Abdominal coarctation and Alagille syndrome

Structural cardiac defects such as peripheral pulmonary stenosis are well-described in Alagille syndrome (AS), which is transmitted in an autosomal dominant inheritance. The genetic defect, with incomplete penetrance and variable expression, is localized to the short arm of chromosome 20. Abdominal coarctation is an uncommon congenital anomaly, with a spectrum of symptoms that may range from hypertension, intermittent claudication to abdominal pain. The association of abdominal coarctation with AS is rarely described. We report such a patient who also had aberrations of the visceral vascular supply involving the celiac, splenic, and superior mesenteric arteries. The indications to treat the coarctation, and in the context of a patient with AS, in whom liver transplantation may be contemplated at some stage, merit discussion.

Esophageal intramural pseudodiverticulosis associated with a web in a 12-year-old boy

Esophageal intramural pseudodiverticulosis (EIPD) is a rare benign disorder characterized by dilation of the submucosal glands. Its etiology and pathogenesis are largely unknown. So far, less than 10 pediatric cases of EIPD have been reported. The authors present the case of a 12-year-old boy with EIPD that was associated with a cervical esophageal web. He was treated successfully with dilation therapy.

Factors associated with increased respiratory symptoms among asthmatic children in Singapore

Asthma is a common cause of childhood morbidity. The objective of the present study was to evaluate the factors associated with increased asthma morbidity among asthmatic children in Singapore. A cohort of primary school children (n = 6,404, aged 6-13 years) were evaluated using the American Thoracic Society and the Division of Lung Diseases of the National Heart, Lung and Blood Institute, USA (ATS-DLD) respiratory questionnaire. A total of 2,222 of 6,404 children (34.8%) was found to have reported symptoms of wheezing. Of these, 899/2,222 (40.5%) reported symptoms of "increased asthma morbidity". This was associated with the younger age group, male sex and higher socio-economic status. In addition, concurrent or past allergies were strongly associated with increased asthma morbidity, while premature birth and a history of prior childhood respiratory illnesses and Infections were predictive of greater asthma morbidity. No association was found between increased morbidity and presence of domestic pets, parental smoking, childcare attendance, and the season of birth.

Hepatopulmonary syndrome: a rare complication of chronic liver disease in children

An 11-year-old boy with congenital hepatic fibrosis presented with cyanosis at the National University Hospital. Echocardiogram revealed a structurally normal heart with good ventricular function. A pulmonary cause of his cyanosis was suggested on macroaggregated albumin scan and selective pulmonary artery angiogram. Arterial hypoxaemia secondary to intrapulmonary arteriovenous shunting in chronic liver cirrhosis can lead to permanent cyanosis. The potential for a complete reversal of this condition after liver transplantation indicates that arterial hypoxaemia, rather than being a contraindication, should be a reason for early liver transplantation.

Use of soy-protein formulas and soyfood for feeding infants and children in Asia

Soybeans have been cultivated and consumed in Asia for many centuries. Soy products can be found in all households in Asian countries, and Asian children begin to consume soy formulas and soy products at a very young age. In a study of soy exposure in a group of healthy Singaporean children < 10 y of age, 70% had consumed soy products and of those > 95% had consumed soy products before the age of 18 mo. Soy products are commonly used as food flavorings and for weaning Asian children with lactose intolerance or allergy to cow-milk protein. The widespread use of soy formulas and soy products by Asian children is mainly due to the high nutritive value and palatability of these products.

Month of birth and childhood atopic diseases in the tropics

The relationship between the month of birth and prevalence of diagnosed asthma, asthma-like symptoms (wheezing, nocturnal cough, and exercise wheezing), rhinitis, and eczema was investigated in four cohorts each of primary schoolchildren and secondary school (high school) adolescents in Singapore by questionnaire survey. Significantly increased prevalence rates of diagnosed asthma and asthma-like symptoms were observed in certain birth months of the year for two adolescent cohorts, while significant association between birth month and presence of symptoms of rhinitis was found in a cohort of 6-7-year-olds. However, when demographic factors were taken into consideration by multivariate analysis, only the association between asthma, asthma-like symptoms, and birth month remained significant in one of the adolescent cohorts. There was, therefore, only a weak association between the month of birth and atopic disease in our schoolchildren. The overall seasonal trends, however, did show two main seasons (March-May and September-November) associated with higher prevalence of these diseases.

