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Biomedical subjects

S K Chong

Publications and source records attributed to S K Chong.

At least 19 recordsLinked to original sources
PubMed2001

Gastrointestinal problems in the handicapped child.

Gastrointestinal issues are a major chronic problem in 80 to 90% of children with cerebral palsy and in children with neurodevelopmental disabilities who are at special risk of developing malnutrition because of uncoordinated swallowing, gastroesophageal reflux, and constipation. In addition to poor linear growth, there is a decrease in muscle strength and coordination, impaired cerebral function leading to decreased motivation and energy. Significant neurodevelopmental progress can be achieved with improved nutritional status. A multidisciplinary approach, with input from neurologists, gastroenterologists, nurses, occupational therapists, and dieticians, can make a major contribution to the medical wellbeing and quality of life of these children. Different neurological diseases ( eg, spinal dysraphism, syringomyelia, tethered cord syndromes) can give rise to gastrointestinal dysfunction and symptoms that may need different gastrointestinal or surgical management. The introduction of new drugs, including proton pump inhibitors and innovative endoscopic and surgical techniques in the management of gastroesophageal reflux disease and constipation also may have an impact on the treatment of neurologically handicapped children in the future.

Child↗
PubMed2001

Experience with juvenile polyps in North American children: the need for pancolonoscopy.

We report a recent experience with juvenile polyps (JP) in a large cohort of North American children to determine if a pancolonoscopy (PC) is needed in all children with suspected polyps. We reviewed hospital charts of all patients with JP seen over a 9-yr period (January, 1990-October, 1998). A total of 331 JP were encountered during 195 procedures in 184 patients (64% males, 88% white, mean age 5.93 yr [range 0.42-15.5 yr], median age 4.84 yr). Painless rectal bleeding was the commonest symptom. PC was performed in 42% (82/195) of procedures, and 177 JP were encountered: 54% (97/177) were in the rectosigmoid colon, 14% (24/177) were in the descending colon, and 32% (56/177) were proximal to the splenic flexure (i.e., proximal polyps). Overall, proximal polyps were seen in 37% (31/82) of PC. Only proximal polyps were noted in 12% (10/82) of PC. Five patients were re-endoscoped after an initial limited examination because of continuing symptoms from proximal polyps. All but one of the polyps had typical features of a JP on histological examination. Though most JP are located in the left colon, a PC should be the initial procedure because: 1) 37% of PC revealed proximal polyps, 2) 32% of polyps were located proximal to splenic flexure, 3) persistence of symptoms from missed proximal polyp(s) necessitates a repeat study with attendant risks, and 4) there is a possibility of malignant transformation in an unidentified JP.

Adenomatous Polyposis Coli↗
PubMed2000

Recurrent abdominal pain in children--a retrospective study of outcome in a group referred to a pediatric gastroenterology practice.

Recurrent abdominal pain (RAP) affects a significant number of children each year. We reviewed our experience over a 2-year period to determine the outcome of patients who were referred for pediatric gastroenterology consultation. We identified 356 patients, 149 (42%) male and 207 (58%) female. All patients underwent a thorough interview and complete physical examination. Patients suspected of having irritable bowel syndrome (IBS) were treated as such without further initial evaluation. Others underwent an initial blood and urine evaluation. When these initial screening studies were negative, additional studies were performed including abdominal ultrasonography, radiography, and/or endoscopy of the upper gastrointestinal (GI) tract if the history suggested a possible diagnosis that could be excluded or confirmed by such tests. There was no identifiable diagnosis in 43.5% of the patients studied. IBS was diagnosed in 25.8% of all patients. Constipation was diagnosed in 3.7%. Miscellaneous causes, including GI mucosal lesions, and renal and pancreatic disorders were found in an additional 27% of patients. In a follow-up survey, more than 70% of the treated respondents were improved (i.e., their RAP had resolved or was markedly improved). We conclude that most children with RAP have a functional disorder. Patients with an organic cause for pain can be identified and treated in a cost-effective manner with carefully planned evaluation.

