An Outbreak of Epidemic Keratoconjunctivitis by Adenovirus Type 8 in a Neonatal Intensive Care Unit

PURPOSE: Epidemic keratoconjunctivitis (EKC) caused by adenovirus is a highly contagious disease, which has been reported as outbreaks involving adults in the community. However, there has been no report on EKC outbreak by adenovirus in a neonatal intensive care unit (NICU) in Korea. Aims of this study were to investigate the EKC outbreak by adenovirus type 8 in NICU and to confirm an effectiveness of polymerase chain reaction (PCR) for diagnosis. METHODS: Conjunctival swab or nasopharyngeal aspirate specimens were taken from all patients and tested by viral culture and PCR. Adenovirus serotype was determined by sequencing of PCR product of selected region of hexon gene using the virus isolates or specimens. RESULTS: An outbreak of EKC occurred which was involving 12 preterm infants in the NICU of the Seoul National University Children's Hospital between July 12th and August 1st, 2005. Three hospital staffs and one family member of the neonate were also affected. Adenovirus was detected in 12/12 (100%), 6/11 (54.5%) by PCR and virus culture, respectively. Eleven PCR-positive neonates were identified as serotype 8 by sequencing. The first affected 4 babies have had routine ROP (retinopathy of prematurity) examinations one week ago. While previous outbreaks were sustained for a few months, the event in our unit was controlled without complications in 3 weeks. CONCLUSION: We analyzed the EKC outbreak by adenovirus type 8 in NICU. Adenovirus serotype was identified by PCR and sequencing with high sensitivity for the first time in Korea, so we suggest this method can be very useful for rapid diagnosis and infection control.

Clinical characteristics of severe meconium aspiration syndrome / 소아과

PURPOSE: This study aims to describe the clinical characteristics of severe meconium aspiration syndrome (MAS) which required mechanical ventilation over 48 h and to delineate the progress of respiratory failure and radiographic findings in severe MAS. METHODS: Twelve infants admitted to the Neonatal Intensive Care Unit (NICU) of the Seoul National University Bundang Hospital diagnosed with severe MAS from January 2004 to July 2007 were analyzed retrospectively. RESULTS: The presence of persistent pulmonary hypertension of the newborn (PPHN) is the only independently significant risk factor for a longer hospital stay and longer duration of mechanical ventilation. Surfactant replacement therapy (SRT) was not randomized but only performed in infants with radiographic findings for respiratory distress syndrome (RDS). In the presence of radiographic findings for RDS, the duration of high-frequency oscillatory ventilation was significantly longer. PPHN developed in 8 infants (75%). The PPHN group had a significantly longer duration of mechanical ventilation. All infants who received SRT showed radiographic improvement within 12 h, but there was no significant change in the severity score during the same period. Infants without the PPHN complications showed significant decrease in the severity score within 12 h after SRT, whereas infants with PPHN complications did not. CONCLUSION: The clinical course of severe MAS differed significantly depending on the development of PPHN. SRT conferred radiographic improvement in infants who showed radiographic findings for RDS, but did not influence the clinical course of MAS significantly.

Decreased Expression of Transforming Growth Factor-beta1 in Bronchoalveolar Lavage Cells of Preterm Infants with Maternal Chorioamnionitis

Maternal chorioamnionitis has been associated with abnormal lung development. We examined the effect of maternal chorioamnionitis on the expression of transforming growth factor-beta1 (TGF-beta1) in the lungs of preterm infants. A total of 63 preterm (< or =34 weeks) infants who were intubated in the delivery room were prospectively enrolled. Their placentas were examined for the presence of chorioamnionitis. Bronchoalveolar lavage (BAL) fluid and cells were obtained shortly after birth. TGF-beta1 was measured in BAL fluid and TGF-beta1 mRNA expression was determined by reverse transcription polymerase chain reaction (RT-PCR) in BAL cells. TGF-beta1 mRNA expression in BAL cells showed a positive correlation with gestational age (r=0.414, p=0.002). TGF-beta1 mRNA expression was significantly decreased in the presence of maternal chorioamnionitis (0.70+/-0.12 vs. 0.81+/-0.15, p=0.007). Adjustment for gestational age, birth weight, and delivery mode did not nullify the significance. TGF-beta1 mRNA expression was marginally significantly decreased in preterm infants who developed bronchopulmonary dysplasia (BPD) later (0.75+/-0.11 vs. 0.82+/-0.15, p=0.055). However, adjustment for gestational age, patent ductus arteriosus (PDA), and maternal chorioamnionitis nullified the significance. These results might be an indirect evidence that maternal chorioamnionitis may inhibit normal lung development of fetus.

