Differential Diagnosis for Watery Stool in an 11-Month-Old for 2 Weeks
Single Most Likely Diagnosis
- Viral Gastroenteritis: This is the most common cause of watery stools in infants, often due to rotavirus, norovirus, or adenovirus. The symptoms typically include watery diarrhea, vomiting, and sometimes fever, which can lead to dehydration if not managed properly.
Other Likely Diagnoses
- Lactose Intolerance: After a viral infection, some children can develop transient lactose intolerance, leading to watery stools. This condition usually resolves on its own once the intestinal lining heals.
- Toddler's Diarrhea: A common condition in toddlers characterized by chronic, watery diarrhea, often associated with a diet high in fruit juices or sugars that can be poorly absorbed.
- Food Allergy or Intolerance: Allergies to foods like milk, soy, or eggs, or intolerance to certain food components, can cause chronic watery diarrhea in infants.
- Infectious Causes (Bacterial or Parasitic): Though less common than viral causes, bacterial infections like Salmonella or Campylobacter, or parasitic infections, can cause watery diarrhea.
Do Not Miss Diagnoses
- Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause intermittent abdominal pain, vomiting, and sometimes currant jelly stool. Though it doesn't always present with watery stool, it's a critical diagnosis not to miss due to its potential for intestinal obstruction and necrosis.
- Hirschsprung's Disease: A congenital condition characterized by the absence of ganglion cells in the distal bowel, leading to severe constipation, but in its early stages or partial forms, it might present with watery stools due to enterocolitis.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis are rare in infants but can present with chronic diarrhea, among other symptoms.
Rare Diagnoses
- Congenital Chloridorrhea: A rare genetic disorder leading to excessive chloride loss in the stool, causing chronic watery diarrhea.
- Microvillous Inclusion Disease: A rare congenital disorder affecting the intestinal microvilli, leading to severe, watery diarrhea starting in infancy.
- Tufting Enteropathy: A rare condition characterized by chronic diarrhea due to abnormalities in the intestinal epithelium, often presenting in infancy.