Digestive endoscopy in neonates

Gastrointestinal Endoscopy in the Neonate

Gastrointestinal endoscopy permits direct observation of the alimentary tract, acquisition of mucosal tissue for histopathologic examination, and other diagnostic and therapeutic maneuvers. Endoscopes of appropriate size for many neonates and an expanding array of compatible tools and accessories have broadened what is possible, although few neonatal data exist to guide use. Evaluation and treatment of gastrointestinal bleeding, evaluation and dilation of fibromuscular congenital esophageal stenosis, and the bedside placement of gastrostomy tube have been described. Careful consideration of risks, benefits, and discussions between involved specialties permit patient-specific application of these tools and techniques to augment care of this vulnerable population.

Does bloody aspirate reflect the state of upper gastrointestinal mucosa in a critically ill newborn?

BACKGROUND AND STUDY AIMS

Critically ill newborns have many risk factors to develop stress related mucosal lesions (SRML). We used upper endoscopy to evaluate the presence of SRML in these neonates, to know the specificity and sensitivity of the bloody gastric aspirate to detect SRML and to identify the risk factors associated with the presence of SRML and bloody gastric aspirate.

PATIENTS AND METHODS

This is a cross-sectional study done on 100 critically ill newborn after becoming clinically stable. SRML were diagnosed if there is hyperaemia, erosions or ulcers in the oesophagus, stomach, and/or the duodenum.

RESULTS

SRML were found in 77% of neonates in the NICU though frank bloody aspirate was detected in only 22% of neonates. The presence of bloody aspirate showed low sensitivity (24.68%) and high specificity (86.96%) for the presence of SRML. The presence of bloody gastric aspirate showed a double fold risk for the presence SRML (OR=2.184, CI=0.584-8.171). Factors associated with SRML included respiratory distress (p=0.000, risk=4.006), the use of nasogastric tube (p=0.017, OR=3.281) and the use of triple antibiotics (p=0.001, risk=1.432). Factors associated with the presence of bloody gastric aspirate included the use of nasogastric tube (OR=1.629, p=0.000) and the presence of haemostatic disorders (OR=3.143, p=0.039). It was also associated with lower haemoglobin levels (p=0.000).

CONCLUSION

SRML represents an under-diagnosed problem in NICUs. Absence of bloody gastric aspirate does not exclude the presence of SRML.

Gastrointestinal endoscopy and mucosal biopsy in the first year of life: indications and outcome

OBJECTIVES

Lower threshold and widening indications for paediatric gastrointestinal endoscopy have resulted in a significant increase in the numbers of endoscopic procedures performed in infants. Despite this, knowledge of gastrointestinal mucosal findings in this age group is limited and data on the clinical usefulness of endoscopy are lacking.

METHODS

All of the children younger than 1 year referred to a single tertiary paediatric gastroenterology unit during the period June 1987 to August 2007 who underwent gastrointestinal endoscopy were identified and the clinical indications and histological outcomes were reviewed.

RESULTS

A total of 933 gastroesophageal duodenoscopies and 439 colonoscopies were performed in 1024 cases in a total of 823 infants. In order of frequency, clinical indications were diarrhoea (51%), failure to thrive (41.2%), symptoms of reflux (27.1%), and rectal bleeding (8.5%). Mucosal biopsies were insufficient for assessment in only 2.4% of cases. Mucosal histology was normal in 33.8%, whereas histological abnormalities were identified in 63.8%. Specific histological diagnoses included microvillous inclusion disease, autoimmune enteropathy, graft-versus-host disease post-bone marrow transplantation, tufting enteropathy, and disaccharidase deficiency. There was only 1 colonic perforation complicating endoscopy in a total of 889 cases for which relevant information was available (0.1%).

CONCLUSIONS

In two-thirds of cases, histological abnormalities were detected that influenced management following endoscopic examination and mucosal biopsy in infants. Endoscopy with biopsies is a greatly informative test with low failure and complication rates in the first year of life.

