Neoehrlichia mikurensis-associated secondary capillary leak syndrome and septic shock: a case report

Candidatus Neoehrlichians mikurensis is the agent of an emerging tick-borne zoonosis responsible for systemic inflammatory syndrome mainly in immunocompromised patients and in subjects with underlying hematological or immunological disorders. The reported clinical manifestations include fever, chills, night sweats, weight loss, skin rash, myalgia/arthralgia, and edema limited to the ankles, and the infection is associated with a high incidence of vascular events. We report an unusual case of neoeherlichiosis, diagnosed by means of broad-range eubacterial polymerase chain reaction assay from a sample of spontaneous psoas muscle hematoma, which presented with septic shock and secondary capillary leak syndrome.

A 58-year-old Caucasian Swiss woman undergoing treatment of rituximab presented after 8 weeks of fever, chills, night sweats, and diffuse edema resistant to recently introduced loop diuretics. The patient developed septic shock with anasarca, possibly due to secondary capillary leak syndrome. Extensive microbiological investigations identified Candidatus Neoehrlichia mikurensis from a sample of spontaneous psoas muscle hematoma using eubacterial polymerase chain reaction assay and in subsequent blood samples. The patient fully recovered after 3 weeks of antibiotic therapy with doxycycline.

This case broadens the known clinical spectrum of the disease and may suggest a pathogenic role in hematoma formation, likely related to endothelial tropism and intravascular dissemination of the bacteria. Recognizing such atypical presentations is key to avoiding diagnostic delays. This case also highlights the diagnostic value of eubacterial polymerase chain reaction in emerging tick-borne infections.