Relative bradycardia and lymphopenia in patients with babesiosis

Human Babesiosis

Babesiosis is caused by intraerythrocytic parasites that are transmitted primarily by ticks, infrequently through blood transfusion, and rarely through transplacental transmission or organ transplantation. Human babesiosis is found throughout the world, but the incidence is highest in the Northeast and upper Midwestern United States. Babesiosis has clinical features that resemble malaria and can be fatal in immunocompromised and older patients. Diagnosis is confirmed by identification of Babesia parasites on blood smear or Babesia DNA with polymerase chain reaction. Standard treatment consists of atovaquone and azithromycin or clindamycin and quinine for 7 to 10 days.

Relative Bradycardia in Scrub Typhus

To investigate the relationship between heart rate and temperature, we examined 493 febrile patients with documented disease. These patients were diagnosed serologically and analyzed retrospectively: 337 (68.4%) responded to fever with increased heart rate < 10 beats/minute/°C (relative bradycardia [RB]), and 156 patients had a heart rate response ≥ 10 beats/minute/°C (general heart rate increase [GHRI]). The RB group had a higher median resting heart rate and lower heart rate at maximum temperature than the GHRI group. Despite differences in heart rate response, no significant differences were seen in clinical outcomes (acute kidney injury, systemic inflammatory response syndrome (SIRS), and death). We concluded that most patients with scrub typhus presented with RB. In scrub typhus infection, RB can be included as one of the clinical features for differential diagnosis from other infectious diseases.

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.

Electrocardiographic abnormalities and relative bradycardia in patients with hantavirus-induced nephropathia epidemica

BACKGROUND

Nephropathia epidemica (NE), caused by Puumala virus (PUUV), is characterized by acute kidney injury (AKI) and thrombocytopenia. Cardiac involvement with electrocardiographic (ECG) abnormalities has been previously reported in NE; however, its prognostic value is unknown. Relative bradycardia is an important clinical sign in various infectious diseases, and previous smaller studies have described pulse-temperature deficit in patients with PUUV infection.

METHODS

We performed a cross-sectional survey of 471 adult patients with serologically confirmed NE. Data were collected retrospectively from medical records and prospectively at follow-up visits. Patients for whom ECGs were recorded during the acute phase of disease were enrolled retrospectively (n=263). Three patients were excluded because of documented pre-existing ECG abnormalities prior to NE. All patients with ECG abnormalities during the acute phase underwent follow-up.

RESULTS

A total of 46 patients had ECG abnormalities at the time of admission to hospital (18%). T-wave inversion was the most frequent ECG abnormality (n=31 patients), followed by ST segment changes (nine patients with elevation and six with depression). No major adverse cardiac events occurred during follow-up (median 37months; range 34-63months). Of note, ECG abnormalities reverted to normal in the majority of the patients during follow-up. During the acute phase of NE, 149 of 186 patients had relative bradycardia, without implications for disease course.

CONCLUSIONS

Transient ECG abnormalities were detected in 18% of patients during acute NE but were not associated with negative cardiovascular outcome. Relative bradycardia was identified in 80% of the patients with acute NE.

Fatal Babesia canis canis infection in a splenectomized Estonian dog

A previously splenectomized dog from Estonia was presented with a sudden lack of appetite and discoloration of the urine. Despite supportive therapy, its condition deteriorated dramatically during 1 day. Severe thrombocytopenia and high numbers of protozoan hemoparasites were evident in blood smears, and the hematocrit dropped from 46 to 33 %. The dog was euthanized before specific antibabesial treatment was initiated. Blood samples from the dog and from two other dogs in the same household tested positive for Babesia using molecular methods, and the sequences of partial 18S rRNA gene confirmed the causative species as Babesia canis canis. The risk of severe, rapidly progressing babesiosis in splenectomized dogs merits awareness.

Ehrlichia chaffeensis presenting with bilateral anterior thigh pain (Louria's sign)

Bilateral anterior thigh pain may indicate bacteremia (Louria's Sign). We present a case of Ehrlichiosis due to Ehrlichia chaffeensis whose predominant presenting symptom was localized bilateral anterior thigh pain.

Fever of unknown origin (FUO) due to babesiosis in a immunocompetent host

Fevers of unknown origin (FUOs) are defined as prolonged fevers of 101 degrees F or greater lasting 3 or more weeks that remain undiagnosed after comprehensive inpatient/outpatient laboratory testing. Tick-borne infections are uncommon causes of FUOs. Any infectious disease accompanied by prolonged fevers can present as an FUO if the diagnosis is not suspected or if specific laboratory testing is not done to confirm the diagnosis. Babesiosis is transmitted by the Ixodes scapularis ticks endemic to areas in the northeastern United States. We present the case of a 73-year-old, non-human immunodeficiency virus, male from Long Island who presented with FUO for 6 weeks. As with malaria, there are usually few or no localizing signs in babesiosis. During the patient's hospitalization, babesiosis was suspected on the basis of nonspecific laboratory findings, that is, relative lymphopenia, thrombocytopenia, thrombocytopenia, and an elevated lactate dehydrogenase. When babesiosis was considered in the differential diagnosis, stained blood smears demonstrated the red blood cell inclusions of babesiosis. In the hospital, the patient developed noncardiac pulmonary edema, which rapidly resolved which has been described as a rare complication of babesiosis. He also had an elevated immunoglobulin-M Lyme titer indicating coinfection with Lyme disease. Although his hemolytic anemia persisted for weeks, he only had 3% parasitemia and intact splenic function. We believe this to be the first case of babesiosis presenting as an FUO in a normal host.

