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

Siderits, Richard MD, FCAP, FAPWCA, FIAC*†; Mikhail, Nagy MD, FCAP*‡; Ricart, Carlos MD, FCAP*‡; Abello-Poblete, Maria Veronica MD; Wilcox, Carisa MS; Godyn, Janusz J. MD, FCAP*†‡

Infectious Diseases in Clinical Practice: May 2008 - Volume 16 - Issue 3 - p 182-186
doi: 10.1097/IPC.0b013e31809fe523
Case Reports

We present 3 cases of babesiosis: (a) in a patient (50-year-old man) who, immediately after splenectomy for spleen rupture, developed fulminant Babesia infection and subsequently was treated successfully; (b) babesiosis in a patient (71-year-old man) whose spleen ruptured and his postsplenectomy course was uneventful due to the fact that Babesia infection was recognized timely and treated in the perioperative period; and (c) babesiosis in a patient (66-year-old woman) who underwent splenectomy in the past and years later developed Babesia infection with fulminant course. Three major conclusions: (1) babesiosis may cause or contribute to spleen rupture, as the first 2 cases showed; (2) babesiosis may be a severe disease in a postsplenectomy patient, independent if recent or remote, as first and third cases showed; and (3) clinical and morphological warning: babesiosis may not be readily identified after splenectomy because of overwhelming reactive thrombocythemia (first case) or may not be recognized because of overwhelming infestation not corresponding to textbook pictures or personal experience with typical cases (third case). A patient undergoing splenectomy should be carefully checked for preexisting babesiosis to ensure an uncomplicated postsplenectomy course.

*Department of Pathology and Laboratory Medicine, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, †Department of Pathology, Robert Wood Johnson University Hospital, Hamilton, ‡Blood Bank and Transfusion Medicine, and Southern Ocean County Hospital, Manahawkin, NJ.

Address correspondence and reprint requests to Richard Siderits, MD, FCAP, FIAC, Department of Pathology, Robert Wood Johnson University Hospital-Hamilton, Hamilton, NJ. E-mail:

Although the association of babesiosis with spontaneous rupture of the spleen has been referenced anecdotally in popular media and local newspaper articles, it has not, to our knowledge, been described in the medical literature. This article describes the presentation and clinical course for 2 patients with babesiosis who presented with spontaneous rupture of the spleen and compares them with babesiosis in a previously splenectomized patient. We believe that the sequestration of parasitized erythrocytes may cause a subclinical splenopathy, which renders the spleen susceptible to spontaneous rupture or possibly following relatively minor trauma. Two of our patients presented to the emergency department with abdominal pain, decreased platelet, fever, arthralgia, and symptoms of oligovolemia. These patients had experienced spontaneous rupture of the spleen, which required surgical splenectomy, and babesiosis was identified during the related hospitalization. However, postsplenectomy thrombocytosis was found to initially obscure the parasitized erythrocytes in 1 patient. The third patient developed infection in the long term after splenectomy. All these patients were treated with antiparasitic antibiotics and recovered fully. In a patient with spontaneous rupture of the spleen, fever, anemia, and arthralgia, overwhelming and potentially life-threatening postsplenectomy babesiosis should be maintained within the differential diagnosis.

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A 50-year-old white man with no known significant medical history presented to the emergency room complaining of left upper quadrant pain, moderate-grade fever for 5 days, and a recent episode of syncope. He was involved in many outdoor activities, including camping trips in Southern New Jersey. He has not traveled outside the United States. Two weeks before admission, he played "paint ball" games, and 1 week before admission, while sparring in martial arts, the patient reportedly received multiple glancing and protected blows on the area of the left chest and abdomen. A few days later, the patient noted flulike symptoms of malaise and low-grade fever accompanied by increasing abdominal pain. He sought consultation with his primary physician and subsequently experienced an episode of syncope in the physician's office.

On admission, the patient had a temperature of 98.6°F, pulse rate of 78 beats per minute, and blood pressure of 128/77 mm Hg. There was mild tenderness on the left upper quadrant with area of cutaneous erythema from a "paint ball" strike 2 weeks before admission. Patient was anemic and thrombocytopenic. Computed tomography (CT) scan of the abdomen and pelvis with intravenous (IV) and oral contrast revealed enlargement of the spleen with subcapsular and perisplenic fluid collection highly suggestive of splenic rupture. While in the emergency room, the patient experienced hypotensive shock with a drop in blood pressure to 90/60 mm Hg and subsequently underwent emergency splenectomy, with transfusion of 2 U of packed red blood cells (RBCs), and was placed on levofloxacin (Levaquin) 500 mg daily, ertapenem sodium 1 g daily for 3 days, and metronidazole 500 mg IV every 6 hours for 3 days. The removed spleen was enlarged (276 g) and was markedly congested. The sinusoids showed a ragged appearance with subcapsular hemorrhage, hematoma, torn capsule, and exceedingly rare sinusoidal intraerythrocytic parasites, as examined microscopically several days later, after the specimen histological processing was completed. The splenic Babesia was carefully looked for because the parasites were already identified in the peripheral blood smear.