Abdominal Pain↗
PubMed1999

Clinical applications of technetium Tc 99m hexamethyl propylene amine oxime leukocyte scan in children with inflammatory bowel disease.

BACKGROUND: Labeled leukocyte imaging is a helpful diagnostic tool in the detection of inflammation and sepsis. The technetium Tc 99m hexamethyl propylene amine oxime (99mTc HMPAO)-labeled leukocyte scan has been found to be more sensitive than the Indium-111 labeled leukocyte scan in detecting inflammatory bowel disease, with reported sensitivities of 95% to 100%. Experience with the 99mTc HMPAO-labeled leukocyte scan was examined and its clinical applications evaluated in the immediate treatment of patients with inflammatory bowel disease. METHODS: A retrospective chart review was undertaken that included pediatric patients who underwent 99mTc HMPAO-labeled leukocyte scan at the James Whitcomb Riley Hospital for Children. The disease activity of patients with inflammatory bowel disease was assessed. The leukocyte scan was performed according to the manufacturer's specifications, and images were obtained 30 minutes and 2 hours after administration of the radiopharmaceutical. RESULTS: During the period of July 1996 through November 1997, 41 scans were performed in 35 patients. Twenty-nine patients had histologically proven inflammatory bowel disease: 24 with Crohn's disease, 4 with ulcerative colitis, and 1 with indeterminate colitis. Active inflammatory bowel disease was suspected in 24 patients when the leukocyte scan was performed. Twenty of the 24 patients (83% sensitivity) had abnormal findings in leukocyte scans that prompted more aggressive management in 15 (75%). Six of the 15 who were receiving maximum medical therapy underwent surgical resection of severely affected bowel segments, and medical treatment was intensified in the other 9. The remaining 5 patients were receiving optimal medical therapy, instituted at their recent visit, and did not require further medication adjustments. Four of the 24 patients with active inflammatory bowel disease had normal leukocyte scans (17% false-negative rate), 3 of whom were receiving corticosteroid therapy at the time the scans were performed. All of the 11 patients in whom inflammatory bowel disease was in remission and 6 patients who did not have inflammatory bowel disease had normal findings in leukocyte scans (100% specificity). CONCLUSIONS: Although a tissue diagnosis is still recommended, obtained during upper and lower gastrointestinal endoscopic examinations, and contrast radiography of the small bowel for the initial work-up of patients with suspected inflammatory bowel disease, the 99mTc HMPAO-labeled leukocyte scan is a safe and useful diagnostic adjunct for subsequent evaluation of patients known to have inflammatory bowel disease. The results of 99mTc HMPAO-labeled leukocyte scans directly influenced treatment of 75% of the study patients with active inflammatory bowel disease, which included the decision to refer patients for surgical intervention.

Adolescent↗
PubMed1999

Disaccharidase activities in children: normal values and comparison based on symptoms and histologic changes.

