From the Guidelines
The diagnostic workup for chronic diarrhea in pediatric patients should begin with testing for Giardia, as recommended by the AGA, due to its high prevalence and excellent treatment outcomes, as evidenced by the high-quality study published in Gastroenterology in 2019 1. The workup for chronic diarrhea in children should be a step-wise approach, starting with a thorough history and physical examination, focusing on duration, frequency, consistency, and associated symptoms. Initial laboratory tests should include:
- Complete blood count
- Comprehensive metabolic panel
- C-reactive protein
- Erythrocyte sedimentation rate
- Stool studies (culture, ova and parasites, Clostridium difficile toxin, and fecal calprotectin)
- Giardia antigen test or polymerase chain reaction for Giardia test, as recommended by the AGA 1 Celiac disease screening with tissue transglutaminase IgA and total IgA is also recommended. If these initial tests are inconclusive, further evaluation may include:
- Abdominal imaging
- Endoscopy with biopsies
- Specialized tests like hydrogen breath testing for carbohydrate malabsorption or pancreatic elastase for exocrine pancreatic insufficiency Common causes to consider include:
- Post-infectious enteritis
- Inflammatory bowel disease
- Celiac disease
- Irritable bowel syndrome
- Food allergies or intolerances Nutritional assessment is crucial as chronic diarrhea can lead to malnutrition, dehydration, and growth failure. Management depends on the underlying cause but should include adequate hydration, electrolyte replacement, and specific treatments for identified conditions. For symptomatic relief while awaiting diagnosis, dietary modifications like reducing lactose or fermentable carbohydrates may help. The workup should be tailored to the child's age, as certain conditions are more prevalent in specific age groups, and should progress from less to more invasive investigations, with the goal of minimizing morbidity, mortality, and improving quality of life.
From the Research
Diagnostic Workup for Chronic Diarrhea in Pediatric Patients
The diagnostic workup for chronic diarrhea in pediatric patients involves a step-by-step approach to determine the underlying cause of the condition.
- A complete history and physical examination are essential in evaluating chronic diarrhea in pediatric patients 2, 3.
- Stool analysis, including characterization of stool as watery, fatty, or bloody, can help narrow down the differential diagnosis 3, 4.
- Laboratory tests, such as complete blood count, C-reactive protein, and basic metabolic panel, may be useful in evaluating for pathologies such as celiac disease or inflammatory bowel disease 5.
- Genetic tests, including whole-exome and genome sequencing, can be used to diagnose congenital diarrheas and enteropathies (CODEs) in infants 3.
- A diagnostic approach based on stool characteristics, histologic features, responses to dietary modifications, and genetic tests can be used to determine the cause of diarrhea in infants 3.
Evaluation of Chronic Diarrhea in Infants
In infants, the evaluation of chronic diarrhea involves:
- Exclusion of common causes of diarrhea, such as allergies and infectious agents 3.
- Analysis of stool characteristics, including watery, fatty, or bloody stool 3, 4.
- Histologic features, such as villus to crypt ratio in intestinal biopsies, can help diagnose defects in digestion, absorption, or enterocyte structure 3.
- Model systems, such as enteroids or induced pluripotent stem cells, can be used to analyze the functional effects of gene mutations 3.
Diagnostic Tests for Chronic Diarrhea
Various diagnostic tests can be used to evaluate chronic diarrhea in pediatric patients, including: