Low risk of bacteremia in febrile children with recognizable viral syndromes

BACKGROUND: Previous studies of occult bacteremia in febrile children have excluded patients with recognizable viral syndromes (RVS). There is little information in the literature regarding the rate of bacteremia in febrile children with RVS. OBJECTIVE: To determine the rate of bacteremia in children 3 to 36 months of age with fever and RVS. METHODS: We performed a retrospective analysis of all patients 3 to 36 months of age with a temperature > or =39 degrees C seen during a 5 1/2-year period in the Emergency Department of a tertiary care pediatric hospital. From this group those with a discharge diagnosis of croup, varicella, bronchiolitis or stomatitis and no apparent concomitant bacterial infection were considered to have an RVS. The rate of bacteremia was determined for those subjects with RVS who had blood cultures. RESULTS: Of 21,216 patients 3 to 36 months of age with a temperature > or =39 degrees C, 1347 (6%) were diagnosed with an RVS. Blood cultures were obtained in 876 (65%) of RVS patients. Of patients who had blood cultures, true pathogens were found in only 2 of 876 (0.2%) subjects with RVS [95% confidence interval (CI) 0.01, 0.8%]. The rate of bacteremia was 1 of 411 (0.2%) for subjects with bronchiolitis, O of 249 (0%) for subjects with croup, O of 123 (0%) for subjects with stomatitis and 1 of 93 (1.1%) for subjects with varicella. CONCLUSIONS: Highly febrile children 3 to 36 months of age with uncomplicated croup, bronchiolitis, varicella or stomatitis have a very low rate of bacteremia and need not have blood drawn for culture.     

Bacteremia with otitis media

To investigate the occurrence and outcome of bacteremia associated with otitis media, charts were reviewed from patients who were 3 to 36 months of age, had temperatures greater than or equal to 39 degrees C, and were diagnosed with isolated clinical otitis media. A total of 2982 patients were identified. Blood cultures were obtained from 1666 (56%). Of the 1666 patients, who had blood drawn for cultures, 50 (3.0%) had bacteremia. These included 39 with Streptococcus pneumoniae, 4 with Haemophilus influenzae, 2 with Neisseria meningitidis, 3 with Salmonella species, and 2 with Staphylococcus aureus. The incidence of bacteremia increased at higher temperatures, being 1.9% at temperatures less than or equal to 40 degrees C and 5.0% at temperatures greater than 40 degrees C. Younger children were more likely to have bacteremia; 3.7% less than or equal to 12 months of age, 2.4% 13 to 24 months of age, and 1.9% 25 to 36 months of age had blood culture results that were positive (not significant). Reevaluation of the 50 bacteremic patients showed that 9 patients had continued fever, 3 patients had persistent bacteremia, pneumonia developed in 1 patient, and meningitis developed in 1 patient. It was concluded that (1) 3% of young febrile children with otitis media have bacteremia at the time of evaluation, a rate comparable to that previously reported in children with no focus of infection; (2) the incidence of bacteremia increases at higher temperatures; and (3) most febrile children with otitis media do well. The clinician must therefore weigh the potential benefit of drawing a blood culture to identify children at risk for complications against the inherent cost, inconvenience, and discomfort.     

Should blood cultures be obtained in the evaluation of young febrile children without evident focus of bacterial infection? A decision analysis of diagnostic management strategies

The technique of decision analysis was used to compare the benefits (prevention of major infectious sequelae of bacteremia) and risks (unnecessary hospitalization and intravenous antibiotic treatment of children whose bacteremia would have resolved spontaneously, discomfort of venipuncture) of alternative diagnostic management strategies in the evaluation of children 3 to 24 months of age with fever (rectal temperature greater than or equal to 39 degrees C) of acute (less than or equal to 4 days) onset and without evident focus of bacterial infection. The diagnostic strategies compared at the initial visit were blood culture in all, blood culture in none, and selective blood culture (restricted to children judged to be at high risk). Probability estimates were based on published epidemiologic studies and case series, and utilities were elicited from mothers of 3- to 24-month-old children and from pediatricians. Based on initial probabilities and utilities, the "no blood culture" strategy had the highest expected utility, followed closely by the "selective blood culture" strategy, with the "blood culture all" strategy a distant third. Sensitivity analyses based on increased risk of major infectious sequelae or of bacteremia had no effect on the ranking of the three initial management options. Eliminating the "disutility" of venipuncture or augmenting the disutility of major infectious sequelae also failed to alter the ranking. Even when an extreme relative disutility for major sequelae was assumed, the "blood culture all" strategy was not favored. Thus, the risk of unnecessary hospitalization and intravenous antibiotic treatment of the relatively large number of children whose bacteremia spontaneously resolves appears to outweigh the benefit of preventing serious infectious sequelae in the few children in whom positive blood culture results permit timely intervention. The explicitness and coherence of the decision analysis approach should help in developing a rational diagnostic approach to the young febrile child.     

