Differential Diagnosis for Underweight 9 Month Old Boy
Single Most Likely Diagnosis
- Gastroenteritis: This is the most likely diagnosis given the symptoms of recurrent diarrhea and emesis, which are common presentations of gastroenteritis in infants. The decreased appetite and underweight status could be secondary to the gastrointestinal symptoms.
Other Likely Diagnoses
- Lactose Intolerance: This condition could lead to diarrhea, emesis, and decreased appetite due to malabsorption of lactose, a common sugar found in milk and other dairy products.
- Food Allergy or Intolerance: An allergy or intolerance to a specific food, such as cow's milk protein, could cause similar gastrointestinal symptoms.
- Infectious Causes (e.g., Rotavirus, Norovirus): These viruses are common causes of gastroenteritis in infants and could explain the recurrent diarrhea and emesis.
Do Not Miss Diagnoses
- Intussusception: Although less common, intussusception is a life-threatening condition that can cause abdominal pain, vomiting, and bloody stools. It's crucial to consider this diagnosis to avoid missing a potentially fatal condition.
- Hirschsprung's Disease: This congenital condition affects the large intestine and can cause severe constipation, but in some cases, it may present with diarrhea and vomiting due to intestinal obstruction.
- Inflammatory Bowel Disease (IBD): Although rare in infants, IBD (e.g., Crohn's disease, ulcerative colitis) can cause chronic diarrhea, weight loss, and decreased appetite.
Rare Diagnoses
- Celiac Disease: An autoimmune reaction to gluten, which can cause malabsorption and gastrointestinal symptoms, although it's less common in infants.
- Congenital Infections (e.g., Congenital HIV, Congenital Syphilis): These infections can cause a range of symptoms, including gastrointestinal issues, and should be considered in the differential diagnosis, especially if the infant has a high-risk exposure history.
- Endocrine Disorders (e.g., Congenital Adrenal Hyperplasia): Certain endocrine disorders can cause weight loss, decreased appetite, and gastrointestinal symptoms, although they are relatively rare.