Clinical profile, referral trends, and real-world application of vibration-controlled transient elastography in children with non-alcoholic fatty liver disease in Singapore

Background and Aim

Pediatric non-alcoholic fatty liver disease (NAFLD) is a progressive disorder that is increasing in incidence globally. The study aims to describe the clinical profile and longitudinal outcome, including the utility of vibration-controlled transient elastography (VCTE), in children with NAFLD at a single tertiary liver unit in Singapore.

Methods

Retrospective review of patients aged 0-18 years referred for NAFLD from 2003 to 2020 was conducted. Diagnosis was based on persistent elevation of alanine transaminase ≥2× the upper limit of normal in at-risk patients, and/or radiologic detection of hepatic steatosis, with the exclusion of other etiologies. VCTE-derived liver stiffness measurements (LSMs) ≤7.0 , 7.1-9.0, and ≥9.1 kPa were used to differentiate normal (F0-F1), significant fibrosis (F2), and advanced fibrosis (F3-F4), respectively.

Results

The study included 210 patients (72.4% male, mean age 11.6 years). New cases increased from 1.7/1000 referrals in 2003-2008 to 12.7 and 24.5/1000 referrals in 2009-2014 and 2015-2020, respectively. Significant proportion had dyslipidemia (41.4%), impaired glucose tolerance/diabetes (IGT/DM, 26.7%), and hypertension (17.1%). Only 6.2% had resolution of NAFLD after a mean follow-up of 3.7 years. Based on VCTE (n = 65), 41.5% had normal LSM, while 26.2% and 32.3% had increased likelihood of significant and advanced fibrosis, respectively. Age ≥16 years (odds ratio [OR] 8.9), IGT/DM (OR 6.5), and aspartate transaminase >70 U/L (OR 11.0) were independent risk factors associated with increased likelihood of advanced fibrosis.

Conclusion

Incidence of pediatric NAFLD has increased dramatically in Singapore. Based on LSM estimation, pediatric NAFLD may be associated with an increased risk of developing advanced fibrosis by late adolescence.

Demographics, aetiology and outcome of paediatric acute liver failure in Singapore

Introduction

The aetiology of paediatric acute liver failure (PALF) varies widely according to age, and geographic and socioeconomic factors. This study aimed to examine the epidemiology, aetiology and outcome of PALF in Singapore at a single centre.

Methods

A retrospective review was performed of patients aged 0-18 years who were diagnosed with PALF from 2007 to 2019. PALF was defined by: absence of chronic liver disease; biochemical evidence of acute liver injury; and coagulopathy, non-correctible by vitamin K, defined as prothrombin time (PT) ≥20 seconds or international normalised ratio (INR) ≥2.0 regardless of hepatic encephalopathy (HE) or PT ≥15 seconds or INR ≥1.5 in the presence of HE.

Results

34 patients were included. Median age at diagnosis was 10 months (range 7 days to 156 months). The top three causes of PALF were indeterminate (41.2%), metabolic (26.5%) and infectious (26.5%) aetiologies. A metabolic disorder was the most frequent aetiology in infants <12 months (38.9%), whereas an indeterminate cause was the most common in children >12 months (50%). No cases of viral hepatitis A or B presenting with PALF were detected. Overall spontaneous recovery rate (survival without liver transplantation [LT]) was 38.2%, and overall mortality rate was 47.1%. Six patients underwent living-donor LT, and the post-transplant survival at one year was 83.3%.

Conclusion

The aetiologic spectrum of PALF in Singapore is similar to that in developed Western countries, with indeterminate aetiology accounting for the majority. PALF is associated with poor overall survival; hence, timely LT for suitable candidates is critical to improve survival outcomes.

Hepatocellular Carcinoma in the Absence of Cirrhosis in a Child With Inactive Chronic Hepatitis B Infection

Chronic hepatitis B infection has been identified as an important risk factor for developing hepatocellular carcinoma (HCC) especially in the presence of hepatitis and liver cirrhosis. However, here we describe an unusual case of a child with chronic hepatitis B infection who developed HCC in the absence of active hepatitis or cirrhosis. This case serves to highlight the importance of regular HCC surveillance for all children with chronic hepatitis B, regardless of presence or absence of hepatitis or cirrhosis.

From the 20th to the 21st century: the first 100 years of paediatrics in Singapore

In Singapore, paediatrics as a separate discipline was started in 1921 at Singapore General Hospital (SGH). From Mistri Wing to Alexandra Hospital (AH) and Tan Tock Seng Hospital (TTSH), paediatrics was started at National University Hospital (NUH) and the Children’s Hospital at KK Women’s and Children’s Hospital (KKH) from 1997. After World War II, neonatology started in KKH, followed by Toa Payoh Hospital (TPH), AH, NUH and SGH. Neonates from TPH and AH were moved to KKH in 1990. Our pioneering giants include Dr Gopal Haridas, Professors Wong Hock Boon (First Paediatrics Professor), Tan Cheng Lim and Tan Kim Leong. Paediatrics in Singapore is resplendent with many achievements. Prof Wong identified the relationship of hyperbilirubinaemia/kernicterus with glucose-6-phosphate dehydrogenase (G6PD) deficiency and initiated G6PD deficiency screening. This has saved many lives and improved the overall health of children in Singapore. 100 years on, we stand firmly on the shoulders of our pioneering clinician giants as we face the paediatric millennial health needs of this new century.

Analysis of Cholangitis Rates with Extended Perioperative Antibiotics and Adjuvant Corticosteroids in Biliary Atresia

PURPOSE

There is no consensus regarding adjuvant therapies following Kasai portoenterostomy (KP) for biliary atresia (BA). This study aimed to analyze the effect of extended perioperative intravenous antibiotics (PI-Abx) and adjuvant corticosteroid on cholangitis and jaundice clearance rates in the 3 years post-KP in children with BA.

