Babesiosis, Significance of Spleen Function Illustrated by Postsplenectomy Course in 3 Cases

Babesiosis-associated Splenic Rupture: Case Series From a Hyperendemic Region

BACKGROUND

Spontaneous splenic rupture is an increasingly reported complication of babesiosis and has been described as a severe complication.

METHODS

We performed a retrospective chart review in a high-prevalence area to identify 7 cases of babesiosis-related splenic rupture between 2014 and 2016.

RESULTS

Splenic rupture occurred in approximately 1% of babesiosis cases. Compared to cases without splenic rupture, these patients were younger (by >10 years), healthier (most with ≤1 comorbidity), had a lower degree of parasitemia (<10%), and were less likely to have end-organ dysfunction other than their splenic involvement.

CONCLUSIONS

Younger, healthier patients may be more prone to develop splenic rupture, as splenic histiocytes engage in more robust erythrophagocytosis, leading to pathological mechanical strain and rupture.

Splenic Complications of Babesia microti Infection in Humans: A Systematic Review

Splenic complications of acute Babesia microti infection include splenomegaly, splenic infarct, and splenic rupture. These complications are relatively rarely reported, and the aim of this research was to synthetize data on this topic according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the PubMed database. In this review, we find that unlike other severe complications of babesiosis, splenic infarct and rupture occur in younger and immunocompetent patients, and they do not correlate with parasitemia level. Furthermore, admission hemoglobin of 10 mg/dl or less, platelet count of 50 × 10⁹/L or less, presence of hemodynamic instability, and splenic rupture were associated independently with an increased risk of requiring splenectomy. As babesiosis is an emerging tick-borne zoonosis, we hope that this review will help to raise awareness among clinicians regarding this rare but potentially life-threatening complication.

Splenic findings in patients with acute babesiosis

PURPOSE

To identify the imaging manifestations of splenic involvement in babesiosis, a potentially fatal tick-borne zoonosis with multi-organ involvement.

METHODS

In our single center HIPAA compliant IRB-approved study, we performed a retrospective search of the electronic medical record at our institution to identify all patients with known or suspected acute babesiosis from 2000 to 2017. We then reviewed all abdominal imaging of patients with confirmed disease to identify incidence and characteristics of splenic involvement. Splenomegaly was determined using a height- and gender-adjusted reference.

RESULTS

After exclusions, 63 patients with a confirmed diagnosis of babesiosis and contemporaneous imaging of the spleen were included in the final cohort. Within this cohort, 56 (89%) had splenomegaly at a minimum and 13 had splenic infarcts. Splenic rupture was present in eight patients with three having a pseudoaneurysm. In 14 patients with follow-up imaging, the spleen subsequently diminished in size. One additional patient with ruptured spleen underwent emergency splenectomy prior to imaging.

CONCLUSION

Although the literature suggests splenic involvement is a rare finding, acute parasitemia with babesiosis commonly affects the spleen. Recognition of this association can aid radiologists diagnosing splenic involvement in babesiosis and can lead to appropriate intervention in the minority with splenic hemorrhage.

Zoonotic Babesia: A scoping review of the global evidence

BACKGROUND

Babesiosis is a parasitic vector-borne disease of increasing public health importance. Since the first human case was reported in 1957, zoonotic species have been reported on nearly every continent. Zoonotic Babesia is vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes scapularis, the tick species responsible for transmitting the pathogens that also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted climate change is expected to impact the spread of vectors, which is likely to affect the distribution of vector-borne diseases including human babesiosis.

METHODS

A scoping review has been executed to characterize the global evidence on zoonotic babesiosis. Articles were compiled through a comprehensive search of relevant bibliographic databases and targeted government websites. Two reviewers screened titles and abstracts for relevance and characterized full-text articles using a relevance screening and data characterization tool developed a priori.

RESULTS

This review included 1394 articles relevant to human babesiosis and/or zoonotic Babesia species. The main zoonotic species were B. microti, B. divergens, B. duncani and B. venatorum. Articles described a variety of study designs used to study babesiosis in humans and/or zoonotic Babesia species in vectors, animal hosts, and in vitro cell cultures. Topics of study included: pathogenesis (680 articles), epidemiology (480), parasite characterization (243), diagnostic test accuracy (98), mitigation (94), treatment (65), transmission (54), surveillance (29), economic analysis (7), and societal knowledge (1). No articles reported predictive models investigating the impact of climate change on Babesia species.