Initial postoperative course was unremarkable except for a drop in hemoglobin from 11.4 g/dL on admission to 9.3 g/dL. On the third hospital day, the patient developed fever of 101.3°F and subsequently demonstrated postsplenectomy reactive thrombocytosis of 458,000/μL to a high level of 858,000/μL on the seventh hospital day. During this time, he developed superficial thrombophlebitis of the left upper extremity, a clot in the basilic vein, and a pulmonary embolus for which enoxaparin sodium (Lovenox) subcutaneously every 12 hours and coumadin were given. The patient remained febrile, reaching a maximum temperature of 103°F with chills on the 10th hospital day, and noticed his urine to be dark. Despite transfusion of packed erythrocytes, the patient continued to show hemolysis with elevation of bilirubin and transaminases.

In a postsplenectomy peripheral smear, Babesia intraerythrocytic ring forms were found in approximately 3% of the erythrocytes within a background of partially obscuring platelets. Babesiosis Ab-IgG and Ab-IgM levels were both elevated. No other concomitant tick-related infections (such as Lyme disease or ehrlichiosis) were detected. The patient was started on treatment of Babesia with atovaquone and azithromycin while the other antibiotics were discontinued. During the course of the treatment, the patient continued to show steady, albeit slow, improvement. Serial hematocrits, lactate dehydrogenase, and transaminase levels showed improvement. On the sixth day of antibiotic treatment, parasitemia decreased to 0.5% erythrocytes. The patient was cleared for discharge and continued to do well on a follow-up.

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A 71-year-old man was found unresponsive on the floor by his wife. When EMS arrived, the patient had regained consciousness with a blood pressure of 70 mm Hg. Intravenous lines were placed, and the patient was resuscitated. Upon admission in the emergency department, he complained of abdominal pain. A CT scan of the abdomen showed splenic injury and hemoperitoneum.

Results of a physical examination found the patient to be afebrile, alert, and oriented. His blood pressure was 96/58 mm Hg with an irregular heart rate of 80 beats per minute. The patient's oxygen saturation was 93% on room air. Pupils were equal and reactive, and the sclerae were mildly icteric. Examination of the chest found distant breath sounds bilaterally with occasional wheezes. The patient's abdomen was diffusely tender to palpitation, predominantly in the upper and lower left quadrants, with no guarding, rigidity, or rebound tenderness.

Results of laboratory tests were as follows: hemoglobin, 9.2 g/dL; white blood cell (WBC) count, 6600/μL; hematocrit, 0.25; platelet count, 72,000/μL; blood urea nitrogen level, 11 mg/dL; serum creatinine, 0.9 mg/dL; prothrombin time, 13.4 seconds; partial thromboplastin time, 27.9 seconds; total bilirubin, 2.4 mg/dL; sodium, 129 mmol/L; potassium, 3.3 mmol/L; chloride, 100 mmol/L; and calcium, 7.8 mg/dL.

During surgery, 2.5 to 3.0 L of blood and blood clots in the abdominal cavity as well as severe splenomegaly with 6 grade II lacerations were noted. Pathological findings revealed a ruptured spleen with subcapsular hematoma. Microscopically, the enlarged spleen showed marked congestion, hemorrhagic infarction, and extramedullary hematopoiesis with multiple small intraparenchymal abscesses and few intraerythrocytic parasites consistent with Babesia. These findings were correlated and confirmed upon examination of the patient's peripheral blood smears. The patient was admitted to the intensive care unit and given 2 U of packed RBCs postoperatively.

He was treated with clindamycin 600 mg orally TID, quinine 150 mg orally TID, and amoxicillin clavulanate (Augmentin) 875 mg orally TID. His hemoglobin and hematocrit levels remained stable, and his activities were gradually increased. The patient was discharged 10 days after admission.

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Diagnostic Evaluation of Peripheral Blood for Both Cases

Romanowsky-stained peripheral blood smear showed intraerythrocytic parasites presenting as single-ring forms and rare pathognomonic tetrads ("Maltese cross"). No pigment was seen.

Figures 1 and 3 show representative findings in peripheral smears.





Figures 2 and 4 show sections of resected spleens in both patients.