Temperature response to acetaminophen and risk of occult bacteremia: a case-control study

A case-control study of 34 children with occult bacteremia was conducted to test the hypothesis that nonresponse to acetaminophen (decrease less than or equal to 0.8 degrees C) is a risk factor for occult bacteremia. Febrile children visiting the emergency center from May 1986 to October 1987 were monitored for occult bacteremia. Inclusion criteria were age 2 months to 6 years, temperature greater than or equal to 38.9 degrees C, and having a blood culture. Exclusion criteria were serious acute or chronic illness, sponging for fever reduction, current therapy with antibiotics or steroids, and admission to the hospital. Records of 3892 febrile children were reviewed. Of these, 2101 (54%) had a blood culture and 1028 (26%) were eligible. All patients (positive blood culture) were matched with two control subjects (negative blood culture). Patients and control subjects had similar age, gender, ethnicity, height of initial temperature, time to second temperature, and dose of acetaminophen. The estimated risk of occult bacteremia for nonresponders was 9.2 (95% confidence interval 2.7, 32.0). We conclude that children who do not respond to acetaminophen by at least a 0.8 degrees C decrease in temperature have an increased risk of occult bacteremia. However, achieving a response to acetaminophen does not eliminate the possibility that the child has occult bacteremia.     

Temperature and total white blood cell count as indicators of bacteremia

This study was designed to quantify more precisely the accuracy of magnitude of rectal temperature and total white blood cell (WBC) count as indicators of bacteremia in children with an obvious focal bacterial infection. A total of 955 children, aged 3 to 36 months, who had rectal temperature greater than or equal to 39.0 degrees C and were seeking care at either of two urban pediatric emergency departments had blood drawn for culture; 885 had blood drawn for WBC count. Twenty-seven had bacteremia. Various combinations of temperature and WBC count were selected to construct receiver-operating-characteristic curves by plotting sensitivity vs false-positive rate (1 - specificity). The receiver-operating-characteristic curve of WBC count provided significantly better diagnostic information than the curve for temperature increments above 39.0 degrees C. Each increment of 0.5 degrees C led to large decrements in sensitivity and false-positive rates. At a WBC count cutoff of 10,000/mm3, the sensitivity was 92% while the false-positive rate was 57%. Using this cutoff point, the clinician could have avoided performing 368 of 955 blood cultures and missed only 2 of 26 children with bacteremia. Receiver-operating-characteristic curves combining WBC count and temperature increments above 39.0 degrees C provided no better diagnostic information than that of WBC count at a temperature cutoff of 39.0 degrees C. It is concluded that increments in temperature above 39.0 degrees C provided additional diagnostic specificity for bacteremia only at the expense of unacceptable decreases in sensitivity. Total WBC count provided better information. A WBC count cutoff of 10,000/mm3 increased specificity with minimal decrease in sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Risk of serious bacterial infection in children with fever without a source in the post-Haemophilus influenzae era when antibiotics are reserved for culture-proven bacteremia