The Effects of Bone Marrow-Derived Mesenchymal Stem Cells on Alveolarization Inhibition Induced by Hyperoxia in Neonatal Rat

PURPOSE: We sought to determine whether bone marrow-derived mesenchymal stem cells (BMMSC) could attenuate the inhibition of alveolarization induced by hyperoxia. METHODS: Human BMMSC (SNU-hMSC) were infused into the peritoneal cavity (IP) or trachea (IT) of neonatal rats exposed to hyperoxia (90% O2 from D1) on D5. The rats were then exposed to the same degree of hyperoxia for another 9d and sacrificed on D21. Morphometric analysis of the lungs and immunofluorescent staining in order to determine cell fates of infused SNU-hMSC were performed. RESULTS: The airspace of the hyperoxia control group (90% O2 for 14d) was significantly larger and more simple (mean linear intercept [Lm] : 68+/-16 micrometer vs 33+/-3 micrometer) and the alveolar surface area [SA] was significantly smaller (646+/-72 cm2 vs 1,042+/-477 cm2) than those of the normoxia control group. The Lm of the BMMSC- infused groups was significantly shorter irrespective of infusion route (52+/-2 micrometer [IP], 50+/-8 micrometer [IT] vs 68+/-16 micrometer) and the SA of the BMMSC IP infusion group was significantly larger (646+/-172 cm2 vs 346+/-142 cm2) than those of the hyperoxia control group. The IT-, but not IP-, infused BMMSC groups were observed in lung tissue and assumed to be type I and type II alveolar epithelial cell phenotypes. CONCLUSION: BMMSC, when infused into neonatal rats exposed to hyperoxia, significantly attenuated the inhibition of alveolarization irrespective of the infusion route. It seems that BMMSC, when infused IT, engrafts into lung tissue and differentiates into alveolar epithelial cells. These results indicate that BMMSC could be considered as a potential candidate therapy for bronchopulmonary dysplasia.

A Comparison of Necrotizing Enterocolitis and Spontaneous Intestinal Perforation in Preterm infant

PURPOSE: Besides necrotizing enterocolitis (NEC), the most common cause of intestinal perforation in preterm infants, there is another condition called spontaneous intestinal perforation (SIP) which, though it does not have the clinical or histological nature of NEC has been reported with increasing tendency. Aims of this study are to analyze gastrointestinal perforation in preterm infants and to speculate any difference in clinical manifestations, perinatal histories, and laboratory results between NEC and SIP. METHODS: A retrospective review of medical records of preterm infants with gastrointestinal perforations in the neonatal intensive care unit of Seoul National University Children's Hospital between January 2000 and August 2007 was performed. Preterm infants who underwent surgical intervention, and who had available histologic specimens, were enrolled. RESULTS: A total of 29 preterm infants were enrolled. They were classified into three groups: Group NEC (n=18), Group SIP (n=6), and Group Others (n=5). Group Others consisted of two patients with ileal atresia, one with meconeum ileus, one with omphalocele and one with anal atresia. Onset of perforation was delayed in Group NEC compared with that of Group SIP (18.1+/-13.0 versus 6.7+/-4.2; P<0.05) and enteral feeding before perforation was more frequent in Group NEC (94.4% versus 50%; P<0.05). CONCLUSION: During seven years and eight months, there were six cases of SIP and 18 cases of NEC in preterm infants. As well as NEC, SIP should be considered when gastrointestinal perforation is suspected, especially when patients with early onset time and no enteral feeding.