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Case Comparison

In both cases, the patients were brought to the emergency room because of a history of syncope associated with increasing abdominal pain. The syncopal attacks could be attributed to the decrease in blood pressure present in both, to a low of 70 mm Hg in the second case. Blood tests done for each of them revealed low hemoglobin with a normal WBC count. Fortunately, CT scans were ordered, and the presence of splenic rupture was recognized early in each case. Emergency splenectomy proved to be life saving for both of them.

The difference between the two is the postsplenectomy clinical course. After the procedure, the first case developed progressive decrease in hemoglobin associated with fever and was diagnosed with Babesia in postoperative peripheral blood smear and spleen sections, shedding light on the cause of the continuous hemolysis. The necessary antibiotics were administered then. In contrast in the second case, the babesial forms were identified in a perioperative peripheral blood smear, confirmed by diagnostic intraerythrocytic babesial forms present in the ruptured spleen, and the patient was treated early without developing hemolysis. Both patients did well with antibiotic treatment and recovered completely.

The following additional illustrative case demonstrates importance of maintaining a high index of suspicion regarding babesial infection in the asplenic patient.

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A 66-year-old white woman, with no recent travel history and with history of an accident-related splenectomy, presented with a temperature of 101°F, feeling generalized sickness of severe degree and loosing mental abilities according to a friend's observation. Her blood count showed mild reactive leukocytosis (WBC count, 16,700/μL) with left neutrophilic shift and toxic granulation, and mild monocytosis. There was moderate normocytic anemia (8 g/dL) with polychromasia, Howell-Jolly bodies, and nucleated RBCs. Platelets were normal in number, with occasional macroplatelets noted. Her attending physician planned to rule out chronic loss of blood in the gastrointestinal and genitourinary systems, with subsequently occult blood in stool negative. Sedimentation rate was 129 mm/h (reference range, 0-20 mm/h). Total bilirubin was 1.6 mg/dL (reference range, 0.2-1.0 mg/dL), with direct 0.3 mg/dL (reference range, 0-0.5 mg/dL). Serum iron of 89 μg/dL (reference range, 35-175 μg/dL) with ferritin 5846 ng/mL (reference range, 10-291 ng/mL) as well as haptoglobin less than 8.0 mg/dL (43-212 mg/dL), lactate dehydrogenase 1191 U/L (reference range, 91-180 U/L), and reticulocyte count of 7.7% (reference range, 0.6%-2.7%) confirmed significant hemolysis. Urine morphology showed "large amount of hemolyzed blood on slide." Direct Coombs was negative. The review of the peripheral blood smear revealed numerous erythrocytes that contained small ring-form parasites, single or multiple (including tetrads). Some parasites were found outside the erythrocytes, forming aggregates that probably embolized capillaries and impaired tissue oxygenation. The patient had Po2 of 70.0 mm Hg (reference range, 75-100 mm Hg) in radial artery on 5 L by nasal cannula. Double blood cultures and urine culture were negative.

The peripheral blood smear was reviewed by a pathologist, and the above findings were reported. It was directly brought to the attention of an infectious disease specialist consulting this case that the patient was infested by Babesia parasites. Despite early skepticism, the infectious disease consultant was convinced to begin treatment. The treatment included quinine sulfate 520 mg orally TID and clindamycin phosphate 600 mg IV QID. High temperature persisted for more than a week with parasites slowly decreasing in number. However, the patient began recovering mentally quickly and reported improvement subjectively soon after the beginning of treatment.

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Splenopathies of various etiologies may render the spleen susceptible to spontaneous rupture after relatively minor trauma. Spontaneous rupture of the spleen has been seen in association with several infectious diseases including cytomegalovirus, Schistosoma, dengue, Bartonella henselae, salmonellosis, Plasmodium vivax, Q fever, hydatid cysts, and Epstein-Barr virus.1-8 Splenitis with rupture may also serve as a sentinel for other pathophysiologic processes such as bacterial endocarditis.9-11 Spontaneous splenic rupture has also been seen in association with various autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and polyarteritis nodosa.12

Human babesiosis or "Nantucket fever" is an illness transmitted by ticks of the genus Ixodes and caused by an intraerythrocytic protozoan of the genus Babesia.13 The life cycle of Babesia has no known exoerythrocytic stage. The fertilized gametes migrate from the tick gut to the tick salivary gland. Sporozoites from the tick bite infect the erythrocytes directly. Trophozoites reproduce within the RBCs by binary fission. Transmitted by the Ixodes tick, Babesia may use virtually any mammal as a host for the infection.