METHODS

Data of patients who underwent KP between 1999-2018 at a single center were retrospectively analyzed. Group A (1999-2010) received PI-Abx for 5 days, Group B (2010-2012) received PI-Abx for 5 days plus low-dose prednisolone (2 mg/kg), and Group C (2012-2017) received PI-Abx for 14 days plus high-dose prednisolone (5 mg/kg).

RESULTS

Fifty-four patients were included with groups A, B, and C comprising 25, 9, and 20 patients, respectively. The number of episodes of cholangitis was 1.0, 1.6, and 1.3 per patient (p=NS) within the first year and 1.8, 2.3, and 1.7 (p=NS) over 3 years in Groups A, B, and C, respectively. The jaundice clearance rate at 6 months was 52%, 78%, and 50% (p=NS), and the 3-year native liver survival (NLS) rate was 76%, 100%, and 80% (p=NS) in Groups A, B, and C, respectively. A near-significant association was observed between the incidence of cholangitis within the first year and decompensated liver cirrhosis/death at 3 years post KP (p=0.09). Persistence of jaundice at 6 months was significantly associated with decompensated cirrhosis/death at 3 years (p<0.001).

CONCLUSION

The extended duration of PI-Abx and adjuvant corticosteroids was not associated with improved rates of cholangitis, jaundice clearance, or NLS in patients with BA.

Liver transplantation in children: the Singapore experience

Paediatric liver transplantation has come a long way since its acceptance as a treatment option for children with end-stage liver disease. From 1990 to 2020, a total of 434 liver transplants were performed in National University Hospital, Singapore, out of which 143 were performed in children. The majority of the liver grafts were from living donors, mainly the parents. Our long-term survival rates are comparable to those of major transplant centres worldwide. These patients usually have a productive and good quality of life.

Paediatric gastroenterology in Singapore: historical aspects and recent advances

Paediatric gastroenterology in Singapore began in the 1970s. Led by Professor Phua Kong Boo and Professor Quak Seng Hock, paediatric gastroenterology has enjoyed significant strides in the areas of diagnostics, interventions, patient care and research. Several advances such as endoscopy, parenteral nutrition and liver transplantation are well established. The first paediatric small bowel transplant is anticipated in the next decade. Robust research activities have ensured the generation of local data on gastrointestinal disorders. One such research led to the discovery of the changing trends in the incidence of inflammatory bowel disease among the paediatric population in Singapore. The impact of the nation’s paediatric gastroenterology extends internationally, with the notable involvement of Professor Phua in developing the rotavirus vaccine trials and other ongoing collaborative work with international centres. This review explores the history of paediatric gastroenterology from its origins to its remarkable transformation over the decades as centres of excellence in the region.

Heterozygous missense variant in EIF6 gene: A novel form of Shwachman-Diamond syndrome?

Shwachman-Diamond syndrome (SDS) is a rare multisystem ribosomal biogenesis disorder characterized by exocrine pancreatic insufficiency, hematologic abnormalities and bony abnormalities. About 90% of patients have biallelic mutations in SBDS gene. Three additional genes-EFL1, DNAJC21 and SRP54 have been reported in association with a SDS phenotype. However, the cause remains unknown for ~10% of patients. Herein, we report a 6-year-old Chinese boy, who presented in the neonatal period with pancytopenia, liver transaminitis with hepatosplenomegaly and developmental delay, and subsequently developed pancreatic insufficiency complicated by malabsorption and poor growth. Exome sequencing identified a novel de novo heterozygous variant in EIF6 (c.182G>T, p.Arg61Leu). EIF6 protein inhibits ribosomal maturation and is removed in the late steps of ribosomal maturation by SBDS and EFL1 protein. Given the interaction of EIF6 with SBDS and EFL1, we postulate heterozygous variants in EIF6 as a novel cause of Shwachman-Diamond-like phenotype. We compared the phenotype of our patient with those in patients with mutation in SBDS, EFL1, DNAJC21, and SRP54 genes to support this association. Identification of more cases of this novel phenotype would strengthen the association with the genetic etiology.

Conjugated hyperbilirubinemia presenting in first fourteen days in term neonates

AIM

To describe the etiology and characteristics of early-onset conjugated hyperbilirubinemia (ECHB) presenting within 14 d of life in term neonates.

METHODS

Retrospective review was performed of term infants up to 28-d-old who presented with conjugated hyperbilirubinemia (CHB) at a tertiary center over a 5-year period from January 2010 to December 2014. CHB is defined as conjugated bilirubin (CB) fraction greater than 15% of total bilirubin and CB greater or equal to 25 μmol/L. ECHB is defined as CHB detected within 14 d of life. “Late-onset” CHB (LCHB) is detected at 15-28 d of life and served as the comparison group.

RESULTS

Total of 117 patients were recruited: 65 had ECHB, 52 had LCHB. Neonates with ECHB were more likely to be clinically unwell (80.0% vs 42.3%, P < 0.001) and associated with non-hepatic causes (73.8% vs 44.2%, P = 0.001) compared to LCHB. Multifactorial liver injury (75.0%) and sepsis (17.3%) were the most common causes of ECHB in clinically unwell infants, majority (87.5%) had resolution of CHB with no progression to chronic liver disease. Inborn errors of metabolism were rare (5.8%) but associated with high mortality (100%) in our series. In the subgroup of clinically well infants (n = 13) with ECHB, biliary atresia (BA) was the most common diagnosis (61.5%), all presented initially with normal stools and decline in total bilirubin but with persistent CHB.

CONCLUSION

Secondary hepatic injury is the most common reason for ECHB. BA presents with ECHB in well infants without classical symptoms of pale stools and deep jaundice.

Seventeen years of Kasai portoenterostomy for biliary atresia in a single Southeast Asian paediatric centre

AIM

Biliary atresia (BA) has preponderance in Asian populations with Kasai portoenterostomy (KP) regarded as the first-line standard of care. Yet reports from Southeast Asia remain scant. This study reviews the demographics, short- and medium-term outcomes for our cohort, and evaluates prognostic factors for outcome.