Recent outcome of extremely low birth weight infants: The use of CRIB(clinical risk index for babies) II score for analyzing the survival rate / 소아과

PURPOSE: The survival rate of infants weighing less than 1,000 g at birth(extremely low birth weight infants, ELBWI) has increased due to recent advances in perinatal and neonatal intensive care. The purpose of this study was to evaluate the survival rates of ELBWI born at Seoul National University Hospital during the last six years. METHODS: A total of 99 infants were divided into three groups(period I : 2000 to 2001, period II: 2002 to 2003, period III: 2004 to 2005) based on date of birth. We compared the survival rate of ELBWI over the three periods, using CRIB II score for adjustment for clinical severity. RESULTS: Overall survival rate of ELBWI was 74.7 percent. The survival rate of ELBWI increased over the three periods(period I: 60.7 percent, period II : 73.3 percent, period III: 85.3 percent). The threshold of viability(defined as survival of at least 50 percent of infants) was 25 weeks of gestation and 600 g at birth. The birth weight-specific survival rates increased considerably over the three periods for infants < 750 g at birth(period I: 10 percent, period II: 46.2 percent, period III: 70.6 percent). The survival rates of ELBWI over the three periods increased much remarkably after adjustment for clinical severity by CRIB II score. CONCLUSION: In our institution, survival rates of ELBWI during the last six years continued to improve, particularly for infants weighing < 750 g at birth. This increase in survival rates was not associated with the clinical severity of ELBWI.

Frequency and Etiologies of Hypotension in Extremely Low Birth Weight Infants

PURPOSE:Hypotension is common in extremely low birth weight infants (ELBWI) and the treatment becomes important as the survival rate of ELBWI is increasing. This study is to investigate frequency and etiologies of hypotension in ELBWI. METHODS:40 patients admitted to the NICU of Seoul National University Children's Hospital from September 2004 to June 2006 were included retrospectively. Definition of hypotension was 1) mean arterial blood pressure below 30 mmHg or below the gestational age, 2) decreased urine output or metabolic acidosis, and 3) use of inotropics. Hydrocortisone was used for inotrope-resistant hypotension. Clinical characteristics of patients with hypotension were compared with those of others without hypotension. RESULTS:Mean gestational age and mean birth weight of 40 patients was 26(+6)+/-2(+1) weeks and 787+/-149 g. 20 patients had hypotension. 17 events were within 1 week of postnatal age, 5 from 1 to 2 weeks, and 9 after 2 weeks. The etiologies of hypotension within 1 week were PDA in 12 cases, and bleeding in 4 cases. PDA, post-operative condition, adrenocortical insufficiency, and sepsis were the probable etiologies of hypotension after 2 weeks. Among 12 patients recieved hydrocortisone, 9 responded to hydrocortisone. Patients with hypotension were significantly low in gestational age and birth weight. Incidence of IVH and ROP were significantly high in patients with hypotension. CONCLUSIONS:Hypotension was frequent in ELBWI and the etiologies of hypotension were various according to postnatal ages. Significant proportion of hypotension was inotrope-resistant in ELBWI. Further studies about etiologies are in need with reference of this study.

Perinatal Outcome in Preterm Infants with Abnormal Umbilical Artery Doppler Results : Emphasizing on Early Onset Thrombocytopenia and its Risk Factors

PURPOSE:Umbilical artery Doppler study is a commonly used non-invasive tool in high risk pregnancies because of its good correlation with the degree of placental insufficiency. We analyzed hematologic profiles and perinatal outcome of preterm infants with abnormal umbilical artery Doppler results and the risk factors of early onset thrombocytopenia. METHODS:We retrospectively reviewed the medical records of preterm infants under 35 weeks of gestational age at birth who were admitted to the neonatal intensive care unit of Seoul National University Children's Hospital from January 1, 2002 through December 31, 2004, and whose mothers had undergone umbilical artery Doppler studies within 5 days before delivery. Sixty two neonates were divided into three groups; the 1st group was defined as the patients with normal umbilical artery (UA) systolic/diastolic (S/D) ratio, the 2nd group, with increased UA S/D ratio above 95 percentile, and the 3rd, with absent or reversed end-diastolic flow (AREDF). RESULTS:Mean nucleated red blood cell (nRBC) counts per 100 white blood cells (WBCs) were 14.2 (0-150), 91.0 (0-262), 301.4 (6-884) (P<0.001), mean WBC counts were 10.8 (0- 34.1), 9.2(3.4-23.9), 5.9(0.5-15.2) (x1,000/mm(3)) (P=0.007), and mean platelet counts were 215.5+/-69.2, 185.9+/-96.7, 100.2+/-50.3 (x1,000/mL) (