Gastroesophageal reflux in preterm infants: norms for extended distal esophageal pH monitoring

BACKGROUND

Preterm infants are predisposed to gastroesophageal reflux, which may manifest itself in many ways ranging from failure to thrive to vomiting. Extended distal esophageal pH monitoring is the gold standard for diagnosing reflux in the preterm infants and it is our objective to establish extended distal esophageal pH norms (reference values) for well, asymptomatic preterm infants and to compare with norms already established for term infants, children, adolescents, and adults.

METHODS

Twenty-one well, asymptomatic preterm infants consuming at least 70% of required maintenance oral feedings were recruited. The mean +/- standard deviation birth weight was 1549 +/- 439 g (range, 670-2470 g); the mean postconceptional age was 30.7 +/- 2.6 weeks (range, 25-35 weeks) and the mean postnatal age was 14 +/- 9 days (range, 2-40 days). Extended distal esophageal pH monitoring was performed on each of the infants, and the following parameters were calculated: reflux index, number of reflux episodes per day, number of reflux episodes lasting more than 5 minutes per day, and the longest recorded reflux episode.

RESULTS

The mean reflux index was 0.7 +/- 1.1%, the mean number of reflux episodes per day was 7.6 +/- 11.2, the mean number of reflux episodes lasting more than 5 minutes per day was 0.5 +/- 1.1 and the mean longest recorded reflux episode was 4.2 +/- 6.1 minutes. These results were comparable to those seen in term infants, children, adolescents, and adults. The trends for pH norms according to postconceptional age and postnatal age seemed to suggest that lower esophageal sphincter maturation might be related to postconceptional age, but the differences observed were not statistically significant (p > 0.05).

CONCLUSION

The norms (reference values) for well, asymptomatic preterm infants were comparable to those seen in term infants, children, adolescents, and adults. With the establishment of these norms, the search for a causal link between many of the respiratory problems encountered in prematurity and gastroesophageal reflux may be aided and the complications associated with gastroesophageal reflux may consequently be reduced.

Liver transplant in Singapore--coming of age

BACKGROUND/AIM OF STUDY

Liver transplantation was first performed in 1967, and has become an accepted form of treatment worldwide for chronic liver diseases, acute liver failure and certain metabolic diseases. We document our experience in Singapore over the last 7 years since the first transplant was performed in 1990.

METHOD

Retrospective study at National University Hospital, Singapore.

RESULTS

Twenty-two operations (10 paediatric and 12 adults) have been performed with the last 17 having been performed in the last 17 months. Currently, there are 15 survivors (68%) since 1990, and percentage survival is even better if one considers the cases from the last 17 months when the majority of cases (17 transplants-77%) were performed (77% survival). The most common indication for transplant was biliary atresia for the paediatric group, while the adults were transplanted for hepatitis B and C cirrhosis, primary biliary cirrhosis, and fulminant liver failure. Tacrolimus is the main immunosuppression (10 patients), with the remaining 5 patients on cyclosporine. Various surgical techniques (living donor, graft reduction) have been employed successfully to provide a complete transplant service. Hospital and ICU stays are within normal limits and the hospital charges range from a low of S$30,000 to S$141,000.

CONCLUSION

Liver transplantation has become a reality in Singapore with outcomes comparable to other transplant centres. The shortage of donors remains the greatest stumbling block for further expansion.

Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.