METHODS

All patients diagnosed with BA between January 1997 and December 2013 were included. Clinical data were obtained from medical records. Jaundice clearance was defined as total bilirubin < 20 µmol/L within 6 months after KP. Two-year and 5-year native liver survival (NLS) were determined. Prognostic factors examined included gender, ethnicity, associated anomalies, age at KP, post-KP cholangitis and clearance of jaundice within 6 months.

RESULTS

Of 58 patients studied, 31(53.4%) were male. Median age at time of KP was 53 days (range: 28-127). Ethnic distribution showed 32 (55.2%) Chinese, 16 (27.6%) Malays and 10 (17.2%) others. Twenty-one (36.2%) patients achieved jaundice clearance by 6 months. Two-year NLS rate was 36 out of 50 (72%), while 5-year NLS rate was 16 out of 35 (45.7%). Only clearance of jaundice within 6 months had a significant association with NLS (P = 0.006). All other factors showed no significant impact on outcome.

CONCLUSIONS

Our short- and medium-term outcomes after KP for BA are comparable with those reported by most international centres. However, prognostic factors such as age at KP, cholangitis episodes and associated anomalies did not show significant correlation; only clearance of jaundice within 6 months was significantly predictive of NLS.

Prolonged hepatitis and jaundice: a rare complication of paediatric Epstein-Barr virus infection

We herein report the case of a 14-year-old girl with Epstein-Barr virus (EBV) infectious mononucleosis who developed prolonged hepatitis and jaundice. At presentation, she had tender hepatomegaly with a markedly deranged liver function test. Abdominal ultrasonography showed hepatomegaly and a thickened gallbladder wall. During the subsequent 11 weeks, her transaminases showed two further peaks, which corresponded with clinical deterioration. Her highest alanine transaminase level was 1,795 µ/L and total bilirubin level was 154 µmol/L. She recovered fully with conservative management. EBV-related liver involvement is typically mild and self-limiting. We believe that tender hepatomegaly and gallbladder thickening may be important predictors of significant liver involvement. Although multiple transaminase peaks may occur, we do not consider this an indication for antiviral or immunosuppressive therapy. In the absence of strong evidence supporting the use of any specific therapy, we recommend a conservative approach for an immunocompetent patient.

Incidence of rotavirus gastroenteritis by age in African, Asian and European children: Relevance for timing of rotavirus vaccination

Variability in rotavirus gastroenteritis (RVGE) epidemiology can influence the optimal vaccination schedule. We evaluated regional trends in the age of RVGE episodes in low- to middle- versus high-income countries in three continents. We undertook a post-hoc analysis based on efficacy trials of a human rotavirus vaccine (HRV; Rotarix™, GSK Vaccines), in which 1348, 1641, and 5250 healthy infants received a placebo in Europe (NCT00140686), Africa (NCT00241644), and Asia (NCT00197210, NCT00329745). Incidence of any/severe RVGE by age at onset was evaluated by active surveillance over the first two years of life. Severity of RVGE episodes was assessed using the Vesikari-scale. The incidence of any RVGE in Africa was higher than in Europe during the first year of life (≤2.78% vs. ≤2.03% per month), but much lower during the second one (≤0.86% versus ≤2.00% per month). The incidence of severe RVGE in Africa was slightly lower than in Europe during the first year of life. Nevertheless, temporal profiles for the incidence of severe RVGE in Africa and Europe during the first (≤1.00% and ≤1.23% per month) and second (≤0.53% and ≤1.13% per month) years of life were similar to those of any RVGE. Any/severe RVGE incidences peaked at younger ages in Africa vs. Europe. In high-income Asian regions, severe RVGE incidence (≤0.31% per month) remained low during the study. The burden of any RVGE was higher earlier in life in children from low- to middle- compared with high-income countries. Differing rotavirus vaccine schedules are likely warranted to maximize protection in different settings.

Efficacy, Immunogenicity and Safety of a Human Rotavirus Vaccine RIX4414 in Singaporean Infants

INTRODUCTION

This was the first study conducted to evaluate the efficacy of 2 oral doses of the human rotavirus vaccine, RIX4414 in Singaporean infants during the first 3 years of life.

MATERIALS AND METHODS

Healthy infants, 11 to 17 weeks of age were enrolled in this randomised (1:1), double-blinded, placebo-controlled study to receive 2 oral doses of RIX4414 vaccine/placebo following a 0-, 1-month schedule. Vaccine efficacy against severe rotavirus (RV) gastroenteritis (Vesikari score ≥11) caused by wild-type RV strains from a period starting from 2 weeks post-Dose 2 until 2 and 3 years of age was calculated with 95% confidence interval (CI). Immunogenicity and safety of the vaccine were also assessed.

RESULTS

Of 6542 infants enrolled, 6466 were included in the efficacy analysis and a subset of 100 infants was included in the immunogenicity analysis. Fewer severe RV gastroenteritis episodes were reported in the RIX4414 group when compared to placebo at both 2 and 3 year follow-up periods. Vaccine efficacy against severe RV gastroenteritis at the respective time points were 93.8% (95% CI, 59.9 to 99.9) and 95.2% (95% CI, 70.5 to 99.9). One to 2 months post-Dose 2 of RIX4414, 97.5% (95% CI, 86.8 to 99.9) of infants seroconverted for anti-RV IgA antibodies. The number of serious adverse events recorded from Dose 1 until 3 years of age was similar in both groups.

CONCLUSION

Two oral doses of RIX4414 vaccine was immunogenic and provided high level of protection against severe RV gastroenteritis in Singaporean children, during the first 3 years of life when the disease burden is highest.