OBJECTIVE: To determine the rate of serious bacterial infection in children aged 2 to 36 months with fever without a source in the post-Haemophilus influenzae era, when antibiotic therapy is reserved until blood culture results turn positive. DESIGN AND SETTING: Retrospective review of emergency department, urgent care center, and hospital medical records from an urban children's hospital. PARTICIPANTS: Eligible participants were identified from hospital medical record and microbiology laboratory databases. Immunocompetent individuals aged 2 to 36 months with fever without a source were eligible for enrollment. Exclusion criteria were temperature less than 39.0 degrees C, identifiable focus of infection, current or recent antibiotic use, and hospital admission. INTERVENTIONS AND OUTCOME MEASURES: Enrolled participants were assigned to group 1 (blood culture obtained) or group 2 (no blood culture) and did not receive empiric antibiotic treatment in the emergency department, in the urgent care center, or for home use. Demographic and outcome data were collected on all enrolled patients. RESULTS: During the study, 9241 febrile children were identified; 2641 (29%) met the enrollment criteria. Blood cultures (group 1) were performed on 1202 patients (46%), and 37 (3%) had culture-proven occult bacteremia (95% confidence interval, 2.2%-4.2%). Streptococcus pneumoniae was the most prevalent organism (84%). The mean +/- SD time for reporting a positive blood culture finding was 17.5 +/- 8.5 hours. Two patients (0.08%; 95% confidence interval, 0.009%-0.27%) developed serious bacterial infection, and both recovered completely. CONCLUSION: Reserving antibiotic therapy for culture-proven occult bacteremia was not associated with increased risk of developing serious bacterial infection compared with previously published data.     

Association of Serum Soluble Triggering Receptor Expressed on Myeloid Cells Levels in Malignant Febrile Neutropenic Patients with Bacteremia and Fungemia

Objective

Infections are the major cause of morbidity and mortality in febrile neutropenic patients with malignancy. Rapid diagnostic tests are needed for prompt diagnosis and early treatment which is crucial for optimal management. We assessed the utility of soluble triggering receptor expressed on myeloid cells (sTREM-1) in the diagnosis of bacteremia and fungemia in febrile neutropenic patients.

Methods

Sixty-five febrile neutropenic children with malignancy hospitalized in Mofid Children''s Hospital during a period of one year from January 2007 were recruited for this cross sectional study (mean age 66.2± 37 months; 35 females and 30 males). Thirty patients (46.2%) had acute lymphoblastic leukemia, 2 (3.1%) acute myeloid leukemia, one (1.5%) lymphoma and 32 (49.2%) were under treatment for solid tumors. Simultaneous blood samples were collected for measurement of serum sTREM-1 levels and for blood cultures which were grown in BACTEC media. Gold standard for the presence of infection was a positive BACTEC culture as a more sensitive method compared to current blood culture techniques.

Findings

Blood cultures with BACTEC system were positive in 13(20%) patients (12 bacterial and one fungal culture). The mean serum sTREM-1 level in BACTEC positive patients was 948.2±592.9 pg/ml but in BACTEC negative cases it was 76.3±118.8 pg/ml (P<0.001). The optimal cut-off point of sTREM-1 for detecting patients with positive result of BACTEC was 525 pg/ml with sensitivity and specificity of 84.6% and 100%, respectively.

Conclusion

Our study revealed a significant association between serum sTREM-1 level and bacteremia and fungemia in febrile neutropenic patients suffering malignancy with acceptable sensitivity and specificity.     

Prevalence and antimicrobial sensitivity pattern in urinary tract infection in febrile under-5s at a children's emergency unit in Nigeria

The prevalence of urinary tract infection (UTI) in 300 consecutively admitted, febrile, preschool children with and without a focus of infection was evaluated to determine the contribution of UTI to febrile illnesses. Uncentrifuged urine was evaluated by culture and microscopy. The prevalence of UTI was 9% and was significantly higher in girls than in boys. It was also significantly higher when urine infection had been clinically suspected than in those with other diagnoses. Temperature >41 degrees C and abdominal pain were significantly associated with UTI. Other features significantly associated with UTI were fever of at least 7 days duration, a peak evaluation temperature >or=38.3 degrees C and a white blood cell count >10/mm(3). Escherichia coli, Klebsiella pneumonia and Staphylococcus aureus were the only organisms isolated and they all showed high in vitro sensitivity to clavulanic acid-potentiated amoxycillin, gentamicin and ceftriaxone but were poorly sensitive to co-trimoxazole.     

