Use of Procalcitonin Assays to Predict Serious Bacterial Infection in Young Febrile Infants.

IMPORTANCE: The procalcitonin (PCT) assay is an accurate screening test for identifying invasive bacterial infection (IBI); however, data on the PCT assay in very young infants are insufficient. OBJECTIVE: To assess the diagnostic characteristics of the PCT assay for detecting serious bacterial infection (SBI) and IBI in febrile infants aged 7 to 91 days. DESIGN, SETTING, AND PARTICIPANTS: A prospective cohort study that included infants aged 7 to 91 days admitted for fever to 15 French pediatric emergency departments was conducted for a period of 30 months (October 1, 2008, through March 31, 2011). The data management and analysis were performed from October 1, 2011, through October 31, 2014. MAIN OUTCOMES AND MEASURES: The diagnostic characteristics of the PCT assay, C-reactive protein (CRP) concentration, white blood cell (WBC) count, and absolute neutrophil cell (ANC) count for detecting SBI and IBI were described and compared for the overall population and subgroups of infants according to the age and the duration of fever. Laboratory test cutoff values were calculated based on receiver operating characteristic (ROC) curve analysis. The SBIs were defined as a pathogenic bacteria in positive culture of blood, cerebrospinal fluid, urine, or stool samples, including bacteremia and bacterial meningitis classified as IBIs. RESULTS: Among the 2047 infants included, 139 (6.8%) were diagnosed as having an SBI and 21 (1.0%) as having an IBI (11.0% and 1.7% of those with blood culture (n = 1258), respectively). The PCT assay offered an area under the curve (AUC) of ROC curve similar to that for CRP concentration for the detection of SBI (AUC, 0.81; 95% CI, 0.75-0.86; vs AUC, 0.80; 95% CI, 0.75-0.85; P = .70). The AUC ROC curve for the detection of IBI for the PCT assay was significantly higher than that for the CRP concentration (AUC, 0.91; 95% CI, 0.83-0.99; vs AUC, 0.77; 95% CI, 0.65-0.89; P = .002). Using a cutoff value of 0.3 ng/mL for PCT and 20 mg/L for CRP, negative likelihood ratios were 0.3 (95% CI, 0.2-0.5) for identifying SBI and 0.1 (95% CI, 0.03-0.4) and 0.3 (95% CI, 0.2-0.7) for identifying IBI, respectively. Similar results were obtained for the subgroup of infants younger than 1 month and for those with fever lasting less than 6 hours. CONCLUSIONS AND RELEVANCE: The PCT assay has better diagnostic accuracy than CRP measurement for detecting IBI; the 2 tests perform similarly for identifying SBI in febrile infants aged 7 to 91 days.

Can procalcitonin measurement help the diagnosis of osteomyelitis and septic arthritis? A prospective trial.

OBJECTIVES: Procalcitonin (PCT) is an accurate marker for differentiating bacterial infection from non-infective causes of inflammation or viral infection. However, there is only one study in children which tested procalcitonin as a diagnostic aid in skeletal infections. With this study we sought to evaluate the sensitivity, specificity and predictive values of procalcitonin for identifying bone and joint infection in children evaluated in the emergency department for non traumatic decreased active motion of a skeletal segment. METHODS: Patients aged 1 month to 14 years were prospectively included in the emergency department when suspected for osteomyelitis or septic arthritis. Procalcitonin levels, C reactiv protein, white blood cell count were measured and bacteriological samples were collected before initiation of antibiotic treatment. Patients were assigned to 3 groups according to the degree of suspected infection: group 1 confirmed infection, group 2 presumed infection and group 3 non infected patients. RESULTS: Three hundred thirty nine patients were included (118 girls and 221 boys). Group 1 comprised 8 patients (2 had PCT levels > 0.5 ng/ml). Two had osteomyelitis and 6 septic arthritis. Forty children were incuded in group 2 (4 had PCT levels > 0.5 ng/ml). Eighteen had presumed osteomyelitis and 22 presumed septic arthritis. Group 3 comprised 291 children (9 PCT levels > 0.5 ng/ml) who recovered without antibiotic treatment. The specificity of the PCT as a marker of bacterial infection (comparing Group 1 and Group 3) was 96.9% [95% CI, 94.2-98.6], the sensitivity 25% [95% CI, 3.2-65.1], the positive predictive value (PPV) 18.2% [95% CI, 2.3-51.8] and the negative predictive value (NPV) 97.9% [95% CI, 95.5-99.2]. CONCLUSION: PCT is not a good screening test for identifying skeletal infection in children. Larger studies are needed to evaluate still more the place of PCT measurements in the diagnosis of osteomyelitis and septic arthritis.

Neurological consequences of vitamin B12 deficiency and its treatment.

In developed countries, the vitamin B12 deficiency usually occurs in children exclusively breast-fed, whose mothers are vegetarians, causing low stores of vitamin B12. Symptoms of vitamin B12 deficiency appear during the second trimester of life and include failure to thrive, lethargy, hypotonia, and arrest or regression of developmental skills. A megaloblastic anemia can be present. One half of the infants exhibit abnormal movements before the start of treatment with intramuscular cobalamin, which disappear 1 or 2 days after. More rarely, movement disorders appear a few days after treatment, whereas neurological symptoms are improving. These abnormal movements can last for 2 to 6 weeks. If not treated, vitamin B12 deficiency can cause lasting neurodisability. Therefore, efforts should be directed to preventing deficiency in pregnant and breast-feeding women on vegan diets and their infants by giving them vitamin B12 supplements. When preventive supplementation has failed, one should recognize and treat quickly an infant presenting with failure to thrive and delayed development.