ABP Pediatric Gastroenterology key terms

An immune-mediated enteropathy triggered by dietary gluten in genetically predisposed people, causing villous atrophy and crypt hyperplasia of the small bowel with malabsorption, and treated by lifelong gluten exclusion.

Flattening or loss of small intestinal villi seen on biopsy, reducing absorptive surface area; it is the hallmark mucosal lesion of celiac disease but also occurs in other enteropathies.

A graded histologic scheme describing celiac mucosal injury, from increased intraepithelial lymphocytes (type 1) through crypt hyperplasia (type 2) to partial and total villous atrophy (types 3a to 3c).

The preferred serologic screening test for celiac disease; it must be interpreted alongside a total IgA level because IgA deficiency can produce a false-negative result.

Increased lymphocytes within the surface epithelium of small bowel mucosa, an early and sensitive but nonspecific marker of gluten-sensitive and other inflammatory enteropathies.

Elongation and increased mitotic activity of intestinal crypts occurring as a regenerative response to surface epithelial injury, commonly accompanying villous atrophy in celiac disease.

The most common primary immunodeficiency, defined by very low serum IgA with normal IgG and IgM; it predisposes to mucosal infections and can cause falsely negative IgA-based celiac serology.

A therapy for active Crohn disease using a complete liquid formula as the sole calorie source for several weeks, inducing mucosal healing without the adverse effects of corticosteroids.

Endoscopic restoration of normal-appearing intestinal mucosa with resolution of ulceration, now a key treatment target in inflammatory bowel disease because it predicts fewer relapses and surgeries.

A chronic transmural inflammatory bowel disease that can affect any part of the gastrointestinal tract with skip lesions, and in children commonly presents with abdominal pain, diarrhea, and growth failure.

A validated noninvasive scoring tool using symptoms such as stool frequency, rectal bleeding, and activity level to grade disease severity and monitor response in children with ulcerative colitis.

An abnormal tract connecting the anal canal to the perianal skin, a common complication of Crohn disease that may require imaging, antibiotics, immunomodulators, or surgical drainage.

A chronic allergen-driven inflammatory disorder causing esophageal eosinophilia, dysphagia, and food impaction, diagnosed by biopsy and treated with dietary elimination, proton pump inhibitors, or topical steroids.

Presence of numerous eosinophils on esophageal biopsy, the defining histologic feature of eosinophilic esophagitis, though it can also occur in reflux or other conditions.

Acute lodgment of a food bolus in the esophagus causing chest discomfort and inability to swallow saliva; in children it often reveals an underlying motility or eosinophilic disorder.

Troublesome symptoms or complications resulting from retrograde flow of gastric contents into the esophagus, distinct from the common and often benign physiologic reflux of infancy.

A catheter-based test that detects both acidic and nonacidic reflux episodes by measuring impedance changes along the esophagus, useful when symptoms persist despite acid suppression.

A surgical procedure wrapping part of the stomach around the distal esophagus to reinforce the antireflux barrier, reserved for selected children with refractory or complicated reflux.

Thickening of the pyloric muscle causing nonbilious projectile vomiting in young infants, with a palpable olive and characteristic electrolyte and ultrasound findings requiring surgical pyloromyotomy.

Surgical division of the hypertrophied pyloric muscle, the definitive treatment for hypertrophic pyloric stenosis, usually performed after correcting dehydration and electrolyte derangement.

A biochemical pattern of low chloride and raised bicarbonate caused by repeated vomiting of gastric acid, classically seen in hypertrophic pyloric stenosis and corrected with saline-containing fluids.

Telescoping of one bowel segment into the adjacent segment, causing colicky pain, vomiting, and bloody stools in young children; ultrasound is diagnostic and enema reduction is first-line therapy.

A congenital outpouching of the distal ileum from incomplete obliteration of the vitelline duct, which may bleed from ectopic gastric mucosa or cause obstruction and intussusception.

A nuclear imaging study that detects ectopic gastric mucosa by its uptake of pertechnetate, commonly used to evaluate painless lower gastrointestinal bleeding from a Meckel diverticulum.

Malabsorption and fluid losses resulting from insufficient functional intestinal length after resection or congenital loss, managed with parenteral nutrition and gradual intestinal rehabilitation.

Cholestatic liver injury developing in children dependent on long-term parenteral nutrition, driven by lack of enteral feeding, recurrent sepsis, and altered bile acid metabolism.

Delivery of nutrients intravenously when the gastrointestinal tract cannot meet needs, requiring careful monitoring for infection, electrolyte disturbance, and hepatobiliary complications.

Impaired bile formation or flow producing conjugated hyperbilirubinemia, pruritus, and pale stools; in infants it always warrants prompt evaluation to exclude biliary atresia.

Progressive fibro-obliteration of the extrahepatic bile ducts presenting with neonatal jaundice and acholic stools, treated surgically by Kasai portoenterostomy to restore bile drainage.

An operation that excises the fibrotic extrahepatic biliary remnant and connects a Roux limb to the liver hilum to allow bile drainage in infants with biliary atresia.

A chronic immune-mediated liver inflammation marked by elevated transaminases, autoantibodies, and interface hepatitis, responsive to immunosuppression with corticosteroids and thiopurines.

A chronic cholestatic liver disease producing strictures and beading of bile ducts, strongly associated with inflammatory bowel disease and carrying risk of cholangiocarcinoma.

A noninvasive imaging technique that visualizes the biliary and pancreatic ducts without contrast injection, useful for detecting strictures, stones, and ductal anomalies in children.

Sudden pancreatic inflammation diagnosed by characteristic pain plus elevated lipase or imaging findings, managed mainly with fluids and early enteral nutrition rather than antibiotics.

A pancreatic enzyme that digests triglycerides; serum levels rise in acute pancreatitis and remain elevated longer than amylase, making it preferred for diagnosis in children.

An autosomal recessive disorder of chloride transport causing thick secretions that obstruct pancreatic ducts and airways, leading to pancreatic insufficiency, steatorrhea, and chronic lung disease.

A stool test measuring pancreatic elastase, an enzyme that survives intestinal transit; low values indicate pancreatic exocrine insufficiency such as that caused by cystic fibrosis.

Excessive fat in stool producing bulky, greasy, foul-smelling stools, reflecting fat malabsorption from pancreatic insufficiency, cholestasis, or mucosal disease.

Inadequate weight gain or growth velocity relative to age standards, a sensitive marker of chronic undernutrition or gastrointestinal disease that requires serial measurements and dietary assessment.

The number of standard deviations a measurement lies from the reference mean for age and sex, used to classify nutritional status and track growth over time.

A simple field measurement of arm muscle and fat that estimates nutritional status and identifies severe acute malnutrition when combined with weight-for-height criteria.

A noninvasive test measuring breath hydrogen after a sugar load to detect carbohydrate malabsorption or small intestinal bacterial overgrowth, though results require careful interpretation in children.

Symptoms of bloating, gas, and diarrhea after lactose ingestion due to reduced lactase activity, usually developmental and distinct from cow milk protein allergy.

Flexible endoscopic examination of the esophagus, stomach, and duodenum that allows direct visualization and biopsy, performed under sedation in children for diagnosis and therapy.

Use of sedative and analgesic drugs to tolerate a procedure while maintaining airway reflexes, requiring appropriate monitoring, fasting, and trained personnel in pediatric endoscopy.