Discordance between data acquired by history and findings of physical examination: a phenomenal paradox

BACKGROUND

History and physical examination are the basis of any diagnosis. The findings of the physical examination usually corroborate the thoughts generated by the medical history. However, it is not uncommon for the physician to note discrepancies between the history and the physical examination.

METHODS

Two physicians provided a list of diseases they have encountered in which there is occasionally discordance between the data retrieved from the patient's medical history and the findings of the physical examination. To verify the data from knowledge and experience, we resorted to two main medical textbooks and relevant articles from PubMed.

RESULTS

We identified 25 diseases where a discordance between history and physical examination may frequently be observed. These diseases cover a wide spectrum of systems (i.e., neurological, cardiological, respiratory, and gastrointestinal).

DISCUSSION

A variety of diseases are associated with a discordance between the findings one might expect based on the medical history and the actual findings of the physical examination. Physicians need to be aware of this paradox, as misdiagnosis can be detrimental in some of these diseases. We acknowledge that this is just a sample, and not an exhaustive list, of all diseases with such a discordance.

Pulmonary complications of babesiosis: case report and literature review

Reported here is a rare case of babesiosis with pulmonary complications followed by a review of the literature. Babesiosis presents clinically as a malaria-like illness with fever, chills, headache, fatigue with lymphopenia, atypical lymphocytes, mildly or transiently elevated serum transaminases, thrombocytopenia, and increased lactate dehydrogenase (LDH) levels. The diagnosis of babesiosis is based on identification of Babesia spp. on a peripheral blood smear. Babesiosis is usually mild in normal hosts, but it may be severe or even fatal in asplenic patients. Pulmonary manifestations are rare in babesiosis, but non-cardiogenic pulmonary edema (NCPE) is the most frequent manifestation. NCPE in babesiosis does not appear to be related to the degree of parasitemia or splenic function and its onset may be early or late. NCPE usually resolves rapidly with supportive treatment; it is rarely fatal. Clinicians should suspect NCPE in patients with babesiosis who acutely develop shortness of breath and have chest radiograph findings compatible with acute pulmonary edema without cardiomegaly or pleural effusions.

Coinfecting deer-associated zoonoses: Lyme disease, babesiosis, and ehrlichiosis

The heightened worldwide recognition of the health burden of tickborne infection derives largely from the increasing incidence of Lyme disease, human babesiosis, and human granulocytic ehrlichiosis, both individually and in concert. Because these infections share the same rodent reservoir and tick vector hosts, they can be cotransmitted to human hosts. Indeed, human coinfections involving various combinations of these pathogens are common, and some tend to be particularly severe. Diagnostic procedures and clinical management of the resulting disease syndrome is rendered complex by the diversity of pathogens involved and by the unusual diversity and duration of symptoms.

Babesiosis

A case of human babesiosis is presented. This case emphasizes the need to consider tick-borne disease in anyone who presents with prolonged and undulating fevers, chills, headache, myalgias, and arthralgias. This holds true particularly in areas endemic for tick-borne diseases, even in the absence of a history of tick bite. These symptoms, associated with signs of intravascular hemolysis, thrombocytopenia, and renal insufficiency in a patient who resides in, or with recent travel to, the Northeastern United States, strongly suggest a diagnosis of babesiosis.

Human babesiosis: an emerging tick-borne disease

Human babesiosis is an important emerging tick-borne disease. Babesia divergens, a parasite of cattle, has been implicated as the most common agent of human babesiosis in Europe, causing severe disease in splenectomized individuals. In the US, Babesia microti, a babesial parasite of small mammals, has been the cause of over 300 cases of human babesiosis since 1969, resulting in mild to severe disease, even in non-splenectomised patients. Changing ecology has contributed greatly to the increase and expansion of human babesiosis in the US. A relatively recently described babesial parasite, the WA1-type, has been shown to be the causative agent in seven human cases in the western US. This parasite is closely related to babesial parasites isolated from large wild ungulates in California. Like B. microti, WA1-type parasites cause mild to severe disease and the immunopathogenesis of these parasites is distinctly different from each other in experimental infections of hamsters and mice. A B. divergens-like parasite was also identified as the cause of a fatal human babesiosis case in Missouri. Isolated cases of human babesisosis have been described in Africa and Mexico, but the causative parasites were not well characterized. Standard diagnostic techniques for human infection, such as examination of Giemsa-stained thin blood smears and serology, have been complemented with molecular techniques, such as PCR. Current treatment for babesiosis is focused on a regimen of clindamycin and quinine, although new drugs have shown promise. Prevention of infection relies on self-monitoring for the presence of ticks and, in some locations, targeted application of pesticides to decrease tick abundance. Identification of human infection with Babesia spp. will probably increase as physicians and the public become more aware of the disease, as people live and recreate in rural tick-infested areas, and as the numbers of immunocompromised individuals increase.