anaplasmosis
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Etiology
Epidemiology
- reservoir: deer & rodents
- vectors: ticks: Ixodes scapularis, Dermacentor variabilis
- same vectors as Lyme disease
- most commonly encountered April-September
- infrequently found in Caribbean[1]
Pathology
- tickborne rickettsial infection of neutrophils
Clinical manifestations
- may be evidence suggesting tick bite
- may present as coinfection with Lyme disease[1][4]
- symptoms similar to ehrlichiosis
- fever 1-2 weeks after tick bite
- headache
- myalgia
- arthralgia
- rash less common than ehrlichiosis (uncommon)[1]
- symptoms may persist for months in untreated patients
- chronic fatigue is NOT characteristic
* same tick vectors as Lyme disease
Laboratory
- complete blood count (CBC)
- leukopenia (variable), thrombocytopenia
- chemistry 14 panel
- elevated serum transaminases (~ 2-fold)[1]
- case report of hyponatremia (serum sodium = 130 mmol/L)[5]
- Anaplasma phagocytophilum DNA
- Anaplasma marginale DNA or Anaplasma marginale rRNA
- microscopic examination of peripheral blood smear
- generally will NOT show organism
- staining of peripheral blood neutrophils & monocytes for morula or intracytoplasmic loose aggregrates of bacteria within monocytes (E chaffeensis) or granulocytes (A phagocytophilum) is diagnostic
- serology: acute & convalescent serum
- may be negative early in the disease (< 2-4 weeks)
Complications
- multiorgan failure; mortality 3% in treated patients
- coinfection with another tick-borne infection may occur[1]
Differential diagnosis
Management
- doxycycline PO or IV for 10-14 days[5]
- empiric treatment in patient with suspected disease
- delayed treatment associated with poor outcome[1]
- response to treatment may occur in 1-3 days
- continue treatment for several days after patient has become afebrile
- rifampin may be alternative in pregnant women[1]
More general terms
Additional terms
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018, 2021.
Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022 - ↑ Dumler JS, Choi K, Garcia-Garcia JC, Barat NS, Scorpio DG, Garyu JW, et al. Human granulocytic anaplasmosis and Anaplasma phagocytophilum. Emerg Infect Dis [serial on the Internet]. 2005 Dec http://www.cdc.gov/ncidod/EID/vol11no12/05-0898.htm
- ↑ Ismail N, Bloch KC, McBride JW. Human ehrlichiosis and anaplasmosis. Clin Lab Med. 2010 Mar;30(1):261-92 PMID: https://www.ncbi.nlm.nih.gov/pubmed/20513551
- ↑ 4.0 4.1 Horowitz HW, Aguero-Rosenfeld ME, Holmgren D et al Lyme disease and human granulocytic anaplasmosis coinfection: impact of case definition on coinfection rates and illness severity. Clin Infect Dis. 2013 Jan;56(1):93-9. PMID: https://www.ncbi.nlm.nih.gov/pubmed/23042964 Free Article
- ↑ 5.0 5.1 5.2 Kobayashi KJ, Weil AA, Branda JA Case 16-2018: A 45-Year-Old Man with Fever, Thrombocytopenia, and Elevated Aminotransferase Levels. N Engl J Med 2018; 378:2023-2029. May 24, 2018 https://www.nejm.org/doi/full/10.1056/NEJMcpc1712227
- ↑ ARUP Consult: Anaplasma phagocytophilum and Ehrlichia Species
Anaplasmosis and Ehrlichiosis The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/anaplasma-phagocytophilum-coltivirus-colorado-tick-fever-and-ehrlichia-species