Varicella exposure in a neonatal intensive care unit: emergency management and control measures

We describe an exposure of varicella zoster virus in our neonatal intensive-care unit and the emergency procedures instituted to prevent an outbreak. Fifty-seven infants and 129 staff members were exposed but none developed chickenpox. The measures included rapid identification of varicella antibody status in all neonates and those staff members with uncertain history of varicella infection; cohorting of exposed infants according to immune status; and prompt administration of varicella zoster immunoglobulin to susceptible patients. The recommendation of the American Academy of Pediatrics did not accurately predict the immune status of preterm infants, as only one of the eight susceptible infants would have qualified for immunoglobulin prophylaxis if their guidelines had been followed. Mass screening of all exposed infants using the varicella zoster enzyme linked immunosorbent assay (ELISA) test was the only reliable means of determining the immune status. Of the four risk factors evaluated for the prediction of antibody status: gestational age, postnatal age, birthweight and episodes of blood transfusion, only postnatal age was found to independently predict the immune status of our patients. Because varicella zoster susceptible staff members are difficult to identify on the basis of history, we suggest that prospective screening of staff in high-risk units be undertaken and vaccination with live varicella vaccine be offered to susceptibles.

Use of eyepatches in phototherapy: effects on conjunctival bacterial pathogens and conjunctivitis

We conducted a randomized controlled trial to determine the effects of eye occlusion on the risk of eye infection in full term newborn infants receiving phototherapy. Among 102 infants whose eyes were occluded with eyepatches, pathogens were isolated from 50 eyes of 33 infants. The positive isolation rate was significantly higher than that of a group of control infants (n = 101) whose eyes were protected by a headbox made of light-proof plastics. Among the latter group pathogens were detected in 22 eyes of 14 infants. In addition significantly more infants in the eyepatches group had purulent eye discharge (23 of 102 vs. 9 of 101, P = 0.013) and clinical conjunctivitis (13 of 102 vs. 2 of 101, P = 0.004) than the controls. Proper eye care is imperative when eyepatches are used on infants receiving phototherapy, and alternative methods of eye protection should be considered.

Isolated congenital tuberculosis otitis in a preterm infant

We report an unusual case of localized congenital tuberculosis otitis in a preterm infant. Unlike disseminated congenital cases, the manifestations of localized otitis are associated with a triad of signs: (i) regional lymphadenopathy in the absence of typical systemic features of tuberculosis; (ii) delayed onset of presentation; and (iii) refractory otitis unresponsive to conventional antimicrobial agents. The need for greater diligence in looking for neonatal tuberculosis is emphasized, especially in an ethnic or socioeconomic environment where the disease is prevalent.

Chest position and pulmonary deposition of surfactant in surfactant depleted rabbits

AIMS

To investigate the correlation between chest position and the distribution of surfactant in the lungs of surfactant depleted rabbits, to corroborate current guidelines on the intratracheal instillation of exogenous surfactant in newborns.

METHODS

Twelve tracheotomised rabbits, depleted of pulmonary surfactant by saline bronchoalveolar lavage, were given intratracheal 99m Technetium labelled Exosurf in three positions (prone, right side down, and left side down) (n = 4 in each group). They were monitored for 10 minutes using dynamic gamma scintigraphy monitoring. Instillation completed, the lateral lying animals were turned to the opposite side to determine whether redistribution of the surfactant had taken place. The amount of radiolabelled surfactant deposited at the peripheral, central, dorsal and ventral parts of the lungs was then estimated by gamma counting of the lung sections at necropsy.

RESULTS

Both gamma scintigraphy and gamma counting showed similar rates and total amount of surfactant accumulation in both lungs of the prone animals. In the lateral lying animals surfactant accumulated at a significantly faster rate in the dependent lungs: the amount of surfactant deposition was three to 14-fold that in the raised lungs (p = 0.017; nested ANOVA). Changing the chest position immediately after instillation did not redistribute the surfactant. In all three groups of animals there was no significant difference in deposition between the peripheral, central, ventral and dorsal parts of the lungs.