BACKGROUND: The relationship between symptoms, intestinal mucosal histology, and disaccharidase activities is not well defined. An analysis of disaccharidase activities was performed in children grouped by age, symptoms, and intestinal mucosal histology and normal values established. METHODS: Disaccharidase activities and histology of 246 endoscopically obtained duodenal biopsies in 232 patients (121 girls; age range, 0.08-17 years; mean, 5.9 years) in a 3-year period were reviewed. Patients were divided into two groups based on absence (group 1; n = 142) or presence (group 2; n = 90) of diarrhea and were subdivided by age into, less than 24 months of age and 24 months of age or more. Histologic changes within groups were classified as (A) normal, (B) mild, or (C) moderate to severe based on villus height abnormalities. A questionnaire was sent to 34 patients with hypolactasia to assess the efficacy of lactose avoidance and/or lactase supplementation. RESULTS: All group 1 patients had normal findings in analysis of mucosal specimens, and their disaccharidase activities showed normal values because they had no diarrhea. The geometric means (95% confidence interval) in children aged less than 24 months are (in micromoles of substrate hydrolyzed per minute at 37 degrees C per gram protein) (units [U]) lactase, 36.7 (13.4-100.4); maltase, 178.5 (88.9-356.3); palatinase, 12.7 (3.8-41.5); and sucrase 60.0 (24.0-148.1). In children 24 months of age or more, the values are 23.2 (3.9-108.1), 167.6 (78.8-355.9), 12.7 (4.9-32.9), and 51.0 (20.5-126.0), respectively. Only lactase activity decreased with age (p < 0.05). No differences in disaccharidase activities were noted in patients with and without diarrhea if the mucosal histology was normal (group 1A vs. 2A). In patients with diarrhea, values were commensurate with the degree of mucosal injury, especially in the older group. Twenty-two of 27 patients (81%) who responded to the questionnaire had benefited from lactase supplementation and/or lactose avoidance. CONCLUSIONS: We have established normal values for disaccharidase activities in the pediatric population. Although the disaccharidase activities correlate more with degree of intestinal mucosal injury than with symptoms, their activities are difficult to predict accurately based on these criteria. If required, disaccharidase activities should be measured biochemically.

Adolescent↗
PubMed1999

Tyrosinemia type 1 should be suspected in infants with severe coagulopathy even in the absence of other signs of liver failure.

Tyrosinemia type l is an inherited metabolic disorder attributable to deficiency of fumarylacetoacetate hydrolase, a terminal enzyme in the degradation pathway of tyrosine. Affected individuals may present with any of a number of signs and symptoms, including failure to thrive, fever, vomiting, diarrhea, hepatomegaly, ascites, jaundice, renal Fanconi syndrome, or conditions such as rickets and hepatocellular carcinoma.1 If untreated, the patient may die of acute liver failure before the second year of life, or from chronic liver failure or hepatocellular carcinoma before the end of the second decade of life.2 Although overt liver failure with coagulopathy may be part of the presentation of tyrosinemia, a significant coagulopathy in the absence of overt signs of liver disease has not been emphasized as a clue to the diagnosis of this condition. We report two tyrosinemic infants who presented with severe coagulopathies and no other signs of liver failure to stress this diagnostic point.

Amino Acid Metabolism, Inborn Errors↗
PubMed1999

Electrogastrography in cyclic vomiting syndrome.

Children with cyclic vomiting syndrome have a characteristic periodicity, and this could be due to abnormal gastric myoelectrical activity detectable by cutaneous electrogastrography (EGG). Fifteen children, aged 4-15 years, with CVS (eight symptomatic and seven asymptomatic at the time of study) underwent EGG and were compared to five normal and four disease control children. The relative tachygastria activity (RTA) or power ratio was calculated in each group. Five of the eight symptomatic CVS children showed marked episodes of tachygastria preprandially and all showed tachygastria postprandially. The asymptomatic CVS children showed tachygastria only postprandially after the test meal. RTA index and or power ratio of symptomatic children was significantly different from the asymptomatic CVS children (P = 0.001), normal (P = 0.007) and disease control children (P = 0.006). In a subsequent study, 2-hr gastric emptying 99mTc scintiscans were performed in 28 CVS children and compared to eight healthy control children. Twelve of 16 CVS children (75%) showed abnormal gastric emptying, and 7 of 28 (25%) showed abnormal EGG with significant tachygastria. The CVS children had significantly higher RTA both preprandially (P < 0.05) and postprandially (P < 0.05). Our results demonstrate that accelerated gastric rhythm was seen during the acute episodes of half of the CVS patients studied. Abnormal EGGs and higher RTA or power ratios were associated with delayed gastric emptying in the CVS children. Abnormal gastric myoelectrical activity may play a role in the pathogenesis of CVS syndrome.

