019

Microbiology

  • Small, obligate intracellular Gram-negative bacterium
  • Related to Ehrlichia and Rickettsiae
  • Tropism for neutrophils

Clinical Presentation

  • Incubation period of 1 to 2 weeks
  • Usually an acute undifferentiated fever
  • Can be mild or severe
  • Fever, headache, malaise, and myalgias are common
  • Can also cause nausea, vomiting, diarrhea, cough, arthralgias, nuchal rigidity, and confusion
  • Less than 10% have rash, most of which is concurrent Lyme disease
  • 36% of cases require hospitalization, and it is severe in 3 to 7%
  • Severe complications include respiratory failure, septic shock, rhabdomyolysis, hemorrhage, and opportunistic infections
    • Rare meningoencephalitis
  • Higher case-fatality rate in Shandong Province in China, for no clear reason (16% versus 2.6%)
  • Thrombocytopenia, lerkopenia, and mild anemia are common
    • Return to normal range within 14 days, but with persistent left shift
  • Abnormal liver enzymes are common in the first 7 days

Diagnosis

  • 20-80% of patients will have circulating neutrophils with detectable morulae on blood film (in neutrophils/granulocytes)
  • Serology used to diagnose, by measuring IgG levels ≥1:64 or a fourfold rise
    • IgM testing less sensitive and specific
  • Culture not done routinely
  • PCR possible

Management

  • Doxycycline 100 mg po bid