The clinical presentation of babesiosis is characterized by fever, arthralgia, and hemolytic anemia. Risk factors for clinically severe infection include increasing age, immunosuppression, and postsplenectomy or asplenic state.14,15 Transfusion-transmitted Babesiosis has been described, and it is interesting to note that 1 study showed 3% to 8% seropositivity for Babesia in the general population of blood donors.16-19 Although Romanowsky-stained peripheral blood can identify ring forms in parasitized erythrocytes, a babesial infection may also be identified by polymerase chain reaction.20 Because the spleen removes RBCs containing Babesia parasites from the blood, asplenic patients may be at higher risk for severe infection.13 Therefore, splenectomized individuals may be at increased risk for infection presenting as overwhelming sepsis by Babesia.21 Septic shock in asplenic patients and renal failure caused by babesiosis have been documented.22

Therefore, patients who have experienced spontaneous splenic rupture or who are asplenic may suffer life-threatening infections associated with Babesia and may require exchange transfusion and antibiotic therapy.23-25

Although resolution of imaged splenic disruption may obviate the need for splenectomy, this may still represent a prudent course of action in avoiding spontaneous rupture of the spleen.26 The most common indications for a splenectomy include symptomatic splenic abscess, infarct, splenomegaly, severe hypersplenism, prophylaxis for splenic rupture, and neoplastic exclusion.27,28

Clinically, babesiosis varies from mild and self-limiting to life-threatening sepsis with fever, myalgia, anemia, and hepatosplenomegaly. Parasitized erythrocytes lack the deformability needed to transit the splenic sinusoids and are therefore sequestered within the spleen. As a result, the development of subclinical splenomegaly may render the spleen susceptible to spontaneous rupture with relatively minor trauma.

Splenic rupture or asplenic state can be associated with overwhelming babesial sepsis and may be life threatening. Importantly, relative thrombocythemia in postsplenectomy (or asplenic) patients can obscure intraerythrocytic ring forms in peripheral smear, possibly delaying identification of the infection.

The diagnosis of babesiosis is supported identifying trophozoites of Babesia within erythrocytes either in peripheral blood or within erythrocytes in splenic sinusoids. There is no documented extraerythrocytic form except when associated with lysed RBCs. Diagnosis is best accomplished by evaluating Romanowsky-stained peripheral blood smears. Although similar to the intraerythrocytic ring forms of Plasmodium falciparum, those of Babesia are generally smaller and more variable in size with rare extracellular trophozoites and multiple infected erythrocytes. Clinical samples of Babesia may rarely present a tetrad or "Maltese cross" within a single erythrocyte. Definitive diagnosis may require serologic testing, hamster inoculation, or polymerase chain reaction amplification.

A review of the literature failed to show other reported cases of splenic rupture specifically because of a Babesia infection. However, a similar case study reported in 1982 by the Harvard Public School of Health documented a 60-year-old man who was hospitalized with a splenic rupture, given 4 transfusions, and splenectomized a day after admission. Two weeks after the patient's discharge, he was readmitted with shaking, chills, and a temperature of 39°C. Blood films were positive for Babesia microti. However, the Babesia infection had not been identified as the etiological agent of the splenomegaly.

Infections with Babesia may be overwhelming and life threatening in asplenic, elderly, or immunocompromised patients, as these cases also demonstrate and may require prompt antibiotic treatment with atovaquone and azithromycin or with an alternative regimen of clindamycin and quinine. The dosages should be adjusted to the severity of the infection on the presentation. Postsplenectomy patients may generally need higher doses. In addition, a supplemental exchange transfusion may also be considered in severe cases. However, an infectious disease consultation is recommended in all the clinically advanced cases.

In summary, we believe that the relative hypersplenism and associated splenomegaly seen with babesiosis may render the spleen susceptible to spontaneous rupture, possibly after relatively minor trauma. The postsplenectomy thrombocytosis may mask a life-threatening, overwhelming infection. The first 2 cases presented in this article suggest that babesiosis may be included in the differential diagnosis for a patient with fever, arthralgia, and anemia who presents with spontaneous rupture of the spleen. During the peak season of infection, May through September, Babesia should be considered in the differential diagnosis of patients (inparticular, those from areas endemic for Lyme disease, babesiosis, and human granulocytic ehrlichiosis) who exhibit hemolyticanemia, fatigue, thrombocytopenia, and fever.29,30 In the event of spontaneous splenic rupture in a patient with continued fever, anemia, and arthralgia, the postsplenectomy babesial infection should be maintained in the differential diagnosis, especially in light of partially obscuring postsplenectomy thrombocythemia.

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The authors thank the editors for their suggestions and guidance in the presentation of this paper.

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