Adolescent↗
PubMed1998

Pancreatic enzyme supplementation in cystic fibrosis patients before and after fibrosing colonopathy.

BACKGROUND: In 1994 we cared for nine cystic fibrosis patients with fibrosing colonopathy. To evaluate the relationship between fibrosing colonopathy and supplemental pancreatic enzymes we reviewed our dosing of enzymes prior to fibrosing colonopathy development and then evaluated the subsequent effect of drastically reducing pancreatic enzyme dose. METHODS: We retrospectively reviewed pancreatic enzyme dosing for 267 cystic fibrosis patients with pancreatic insufficiency. The supplemental enzyme history of nine patients with fibrosing colonopathy was contrasted with the history of 258 nonaffected patients. The pancreatic enzyme doses of 75 patients taking at least 6,000 U lipase/kg/meal were systematically reduced to approximately 2,000 lipase units/kg/meal. We evaluated the effect of this dose reduction on change in height and weight z scores one year after achievement of stable enzyme dose. RESULTS: In the year prior to diagnosis patients with fibrosing colonopathy took a significantly larger pancreatic enzyme dose, whether assessed by highest dose or cumulative dose, than did nonaffected patients. Similar results were observed after controlling for sex and age. All 75 patients on at least 6,000 U lipase/kg/meal were able to tolerate a significant reduction in dose while achieving clinically acceptable nutrient absorption, with no change over one year in height and weight z scores. CONCLUSIONS: Our data demonstrate a strong relationship between very high doses of pancreatic enzyme supplementation and formation of fibrosing colonopathy. These very high doses do not appear to be needed for adequate nutrient absorption and growth.

Adolescent↗
PubMed1998

Further studies of anti-endomysium and anti-gliadin antibodies in patients with suspected celiac disease.

BACKGROUND: The finding of characteristic small intestinal mucosal abnormalities on histologic examination of a biopsy specimen remains the first requirement for the diagnosis of celiac disease. A reliable and noninvasive test would be ideal for the patient's convenience and for reducing health-care costs. The sensitivity and specificity of anti-gliadin antibodies (AGA-immunoglobulin [Ig] G, AGA-IgA) have been variable; anti-endomysium IgA (EmA-IgA) is more helpful. In an earlier study conducted at the authors' institution, celiac disease was present in 19 patients examined from 1992 to 1995. Anti-endomysium titers were higher than normal in all 19 patients (100%). Total villous atrophy was seen in 14 of 17 biopsy specimens (82%) and subtotal atrophy in 3 (18%). The purpose of the current study was to evaluate further the accuracy of EmA-IgA in diagnosing celiac disease. METHODS: One hundred seven patients were screened for celiac disease between March 1996 and July 1997. The level of EmA-IgA was measured in all patients, and AGA-IgG and AGA-IgA were measured in 104 patients. Forty-six patients underwent endoscopic biopsy of the small bowel, with measurement of disaccharidase enzymes in 45 patients. RESULTS: Five of 46 patients had celiac disease (three boys and two girls; mean age, 5.3 years; 2-9.5 years); one also had cystic fibrosis and another had insulin-dependent diabetes mellitus. All five had marked to complete villous atrophy with crypt hyperplasia and increased serum EmA-IgA (100% sensitivity). None of the remaining patients had increased EmA-IgA (100% specificity). Serum levels of AGA-IgG and AGA-IgA were increased in all four celiac disease patients (100% sensitivity), but they were also high in patients without celiac disease (38% and 92% specificity, respectively), which compromises their diagnostic value. None of the patients confirmed to have celiac disease had IgA deficiency. Abnormal disaccharidase enzyme activities were documented in all five celiac disease patients: severe generalized deficiency (n = 2), moderately severe generalized deficiency (n = 2), and alactasia with moderate deficiency of the alpha-glucosidases (n = 1). CONCLUSIONS: This study confirmed the reliability and accuracy of EmA-IgA in the diagnosis of celiac disease. Small bowel biopsy may be unnecessary in EmA-positive patients in whom celiac disease is suspected.

