The following is a summary of “Unexplained hypothermia is associated with bacterial infection in the Emergency Department,” published in the September 2023 issue of Emergency Medicine by Baisse, et al.
The early detection and treatment of bacterial infections can significantly improve patient outcomes. In the emergency department (ED), a patient’s body temperature is an important diagnostic and prognostic marker for infections. For a study, researchers sought to assess the prevalence of community-acquired bacterial infections and evaluate the diagnostic accuracy of traditional biological markers in patients who present to the ED with hypothermia.
The retrospective, single-center study occurred over one year before the COVID-19 pandemic. Adult patients admitted to the ED with hypothermia (body temperature < 36.0 °C) were included. Patients with a clear cause of hypothermia and those with viral infections were excluded. Infection diagnosis was based on predefined criteria: presence of a potential source of infection, microbiology data, and patient response to antibiotic therapy. The study analyzed the association between traditional biomarkers (white blood cells, lymphocytes, C-reactive protein [CRP], Neutrophil to Lymphocyte Count Ratio [NLCR]) and underlying bacterial infections using univariate and multivariate (logistic regression) analyses. Receiver operating characteristic curves were used to determine threshold values offering each biomarker’s best sensitivity and specificity.
Of 490 patients admitted with hypothermia, 281 were excluded due to specific causes or viral infections. The study focused on 209 patients (108 men, mean age: 73 ± 17 years). Bacterial infections were diagnosed in 59 patients (28%) and were primarily caused by Gram-negative microorganisms (68%). CRP had an area under the curve (AUC) of 0.82 with a confidence interval (CI) between 0.75 and 0.89. The AUC for leukocyte, neutrophil, and lymphocyte counts was 0.54 (CI: 0.45–0.64), 0.58 (CI: 0.48–0.68), and 0.74 (CI: 0.66–0.82), respectively. The AUC for NLCR and quick Sequential Organ Failure Assessment (qSOFA) was 0.70 (CI: 0.61–0.79) and 0.61 (CI: 0.52–0.70), respectively. The multivariate analysis identified CRP ≥ 50 mg/L (OR: 9.39; 95% CI: 3.91–24.14; P < 0.01) and NLCR ≥10 (OR: 2.73; 95% CI: 1.20–6.12; P = 0.02) as independent variables associated with the diagnosis of underlying bacterial infection.
Community-acquired bacterial infections accounted for one-third of diagnoses in patients presenting to the ED with unexplained hypothermia. CRP levels and NLCR were valuable for diagnosing the causative bacterial infection.