Presence of domestic pets and respiratory symptoms in asthmatic children

The allergens of domestic pets such as cats, dogs and birds, have been known to sensitive predisposed individuals. In Singapore, approximately 25% to 35% of our atopic populations are sensitised to cat, dog or bird feather allergens. It is not known, however, if the presence of such domestic pets would translate to higher rates of sensitisation, or more importantly, give rise to increased respiratory symptoms. This study evaluated the association between the presence of domestic pets at home and the prevalence of respiratory symptoms among asthmatic children in Singapore. The parents of 1517 doctor-diagnosed asthmatic children were interviewed using the American Thoracic Society-Division of Lung Diseases respiratory questionnaire. More than 20% were found to have domestic pets (cats, dogs or birds) at home. Of these, those with exposure to passive smoke in the home were excluded. A total of 188 current pet owners (cats, dogs and birds) were demographically-matched for sex, race and socio-economic status (type of housing) to those without pets, past or current. Compared to those without pets, asthmatic children with pets at home had a higher prevalence of coughing with cold [relative risk (RR) 1.30; 95% confidence interval (CI) 1.01 to 1.69]; wheezing with cold (RR 1.42; CI 1.07 to 1.90), wheezing with shortness of breath (RR 1.33; CI 1.00 to 1.82), exercise-induced wheezing (RR 1.68; CI 1.10 to 2.56); and increased phlegm production or congestion with cold (RR 1.38; CI 1.00 to 1.91). This study suggests that the presence of domestic pets increases the prevalence of respiratory symptoms in asthmatic children. Those with predisposition to these allergens should avoid having these pets in the home or take specific precautions in avoiding their allergens.

Glucose-6-phosphate dehydrogenase deficiency in Singapore

Glucose-6-phosphate dehydrogenase (G6PD) in man is an X-linked enzyme. The deficiency of this enzyme is one of the most common inherited metabolic disorders in man. In Singapore, three clinical syndromes associated with G6PD deficiency had been described: severe haemolysis in neonates with kernicterus, haemoglobinuria and "viral hepatitis"-like syndrome. The human G6PD monomer consists of 515 amino acids. Only the tetrameric or dimeric forms composed of a single type subunit are catylitically active. The complete amino acid sequence of G6PD had been elucidated in man and various other animals. The region of high homology among the enzymes of various animals is presumably functionally active. Among the Chinese in Singapore, three common molecular variants had been identified: Canton (nt 1376 G --> T), Kaiping (nt 1388 G --> A) and Mediterranean (nt 563 C --> T) in frequencies of 24%, 21% and 10% respectively. In addition, two common mutants (Gaozhou, nt 95 A --> G and Chinese 5, nt 1024 C --> T) have been detected in Singapore Chinese in low frequencies. In Malays, 6 different deficient variants are known in Singapore (3 new, 1 Mahidol, 1 Indonesian and 1 Mediterranean).

Lung function reference values in Singaporean children aged 6-18 years

BACKGROUND

A study was undertaken to produce reference values of lung function in Chinese children and a means of calculating adjusted standard deviation scores of lung function for Malay and Indian ethnic groups.

METHODS

A cross sectional study of lung function (forced expiratory volume in one second and forced vital capacity) measured with a Jaeger spirometer was performed in a representative sample of Singaporean children made up of 1403 Chinese, 335 Malays, and 206 Indians.

RESULTS

The relation between natural logarithms of lung function and height was approximately linear until 150 cm in boys and 140 cm in girls. At these heights there were abrupt changes in the gradients of both lines. Separate regression lines were derived for heights above and below these inflection points. Significant differences in lung function were seen in Chinese compared with Malay and Indian children. In particular, values were considerably lower among Indian boys.

CONCLUSIONS

The relation between lung function and height in Chinese children is best described by two regression equations over separate height ranges. Information is provided for the calculation of reference values and standard deviation scores, together with the correction factors that need to be applied to derive these values in Malay and Indian children.

Helicobacter pylori infection in children with recurrent abdominal pain

Forty-eight patients with recurrent abdominal pain were studied endoscopically for the presence of gastritis and Helicobacter pylori infection. Fifteen of these children had histological evidence of gastritis with eight of them having concomitant H. pylori infection. The majority of those with H. pylori infection had severe degrees of acute following chronic gastritis.