Parents' utilities for outcomes of occult bacteremia

OBJECTIVE: To describe parents' values for outcomes of occult bacteremia using utility assessment, a quantitative method that incorporates risk preference. DESIGN: Computer-based utility assessment interview. SETTING: Urban children's hospital pediatric emergency department with 50 000 visits annually. PARTICIPANTS: Convenience sample of parents presenting with a child between 3 and 36 months. MAIN OUTCOME MEASURE: Parents' utility values for 8 outcomes from treatment of occult bacteremia: blood drawing, localized infection, hospitalization for antibiotics, meningitis with recovery, meningitis resulting in deafness, minor brain damage, severe brain damage, and death. RESULTS: Ninety-four subjects successfully completed the interview. Mean utilities were 0.9974 for blood drawing, 0.9941 for local infection, 0.9921 for hospitalization, 0.9768 for meningitis with recovery, 0.8611 for deafness, 0.7393 for minor brain damage, 0.3903 for severe brain damage, and 0.0177 for death. All values were significantly different from those that immediately preceded and succeeded (P<.0001), except for local infection vs hospitalization (P = .14). Median utilities for blood drawn, local infection, and hospitalization were 1. There were no significant differences among utilities of parents who presented with a febrile child (temperature > or =39 degrees C), or an afebrile child (temperature <39 degrees C). There were also no significant differences among utilities regardless of whether parents had children with prior experience with the outcomes. CONCLUSIONS: Assessment of utilities for outcomes of occult bacteremia yielded extremely high mean and median values for outcomes without permanent sequelae. This suggests that parents presenting to an emergency department may rationally prefer painful transient experiences, including venipuncture, for their children rather than risk even rare chances of severe outcomes.     

Case-control study of hyperpyrexia in children

To test the association of hyperpyrexia (temperature greater than or equal to 41.1 degrees C) with increased rates of bacteremia and serious bacterial illness in young children, we performed a retrospective case-control study. Seventy-six hyperpyrexic children and an equal number of control cases with temperatures of 39.1-40 degrees C and 40.1-41.0 degrees C were identified. A significantly larger number of diagnostic procedures including blood cultures, urine cultures, chest x-rays and white blood cell counts were performed in the hyperpyrexic children (P less than 0.05). The frequency of serious bacterial infections and bacteremia did not differ among the groups (P greater than 0.05). Hyperpyrexic children need to be evaluated as thoroughly and carefully as any other febrile child but do not merit special consideration.     

Management of the febrile child without a focus of infection in the era of universal pneumococcal immunization

Should strategies of management of invasive disease in the febrile child without focus of infection (occult bacteremia) be reconsidered in communities with universal immunization of infants with the conjugate vaccines for Haemophilus influenzae type b and Streptococcus pneumoniae (PCV7)? The incidence of occult bacteremia is likely to decrease with the virtual elimination of H. influenzae type b and vaccine serotype pneumococcal invasive diseases. The number of children with fever coming to physicians' offices, however, is unlikely to change. The challenge of distinguishing the febrile child with invasive bacterial disease who requires aggressive therapy from the febrile child who has a viral infection and requires only symptomatic therapy will persist. The bacteriology of invasive disease in infants and young children in 2002 will include pneumococcal serotypes not in PCV7; serotypes in PCV7 that occur in the unimmunized, partially immunized or fully immunized child (vaccine failures); Neisseria meningitidis; Salmonella spp., group A Streptococcus, Staphylococcus aureus and gram-negative enteric bacilli. Management plans published in the 1990s suggested an aggressive diagnostic approach to the febrile child 3 to 36 months old who was toxic or had a temperature of >39 degrees C. Diagnostic tests included white blood cell counts, cultures of blood and urine and chest radiograph and lumbar puncture as indicated by clinical signs and administration of parenteral ceftriaxone. Although PCV7 was extraordinarily effective in prevention of serotype-specific invasive pneumococcal disease in clinical trials, pediatricians need to know whether the results based on 38,000 enrollees will be maintained as millions of children are immunized. In addition questions about change in serotype of pneumococci causing invasive disease (serotype switching), herd immunity and durability of protection after immunization need to be answered. Until more experience is available to answer these questions, the febrile child without focus of infection should be managed without consideration of immunization with PCV7. Evaluation of the organism (serotype) and the host (acute and convalescent sera) should be undertaken for each case of invasive pneumococcal disease in this era of universal pneumococcal immunization.     