Antibodies↗
PubMed1998

Expression of inducible nitric oxide synthase (iNOS) mRNA in inflamed esophageal and colonic mucosa in a pediatric population.

OBJECTIVE: Increasing evidence suggests that nitric oxide participates in the pathophysiology of intestinal barrier function/dysfunction and inflammation. Increases in inducible nitric oxide synthase (iNOS) mRNA and protein expression have been observed in colonic mucosal biopsies of adults with inflammatory bowel disease (IBD). It is unclear whether iNOS induction is specific for IBD or a reflection of nonspecific mucosal inflammation. Furthermore, the characteristics of iNOS mRNA expression in pediatric patients with gastrointestinal disorders remains ill-defined. Our objective was to examine the relationship between iNOS mRNA expression and gastrointestinal mucosal inflammation in a pediatric population. METHODS: Esophageal and colonic mucosal biopsies were obtained during endoscopy. Total RNA was isolated from these biopsies and reverse transcription-polymerase chain reaction (RT-PCR) performed (35 PCR cycles) using two 20-bp primers that amplified a predicted 372-bp conserved iNOS mRNA fragment. RESULTS: Biopsies were obtained from 29 children (22 boys; mean age 10.6 yr [range 1.7-16.5 yr]). Endoscopic and histological findings included normal esophageal mucosa (n = 3), esophagitis (n = 10), normal rectal mucosa (n = 2), ulcerative colitis (n = 10), and Crohn disease (n = 4). Evidence of iNOS mRNA was detected by PCR amplification in six of 10 patients with ulcerative colitis and in two of four patients with Crohn disease. However, iNOS mRNA was not amplified in any esophageal biopsy or in rectal mucosa biopsies with normal histology. CONCLUSIONS: These data indicate that upregulation of iNOS mRNA expression in colonic mucosa is a feature of IBD in children. iNOS mRNA expression is not upregulated in esophageal mucosa or in the absence of colonic inflammation. Further studies designed to determine the site- and cell-specificity of iNOS mRNA upregulation in mucosal biopsies from children with IBD may further illuminate the pathophysiology of these disorders.

Adolescent↗
PubMed1997

Vertical lines in distal esophageal mucosa (VLEM): a true endoscopic manifestation of esophagitis in children?

BACKGROUND: We observed an endoscopic abnormally in a group of children with histological esophagitis. We termed this finding "vertical lines in esophageal mucosa" (VLEM). We examined the relationship between the presence of VLEM and significant histologic changes in esophageal mucosal biopsies. METHODS: Between January 1, 1992, and August 31, 1994, the senior author (JFF) performed 255 esophageal biopsies. The procedure reports, available endoscopic photographs, and histology reports were reviewed to establish the endoscopic and histologic appearance of the esophageal mucosa. Intraepithelial cells were counted in a blind review of 42 randomly selected biopsies. RESULTS: The esophageal mucosa had a normal appearance on 160 endoscopic studies (Group 1) and VLEM were the only mucosal abnormalities in 41 endoscopies (Group 2). Histology was normal in 92 of 160 biopsies (57.5%) from Group 1, and 1 of 41 biopsies (2.4%) from Group 2. Most patients in Group 2 had eosinophilic esophagitis (34 of 41, 83%, specificity 0.85, sensitivity 0.5, p > 0.001) which was of moderate to severe intensity (31 of 34, 91.2%, specificity 0.88, sensitivity 0.73, p < 0.001). CONCLUSIONS: Histology usually demonstrated moderate to severe inflammation when VLEM were present. VLEM may be a highly specific endoscopic feature of esophagitis in children.

Adolescent↗
PubMed1997

Rapid and effective method for preparation of fecal specimens for PCR assays.