Food allergy: recent advances in pathophysiology and diagnosis

Approximately 5% of young children and 3-4% of adults exhibit adverse immune responses to foods in westernized countries, with a tendency to increase. The pathophysiology of food allergy (FA) relies on immune reactions triggered by epitopes, i.e. small amino-acid sequences able to bind to antibodies or cells. Some food allergens share specific physicochemical characteristics that allow them to resist digestion, thus enhancing allergenicity. These allergens encounter specialized dendritic cell populations in the gut, which leads to T-cell priming. In case of IgE-mediated allergy, this process triggers the production of allergen-specific IgE by B cells. Tissue-resident reactive cells, including mast cells, then bind IgE, and allergic reactions are elicited when these cells, with adjacent IgE molecules bound to their surface, are re-exposed to allergen. Allergic reactions occurring in the absence of detectable IgE are labeled non-IgE mediated. The abrogation of oral tolerance which leads to FA is likely favored by genetic disposition and environmental factors (e.g. increased hygiene or enhanced allergenicity of some foods). For an accurate diagnosis, complete medical history, laboratory tests and, in most cases, an oral food challenge are needed. Noticeably, the detection of food-specific IgE (sensitization) does not necessarily indicate clinical allergy. Novel diagnostic methods currently under study focus on the immune responses to specific food proteins or epitopes of specific proteins. Food-induced allergic reactions represent a large array of symptoms involving the skin and gastrointestinal and respiratory systems. They can be attributed to IgE-mediated and non-IgE-mediated (cellular) mechanisms and thus differ in their nature, severity and outcome. Outcome also differs according to allergens.

Neonatal transient eosinophilic colitis causes lower gastrointestinal bleeding in early infancy

BACKGROUND

Lower gastrointestinal bleeding (LGB), particularly in newborns, is of serious concern and requires urgent investigation and hospital care. Whereas allergic proctocolitis caused by food protein is a significant cause of LGB in infants with eosinophilia, there are several cases of diseases with symptoms similar to those of allergic proctocolitis but without an apparent allergic reaction influence.

PATIENTS AND METHODS

We examined 2 neonates using rectosigmoidoscopy who showed eosinophilia and experienced fresh LGB soon after birth and before their first feedings. Serum eosinic cationic protein (ECP) and platelet activating factor (PAF) levels were also examined in the second case to confirm the involvement of eosinophils for its pathogenesis.

RESULTS

Both patients were in a clinically stable condition, and their abdomens were soft. The results of their blood analyses, abdominal radiographs, and stool cultures were normal, but they had gross eosinophilia: the eosinophil counts were 9014/mm3 (patient 1) and 1955/mm3 (patient 2). Rectosigmoidoscopy with colonic mucosal biopsy revealed nodular lymphoid hyperplasia with a pale mucosal surface and massive oozing with diffuse eosinophilic infiltration in the lamina propria. In patient 2 the serum ECP and PAF levels were elevated to 123 microg/L (normal, <14.7) and 13.1 micromol/L/min (normal, <6). A few days after intravenous hydration therapy, LGB was no longer detected, and the serum ECP and PAF levels returned to normal.

CONCLUSIONS

Inasmuch as these infants had LGB similar to allergic proctocolitis without any allergic reactions, we suggest that infiltrated eosinophils in the colonic mucosa could be involved in the pathogenesis of LGB in early infancy.

Morphometric histology for infant gastroesophageal reflux disease: evaluation of reliability in 497 esophageal biopsies

OBJECTIVES

We sought to determine the reliability of morphometric measurements on infant esophageal biopsies using a light microscope with eyepiece micrometer.

METHODS

We measured epithelial thickness, basal layer thickness (B), papillary height (P) and epithelial lymphocyte and eosinophil numbers on approximately 500 existing esophageal suction biopsies from infants previously evaluated for reflux esophagitis. We tested these measurements for interobserver, test-retest and internal consistency reliability.

RESULTS

Infants ages 0.25 to 23.75 (median, 6.25) months provided 497 biopsies. Both investigators scoring the biopsies independently judged 93% of them scorable. Of the biopsies scored by both, the 2 readings were within 0.15 of each other for P in 97% and for B in 81%. In addition to these correlative measures of consistency, categoric measures demonstrated that 373 (89%) of the 420 scorable biopsies with visible papillae produced agreement as to P being abnormal (317, 85%) or normal (56, 15%). Similarly, 360 (78%) of the 463 scorable biopsies produced agreement as to B being abnormal (339, 94%) or normal (21, 6%). P values were 0.17 to 0.94 (median, 0.67), and B values were 0.13 to 0.91 (median, 0.34). Lymphocytes numbered 0 to 40 (median 5) per high-power field. Only 12% had any eosinophils; none of those with completely normal morphometrics had any eosinophils; and only 2% had >5 eosinophils per high-power field.

CONCLUSIONS

Simple quantitative esophageal histological morphometric parameters are reliably measurable on suction biopsies from infants using a light microscope fitted with an ocular micrometer, even by nonpathologists.