Paediatric inflammatory bowel disease in a multiracial Asian country

INTRODUCTION

This study examined the characteristics and trends in the incidence of inflammatory bowel disease (IBD) among children in Singapore.

METHODS

We retrospectively reviewed all patients under 18 years diagnosed with IBD over a 14-year period. Information on demographics, disease presentation, laboratory findings, radiological investigations, and endoscopic and histological findings were obtained from the patients' medical records.

RESULTS

32 patients were diagnosed with IBD, 30 of whom had Crohn's disease and 2 had ulcerative colitis. The incidence of IBD rose from an initial rate of 2.2 per 100,000 patients in the year 2000 to a peak of 11.4 patients per 100,000 patients by 2008. Median age of onset of symptoms was 10.5 years. There were more boys (63%) than girls in the group and a higher representation of Indians (34.4%). The most common presenting symptoms were abdominal pain (87.5%), diarrhoea (75.0%) and weight loss (71.9%). Extraintestinal manifestations such as fever and arthralgia were found in over 50% of patients. The most common physical findings were perianal abnormalities (56.3%), mouth ulcers (37.5%) and growth failure (15.6%). Abnormal laboratory findings such as low albumin, raised erythrocyte sedimentation rate, anaemia, thrombocytosis and high C-reactive protein were found in nearly half of the patients. Endoscopic and histological findings showed that a majority of patients (90.6%) also had evidence of inflammation in the upper gastrointestinal tract.

CONCLUSION

Paediatric IBD is on the rise. The higher occurrence in Indians, earlier onset and more florid presentation may suggest different genetic and environmental influences specific to Asian children.

Incidence of intussusception in Singaporean children aged less than 2 years: a hospital-based prospective study

Background

Continuous surveillance for intussusception (IS) is important for monitoring the safety of second-generation rotavirus vaccines. The present study aimed to assess the incidence of IS in Singaporean children aged < 2 years.

Methods

This was a prospective, hospital-based, multi-center surveillance conducted in seven hospitals - two public hospitals and five private medical centers between May 2002 and June 2010 in Singapore. Diagnosis of IS (definite, probable, possible, suspected) was based on the case definition developed by the Brighton Collaboration. Children < 2 years of age who were diagnosed with IS were enrolled in this study. Incidence of IS was calculated per 100,000 child-year with its 95% confidence interval.

Results

Of the 178 children enrolled, 167 children with definite IS cases were considered for final analyses; 11 were excluded (six diagnosed as probable IS and four diagnosed as suspected IS; one child’s parents withdrew consent). Mean age of children with definite IS was 11.6 ± 6 months; 67.7% were males. The overall incidence of IS was 28.9 (95% CI: 23.0–34.8) and 26.1 (95% CI: 22.2–30.0) per 100,000 child-year in children < 1 year and < 2 years of age, respectively. The majority of IS cases (20 [12.0%]) were reported in children aged 6 months. Most children (98.2% [164/167]) recovered, two (1.2%) children recovered with sequelae and one (0.6%) child died of septic shock.

Conclusions

The incidence of IS remained low and stable in Singaporean children aged < 2 years during the study period (May 2002 to June 2010).

Trial registration

NCT01177839

Cap polyposis: A rare cause of rectal bleeding in children

AIM: To evaluate the clinicopathological features and treatment outcomes of cap polyposis in the pediatric population.

METHODS: All pediatric patients with histologically proven diagnosis of cap polyposis were identified from our endoscopy and histology database over a 12 year period from 2000-2012 at our tertiary pediatric center, KK Women’s and Children’s Hospital in Singapore. The case records of these patients were retrospectively reviewed. The demographics, clinical course, laboratory results, endoscopic and histopathological features, treatments, and outcomes were analyzed. The study protocol was approved by the hospital institutional review board. The histological slides were reviewed by a pediatric histopathologist to confirm the diagnosis of cap polyposis.

RESULTS: Eleven patients were diagnosed with cap polyposis. The median patient age was 13 years (range 5-17 years); the sample included 7 males and 4 females. All of the patients presented with bloody stools. Seven patients (63%) had constipation, while 4 patients (36%) had diarrhea. All of the patients underwent colonoscopy and polypectomies (excluding 1 patient who refused polypectomy). The macroscopic findings were of polypoid lesions covered by fibrinopurulent exudates with normal intervening mucosa. The rectum was the most common involvement site (n = 9, 82%), followed by the rectosigmoid colon (n = 3, 18%). Five (45%) patients had fewer than 5 polyps, and 6 patients (65%) had multiple polyps. Histological examination of these polyps showed surface ulcerations with a cap of fibrin inflammatory exudate. Four (80%) patients with fewer than 5 polyps had complete resolution of symptoms following the polypectomy. One patient who did not consent to the polypectomy had resolution of symptoms after being treated with sulphasalazine. All 6 patients with multiple polyps experienced recurrence of bloody stools on follow-up (mean = 28 mo).

CONCLUSION: Cap polyposis is a rare and under-recognised cause of rectal bleeding in children. Our study has characterized the disease phenotype and treatment outcomes in a pediatric cohort.

Journey of KK Children's Hospital — Collective Memories

This paper presents the collective memories of many individuals who were closely associated with the growth and development of the Children's Hospital. It is based on the perspective of the authors' personal recollections and by no means the whole of this exciting story. The focus is on the development of paediatric medicine in KK Women's and Children's Hospital (KKH). Neonatology will be discussed in a separate paper.

Obstructive Uropathy in a Child with Severe Chronic Constipation

Urinary symptoms are well-described in children with chronic constipation which include enuresis, urgency and recurrent urinary infections. Renal tract obstruction is a rare complication of severe chronic constipation. We describe a case of a 10-year-old boy with a history of long-standing constipation who presented with obstructive uropathy. Treatment strategies involved intensive medical therapy, parental education, behaviour modification strategies and close follow-up in a specialised constipation clinic. The obstruction was reversed and medications were discontinued after six months. Successful management of children with chronic constipation involves a multi-disciplinary approach in a specialised constipation clinic.

