Neonatal case of late-onset sepsis involving group B Streptococcus type Ib.

Group B Streptococcus (GBS) is an important pathogen that causes neonatal sepsis and meningitis, which have high mortality and morbidity. Most cases of infection are early onset, with late onset infections being less common. Moreover, many cases of infection are caused by type III GBS, while type Ib GBS infections are rare. We report a case of late-onset infection by type Ib GBS. A female neonate weighing 574 g was delivered at 27 weeks' gestation. An endotracheal tube was inserted shortly after birth because of respiratory distress syndrome, and ampicillin was administered by the age of 3 days. At the age of 54 days after cardiopulmonary adaptation had been achieved, the patient presented with tachycardia following refractory apnea and bradycardia, and her skin became pale. She was suspected of having sepsis, and intensive treatment, including intubation and administration of catecholamines, was started. Despite these measures, the patient died after 5 hours after the onset of sepsis. Type Ib GBS infection may be more frequent in Japanese infants because of the low concentration of IgG antibodies against type Ib in pregnant Japanese women.

Intussusception in an extremely premature infant following bacterial sepsis.

Intussusception occurring in premature infants is exceedingly rare and shows substantially different characteristics from that in the typical age group or non-premature neonates. We present a case of intussusception in an extremely premature infant following bacterial sepsis, in which necrotizing enterocolitis was initially suspected. The correct diagnosis was made at 35 days old using abdominal ultrasonography, but the general condition of the infant had deteriorated to the point where surgery could not be performed. The patient died of multiple organ failure, and autopsy revealed ileo-ileal intussusception without a recognizable anatomical leading point. Possible mechanisms for this rare clinical entity are discussed.

Idiopathic severe constriction of the fetal ductus arteriosus: a possible underestimated pathophysiology.

Idiopathic intrauterine constriction/closure of the ductus arteriosus, which is distinct from that secondary to maternal exposure to non-steroidal anti-inflammatory drugs, such as indomethacin, or structural cardiac defect, is an uncommon event that often results in severe fetal-neonatal morbidity and mortality. We reported a case of idiopathic fetal ductal constriction, in which the diagnosis was confirmed by documentation of an abnormal four-chamber view of the fetal heart at 38 weeks of gestation on obstetric ultrasound examination. A female infant weighing 2,816 g was born by Cesarean section, and her postnatal course was mild; transient tachypnea requiring only several days of supplemental oxygen with spontaneous regression of the abnormal echocardiographic findings by 3 months of age. The incidence of idiopathic constriction/closure of the fetal ductus arteriosus may be underestimated, particularly with a negative history of maternal drug exposure and mild postnatal clinical presentation.

Hematopoietic capacity of preterm cord blood hematopoietic stem/progenitor cells.

Full-term cord blood (TCB) hematopoietic stem/progenitor cells (HSC/HPCs) are used for stem cell transplantation and are well characterized. However, the properties of preterm cord blood (PCB) HSC/HPCs remain unclear. In the present study, we compared HSC/HPCs from TCB and PCB with respect to their expression of surface markers, homing capacity and ability to repopulate HSCs in the NOD/Shi-scid mice bone marrow. The proportion of CD34+CD38- cells was significantly higher in PCB. On the other hand, the engraftment rate of TCB CD34+ cells into NOD/Shi-scid mice was significantly higher than PCB CD34+ cells. The expression of VLA4 was stronger among TCB CD34+ cells than PCB CD34+ cells. Moreover, there was a positive correlation between the proportion of CD34+CXCR4+ cells and gestational age. These data suggest that the homing ability of HSCs increases during gestation, so that TCB may be a better source of HSCs for transplantation than PCB.

Prenatal diagnosis of isolated congenitally corrected transposition of the great arteries.

