La procalcitonine, un marqueur de l'infection bactérienne

[Usefulness of serum procalcitonin in the early diagnosis of maternal-fetal bacterial infection. A prospective study]

Early diagnosis avoiding unnecessary treatment of maternal-fetal bacterial infection remains one of the greatest challenges for obstetricians and pediatricians. To meet these objectives, many inflammatory mediators were used, including procalcitonin (PCT). The aim of our study was to determine the usefulness of PCT in early diagnosis and management of neonatal infection.

SUBJECTS AND METHODS

Over a period of 8 months, all living newborns with highly suspected maternal-fetal bacterial infection who were to receive antibiotic treatment according to our neonatal unit protocol were included in this prospective study. Serum PCT concentrations were determined at birth and after 12h of life using a specific immunoluminometric assay. Two distinct populations were defined based on clinical, biological, and bacteriological criteria: group 1: infected neonates, and group 2: noninfected neonates.

STATISTICAL METHODS

We compared PCT means in different groups and determined the cut-off value correlated with maternal-fetal bacterial infection by analyzing the receiver operating characteristics curve (ROC).

RESULTS

A total of 130 neonates were included in the study: 38 (29%) were classified in group 1 with 29 possible infections and 9 defined infections, including 5 cases of septicemia. The average PCT at birth in group 1 was significantly higher than in group 2 (3.52 ± 8.19 ng/ml vs 0.43 ± 0.73 ng/ml; P<0.001). The PCT threshold value at birth found by the ROC curve with the highest sensitivity (71.1%) and highest specificity (62%) was 0.215 ng/ml. The negative predictive value (NPV) was 83.8%, making it possible to avoid unnecessary treatment in the majority of the cases. The PCT threshold value within 12h of birth was 3.78 ng/ml, for a sensitivity of 89.5% and 1 NPV of 94.4%.

CONCLUSION

PCT is a valuable biological examination because it can be administered early, it is sensitive, and it has a NPV. These characteristics make PCT a biological argument that can be used in the initial decision on whether to administer antibiotics. Another study will be conducted to establish the cut-off value.

[Is procalcitonin able to help in pediatric appendicitis diagnosis?]

BACKGROUND

Appendicitis clinical diagnosis in children is difficult and the acute inflammatory markers hyperleucocytis and CRP do not contribute to it.

OBJECTIVE

To study the predictive value of procalcitonin (PCT) and to assess variations of its serum level according to inflammatory lesions in paediatric appendicitis.

PATIENTS AND METHOD

Among 101 children aged two and 15, hospitalized for painful abdominal syndromes, 70 underwent operation for acute appendicitis and appendiceal peritonitis, 31 had no operation. PCT was evaluated in all children, normal serum concentration was <0,5 microg/L. Every appendicectomy part has been examined through histological analysis to confirm the diagnosis and the histological lesions have been classified into three categories according to their severity.

RESULTS

Out of 70 appendix analysed at histology, 68 (97%) were healthy and 2 (3%)were unhealthy. Among the 68 cases of healthy appendix, 19 had a PCT higher than 0,5 microg/L and among 33 cases of unhealthy appendix 4 had a PCT higher than 0,5 microg/L. The PCT mean of healthy children was not significantly different from unhealthy appendix population, appendicitis prevalence was 0,67, PCT sensitivity 28%: IC 95% [18-40], specificity 88%: IC 95% [72-97], positive predictive value 83%: IC 95% [61-95], and negative predictive value 37%: IC 95% [26-49]. PCT mean increases with the severity of inflammatory lesions of the appendix (P=0,0051).

CONCLUSION

PCT has not a good predictive value in acute paediatric appendicitis but remains a good indicator of severity in paediatric appendicitis.

[Value of eosinopenia in inflammatory disorders: an "old" marker revisited]

PURPOSE

The value of eosinopenia as a test in favour of an infectious disease was suggested by Schilling since 1929. We tried to verify this hypothesis with a prospective and multicentric study.

PATIENTS AND METHODS

One thousand and thirty-eight patients were included (82 females and 56 males, means age: 71.8 years). Diagnoses were: 83 infectious diseases, 38 systemic diseases, 10 neoplasia and 7 miscellaneous.

RESULTS

The mean value of eosinophils was 72/mm3 in bacterial infectious diseases and 214/mm3 in non infectious diseases (p < 0.01). When leukocytes were higher than 10,000/mm3 and eosinophils counts less than 40/mm3, predictive value for an infectious bacterial disease was 100% as well as specificity. Under same conditions, when protein C reactive was higher than 100mg x l(-1), the predictive value was 85% and the specificity was 57%.

CONCLUSION

Our study shows that an inflammatory syndrome associated with hyperleucocytosis above 10,000/mm3 and eosinophils counts under 40/mm3 seems strongly related to bacterial infectious diseases.