Bacteremia in children afebrile at presentation to an emergency room

Charts of 182 outpatient children with bacteremia caused by Streptococcus pneumoniae, Haemophilus influenza type b or Neisseria meningitidis were reviewed. Twenty-four patients (13%) were afebrile (temperature less than 37.8 degrees C) at presentation. Five afebrile patients had no history of fever. Four of the five had localizing signs of infection and one appeared toxic. Afebrile patients were not strikingly different from febrile bacteremic patients by any assessments. Bacteremia in children cannot be excluded on the basis of absence of fever by history and examination. Blood cultures should be performed on afebrile children who either have localizing signs of serious bacterial infection or appear toxic.     

Peripheral white blood cell counts and bacterial meningitis: implications regarding diagnostic efficacy in febrile children

In order to investigate the clinical value of peripheral white blood cell variables for the diagnosis of bacterial meningitis among young, febrile children, we compared total peripheral white counts, total segmented neutrophil counts, total band counts, and the ratio of immature-to-total neutrophils (I:T ratio) among 46 children with bacterial meningitis, 130 children with aseptic meningitis, and 56 febrile children with culture confirmed extrameningeal bacterial infection. Children with bacterial meningitis were comparable to those with aseptic meningitis with respect to median total white blood cell counts and median total segmented neutrophil counts but had a significantly higher median total band count (1760/microliters vs 378/microliters, P = 0.0001) and a significantly higher median I:T ratio (0.40 vs 0.09, P less than 0.001). In contrast, children with bacterial meningitis were comparable to those with an extrameningeal bacterial infection with respect to median total band count but had a significantly lower median total peripheral white count (10,650/microliters vs 15,300/microliters, P = 0.0013), a lower median total segmented neutrophil count (4511/microliters vs 6796/microliters, P = 0.023), and a significantly higher median I:T ratio (0.40 vs 0.15, P less than 0.001). Children with meningitis who were bacteremic at presentation had a significantly lower total white cell count (P = 0.001) and significantly higher I:T ratio (P = 0.005) when compared with children who had an extrameningeal infection and concurrent bacteremia at presentation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bacteremia in 28 ambulatory children: relationship to pneumonitis and meningitis

Bacteremia with known pathogens was documented in 28 acutely ill, febrile outpatients during a 29-month period. All of the children were previously healthy and were initially managed as outpatients. Eight patients presented with no identifiable focus of infection. Twenty patients had either otitis media or pneumonitis. An association between otitis media and bacteremia with H. influenzae type b was noted in 5 patients. Bacterial meningitis occurred subsequently in 7 patients (25%); 1 death occurred in this group. The blood culture, as an outpatient procedure, was helpful in establishing a bacterial etiology in selected children with either high fever (with or without otitis media), febrile seizures, or pneumonia. In addition, the positive blood culture was a vital aid in identifying the young child at risk for meningitis.     

Bacteremia in febrile children with lobar pneumonia and leukocytosis

A retrospective analysis of 86 consecutive cases of childhood pneumonia with clinical features indicative of bacterial etiology was performed to delineate the prevalence of and characteristics associated with accompanying bacteremia. All patients had temperature greater than or equal to 40 degrees C, a lobar pulmonary infiltrate on chest radiograph, and a peripheral white blood cell concentration greater than 20,000/mm3 or absolute band count greater than 2,000/mm3. Associated clinical findings included 44% with an "ill" appearance, 37% with respiratory rate greater than or equal to 60/minute, 20% with heart rate greater than or equal to 200/minute, 33% with otitis media. Only one of 86 patients had a bacterial pathogen isolated by blood culture (Haemophilus influenzae, type b). In children older than four months of age with pneumonia whose characteristics are indicative of bacterial etiology, associated clinical findings and laboratory data are insensitive markers for distinguishing those with concomitant bacteremia. The rate of bacteremia in this group of patients is low; if the clinical situation warrants, most with these features do not require empiric hospitalization with parenterally administered antibiotic therapy pending blood culture results.     

