Neurologic symptom | No. (%) patients | Peak parasitemia, no. (%) patients | p value | ||
---|---|---|---|---|---|
<1.0%, n = 45 | 1.0%–10.0%, n = 81 | >10.0%, n = 37 | |||
Headache | 52 (31.9) | 14 (31.1) | 28 (34.6) | 10 (27.0) | 0.711 |
Confusion/delirium | 27 (16.6) | 2 (4.4) | 13 (16.1) | 12 (32.4) | 0.003 |
Impaired consciousness | 24 (14.7) | 4 (8.9) | 9 (11.1) | 11 (29.7) | 0.018 |
Ataxia/gait disorder | 17 (10.4) | 3 (6.7) | 10 (12.4) | 4 (10.8) | 0.632 |
Vision impairment | 10 (6.1) | 5 (11.1) | 4 (4.9) | 1 (2.7) | 0.266 |
Acute syncope | 6 (3.7) | 2 (4.4) | 4 (4.9) | 0 (0.0) | 0.482 |
Language deficit | 5 (3.1) | 0 (0.0) | 5 (6.2) | 0 (0.0) | 0.106 |
Nerve pain | 4 (2.5) | 1 (2.2) | 2 (2.5) | 1 (2.7) | 1.000 |
Focal weakness | 3 (1.8) | 1 (2.2) | 1 (1.2) | 1 (2.7) | 0.794 |
Tremor | 3 (1.8) | 1 (2.2) | 2 (2.5) | 0 (0.0) | 1.000 |
Seizure | 2 (1.3) | 1 (2.2) | 0 (0.0) | 1 (2.7) | 0.252 |
Table 1. Neurologic symptoms during hospital admissions for babesiosis in patients admitted to Yale-New Haven Hospital, New Haven, Connecticut, USA, January 2011–October 2021*
*Total sample (n = 163); Column percentages do not sum to 100% due to many patients being affected by multiple neurologic conditions throughout hospitalization. Boldface type indicates statistical significance.
Imaging | No. (%) patients |
---|---|
Neuroimaging modality | |
Computed tomography | 28 (17.2) |
Magnetic resonance imaging | 7 (4.3) |
Electroencephalogram | 2 (1.2) |
Indication | |
Altered mental status/confusion | 15 (9.2) |
Headache | 8 (4.9) |
Fever | 5 (3.1) |
Evaluate CNS abnormalities | 3 (1.8) |
Weakness | 3 (1.8) |
Dizziness | 1 (0.6) |
Dysphagia, slurred speech | 1 (0.6) |
Fall | 1 (0.6) |
Head injury | 1 (0.6) |
Visual changes | 1 (0.6) |
Syncope | 1 (0.6) |
Numbness | 1 (0.6) |
Fatigue | 1 (0.6) |
Seizure | 1 (0.6) |
Findings | |
Nonspecific white matter changes | 23 (14.1) |
Volume loss | 14 (8.6) |
Acute changes | 2 (1.2) |
Evidence of previous stroke | 3 (1.8) |
Table 2. Imaging indications and findings in patients with neurologic symptoms associated with babesiosis admitted to Yale-New Haven Hospital, New Haven, Connecticut, USA, January 2011–October 2021*
*Total sample consisted of 163 patients. Neuroimaging modalities and indications sum to >33 because some patients received multiple imaging modalities or had multiple indications. CNS, central nervous system.
Laboratory result, median (IQR) | Reference range | Headache | Confusion/delirium | Impaired consciousness | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Yes, n = 52 |
No, n = 111 |
p value† | Yes, n = 27 |
No, n = 136 |
p value† | Yes, n = 24 |
No, n = 139 |
p value† | ||
Hematologic function | ||||||||||
Lowest hematocrit | M, 40%–52%; F, 37%–53% |
25.9 (16.2–35.6) | 26.0 (19.4–32.6) | 0.581 | 24.0 (16.5–31.5) | 26.4 (18.8–34) | 0.088 | 23.6 (15.7–31.5) | 26.4 (18.9–33.9) | 0.024 |
Lowest platelet count | 150–400 × 109/L | 78.5 |
82.0 (23.0–141.0) | 0.881 | 68.0 |
82.0 |
0.339 | 59.5 |
84.0 (17.0–151.0) | 0.084 |
Hepatic function | ||||||||||
Highest AST | 3–40 U/L | 66.0 (25.5–106.5) | 76.0 (38.0–114.0) | 0.277 | 76.0 (42.0–110.0) | 75.5 (32.5–118.5) | 0.813 | 81.0 (48.0–114.0) | 75.0 (33.0–117.0) | 0.909 |
Highest ALT | 3–40 U/L | 61.0 (10.0–112.0) | 63.0 |
0.809 | 54.0 |
63.5 (12.5–114.5) | 0.568 | 49.0 |
63.0 (13.0–113.0) | 0.441 |
Renal function | ||||||||||
Highest BUN | 7–20 mg/dL | 17.0 (4.5–29.5) | 24.0 |
0.002 | 31.0 |
20.0 (5.5–34.5) | 0.025 | 33.0 |
20.0 (5.0–35.0) | 0.005 |
Highest creatinine | 0.5–1.2 mg/dL | 1.00 (0.96–1.40) | 1.1 (0.3–1.9) | 0.091 | 1.5 (0.7–2.3) | 1.0 (0.5–1.5) | <0.001 | 1.5 (0.3–2.7) | 1.0 (0.5–1.5) | 0.002 |
Lowest GFR | ≥60 mL/min | 76.0 (37.5–114.5) | 67.0 (21.0–113.0) | 0.007 | 46.0 (3.0–89.0) | 73.0 (33.5–112.5) | <0.001 | 47.0 (1.0–93.0) | 73.0 (33.0–113.0) | 0.003 |
Table 3. Laboratory result comparisons by neurologic symptoms in patients with babesiosis admitted to Yale-New Haven Hospital, New Haven, Connecticut, USA, January 2011–October 2021*
*Boldface indicates significance. ALT, alanine transaminase; AST, aspartate transaminase; BUN, blood urea nitrogen; GFR, glomerular filtration rate; IQR, interquartile range. †By Wilcoxon 2-sample test.
