Case records of the Massachusetts General Hospital. Case 6-2011. A 77-year-old man with dyspnea, weakness, and diaphoresis

Anaplasma phagocytophilum Community-Acquired Pneumonia: Case Report and Literature Review

Anaplasma phagocytophilum is an emerging, Gram-negative, and obligate intracellular pathogen that is infrequently implicated as a causative agent of community-acquired pneumonia. In this paper, we report about an immunocompetent patient from the community who presented with fever, cough, and shortness of breath. Chest X-ray and CT showed bilateral lung infiltrates. Extensive workup for other common and uncommon causes of pneumonia was positive for anaplasmosis. The patient recovered completely with doxycycline therapy. In our literature review, we find that in 80% of reported cases of anaplasmosis pneumonia, empiric treatment did not contain doxycycline, which in some cases led to acute respiratory distress syndrome. Clinicians in tick-borne disease endemic regions should be aware of this unusual presentation of anaplasmosis in order to be able to select appropriate antimicrobial regimens and initiate timely management.

Human Granulocytic Anaplasmosis-A Systematic Review of Published Cases

Anaplasma phagocytophilum is an emerging, Gram-negative, obligate intracellular pathogen that is transmitted by a tick vector. Human infection ranges from asymptomatic to severe disease that can present with pancytopenia, multiorgan failure, and death. The aim of this systematic review is to analyze case reports and case series reported over the last two decades in peer-reviewed journals indexed in the Medline/PubMed database according to the PRISMA guidelines. We found 110 unique patients from 88 case reports and series. The most common mode of transmission was tick bite (60.9%), followed by blood transfusion (8.2%). Infection was acquired by blood transfusion in nearly half (42%) of the immunocompromised patients. Most patients reported fever (90%), followed by constitutional (59%) and gastrointestinal symptoms (56%). Rash was present in 17% of patients, much higher than in previous studies. Thrombocytopenia was the most common laboratory abnormality (76%) followed by elevated aspartate aminotransferase (AST) (46%). The diagnosis was most commonly established using whole-blood polymerase chain reaction (PCR) in 76% of patients. Coinfection rate was 9.1% and Borrelia burgdorferi was most commonly isolated in seven patients (6.4%). Doxycycline was used to treat 70% of patients but was only used as an empiric treatment in one-third of patients (33.6%). The overall mortality rate was 5.7%, and one patient died from trauma unrelated to HGA. The mortality rates among immunocompetent and immunocompromised patients were 4.2% (n = 4/95) and 18.2% (n = 2/11), respectively. Four of the six patients who died (66.6%) received appropriate antibiotic therapy. Among these, doxycycline was delayed by more than 48 h in two patients.

Anaplasmosis Presenting With Respiratory Symptoms and Pneumonitis

Anaplasmosis is a now common tick-borne illness that is characterized by the presence of fever, myalgias, thrombocytopenia, and elevated liver function tests. We report 4 cases with an atypical presentation with pulmonary symptoms and imaging findings, along with the characteristics of each patient, clinical course, and response to therapy.