Research Letters

Implications of chills

Core temperature stability is the result of a dynamically regulated balance of heat loss and gain, which is not reflected by a simple thermometer reading. One way in which these changes manifest is in perceived thermal comfort, ‘feeling too cold’ or ‘feeling too hot’, which can activate stress pathways. Unfortunately, there is surprisingly little preclinical research that tracks changes in perceived thermal comfort in response to either disease progression or various treatments. Without measuring this endpoint, there may be missed opportunities to evaluate disease and therapy outcomes in murine models of human disease. Here, we discuss the possibility that changes in thermal comfort in mice could be a useful and physiologically relevant measure of energy trade-offs required under various physiological or pathological conditions.

To determine whether the time lag between blood culture draw and the start of shaking chills is associated with blood culture positivity.

A prospective observational study was undertaken from January 2013 to March 2015 at a referral center in Okinawa, Japan. All enrolled patients were adults with an episode of shaking chills who were newly admitted to the division of infectious diseases. The study exposure was the time lag between blood culture draw and the most recent episode of shaking chills.

Among patients whose blood cultures were obtained within 2 h after shaking chills started, the blood culture positivity was 53.6% (52/97), whereas among patients whose blood cultures were obtained after more than 2 h, the positivity was 37.6% (44/117) (p = 0.019). The adjusted odds ratio of blood culture positivity for samples drawn within 2 h after shaking chills was 1.88 (95% confidence interval 1.01–3.51, p = 0.046). Escherichia coli were the most frequently detected bacteria (58/105).

The positivity of blood cultures obtained within 2 h after the start of the most recent shaking chills was higher than that for blood cultures obtained after 2 h.

There are no guidelines regarding the hospitalization of female patients with acute pyelonephritis (APN); therefore, we performed a retrospective analysis to construct a clinical prediction model for hospital admission.

We conducted a retrospective analysis of a prospective database of women diagnosed as having APN in the emergency department between January 2006 and June 2012. Independent risk factors for admission were determined by multivariable logistic regression analysis in half of the patients in this database. The risk of admission was categorized into 5 groups. The internal and external validations were conducted using the remaining half of the patients and 192 independent patients, respectively.

Independent risk factors for admission were age of 65 years or greater (odds ratio [OR], 2.62; 1 point), chill (OR, 2.40; 1 point), and the levels of segmented neutrophils greater than 90% (OR, 2.00; 1 point), serum creatinine greater than 1.5 mg/dL (OR, 2.41; 1 point), C-reactive protein greater than 10 mg/dL (OR, 2.37; 1 point), and serum albumin less than 3.3 g/dL (OR, 7.36; 2 points). The admission risk scores consisted of 5 categories, which were very low (0 points; 5.9%), low (1 point; 10.7%), intermediate (2 points; 20.7%), high (3-4 points; 51.9%), and very high (5-7 points; 82.8%) risk, showing an area under the curve of 0.770. The areas under the curve of the internal and external validation cohorts were 0.743 and 0.725, respectively.

This model can provide a guideline to determine the admission of women with APN in the emergency department.

We evaluated the value of a single biomarker, biomarker panels, biomarkers combined with clinical signs of sepsis, and serial determinations of biomarkers in the prediction of bacteremia in patients with sepsis.

Adult patients visiting the emergency department because of a suspected infection with at least two of the following symptoms: temperature >38.3 °C or <36 °C, heart rate >90/min, respiratory rate >20/min, chills, altered mental status, systolic blood pressure <90 mmHg, MAP <65 mmHg, and hyperglycemia in the absence of diabetes mellitus were included. Procalcitonin (PCT), interleukin-6 (IL-6), lipopolysaccharide-binding protein (LBP), C-reactive protein (CRP) were measured, and two blood cultures were taken. The analyses included: (1) determination of the biomarker with the highest predictive value for bacteremia and to examine the predictive value of this biomarker in combination with other biomarkers; (2) analysis of the best biomarker data in combination with clinical signs of sepsis; and (3) analysis of serial determinations of the best biomarker.

