Ehrlichiosis associated vasculitis

Fever, pancytopenia, and elevated D-dimer in a 95-year-old woman with ehrlichiosis: a case report

BACKGROUND

Pancytopenia, fever, and elevated D-dimer are significant clinical findings. The differential diagnosis includes hematological malignancies, severe coronavirus disease 2019 (COVID-19), tick-borne illnesses, and other etiologies.

CASE PRESENTATION

We report the case of a 95-year-old woman who presented with high fever (103.6 °F), pancytopenia, and markedly elevated D-dimer (32.21 mg/L; reference range ≤ 0.95 mg/L) in late-autumn during the COVID-19 pandemic at a large academic institution. After remaining persistently febrile, a peripheral blood smear was ordered and revealed parasites consistent with Ehrlichia spp. Doxycycline monotherapy led to symptomatic improvement and resolution of her pancytopenia. During her hospital stay, a computed tomography angiogram of the chest revealed pulmonary emboli, and esophagogastroduodenoscopy uncovered arteriovenous malformations. After appropriate treatment, she was discharged on hospital day 7 and has since done well.

CONCLUSIONS

Overall, our case offers a dramatic, unexpected presentation of ehrlichiosis in a nonagenarian. To our knowledge, this is the first report of concurrent ehrlichiosis and pulmonary embolus.

Vasculitis due to Candidatus Neoehrlichia mikurensis: a cohort study of 40 Swedish patients

BACKGROUND

Candidatus (Ca.) Neoehrlichia (N.) mikurensis is an emerging tick-borne pathogen of humans that is closely related to Ehrlichia and Anaplasma species. This strict intracellular bacterium escapes detection by routine microbiologic diagnostic methods such as blood culture leading to considerable under-diagnosis of the infectious disease it causes, neoehrlichiosis.

METHODS

Here, we describe the vascular and thromboembolic events afflicting a series of 40 patients diagnosed with neoehrlichiosis in Sweden during a 10-year period (2009-2019).

RESULTS

The majority of the patients (60%) developed vascular events ranging from repeated thrombophlebitis, deep vein thrombosis, pulmonary embolism, transitory ischemic attacks to arteritis. Younger age was a risk factor for vascular complications. In contrast, there was no difference in the incidence of vascular events between immunosuppressed and immunocompetent patients. However, there were qualitative differences such that deep vein thrombosis exclusively afflicted the immunosuppressed patients whereas arteritis was restricted to the immunocompetent ones. We also present the case histories of two patients who developed vasculitis mimicking polyarteritis nodosa and giant cell arteritis. Both were cured by doxycycline treatment.

CONCLUSIONS

Ca. N. mikurensis infection should be considered in patients living in tick-endemic areas of Europe and northern Asia who present with atypical vascular and/or thromboembolic events. Early diagnosis and antibiotics targeting this emerging infectious agent can eradicate the infection and prevent the development of new vascular events.

Dermatoses from ticks

Ticks are ectoparasites that cause dermatologic disease directly by their bite and indirectly as vectors of bacterial, rickettsial, protozoal, and viral diseases. In North America, where ticks are the leading cause of vector-borne infection, dermatologists should recognize several tick species. Basic tick biology and identification will be reviewed. Tick bites cause a variety of acute and chronic skin lesions. The tick-borne diseases include Lyme disease, tick-borne relapsing fever, tularemia, babesiosis, Rocky Mountain spotted fever, other spotted fevers, ehrlichiosis, Colorado tick fever, and others. The epidemiology, clinical features, diagnosis, and treatment of these diseases are reviewed with an emphasis on cutaneous manifestations. Finally, the prevention of diseases caused by ticks is reviewed.