Safety and reactogenicity of DTPa-HBV-IPV/Hib and DTPa-IPV/I-Hib vaccines in a post-marketing surveillance setting

Combination vaccines have been shown to improve the timeliness of vaccination and vaccine coverage. Safety and reactogenicity of combined diphtheria-tetanus-acellular pertussis-inactivated poliovirus and Haemophilus influenzae type b vaccine (DTPa-IPV/Hib, Infanrix IPV+Hib, GlaxoSmithKline Biologicals) was assessed in two clinical studies. In Study A, 2,590 subjects received DTPa-IPV/Hib at 3, 4 and 5 months of age with a booster at 18 months. In Study B, 702 subjects received the same schedule but with DTPa-hepatitis B-IPV/Hib (DTPa-HBV-IPV/Hib, Infanrix hexa, GlaxoSmithKline Biologicals) vaccine administered at 5 months of age. Reactogenicity was assessed for four days after each dose using diary cards. Serious adverse events (SAEs) were assessed until 24 months of age. The vaccines were well tolerated. After primary vaccination, irritability was the most frequently reported grade 3 general symptom (0.8% of doses in both studies). Fever (axillary) > 39 degrees C was infrequent (0.3% of doses in Study A; 0.5% of doses in Study B). After the booster dose, the most frequently reported grade 3 symptom was redness (5%) in Study A and pain (0.5%) in Study B. An axillary temperature > 39 degrees C was reported in 1.1% of subjects. Throughout the study period, 646 SAEs were reported, of which 6 SAEs were considered to be vaccination-related. The reactogenicity and safety profile of the combined DTPa-IPV/Hib vaccine was good when used for primary and booster vaccinations in over 3,000 Singaporean infants. Substitution of DTPa-IPV/Hib with DTPa-HBV-IPV/Hib at Month 5 reduced the number of injections required at this age by one.

Immunogenicity, Reactogenicity and Safety of a Diphtheria-Tetanus-Acellular Pertussis-Inactivated Polio and Haemophilus Influenzae Type b Combination Vaccine in a Placebo-controlled Rotavirus Vaccine Study

Introduction: In recent years, acellular pertussis combination vaccines have facilitated compliance with and coverage of the national immunisation programme in Singapore. This phase-II study (Rota-007) evaluated the immunogenicity, reactogenicity and safety of a DTPaIPV/Hib combined vaccine when co-administered with a rotavirus vaccine. Materials and Methods: A total of 2464 children aged 3 months were vaccinated with DTPa-IPV/Hib together with a randomised 1:3 ratio of either placebo (n = 653) or 1 of 3 different formulations of a rotavirus vaccine. Blood samples were collected for immunogenicity analysis 1 month after the third DTPa-IPV/Hib vaccine dose in a subset of subjects (n = 640). Local and general reactogenicity and unsolicited adverse events were recorded during the follow-up after each vaccination. Results: Serological analysis showed >95% response for all antigens in the co-administered DTPa-IPV/Hib vaccine, with no difference between the rotavirus vaccine and placebo groups. No differences in adverse events and reactogenicity were reported in the rotavirus vaccine and placebo groups. Only 0.2% of the subjects reported Grade 3 adverse events. Three subjects (from the vaccine groups) died during the study, which were assessed by the investigators as unrelated to vaccination. No deaths were reported in the placebo group. Conclusion: The combined DTPaIPV/Hib vaccine is safe, well tolerated and highly immunogenic when given alone or coadministered with the rotavirus vaccine for infants in Singapore. Key words: Paediatric, Vaccination

Immunogenicity, reactogenicity and safety of a diphtheria-tetanus-acellular pertussis-inactivated polio and Haemophilus influenzae type b vaccine in a placebo-controlled rotavirus vaccine study

INTRODUCTION

In recent years, acellular pertussis combination vaccines have facilitated compliance with and coverage of the national immunisation programme in Singapore. This phase-II study (Rota-007) evaluated the immunogenicity, reactogenicity and safety of a DTPa-IPV/Hib combined vaccine when co-administered with a rotavirus vaccine.

MATERIALS AND METHODS

A total of 2464 children aged 3 months were vaccinated with DTPa-IPV/Hib together with a randomised 1:3 ratio of either placebo (n=653) or 1 of 3 different formulations of a rotavirus vaccine. Blood samples were collected for immunogenicity analysis 1 month after the third DTPa-IPV/Hib vaccine dose in a subset of subjects (n = 640). Local and general reactogenicity and unsolicited adverse events were recorded during the follow-up after each vaccination.

RESULTS

Serological analysis showed >95% response for all antigens in the co-administered DTPa-IPV/Hib vaccine, with no difference between the rotavirus vaccine and placebo groups. No differences in adverse events and reactogenicity were reported in the rotavirus vaccine and placebo groups. Only 0.2% of the subjects reported Grade 3 adverse events. Three subjects (from the vaccine groups) died during the study, which were assessed by the investigators as unrelated to vaccination. No deaths were reported in the placebo group.

CONCLUSION

The combined DTPa- IPV/Hib vaccine is safe, well tolerated and highly immunogenic when given alone or coadministered with the rotavirus vaccine for infants in Singapore.

The epidemiology of paediatric intussusception in Singapore: 1997 to 2004

INTRODUCTION

The world's first rotavirus vaccine, Rotashield or RRV-TV, was registered in the US in 1998, but withdrawn within a year because of an observed association with intussusception (IS). Surveillance for IS has consequently become important in safety monitoring of new-generation rotavirus vaccines during development. Post-marketing surveillance is also important, and requires the availability of local baseline epidemiology data on IS.

MATERIALS AND METHODS

An eight-year study of IS in children under 2 years of age in Singapore was performed by retrospective review of admissions to KK Women's and Children's Hospital, the main paediatric hospital, from 1997 to 2001, followed by prospective surveillance of all hospitals from 2001 to 2004, using the case definition of the Brighton Collaboration Intussusception Working Group.