CONCLUSIONS

Pulmonary distribution of intratracheally instilled surfactant is largely determined by gravity, and changing the chest position after instillation does not result in any redistribution of the surfactant. During the instillation of exogenous surfactant to newborn infants, keeping the chest in the horizontal position may therefore result in the most even distribution of the surfactant in the two lungs. Further deposition studies are required to evaluate the validity of the current recommendations on surfactant administration.

Comparison of antithrombin III, protein C and protein S levels in capillary and venous blood of newborn infants

The plasma concentrations of antithrombin III, protein C and protein S in capillary and venous blood samples obtained simultaneously from 30 neonates were compared in order to determine the suitability of using capillary blood for estimation of these proteins with anticoagulant action. Our findings showed that while capillary and venous blood did not differ significantly in antithrombin III functional activity and protein C antigen levels, the capillary samples had significantly lower protein C functional activity and higher antithrombin III antigen level. Protein S antigen level was also significantly higher in the capillary samples although the difference was relatively small. The capillary and venous concentrations of the binding protein of protein S, C4b binding protein, were almost identical.

Preterm infants with patent ductus arteriosus: treatment with an enteral preparation of indomethacin

Forty-one preterm infants with a mean gestational age and birthweight of 29.7 weeks and 1322 g, respectively, were treated with an enteral preparation of indomethacin for the closure of haemodynamically significant patent ductus arteriosus. The indomethacin was prepared by diluting the content of the commercially available 25-mg indomethacin capsule with lactose by the method of trituration. The mixture was suspended in solution form just prior to administration to the infants. The ductus arteriosus was successfully closed in 29 infants, giving an overall success rate of 71%. The response to treatment was considered satisfactory, except for infants whose birthweights were less than 750 g. Only two infants (5%) developed major complications, both in the form of ileal perforation. As the outcome of treatment with this enteral preparation of indomethacin was comparable with that of the intravenous preparation reported in previous studies, it would be an acceptable alternative to the intravenous preparation in areas where the latter is not available or considered expensive.

Long-term survival of a baby with homozygous alpha-thalassemia-1

Triplets born to a Chinese woman consisted of 2 healthy boys and a girl with hemoglobin Bart's hydrops syndrome. The girl with hemoglobin Bart's hydrops syndrome, confirmed by gene analysis to be homozygous for alpha-thalassemia-1, survives for 27 months at the time of reporting. The dilemma in sustaining her life and the availability of other therapeutic options are briefly discussed. This is the third case report of homozygous alpha-thalassemia-1 with long-term survival.

A five-year prospective study of septicaemia in hospitalized children in Hong Kong

In a 5-year prospective study in a Hong Kong teaching hospital there were 344 clinically significant episodes of paediatric septicaemia. Many of the microbiological and clinical features were similar to those reported in Japanese and Western studies but there were some important differences. Half of the episodes (or 70% if neonatal infections are excluded) were community-acquired. The commonest organisms found were Salmonella spp (15% of all and 27% of community-acquired infections); this was related to the high local incidence of salmonellosis and typhoid fever. Salmonella typhi, which was responsible for one-third of the salmonella septicaemias, was usually seen in school-age children, while non-typhoid salmonellae were common in infants. Methicillin-resistant Staphylococcus aureus, which are now endemic in Hong Kong hospitals, was a common cause of hospital-acquired septicaemia. Pneumococcal septicaemia accounted for 22% of episodes in infants and pre-school children, but Haemophilus influenzae was uncommon (2% of all episodes) and there was no case of meningococcal septicaemia. The rarity of invasive infection with H. influenzae and Neisseria meningitidis in Hong Kong children is unexplained.