Of 342 included patients, PCT had the best predictive value for bacteremia with an area under the curve of 0.80, sensitivity 89%, specificity 58%. The predictive value of a combination of PCT plus a panel of other biomarkers, clinical signs, or analysis of serial PCT levels did not lead to a significant improvement of the predictive value of PCT alone.

The ability of PCT to predict bacteremia in patients with sepsis does not further improve when combined with IL-6, LBP, CRP, clinical signs, or serial measurements. Naturally, this does not exclude that a panel of other biomarkers may lead to different results.

Bacteremia is a severe bacterial infection with significant mortality and morbidity. Clinical parameters that reliably predict the presence of community-onset bacteremia are less elucidated.

During 96 randomly selected days between August 2006 and July 2007, a prospective study was conducted to analyze the risk factors of community-onset bacteremia among febrile adults who visited the emergency department (ED) of a medical center. Patients hospitalized in the 30 days prior to the study, patients experiencing consciousness alteration, and nursing facility residents were excluded.

The mean age of the 396 febrile adults enrolled in the study was 53.8 years (range, 18–95 years), and 60 (15.2%) patients had true bacteremia, with the predominance of monomicrobial Gram-negative pathogens (42 patients). In a multivariate analysis, several factors were independently associated with community-onset bacteremia, including an age of >65 years (odds ratio [OR], 2.81; 95% confidence interval [CI], 1.25–6.33), the presence of rigor (OR, 13.7; 95% CI, 4.47–42.0) or chills (OR, 6.04; 95% CI, 1.10–32.9), a body temperature >39.9 °C (OR, 2.68; 95% CI, 1.03–6.94), blood urea nitrogen >20 mg/dL (OR, 5.56; 95% CI, 2.03–15.7), a blood urea nitrogen/creatinine ratio >16 (OR, 2.29; 95% CI, 1.03–5.11), and thrombocytopenia (OR, 6.09; 95% CI, 1.84–20.0). After scoring each risk factor, a logistic regression model for the prediction of bacteremia was developed, and the area under the receiver operating characteristic curve was 0.91.

Some easily determined clinical parameters were independently associated with community-onset bacteremia among febrile adults, and the most significant predictor was the presence of rigor. Although the proposed predictive model needs further validation, it may be of use for the early identification of bacteremic episodes in ED practice.

Although Staphylococcus aureus bacteremia is a common, serious infection, accurately identifying febrile patients with this diagnosis at the time of initial evaluation is difficult. The purpose of this investigation was to define clinical characteristics present at the time of the initial recognition of fever that were associated with the presence of any bloodstream infection and, in particular, with S. aureus bacteremia.

All patients ≥18 years of age with a new episode of health care-associated fever (temperature ≥38°C) and at least one blood culture drawn were eligible for enrollment into this prospective multicenter cohort study. Multivariable analyses were conducted and internally validated scoring systems were developed to categorize the risk of bacteremia.

Of 1015 patients enrolled, 181 patients (17.8%) had clinically significant bacteremia, including 77 patients (7.6%) with S. aureus bacteremia. Clinical characteristics associated with S. aureus bacteremia were the presence of a hemodialysis graft or shunt (odds ratio [OR] 3.22; 95% confidence interval [CI], 1.85-5.61), chills (OR 2.38; 95% CI, 1.43-3.98), and a history of S. aureus infection (OR 2.68; 95% CI, 1.38-5.20). Peripheral vascular catheters were inversely associated with S. aureus bacteremia (OR 0.42; 95% CI, 0.26-0.69). Clinical characteristics associated with any bloodstream infection were central venous access, chills, history of S. aureus infection, and hemodialysis access.

Among patients with health care-associated fever, the presence of easily recognizable clinical characteristics at the time of obtaining the initial blood cultures can help to identify patients at increased risk for any bloodstream infection, in particular for S. aureus bacteremia.