We have developed a novel method for the preparation of fecal specimens for PCR assays. Approximately 100 mg of solid stool or 200 microliters of liquid fecal sample was thoroughly suspended in 1 ml of water. Fecal debris was removed by low-speed centrifugation (2,800 x g for 2 min). The supernatant was then boiled for 10 min in a water bath and further clarified by high-speed centrifugation (12,000 x g for 5 min). Fifty microliters of the clarified supernatant was then purified by Sepharose CL-6B spin column chromatography, and a portion of the purified supernatant was used for PCR. By this method, stools containing enterotoxigenic Escherichia coli H10407 were amplified by colonization factor antigen I fimbrial gene PCR, with a sensitivity of 100 organisms per reaction. The method was also effective for processing stool specimens for Clostridium difficile toxin A and B gene PCRs. This method is rapid, effective, and simple to perform and will improve the applications of PCR to stool specimens for diagnostic purposes.

Bacterial Typing Techniques↗
PubMed1996

Neuropathy and vasculopathy in colonic strictures from children with cystic fibrosis.

Colonic strictures are rare in patients who have cystic fibrosis, but recently have developed in those who have been treated with delayed-release high-dose pancreatic enzyme supplements. Colonic strictures from eight such pediatric patients showed neural abnormalities consisting of ganglion cell hyperplasia and ectopia, and intermyenteric plexus hyperplasia. Cholinergic and adrenergic stains of mucosal nerve fibers were more prominent in histological sections of the cystic fibrosis strictures than in sections from colons of children without cystic fibrosis. The mean grade of staining with acetylcholinesterase in the lamina propria of the strictured cystic fibrosis colons was 2.38 +/- 1.25, compared with .93 +/- .93 (P < .055) in bowels from children without cystic fibrosis. The mean grade for tyrosine hydroxylase staining in the lamina propria was 2 +/- .97 in the strictures and was .79 +/- .81 (P < .05) in the bowels of children who did not have cystic fibrosis. Vasoactive intestinal peptide staining in bowels from children with cystic fibrosis with and without stricture did not differ significantly from that of children without cystic fibrosis. Vasculopathy consisting of fibrointimal hyperplasia in submucosal veins and mesenteric arteries was found only in colonic strictures owing to cystic fibrosis. Colonic strictures in patients with cystic fibrosis who received high-dose pancreatic enzyme supplements contain ganglion cell abnormalities, and mucosal cholinergic and adrenergic activity may be increased in these strictures. The stricture vasculopathy may be drug-related and/or related to increased catecholamine activity.

Acetylcholinesterase↗
PubMed1996

Hepatic granulomas in children. A clinicopathologic analysis of 23 cases including polymerase chain reaction for histoplasma.

In a 15-year period at the Riley Hospital for Children, granulomas were found in 23 (4%) of a total of 521 liver biopsies. An etiology was identified in 87%: Histoplasma was diagnosed in 15 cases (65%) by polymerase chain reaction (PCR) on paraffin-embedded tissue, serology, and special stains; sarcoidosis was diagnosed in four cases; and schistosomiasis was diagnosed in one case. Serial liver biopsies were available from five patients; granulomas occurred in only one biopsy of the series from each patient. Extrahepatic tissue from six patients contained granulomas, and an etiology for the liver granulomas was identified in all six patients (four histoplasmosis, two sarcoidosis). The extrahepatic tissue from two patients with Histoplasma was diagnostic. We made the following conclusions: that PCR is applicable to archival material and greatly increases the yield of specific infectious diagnoses of liver granulomas compared with conventional diagnostic methods (65 versus 22%); that the infections causing liver granulomas are those that are endemic in a community (e.g., Histoplasma in Indiana); that Histoplasma can coexist with a wide variety of systemic and primary liver diseases; that the likelihood of identifying a cause of liver granulomas is increased if there are extrahepatic granulomas; and that hepatic granulomas may have a limited life span. Treatment of liver granulomas should be determined by the clinical setting and directed at the underlying cause.

Adolescent↗