Lack of usefulness of an abnormal white blood cell count for predicting a concurrent serious bacterial infection in infants and young children hospitalized with respiratory syncytial virus lower respiratory tract infection

BACKGROUND: There continues to be controversy on the most appropriate way to manage infants and young children with fever and documented RSV lower respiratory tract infection (LRTI). The objective of this study was to determine the usefulness of an abnormal white blood cell (WBC) count for predicting a concurrent serious bacterial infection in patients admitted with RSV LRTI. METHODS: The medical records were reviewed of patients discharged with RSV LRTI during the 5 RSV seasons from July 1, 2000 through June 30, 2005. Data were collected on age and gender as well as temperature, complete blood count with manual differential and bacterial cultures obtained at admission. RESULTS: The inclusion criteria was met by 1920 patients. There were 672 febrile patients who had a complete blood count and a bacterial culture. One (5.0%) of 20 patients with a WBC <5000 had a positive culture, 23 (4.7%) of 492 patients with a WBC 5000-14,999 had a positive culture, 5 (4.8%) of 105 patients with a WBC 15,000-19,999 had a positive culture, 2 (5.7%) of 35 patients with a WBC 20,000-24,999 had a positive culture, none of 11 patients with a WBC 25,000-29,999 had a positive culture and 3 (33%) of 9 patients with a WBC >30,000 had a positive culture. Overall, cultures were positive in 34 (5.1%; 95% CI: 3.4-6.8%) of the febrile patients tested and almost all (32; 94%) showed positive urine cultures. CONCLUSION: The probability of an abnormal WBC count <5000 and 15,000-30,000 being associated with a concurrent serious bacterial infection was very low and no different from that of a normal WBC count in febrile patients admitted with RSV LRTI.     

Follow-up of patients with occult bacteremia in pediatric emergency departments.

Blood cultures are frequently obtained in pediatric emergency departments (EDs) from febrile young children at risk for bacteremia and subsequent development of serious bacterial infections. This study of 105 children with occult bacteremia treated in two large urban pediatric EDs describes the follow-up of these patients and the impact that positive blood culture results have on the detection of serious illness. Seventy-seven percent of patients had a follow-up visit in the ED, 8% had follow-up by telephone alone, and 15% were not contacted. Of the patients who returned to the ED, 49% did so because they were notified of the positive blood culture result. The mean time interval for these patients from registration at the initial visit to report of positive blood culture result was 30.0 hours and, from registration at the initial visit to follow-up visit, was 42.7 hours. Thirty-seven percent of those who returned did so because a follow-up visit was scheduled at the initial encounter, and 13% returned because of persistent illness. Ten children (9.6%), five of whom had been notified of the positive blood culture, returned with serious illnesses. Patients whose diagnosis of serious illness was facilitated by blood culture results had shorter delay in identifying cultures as positive than did patients notified of positive results who did not develop serious illness (16.2 vs 31.6 hours; P < 0.05). The delay in follow-up of children with occult bacteremia limits the usefulness of blood cultures in the early detection of serious illness.(ABSTRACT TRUNCATED AT 250 WORDS)     

Value of electronic data for model validation and refinement: bacteremia risk in children with fever and neutropenia