Megakaryocytic phagocytosis in a chromosomally normal neonate with transient myeloproliferative disorder

We report a case of transient myeloproliferative disorder (TMD) involving the megakaryocytic lineage in a cytogenetically normal newborn infant. Prominent megakaryocytic phagocytosis in the bone marrow was observed. This finding might suggest that TMD was due to a self-limiting malignant clone in myelopoiesis.

Echocardiography as a tool for determining the incidence of congenital heart disease in newborn babies: a pilot study in Hong Kong

We studied, with echocardiography as the main tool, the incidence of congenital heart disease in newborn babies in Hong Kong. The population examined was the 20,928 babies who were born alive in the Prince of Wales Hospital from January 1987 to December 1989. All had a thorough physical examination by a paediatrician after birth, and an estimated 95% of the babies who were discharged from hospital received another routine physical examination at one of the five local Maternal and Child Health Centres within two months of birth. All babies with either suspected congenital heart disease or multiple congenital abnormalities were referred to the paediatric cardiologists in the Prince of Wales Hospital for further cardiovascular assessment that included echocardiographic examination. In all, 492 babies had Doppler and cross-sectional echocardiographic studies. Various abnormalities of the cardiovascular system were diagnosed in 216 babies. Almost all the babies who died within two months of life underwent autopsy. This proved the presence of congenital cardiac malformations in 15 babies, of whom 10 had correct echocardiographic diagnoses during life. One had a patent arterial duct which was missed by the echocardiography. The other four babies did not have echocardiographic examination while alive, either because of early death or absence of clinical suspicion. In total, congenital cardiac malformations were confirmed in 221 babies by echocardiographic examination and autopsy. Excluding 82 premature babies with patency of the arterial duct, and 6 babies with transient tricuspid regurgitation, there were 133 cases of structural cardiac malformation in the studied population, giving an incidence of 6.35 per thousand live births.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of periventricular haemorrhage, post-haemorrhagic ventricular dilatation and periventricular leucomalacia in Chinese preterm infants

Serial cranial ultrasound scans were performed in 178 preterm Chinese infants (gestation less than 35 weeks, birthweight less than 2000 g) to study the incidence, age of onset and associating risk factors of periventricular haemorrhage (PVH), and also the occurrence of post-haemorrhagic ventricular dilatation and periventricular leucomalacia (PVL). Sixty-four infants developed haemorrhage, giving an incidence of 36%. Among infants of birthweight less than 1500 and less than 1000 g the respective incidence was 52 and 69%. Seventy-two per cent (46 of 64) of haemorrhages were initially detected within the first 3 days of life, but delayed haemorrhage occurring after 1 week of age occurred in nine infants. In eight of these infants PVH had been shortly preceded by a major clinical disaster. Eleven perinatal factors were found to be significantly associated with PVH but only systemic hypotension showed a significant independent association. Post-haemorrhagic ventricular dilatation developed in 17 (46%) of the 37 infants who survived for more than 1 month after PVH. This was transient in 41%, persistent but stable in 29% and progressive in 29%. PVL was detected in eight infants who survived the initial period following PVH.

Topical prostaglandin E2 gel for cervical ripening and closure of the ductus arteriosus in the newborn

The closure time of the ductus arteriosus was investigated in 29 full term babies born vaginally after induction with prostaglandin E2 and in 22 controls. Serial Doppler echocardiography studies showed a significantly prolonged closure time in babies induced by prostaglandin E2. Whether the difference is related to changes in fetal prostaglandin E2 concentration remains to be established.

Use of peripheral vessels for exchange transfusion

During a five and a half year period, exchange transfusions were performed through the peripheral vessels in 201 of the 214 infants (94%) who required either double volume or partial plasma exchange transfusions. Peripheral vessel exchange transfusion is simple, practicable, and safe with few complications. Technical difficulties in catheterizing the peripheral artery and vein may be overcome by using a 24 gauge catheter, which causes no more catheter induced haemolysis than standard umbilical catheters.