The nature of small bowel luminal fluid lactase

The evidence indicating a mucosal source for the jejunal fluid lactase activity of children is so far inconclusive. Samples of jejunal mucosa and the adjacent fluid were obtained simultaneously from 15 children. Lactase activity was measured at pH 5.9 in mucosa and fluid. Fluid activities showed a significant positive correlation with the activity of the corresponding mucosal homogenate but a stronger correlation was found with an enterocyte microvillous membrane fraction prepared from the same homogenate (r = 0.807 and 0.889, respectively). Kinetic and pH optima studies were consistent with a microvillous membrane origin. Fluid activity and pH optimum were not changed detectably when measured in the presence of an enterocyte lysosomal acid lactase inhibitor. Jejunal fluid lactase activity and its properties closely reflect the microvillous membrane enzyme. Lysosomal acid lactase does not contribute measurably to the total lactase activity of jejunal fluid.

Pre-liver transplantation management of children

Liver transplantation is the accepted treatment for children with end-staged liver diseases nowadays. Currently, the five year actuarial survival rate is about 80%. In children, the most common indication for transplantation is biliary atresia. Due to shortage of donor organs, portoenterostomy is still the initial treatment of choice for young infants with biliary atresia. This will enable the affected infants to continue growing until a suitable donor organ is available. There are a few absolute contraindications to liver transplantation in children. Severe irreversible disease in any other organs and poor psychosocial support are indications for not performing liver transplantation. Appropriate pre-operative assessment and preparations are necessary for a successful transplant. Post-operative course may be marred by rejection, infections and surgical complications. Long term immunotherapy is necessary.

Gastrointestinal infections in Singapore children

Acute gastroenteritis is the commonest gastrointestinal disorder in children. It accounted for about 10% of the admissions to a general paediatric unit in Singapore. About 5% of total paediatric admissions to all the government hospitals in Singapore were due to acute gastroenteritis. Some 50% of the cases had no identifiable organism in the stools. Most of the remaining cases were due to bacterial or viral infections. The commonest bacteria responsible for acute gastroenteritis nowadays is Salmonella species. Other bacteria such as E. coli, Shigella and Campylobacter were responsible for a smaller proportion of bacterial diarrhoea in children. Rotavirus was the commonest viral agent responsible for acute diarrhoea among Singapore children. Most patients had mild diarrhoea and severe dehydration following acute gastroenteritis was not common. About 60% of the patients admitted to hospital were younger than two years of age. Bacterial infections were more common in infancy. Viral diarrhoea were more likely to be watery and bacterial diarrhoea were more likely to be bloody and mucoid. With regard to chronicity, it was the groups with mixed infection or bacteria infection which had a prolonged course. Treatment was directed at maintaining hydration and prevention of complications. Except for secondary lactase deficiency, other long term complications were rare.

Cell-mediated immunity in patients on hemodialysis: relationship with hepatitis B carrier status

We compared cell-mediated immune responses in two groups of patients on hemodialysis. One group of patients were chronic carriers of hepatitis B virus (HBV), and the patients of the other group were HBV antigen negative. Our results show that despite the presence of normal numbers of T cells and an increased CD4/CD8 ratio in both groups of patients compared to healthy controls (p less than 0.0001), only the group of patients who were chronic HBV carriers showed depressed lymphoproliferative responses to phytohemagglutinin (p less than 0.001) and concanavalin A (p less than 0.0001). In contrast, a control group of healthy adult HBV carriers showed normal T cell subsets and lymphoproliferative responses to mitogens, indicating that HBV infection per se did not result in depressed lymphoproliferative responses. These results further substantiate the notion that depressed cell-mediated immunity in chronic renal failure is an important factor in predisposing patients to HBV infection with subsequent development of the chronic carrier state.

Colonoscopy in children with bleeding per rectum

There are few reports of colonoscopy in children. Twenty-six children with bleeding per rectum were examined colonoscopically to determine the aetiology of the bleeding. A total of 32 colonoscopies were performed. Except for 5 children who needed general anaesthesia, all the rest were performed with pethidine and diazepam sedation. The mean age of these 26 children was 63.5 months (SD 57.5 months, range 2 weeks to 180 months). Ten children had histologically confirmed colitis. Five had bleeding juvenile polyps and these were removed endoscopically. One had lymphoid hyperplasia and one had chronic solitary sigmoid ulcer. The rest were normal. It is concluded that colonoscopy can be performed safely in children and it is a good diagnostic and therapeutic procedure.

