Congenital short-bowel syndrome, a condition in which a portion of the small intestine is absent or not functioning properly leading to decreased absorption of both fluids and nutrients. Congenital lactase deficiency, a condition caused by a genetic mutation in which the body cannot digest lactose properly. Glucose-galactose malabsorption, a genetic disorder caused by changes in a protein critical for the transport of glucose and galactose across the intestine which leads to impaired glucose/galactose absorption, dehydration, and severe diarrhea in young children. Typically, the severe diarrhea improves with a diet low in glucose/galactose and the tolerability to glucose/galactose improves with age. Hirschsprungs disease (HSCR), a gut motility disorder characterized by a lack of nerve cells in the large intestine which are needed to move the stool through the digestive tract. In infants, HSCR typically presents when a newborn is unable to pass the first feces, or meconium within 48 hours of birth. Other symptoms include blockage of the intestine, fever, rapid release of stool and flatulence upon rectal examination, and may present with diarrhea in infants. Intestinal pseudo-obstruction (IPO), a gut motility disorder characterized by the inability to contract intestinal walls with symptoms similar to intestinal obstruction but lack a distinguishable cause of obstruction. Signs and symptoms include abdominal pain, dilated or enlarged bowel, constipation and may include diarrhea. Although rare in infants, IPO is a type of congenital disorder that may present with diarrhea in infants.
Chronic diarrhea (alternate spelling: diarrhoea) of infancy, also called toddlers diarrhea, is a common condition typically affecting up to 1.7 billion children between ages 6–30 months worldwide every year, usually resolving by age 4. According to the World Health Organization (WHO), diarrheal disease is the second greatest cause of death in children 5 years and younger. Diarrheal disease takes the lives of 525,000 or more children per year. Diarrhea is characterized as the condition of passing of three or more loose or watery bowel movements within a day sometimes with undigested food visible. Diarrhea is separated into three clinical categories; acute diarrhea may last multiple hours or days, acute bloody diarrhea, also known as dysentery, and finally, chronic or persistent diarrhea which lasts 2–4 weeks or more. There is normal growth with no evidence of malnutrition in the child experiencing persistent diarrhea. In chronic diarrhea there is no evidence of blood in the stool and there is no sign of infection. The condition may be related to irritable bowel syndrome. There are various tests that can be performed to rule out other causes of diarrhea that dont fall under the chronic criteria, including blood test, colonoscopy, and even genetic testing. Most acute or severe cases of diarrhea have treatment guidelines revolving around prescription or non prescription (also known as over the counter or OTC) medications based on the cause, but the treatment protocols for chronic diarrhea focus on replenishing the body with lost fluids and electrolytes, because there typically isnt a treatable cause.