Congenitally corrected transposition of the great arteries (ccTGA) is a rare cardiac defect characterized by the atria connecting with anatomically discordant ventricles and the ventricles connecting with discordant and transposed great arteries, which allows hemodynamic compensation. Most patients with ccTGA have associated intracardiac anomalies, which could be a diagnostic clue, whereas isolated forms are infrequently diagnosed during the neonatal period and in utero. We describe a fetus that was diagnosed with ccTGA and without additional cardiac anomalies at 25 weeks of gestation. The parallel course of the great arteries discovered during a routine obstetric scan indicated this rare cardiac anomaly. Further detailed examination of the ventricular morphology helped to confirm the diagnosis. Despite hemodynamic compensation, the long-term prognosis of ccTGA is uncertain because of the possible development of arrhythmias or heart failure later in life. Our findings showed that fetal echocardiography can detect prenatal ccTGA.

Risk factors for transient tachypnea of the newborn in infants delivered vaginally at 37 weeks or later.

In this case-control study, we examined infants delivered vaginally at 37 weeks or later to identify factors associated with transient tachypnea of the newborn (TTN). We reviewed the obstetric records of all vaginal deliveries at the Japanese Red Cross Katsushika Maternity Hospital from 2005 through 2007. Demographic information and the characteristics of labor were extracted from patient charts. Multivariate analysis identified that the incidence of TTN was significantly associated with nulliparity; a history of infertility therapy, such as in vitro fertilization; augmentation of labor; nonreassuring fetal status; vacuum/forceps delivery; and low Apgar score (<7) at 1 and 5 minutes. In addition, a low Apgar score at 1 minute was the factor most strongly associated with the incidence of TTN (adjusted odds ratio, 20; 95% confidence intervals, 12-34; p<0.001). The present results indicate that the improvement of obstetric surveillance to diminish the frequency of low Apgar scores is important for preventing TTN in infants delivered vaginally at 37 weeks or later.

An infant with congenital nemaline myopathy and hypertrophic cardiomyopathy.

We describe an infant with nemaline myopathy accompanied by hypertrophic cardiomyopathy. The patient required long-term, intermittent positive-pressure ventilation after birth owing to muscle weakness, and cardiac failure developed during infancy. We diagnosed hypertrophic cardiomyopathy with outflow tract obstruction, and treated the heart failure with beta-adrenergic and angiotensin II receptor blockers. We discuss the prognosis of nemaline myopathy combined with hypertrophic cardiomyopathy.

Urinary tract malformation and infection with hyperkalemia and decreased fractional excretion of potassium in an infant.

We describe an uncircumcised male infant treated for urinary tract infection who exhibited multiple hormonal and electrolyte abnormalities consistent with a diagnosis of transient pseudohypoaldosteronism. Successful treatment of the urinary tract infection was accompanied by the resolution of all hormonal and electrolyte abnormalities, including hyperaldosteronemia, hyperreninemia, hyponatremia and hyperkalemia. Radiographic examination revealed marked left dilatation of the renal pelvis and hydroureter but no vesicoureteral reflux. Owing to the possibilities of future renal scarring, decreased renal function, and hypertension, evaluation of urinary tract malformation and appropriate hormonal studies should be performed in infants with urinary tract infection and hyperkalemia.

Prenatal diagnosis of congenital heart disease: clinical experience and analysis.

Over a five-year period, we reviewed 19 fetuses who were prenatally diagnosed with congenital heart disease, including hemodynamically significant arrhythmias. Five of them had fetal tachyarrhythmias, and 14 had structural heart disease. The outcomes were: six intrauterine deaths, five neonatal deaths, and three infant surgeries. Six of the fetuses had chromosomal abnormalities, four had extracardiac anomalies, and two had hydrops fetalis. Of the 96 neonates with congenital heart disease found during the study period, the overall detection rate was 20%; 16% of the neonates with structural cardiac defects and 83% of the neonates with arrhythmias. Some of the complex cardiac defects with normal fetal four-chamber view were difficult to detect prenatally. During the course of the pregnancy, 37% of the fetuses with prenatally diagnosed congenital heart disease were found to have intrauterine growth retardation, and 26% were found to have an abnormal amniotic fluid volume. In view of our findings, a comprehensive screening system should be more frequently considered in order to improve both detection rate and perinatal management.