Differential Diagnosis for a 6-Month-Old Infant with Diarrhea and Vomiting
Single Most Likely Diagnosis
- Viral Gastroenteritis: This is the most common cause of diarrhea and vomiting in infants, often caused by rotavirus, norovirus, or adenovirus. The acute onset and normal vitals support this diagnosis.
Other Likely Diagnoses
- Bacterial Gastroenteritis: Although less common than viral gastroenteritis, bacterial causes such as E. coli or Salmonella can also lead to diarrhea and vomiting in infants.
- Food Intolerance or Allergy: Infants may develop intolerance or allergy to certain foods, leading to gastrointestinal symptoms.
- Infectious Gastroenteritis due to Other Pathogens: Other pathogens like parasites or less common viruses can cause similar symptoms.
Do Not Miss Diagnoses
- Intussusception: A condition where a part of the intestine telescopes into another, which can cause vomiting and diarrhea, and is a surgical emergency.
- Volvolus or Intestinal Obstruction: Conditions that can cause bowel obstruction, leading to severe vomiting and potentially life-threatening if not promptly treated.
- Sepsis or Bacteremia: Although the infant has normal vitals, sepsis can present subtly in young children and is critical to identify early.
- Urinary Tract Infection (UTI): UTIs can cause nonspecific symptoms in infants, including vomiting and diarrhea.
Rare Diagnoses
- Congenital Anomalies of the Gastrointestinal Tract: Conditions such as pyloric stenosis or Hirschsprung's disease, which can present with vomiting or chronic constipation but might have acute exacerbations.
- Inborn Errors of Metabolism: Certain metabolic disorders can present with gastrointestinal symptoms among other systemic signs.
- Toxins or Poisoning: Although rare, ingestion of toxins can cause gastrointestinal symptoms and is crucial to consider, especially if there's a history of potential exposure.