RESULTS

The average IS incidence was 60 per 100,000 in under-ones, and 32 per 100,000 in under-twos, with a downward trend between 1999 and 2004. Ninety-two per cent of subjects were aged below one year, with 51% aged 6 months to 11 months. The mean age at which IS occurred increased from 6.4 months to 12.5 months over the study period. The male-to-female ratio was 1.3:1. No trend in IS numbers was observed over different months of the year.

CONCLUSION

IS in Singapore shows no seasonality, but has demonstrated a trend of decreasing incidence in recent years. While highest in the first year of life, the risk of IS is increasing in the second year of life. Males have a slightly higher risk.

Outcome of liver transplantation for children with liver disease

INTRODUCTION

The advent of liver transplantation has revolutionised the outcome of children with both acute liver failure and chronic end-stage liver disease. The aim of this study was to review the outcome of all paediatric liver transplants performed since the National Liver Transplant Programme began in 1990.

METHODS

A retrospective review of all paediatric liver transplants from 1990 to December 2004 was performed.

RESULTS

46 liver transplants were performed in 43 children, of whom 23 (53.3 percent) were female. Median age at transplant was 21 months (range 11 months to 14 years). The most common indication for liver transplant was biliary atresia (71.7 percent). Living-related transplants accounted for 63 percent (29). Re-transplant rate was 6.5 percent with allograft loss as a result of hepatic artery thrombosis (two) and hepatic vein thrombosis (one). Tacrolimus was the primary immunosuppressive agent used in 89 percent of patients, with a 19.6 percent incidence of acute allograft rejection within the first six months. There were nine deaths. They were related to portal vein thrombosis (three), chronic rejection (one), sepsis (two), post-transplant lymphoproliferative disease (two) and primary graft non-function (one). Overall actuarial one- and five-year survival rate was 85.7 percent and 81.8 percent, respectively.

CONCLUSION

Liver transplantation is an established form of intervention for end-stage liver disease and a variety of liver-related metabolic disease. Our results are comparable to those of well-established liver transplant centres.

A short report on highlights of worldwide development of RIX4414: A Singaporean experience

In Singapore, we conducted a phase II randomized, double-blind, placebo-controlled dose ranging study using an attenuated human rotavirus vaccine, RIX4414. Altogether, 2464 healthy infants were recruited. Two oral doses of vaccine at 104.7, 105.2 or 106.1 ffu or placebo were administered with routine immunizations at 3 and 4 months of age. Seroconversion and 'vaccine take' in the vaccine groups 1-month post dose 2 varied from 76 to 91% and 98 to 100% respectively. Vaccine was well tolerated and did not interfere with response of concomitantly administered vaccines.

A Rotavirus Vaccine for Infants: The Asian Experience

Introduction: Severe rotavirus gastroenteritis in children causes significant morbidity world- wide and substantial deaths in developing countries. Hence, a live attenuated vaccine Rotarix™ was developed with human strain RIX4414 of G1P1A P[8] specificity. RIX4414 trials in infants have begun in developed and developing countries worldwide. An overview of RIX4414 in developed and developing countries and prospects with this vaccine in Asia are presented. Methods: Completed RIX4414 trials have been reviewed. Results: Two oral doses of RIX4414 were well tolerated with a reactogenicity profile similar to placebo. RIX4414 was also highly immunogenic, e.g., in a dose-ranging study conducted in Singapore, 98.8% to100% of infants had a vaccine take after 2 doses. RIX4414 did not affect the immune response of simultaneously administered routine infant vaccines. RIX4414 significantly reduced severe rotavirus gastroen- teritis in settings where multiple serotypes including the emerging G9 type co-circulated. Conclusion: These encouraging results warrant further evaluation of the vaccine worldwide and especially in developing countries with the highest need. Therefore, evaluation of the Rotarix™ vaccine is continuing in large phase III trials in Asia and worldwide. Key words: Asia, Attenuated, Developing countries, Gastroenteritis, RIX4414

A rotavirus vaccine for infants: the Asian experience

INTRODUCTION

Severe rotavirus gastroenteritis in children causes significant morbidity worldwide and substantial deaths in developing countries. Hence, a live attenuated vaccine Rotarix was developed with human strain RIX4414 of G1P1A P[8] specificity. RIX4414 trials in infants have begun in developed and developing countries worldwide. An overview of RIX4414 in developed and developing countries and prospects with this vaccine in Asia are presented.

METHODS

Completed RIX4414 trials have been reviewed.

RESULTS

Two oral doses of RIX4414 were well tolerated with a reactogenicity profile similar to placebo. RIX4414 was also highly immunogenic, e.g., in a dose-ranging study conducted in Singapore, 98.8% to 100% of infants had a vaccine take after 2 doses. RIX4414 did not affect the immune response of simultaneously administered routine infant vaccines. RIX4414 significantly reduced severe rotavirus gastroenteritis in settings where multiple serotypes including the emerging G9 type co-circulated.

CONCLUSION

These encouraging results warrant further evaluation of the vaccine worldwide and especially in developing countries with the highest need. Therefore, evaluation of the Rotarix vaccine is continuing in large phase III trials in Asia and worldwide.

Evaluation of RIX4414, A Live, Attenuated Rotavirus Vaccine, in a Randomized, Double‐Blind, Placebo‐Controlled Phase 2 Trial Involving 2464 Singaporean Infants

BACKGROUND

At present, no rotavirus vaccine is commercially available for use worldwide. Hence, a live, attenuated monovalent vaccine was developed with human strain RIX4414 (G1P1A P[8] specificity). Vaccination trials involving infants are ongoing in developed and developing countries.