BACKGROUND: Validating published risk models in a different time and setting can be a labor-intensive process. Data in electronic format provide the potential to test the validity of risk models without labor-intensive chart reviews and data capture. The authors attempted to use readily available electronic data to find appropriate cases and to validate and refine a previously developed risk model for predicting bacteremia in children with cancer who had fever and neutropenia. PATIENTS AND METHODS: By applying a largely automated case-finding algorithm to linked, electronic clinical and administrative data systems, the authors identified and acquired data regarding 157 episodes of fever and neutropenia in children with cancer admitted to a children's hospital during an 11-month period in 1997. The authors applied a previously developed and validated risk model for bacteremia to this 1997 cohort by assessing the odds ratios among risk groups. The model assigns encounters with absolute monocyte count of 100 cells or more/mm3 to a low-risk group and encounters with an absolute monocyte count of less than 100 cells/mm3 to intermediate-risk (temperature <39.0 degrees C) or high-risk (> or = 39.0 degrees C) groups. In addition, the authors explored whether the new data would have generated the same model. Univariate and multivariable analyses were performed to determine whether there were additional independent predictors of bacteremia. Recursive partitioning of admission absolute monocyte count and temperature was used to assess whether similar cutpoints would be found. RESULTS: There were 12 episodes of bacteremia (7.6%) among the 157 encounters. The previously developed model correctly predicted increasing rates of bacteremia in this 1997 cohort, ranging from 2.5% in the low-risk group (one episode in a child with an infected central line) to 24% in the high-risk group. The odds ratio for the high-risk versus intermediate-risk group was 4.09 (95% confidence interval 1.05-15.91), comparable to the odds ratio of 3.96 in the previously published derivation cohort (95% confidence interval 1.4-11.1). Multivariate analysis of the new data revealed no independent risk factors for bacteremia other than admission absolute monocyte count and temperature. Recursive partitioning of absolute monocyte count and temperature generated risk categories that were somewhat different from those of the original model. The new data yielded three categories: low risk (temperature < or = 39.5 degrees C and absolute monocyte count >10/mm3), intermediate risk (temperature < or = 39.5 degrees C and absolute monocyte count < or = 10/mm3), and high risk (temperature >39.5 degrees C). CONCLUSIONS: Existing electronic data provide an efficient means for case-finding and model validation and refinement. The previously developed bacteremia model had good but not optimal predictive performance in the new data set. Admission absolute monocyte count and temperature remain significant risk factors for bacteremia. Redefining the risk categories, including a much lower cutpoint for admission absolute monocyte count, improved the model's discrimination, which suggests that predictive models need periodic updating.     

Pneumococcal and Haemophilus influenzae type b antigen detection in children at risk for occult bacteremia

We prospectively evaluated pneumococcal and Haemophilus influenzae type b antigen detection in serum and urine of young (3 to 30 months of age) febrile (temperature greater than or equal to 39 degrees C) children at risk for occult bacteremia. Patients with septic shock, meningitis, or epiglottitis were excluded. Of 576 patients, 16 had pneumococcal bacteremia (final diagnoses: primary bacteremia, nine; otitis media, four; pneumonia, two; unknown, one), and five had H influenzae b bacteremia (final diagnoses: primary bacteremia, two; cellulitis, two; arthritis, one). Latex agglutination was positive in all five patients with H influenzae b bacteremia (positive in three of three urine specimens, three of four sera tested) but only one of 16 patients with pneumococcal bacteremia (positive in one of seven urine samples, zero of 13 sera tested). Both assays had specificities of greater than 95%. Nonspecific agglutination occurred in 7% of specimens tested. Enzyme immunoassay for pneumococcal antigen, although more sensitive than latex agglutination, failed to detect antigen in ten sera and three urine specimens from patients with pneumococcal bacteremia. Thus, neither latex agglutination nor enzyme immunoassay was sufficiently sensitive for detection of occult pneumococcal bacteremia. Latex agglutination for H influenzae b holds promise as a sensitive and specific test for rapid diagnosis of occult bacteremia due to H influenzae b.     

Fever in returned travellers: a prospective review of hospital admissions for a 2(1/2) year period.

AIM: To identify causes of fever, treatable diseases, and the most helpful investigations in febrile children, who had travelled to the tropics or subtropics in the preceding year. METHODS: Prospective observational study of all admissions to children's wards in a district general hospital in Birmingham between January 1997 and July 1999. Children with fever >37.5 degrees C and a history of travel to the tropics or subtropics in the preceding 12 months were included. Data were available on 153/162 children; median age was 5 years (range 0.1-15). A total of 133 (85%) children had visited South Asia; only 18/135 had received malarial prophylaxis. Median time to presentation after travel was four weeks. Children were investigated with full blood count, blood film, and stool culture. Other investigations were performed at the discretion of the admitting paediatrician. RESULTS: Diarrhoeal illness (n = 41) and malaria (n = 22) were the most common diagnoses. A treatable cause for the febrile illness was identified in 70 (46%) children. One or more investigations were positive in 60% of children. Stool culture (17% positive) and blood film (14% positive) were the most helpful investigations. Platelet counts greater than 190 x 10(9)/l had a negative predictive value of 97% for malaria in this population. CONCLUSIONS: Children who present with fever and have travelled to the tropics or subtropics in the preceding year, often have a treatable infection. They should have a full blood count, blood film for malarial parasites, stool culture, blood culture, and chest x ray.