Incidence of ABO haemolytic disease of the newborn in a group of Hong Kong babies with severe neonatal jaundice

Two methods were used to determine the incidence of ABO haemolytic disease of the newborn (ABO-HDN) among Hong Kong Chinese infants. The first method employed the Lui elution technique to elute anti-A,B from cord blood of Group A and B babies with a Group O mother, and set out to correlate the titration score of the eluate with the serum bilirubin of the neonates. This method proved to be a failure because of the poor correlation. The second method was mathematical. By comparing the 'expected' frequency of various mother-infant ABO combinations (based on the ABO distribution of our local population) with the 'observed' frequency of a cohort of infants with severe neonatal jaundice, it was found that only two combinations (O-A and O-B mother-infant pairs) were responsible for ABO-HDN, for which the incidence was 1 in 5 among infants with a serum bilirubin level of 300 mumols/L or more.

Management of a hydropic infant with congenital heart block

A baby with congenital heart block and hydrops fetalis diagnosed prenatally was delivered at 36 weeks of gestation. Heart failure was controlled with temporary cardiac pacing which was complicated by perforation of the myocardium. She made an uneventful recovery after implantation of a permanent pacemaker. Sjögren's syndrome A antibodies were detected in her serum. Coincidentally, she also had pulmonary valvular stenosis as a structural abnormality.

Late metabolic acidosis and poor weight gain in moderately pre-term babies fed with a casein-predominant formula: a continuing need for caution

When our neonatal unit opened in 1984 our formula feeding policy for moderately preterm babies was for casein-predominant rather than "humanized" whey-predominant milk formulae to be given. However, an early cluster of cases of late persistent metabolic acidosis prompted an investigation into the acid-base status and weight gain in preterm infants. This study of 70 healthy, moderately preterm (32-35 weeks) Chinese babies has convincingly shown that a casein-predominant low protein formula is associated with significant metabolic acidosis, persisting sometimes for as long as 8 weeks, and poor weight gain when compared with infants fed on either a humanized or a special low-birthweight formula. This is an important message for the many neonatal units in developing countries where the cost of humanized formulae might initially seem prohibitive, encouraging instead casein-predominant formulae when breast milk is not available. Any additional expense incurred in using humanized formulae will be compensated for by the shortened time spent in hospital.

RNA-electrophoresis as a typing method for nosocomial rotavirus infection in a special-care baby unit

During January and February 1988 an outbreak of nosocomial rotavirus infection occurred in a special-care baby unit (SCBU). Seven infants were affected, of whom five had symptoms of diarrhoea. Typing by RNA electrophoresis (electropherotyping) demonstrated that a single rotavirus strain was responsible for the outbreak. The epidemic electropherotype was introduced by an infant with diarrhoea admitted directly into the SCBU from the community. Eight other electropherotypes were identified during January and February in patients with community-acquired rotavirus diarrhoea on other paediatric wards, but the outbreak strain occurred only on the SCBU. Electropherotyping is a useful and rapid method for tracing the epidemiology of hospital-acquired rotavirus infection.

A prospective study on the intrauterine growth of Hong Kong Chinese babies

A prospective study on the birth weight, crown-heel length and head circumference of 8,445 singleton Chinese newborn infants born between 27 and 42 weeks of gestation was conducted in three major regional maternity units in Hong Kong over a 3 1/2-year period. The data were used to construct centile charts for the intrauterine growth of each physical measurement. By careful gestational assessment of the infants, primary exclusion of pregnancies complicated by abnormal fetal or maternal conditions that might have affected fetal growth together with infants of doubtful maturity, these curves depict more accurately the prenatal growth of Chinese infants than those previously published in studies on similar populations of infants. Chinese infants, as shown by the findings of the present study, are similar in their mean weight to Japanese infants and American infants in Denver but are lighter than British and Australian infants, as well as American infants born at sea level.