Comorbid condition | Confusion/delirium, no. (%) | Adjusted odds of confusion/delirium | Impaired consciousness, no. (%) | Adjusted odds of impaired consciousness | ||
---|---|---|---|---|---|---|
OR (95% CI) | p value | OR (95% CI) | p value | |||
Diabetes mellitus | ||||||
No | 140 (13.6) | 1.00 | 140 (10.7) | |||
Yes | 23 (34.8) | 3.04 (1.11–8.34) | 0.031 | 23 (39.1) | 5.36 (1.98–14.48) | <0.001 |
Stroke/transient ischemic attack | ||||||
No | 150 (14.7) | |||||
Yes | 13 (38.5) | 3.06 (0.88–10.66) | 0.079 |
Table 4. Associations between comorbid conditions and neurologic symptoms in patients with babesiosis admitted to Yale-New Haven Hospital, New Haven, Connecticut, USA, January 2011–October 2021*
*Univariate logistic regression models tested associations between the following comorbid conditions and the 3 most frequent neurologic symptoms (headache, confusion/delirium, impaired consciousness): cardiac disorder, hypertension, diabetes mellitus, immunocompromised status, stroke/transient ischemic attack, obesity, chronic kidney disease, migraine, and malignancy. Variables that were significant in unadjusted univariate analysis were entered into a multivariate model for each neurologic symptom. The significance level for univariate and multivariate analysis was set to p<0.05. Boldface indicates statistical significance.
Physicians - maximum of 1.00 AMA PRA Category 1 Credit(s)™
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This activity is intended for infectious disease clinicians, neurologists, internists, and other clinicians caring for patients with neurologic complications of babesiosis.
The goal of this activity is for learners to be better able to describe the type and frequency of neurologic complications of babesiosis and risk factors predisposing patients to neurologic complications, on the basis of a record review of all 163 adult patients admitted to Yale-New Haven Hospital in New Haven, Connecticut, from January 2011 to October 2021 for laboratory-confirmed babesiosis.
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Babesiosis is a globally distributed parasitic infection caused by intraerythrocytic protozoa. The full spectrum of neurologic symptoms, the underlying neuropathophysiology, and neurologic risk factors are poorly understood. Our study sought to describe the type and frequency of neurologic complications of babesiosis in a group of hospitalized patients and assess risk factors that might predispose patients to neurologic complications. We reviewed medical records of adult patients who were admitted to Yale-New Haven Hospital, New Haven, Connecticut, USA, during January 2011–October 2021 with laboratory-confirmed babesiosis. More than half of the 163 patients experienced ≥1 neurologic symptoms during their hospital admissions. The most frequent symptoms were headache, confusion/delirium, and impaired consciousness. Neurologic symptoms were associated with high-grade parasitemia, renal failure, and history of diabetes mellitus. Clinicians working in endemic areas should recognize the range of symptoms associated with babesiosis, including neurologic.
Babesiosis is an emerging parasitic infection with global distribution. The infection is caused by intraerythrocytic protozoa of the genus Babesia. During the past 2 decades, the incidence of babesiosis has increased, particularly in the northeastern and northern midwestern United States. The Centers for Disease Control and Prevention reported an increased babesiosis incidence in Connecticut, USA, from 2011 (2.1 cases/100,000 persons) to 2019 (9 cases/100,000 persons), more than 10 times the incidence reported nationally during that time period[1]. More than 100 species of Babesia have been described in wild and domestic animals. The predominant species causing human disease in the United States is B. microti[1–3]. The disease is transmitted primarily through the bite of an infected ixodid tick, which is capable of transmitting several pathogens at the same time, including Borrelia burgdorferi, the cause of Lyme disease[2–5]. Babesiosis is less commonly transmitted via blood transfusion, organ transplantation, or through the placenta[2,3,6].
Although most persons with babesiosis experience nonspecific influenza-like symptoms, more severe and prolonged disease can occur in persons >50 years of age; those who are immunocompromised due to asplenia, cancer, or HIV/AIDS or who are receiving immunosuppressive drugs; and those who have chronic heart, lung, renal, or liver disease[2,7,8]. Severe infection is associated with high-grade parasitemia and organ failure (e.g., acute respiratory distress syndrome, congestive heart failure, severe hemolytic anemia, or renal failure) and death[2,8–11]. Little has been published about babesiosis-induced central nervous system dysfunction[12,13]. Neurologic complications include headache, syncope, neuropathy, retinal nerve infarcts, and altered state of consciousness[9,12,14–20]. The full spectrum of neurologic complications and underlying pathophysiology are poorly understood, as are factors that predispose patients to neurologic complications.
We conducted this study to investigate the type and frequency of neurologic complications of babesiosis in a group of hospitalized patients and to assess risk factors that predispose patients to neurologic complications. We hypothesized that patients with a diagnosis of babesiosis commonly experience neurologic system manifestations and that those symptoms are most frequent in patients with severe babesiosis. Accordingly, we conducted a retrospective medical record review of all adult patients admitted to Yale-New Haven Hospital (YNHH) in New Haven, Connecticut, USA, during 2011–2021 with laboratory-confirmed babesiosis.