CONCLUSION

Knowledge gaps in the current evidence include research on the economic burden associated with babesiosis, societal knowledge studies, surveillance of Babesia species in vectors and animal hosts, and predictive models on the impact of climate change. The scoping review results describe the current knowledge and knowledge gaps on zoonotic Babesia which can be used to inform future policy and decision making.

Splenic rupture from babesiosis, an emerging concern? A systematic review of current literature

Babesiosis is a relatively common tick-borne parasitic infection of erythrocytes primarily affecting the northeastern United States. Babesiosis' prevalence and presentation have earned it the monikers "malaria of the northeast" and "Nantucket fever". Clinical presentation ranges from asymptomatic infection to severe infection including acute respiratory distress syndrome (ARDS) and disseminated intravascular coagulopathy (DIC) or death. Since 2008, there have been a number of reports of splenic rupture in patients with the disease. We seek to provide a further understanding of this process, with the report of a case of splenic rupture followed by a systematic review of the current literature. We found that 87% of splenic rupture secondary to babesiosis occurred in male patients who are otherwise healthy, with an average of 56 years. Computed tomography is a reliable mode of diagnosis, and hemoperitoneum is the most common imaging finding. Patients with splenic rupture due to human babesiosis were successfully treated by various management strategies, such as conservative non-operative approach, splenic artery embolization, and splenectomy. The modality of treatment depends on patient's clinical course and hemodynamic stability, although spleen conserving strategy should be considered first whenever possible.

Hematologic manifestations of babesiosis

BACKGROUND

Babesiosis, a zoonotic parasitic infection transmitted by the Ixodes tick, has become an emerging health problem in humans that is attracting attention worldwide. Most cases of human babesiosis are reported in the United States and Europe. The disease is caused by the protozoa of the genus Babesia, which invade human erythrocytes and lyse them causing a febrile hemolytic anemia. The infection is usually asymptomatic or self-limited in the immunocompetent host, or follows a persistent, relapsing, and/or life threatening course with multi-organ failure, mainly in the splenectomized or immunosuppressed patients. Hematologic manifestations of the disease are common. They can range from mild anemia, to severe pancytopenia, splenic rupture, disseminated intravascular coagulopathy (DIC), or even hemophagocytic lymphohistiocytosis (HLH).

CASE PRESENTATION

A 70 year old immunocompetent female patient living in New York City presented with a persistent fever, night sweats, and fatigue of 5 days duration. Full evaluation showed a febrile hemolytic anemia along with neutropenia and thrombocytopenia. Blood smear revealed intraerythrocytic Babesia, which was confirmed by PCR. Bone marrow biopsy was remarkable for dyserythropoiesis, suggesting possible HLH, supported by other blood workup meeting HLH-2004 trial criteria.

CONCLUSION

Human babesiosis is an increasing healthcare problem in the United States that is being diagnosed more often nowadays. We presented a case of HLH triggered by Babesia microti that was treated successfully. Also, we presented the hematologic manifestations of this disease along with their pathophysiologies.

Atraumatic splenic rupture from Babesia: A disease of the otherwise healthy patient

Babesiosis, an infection caused by the protozoan Babesia microti and transmitted by the Ixodes scapularis tick, is commonly described in the literature with an approximate incidence of 1000 cases per year (Herwaldt et al., 2012). Infections in North America occur most frequently during the spring and summer months in the Northeastern and Midwestern United States. Babesia can cause a wide spectrum of clinical manifestations ranging from a self-limited febrile illness or mild anemia to severe illness causing acute respiratory distress syndrome (ARDS), disseminated intravascular coagulopathy (DIC) and multisystem organ failure. Severe illness most commonly occurs in elderly, immunocompromised, or asplenic patients (Vannier and Krause, 2012). Splenic rupture has been generally described as a complication of severe illness secondary to babesiosis. We describe a case of spontaneous splenic rupture in an otherwise healthy woman that required emergent splenectomy. Recent case reports suggest that splenic rupture occurs in people without known risk factors for severe babesiosis. Physicians should be aware of this acute presentation in otherwise healthy individuals.