Upper gastrointestinal endoscopy in children

The purpose of this paper is to study the use of upper gastrointestinal (Gl) fiberoptic endoscopy in children. Two hundred consecutive patients referred to one of the authors were reviewed. The indications for performing upper gastrointestinal endoscopy in these 200 patients were: (1) recurrent abdominal pain (46.5%), (2) persistent vomiting (14.5%), (3) haematemesis (14.5%), (4) acute abdominal pain (13%) and (5) other indications such as foreign body removal, failure to thrive and unexplained chest pain (11.5%). The endoscopy was performed with the Olympus P3 or Olympus XP-10 gastroscopes. The sedation used was a combination of intravenous pethidine (2mg/kg) and diazepam (0.5 mg/kg). Among the patients with recurrent abdominal pain, upper Gl endoscopy showed duodenal ulcer in 7 patients (7.5%), duodenitis in 4 (4.3%), oesophagitis in 4 (4.3%) and gastric ulcer in 2 (2.2%). The rest of the patients were normal (81.7%). With regard to persistent vomiting, 37.9% of the patients showed gastroesophageal reflux and 6.9% had a hiatus hernia. Of 29 patients examined endoscopically for upper Gl bleeding, no focus of bleeding was identified in 27.6%. The remaining 72.4% were bleeding from acute gastric erosion (27.6%), oesophagitis (17.2%), oesophageal varices (13.8%), duodenal ulcer (10.3%) and Mallory-Weiss tear (3.5%). The Majority of the patients with acute abdominal pain were normal endoscopically (61.5%). The two common abnormal findings were acute gastritis (27.0%) and acute duodenitis (11.5%). No major complications were encountered during the procedure in these 200 patients. It was concluded that upper Gl endoscopy is useful for defining upper Gl mucosal pathology. The procedure can be performed safely in children under sedation.

Incidence, clinical features and epidemiology of rotavirus gastro-enteritis in hospitalized children

Two hundred and eighteen patients with acute gastro-enteritis (GE) and 67 controls (patients admitted during the period of study for illness other than (GE) were included in this study. Their stool samples were subjected to the following tests to detect the presence of rotavirus: enzyme-linked immunosorbent assay (ELISA), latex agglutination and electron microscopy. Samples positive by any one or more of the above methods were considered positive for rotavirus and were subjected to polyacrylamide gel electrophoresis of viral RNA. Rotavirus was detected in 59 (27.1%) of the 218 GE samples and four (6%) of the control samples. ELISA was the most sensitive test and could detect viral antigen long after the other methods failed to do so.

Accuracy of anorectal manometry in the diagnosis of Hirschsprung's disease

The value of anorectal manometry as a diagnostic tool for Hirschsprung's disease (HD) was assessed in 50 children presenting with chronic constipation. Anorectal manometric studies and rectal biopsy were performed on all children. Biopsy specimens were stained with hematoxylin and eosin and serial sections were examined for ganglion cells. Forty-five children had concordant manometric and histologic results, 15 of whom were positive for HD and 30 negative. In five children, the results were discordant. Using histologic aganglionosis as the reference point for the final diagnosis of HD, the overall accuracy of anorectal manometry as a discriminative test was 90.0%. The sensitivity, specificity, and positive and negative predictive values of manometric studies for the diagnosis of HD were 0.79, 0.97, 0.94, and 0.88, respectively. Factors responsible for the inaccuracies of manometric studies are discussed.

Oral refeeding following acute gastro-enteritis: a clinical trial using four refeeding regimes

A clinical trial using four different oral refeeding regimes was conducted in 100 patients following acute gastro-enteritis. There was no difference in terms of the diarrhoea-relapse rates among the four groups of patients. However, a better weight gain was recorded in the groups using a lactose-free soy formula and a low-lactose low-fat cow's milk formula.