METHODS

This study was a randomized, double-blind, placebo-controlled trial conducted at pediatric hospitals and polyclinics in Singapore for the evaluation of the immunogenicity, reactogenicity, and efficacy of 2 oral doses of RIX4414. In total, 2464 healthy infants (who were 11-17 weeks old when the first dose was administered, which is in accordance with the local immunization schedule) were enrolled to receive RIX4414 at 3 concentrations of virus (10(4.7), 10(5.2), or 10(6.1) focus-forming units) or placebo at 1-month intervals, concomitantly with routinely administered infant vaccines.

RESULTS

The RIX4414 vaccine was highly immunogenic, and virtually all vaccine recipients (98%-100%) experienced "vaccine take" (i.e., a combined immunogenicity end point based on seroconversion and/or shedding of RIX4414 in postvaccination stool samples) after receipt of 2 doses at all 3 dosage levels. Depending on the virus concentration, the anti-rotavirus IgA seroconversion rate varied from 76% (95% confidence interval [CI], 68%-83%) to 91% (95% CI, 85%-95%). Two doses of RIX4414 were well tolerated, with no increase in high fever, severe diarrhea, or vomiting after either dose or with increased viral concentration, compared with placebo. There was no observed interference with routine vaccinations of infants when RIX4414 was coadministered. The calculated efficacy of RIX4414 against rotavirus gastroenteritis was 82% (P = .046); however, this result was considered to be of limited conclusive value because of the low number of rotavirus gastroenteritis episodes identified during the follow-up period.

CONCLUSIONS

The live, attenuated rotavirus vaccine (RIX4414) was well tolerated and highly immunogenic in Singaporean infants. The immunogenicity of routinely administered infant vaccines was not impaired by concomitant administration of RIX4414 vaccine.

A rotavirus vaccine for prophylaxis of infants against rotavirus gastroenteritis

The need for safe and effective vaccines to reduce morbidity and mortality caused by rotavirus gastroenteritis in children is well-known. A live attenuated monovalent rotavirus vaccine (Rotarix) containing human rotavirus strain RIX4414 of G1P1A P[8] specificity is being developed to meet the global need. An overview of RIX4414 trials in developed and developing settings is presented for 3 selected trials conducted in Finland (pilot study), Latin America (Brazil, Mexico and Venezuela) and Singapore involving 5024 infants. The vaccine was well-tolerated, with no increase in any solicited symptoms as compared with the placebo. After 2 doses, 61-91% of vaccinated infants developed rotavirus-specific IgA antibodies. There was no interference with immunogenicity of coadministered routine pediatric vaccines. Rotarix significantly reduced rotavirus gastroenteritis episodes and rotavirus-related hospitalizations in vaccinated infants compared with placebo recipients (P < 0.05). Vaccine efficacy was observed against severe rotavirus gastroenteritis caused by G1 and non-G1 types including the emerging G9 type (P < 0.05) in Latin America. These results show prospects for widespread use of Rotarix to reduce rotavirus disease burden and warrant continued worldwide evaluation.

Biliary atresia: making the diagnosis by the gallbladder ghost triad

OBJECTIVE

To describe the gallbladder ghost triad and evaluate its usefulness in the sonographic diagnosis of extrahepatic biliary atresia (BA).

METHODS

From October 1997 to February 2002, 217 fasted infants with cholestatic jaundice aged 2-12 weeks were examined sonographically. We defined the gallbladder ghost triad as gallbladder length <1.9 cm, lack of smooth/complete echogenic mucosal lining with an indistinct wall and irregular/lobular contour, and used it as a criteria for BA. Gallbladder wall thickness, triangular cord, diffuse periportal echogenicity and hepatic artery calibre were also recorded. Diagnosis of BA was confirmed surgically and histologically.

RESULTS

Thirty of 31 babies with BA demonstrated the gallbladder ghost triad. No false-positives were recorded. The 31st BA baby showed a normal gallbladder at 6 weeks, but developed the ghost triad at 8 weeks. Gallbladder wall thickening was seen in 46/186 non-BA babies, but not in BA. Triangular cord was observed in 24/31 babies. Twenty-two of 186 non-BA babies and 5/31 BA babies showed diffuse periportal echogenicity. The hepatic artery appeared more prominent in BA. All 31 babies diagnosed sonographically as BA had surgery. Three non-BA babies had "negative" laparotomies showing hypoplastic bile ducts.

CONCLUSIONS

The gallbladder ghost triad is a very accurate sign of BA. Indeterminate cases require close follow-up.

Intussusception: a three-year review

INTRODUCTION

Intussusception is the commonest cause of intestinal obstruction in infants and young children.

MATERIALS AND METHODS

This report reviews the clinical presentation, investigations and outcomes of patients with intussusception treated at the KK Women's and Children's Hospital between 1 May 1997 and 30 April 2000.

RESULTS

The study population comprised 160 consecutive patients treated for intussusception at our hospital over this 3-year period. The commonest symptom was vomiting; present in 135 patients (84.4%). A palpable abdominal mass was present in 90 patients (56.3%). The classical features of vomiting, abdominal pain, abdominal mass and rectal bleeding were present together in only 12 patients (7.5%). Abdominal ultrasonography was performed in 155 patients. One hundred and fifty-two patients (98.1%) had the classical target lesion on ultrasonography. Air enema reduction was attempted in all except 6 patients. In the majority of patients (130 or 84.4%), the intussusception was reduced successfully by air enema reduction. There was no association between the duration of symptoms before radiological reduction and the outcome of radiological reduction.

CONCLUSIONS

As the four classical features of intussusception were present together in only 7.5% of our patients, a high index of suspicion is necessary when any of the signs and symptoms are present in an infant or young child. Abdominal ultrasonography is the diagnostic investigation of choice. Air enema reduction was successful in 84.4% of patients and the duration of symptoms did not reduce the success rate. Thus, air enema reduction should be attempted in most patients unless they have absolute contraindications.

