In developed countries, a wide variety of disorders cause chronic diarrheas in children. The causes range from developmental and dietary factors (eg, excessive consumption of juice), to diseases causing malabsorption or maldigestion, or enteric infections (particularly in immunocompromised patients) (table 1) [1,2].
In the developing world, chronic diarrhea typically is associated with serial enteric infections and malnutrition [3,4]. This common pathophysiology calls for a distinct algorithmic approach to diagnosis and treatment, which is discussed separately. (See "Persistent diarrhea in children in developing countries".)
The diagnostic approach to diarrheal diseases in developed countries will be reviewed here. The causes of these diarrheal diseases are discussed separately. (See "Overview of the causes of chronic diarrhea in children".)
Selection of the appropriate strategy to diagnose the cause of chronic diarrhea in a child depends on the presentation of the patient. In most cases, a thorough history and physical examination narrows the range of possibilities. Age at presentation and the population setting (eg, the genetic predisposition of the population) are also important factors to consider. For children presenting with chronic diarrhea in developed countries, the most likely cause in young children (typically one to four years of age) is functional diarrhea. In this young age group, functional diarrhea is also known as chronic nonspecific diarrhea or “toddler’s diarrhea.” In older children and adolescents, functional diarrhea is associated with irritable bowel syndrome (IBS) as defined by the pediatric Rome III criteria [5-8]. Celiac disease is also relatively common, and can be evaluated with a simple serologic screening test. Therefore, it is appropriate to consider these entities early in the evaluation before embarking on extensive laboratory testing. If these steps do not establish a diagnosis, then further laboratory testing can be selected based on history, physical examination, and the stool type. This stepwise strategy is outlined below (algorithm 1A-B).
HISTORY AND EXAMINATION
A detailed history often provides clues to the diagnosis or diagnostic category (table 2).