Differential Diagnosis for Watery Stool in an 11-Month-Old
Single Most Likely Diagnosis
- Viral Gastroenteritis: This is the most common cause of watery stool in infants, often accompanied by vomiting and fever. Viruses such as rotavirus, norovirus, and adenovirus are common culprits.
Other Likely Diagnoses
- Lactose Intolerance: Temporary lactose intolerance can occur after a viral infection, leading to watery stools. This condition is usually self-limiting.
- Toddler's Diarrhea: A common condition in toddlers characterized by loose, watery stools, often related to dietary factors or minor viral infections.
- Food Allergy or Intolerance: Allergies to foods like milk, soy, or eggs can cause watery stools in infants.
- Infectious Causes: Bacterial infections like Salmonella or E. coli can cause watery diarrhea, though they are less common than viral causes.
Do Not Miss Diagnoses
- Intussusception: Although rare, intussusception can cause watery stools and is a medical emergency. It involves the telescoping of a portion of the intestine into another, which can lead to bowel obstruction and ischemia.
- Hirschsprung's Disease: A congenital condition characterized by the absence of ganglion cells in the distal bowel, leading to severe constipation, but can sometimes present with watery stools due to enterocolitis.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis are rare in infants but can cause chronic diarrhea.
Rare Diagnoses
- Congenital Chloridorrhea: A rare genetic disorder leading to excessive chloride loss in the stool, causing watery diarrhea.
- Microvillous Inclusion Disease: A rare congenital disorder affecting the small intestine, leading to severe, watery diarrhea.
- Tufting Enteropathy: A rare condition characterized by chronic diarrhea, often starting in infancy, due to abnormalities in the intestinal epithelium.