Study of the usefulness of clinical and hematologic findings in the diagnosis of neonatal bacterial infections.

Abstract

The purpose of this study was to evaluate the usefulness of clinical and hematologic findings in distinguishing infected from uninfected newborn infants. Of 356 evaluations for infections, 22 (6%) infants were found to have bacterial isolates. Eight of the 52 clinical and historical findings evaluated were found to be statistically associated with infection. Clinical findings of tachypnea/arrhythmia, decreased peripheral perfusion, pallor, hypo- or hyper tension, abdominal distention, irritability, lethargy, and apnea were signifi cantly associated with positive bacterial cultures. Laboratory data found to be significantly associated with infected infants included white blood cell count < 10,000 or ≥20,000/mm 3, absolute neutrophil count < 1,000/mm3, absolute band count > 200/mm3, and neutrophil band forms/mature neutrophils ≥ 0.10. A 5-point scoring system was derived from the data obtained from this study consisting of: ≥ 2 systems involved on clinical assessment; white blood cells < 10,000 or ≥20,000/mm 3; absolute neutrophils < 1,000/mm3; bands/mature neutrophils ≥ 0.10; and age > 1 week. The restrospective use of this scoring system revealed that all infants with life-threatening bacterial infections had three or more of these findings present. All infants suspected of bacterial disease, therefore, who score ≥ 3 points using this system should have antibiotic therapy started and continued until all cultures are negative. In the face of other strong clinical or laboratory evidence of infection, antibiotics should be begun following appropriate cultures, in spite of a low score. So used, the scoring sys tem described can be helpful to clinicians in making decisions concerning newborn infants suspected of bacterial infections.