Making the diagnosis of biliary atresia using the triangular cord sign and gallbladder length

BACKGROUND

To evaluate the accuracy and utility of the triangular cord sign and gallbladder length in diagnosing biliary atresia by sonography.

MATERIALS AND METHODS

Sixty fasted infants with cholestatic jaundice aged 2-12 weeks were examined sonographically using a 5-10 MHz linear array transducer, focusing on the triangular cord sign (as described by Choi et al. [1]), the gallbladder, and ducts. The triangular cord is defined as a triangular or tubular echogenic density seen immediately cranial to the portal vein bifurcation; it represents the fibrotic remnant of the obliterated cord in biliary atresia. The findings were blinded to blood chemistry, (99 m)Tc-DISIDA hepatobiliary scintigraphy, and liver biopsy. Diagnosis of biliary atresia was confirmed at surgery and histology. Non-biliary atresia infants resolved medically. Comparative charges of the various investigations was made.

RESULTS

++ Twelve infants had biliary atresia, and ten demonstrated a definite triangular cord. The two false-negatives had small or nonvisualized gallbladders. No false-positives were recorded. Gallbladder length ranged from 0-1.45 cm with a mean of 0. 52 cm in biliary atresia compared to a mean of 2.39 cm in nonbiliary atresia infants. (99 m)Tc-DISIDA hepatobiliary scintigraphy showed no excretion (false-positive) in 23 % of nonbiliary atresia cases. Scintigraphy and liver biopsy charges were 2 and 6 times that of sonography, respectively.

CONCLUSION

The triangular cord sign and gallbladder length together are noninvasive, inexpensive, and very useful markers for biliary atresia.

Seroprevalence of antibodies against hepatitis A (anti-HAV) in Singapore: the NFDD experience

At the 4th National Foundation for Digestive Disease (NFDD) Day in 1991 where public lectures on prevention of hepatitis and early detection of hepatocellular carcinoma were given, screening of sera obtained from 364 registrants for antibodies to Hepatitis A (IgG) was undertaken. The overall sero-prevalence rate was 50%, with 55% for males and 46% for females with antibodies for HAV. None of the subjects below 20 years old had antibodies to HAV. This rose to 16% for those 21-30 years old and 92% for those above 61 years. This study shows that in Singapore, prevalence of anti-HAV antibodies rise with age and is approaching the low endemicity pattern that is seen in developed countries.

Perineal eruption as an early sign of Kawasaki disease

Kawasaki Disease can present as a diagnostic problem at the early stage of the disease. An interesting and distinctive perineal eruption which appeared early in the course of the disease had been reported recently but sporadically in the medical literature. We reported seven patients with Kawasaki Disease who had this perineal eruption. The rash began two to three days after the onset of fever followed by desquamation in all instances by days five to seven. When compared with other signs of Kawasaki Disease, this rash appeared early. In an earlier study done in the department, the diagnosis of Kawasaki Disease was made on an average of nine days after the onset of fever. This has an important implication as early treatment had been shown to decrease the incidence of coronary arteriectasia which is the most important complication of this disease. We believe that this distinctive perineal eruption is a valuable early clinical finding which may facilitate early diagnosis and treatment of Kawasaki Disease and unless one is aware and actively looked for the perineal eruption, this early sign may be completely missed.

Chemotherapy for hepatoblastoma in children

Hepatoblastoma is an uncommon but highly malignant liver tumour found in childhood. It is associated with high mortality with overall survival of only 35%. Two cases of hepatoblastoma are described. Both had surgical excision of tumour with microscopic residual tumour at the resected margins. They were given adjuvant chemotherapy. Both patients are living well, disease-free and off treatment six years and two years since diagnosis.

Hepatobiliary scintigraphy in the diagnosis of biliary atresia--a Singapore experience

In recent years, 99mTechnetium IDA hepatobiliary scintigraphy has been widely accepted as a highly sensitive and fairly accurate test in the diagnosis of biliary atresia and evaluation of neonatal jaundice. Over a period of 4 years from 1982 to 1986, a total of 110 paediatric patients had undergone 99mTechnetium IDA hepatobiliary scans in our department for prolonged neonatal jaundice. Their scans were reviewed to evaluate the role of this nuclear imaging technique in the diagnosis of biliary atresia. There were 43 true positive and 49 true negative scans. No false negative scan was encountered in our study. Hence the sensitivity was 100%. However, out of the 110 scans, there was misdiagnosis of biliary atresia in 18 cases. This gave a specificity of 73% with an accuracy of 84%. From this study we concluded that 99mTechnetium IDA imaging is a highly sensitive test in the screening of biliary atresia. However, its specificity is possibly limited by the short half life of the radioisotope 99mtechnetium in delayed 24 hr imaging and we feel that this could be improved by using slightly higher doses than what we are presently using.

Intestinal lymphangiectasia--a case report

Primary intestinal lymphangiectasia is a rare cause of protein-losing enteropathy. We report here our first case, a young girl presenting at the age of ten months at the Department of Paediatrics, Singapore General Hospital with generalised oedema and diagnosed to have intestinal lymphangiectasia proven by intestinal biopsy. The literature on some aspects of the subjects is also reviewed.

The mortality of exchange transfusions

A prospective study of the effect and mortality of exchange transfusion was carried out in the Kandang Kerbau Hospital, Singapore. Altogether 140 exchange transfusions were performed on 122 infants. The exchanges were done for hyperbilirubinaemia due to "idiopathic" jaundice, ABO haemolytic disease, and glucose-6-phosphate dehydrogenase deficiency. Eight infants deteriorated during the exchange, in three of whom the procedure had to be terminated prematurely. Two deaths occurred two days after the exchange--the procedure being partly responsible in one case; necrotizing enterocolitis was present in addition to the kernicterus. Exchange transfusion is not without hazards, and should be performed carefully with close monitoring of the clinical status of the infant during and immediately after the procedure.