Differential Diagnosis for Chronic Malabsorption Issues

The following differential diagnosis is organized into categories to help guide the thought process:

• Single Most Likely Diagnosis
  • Giardiasis: This parasitic infection is common in Mexico and can cause chronic malabsorption issues, including constipation in adults and normal bowel movements in children. The lack of diarrhea in all family members does not rule out giardiasis, as it can present with a variety of gastrointestinal symptoms.
• Other Likely Diagnoses
  • Intestinal hookworm infection: Hookworms can cause chronic malabsorption and are prevalent in Mexico. While they often cause diarrhea, constipation can also occur, especially in adults.
  • Strongyloidiasis: This parasitic infection can cause malabsorption and gastrointestinal symptoms, including constipation and normal bowel movements.
  • Small intestine bacterial overgrowth (SIBO): SIBO can cause malabsorption and is more common in individuals living in areas with poor sanitation, such as some parts of Mexico.
• Do Not Miss Diagnoses
  • Celiac disease: Although less likely, celiac disease is an autoimmune disorder that can cause malabsorption and must be considered, especially if the family has been consuming gluten-containing foods.
  • Tropical sprue: This rare condition can cause malabsorption and is often seen in individuals living in tropical regions, including Mexico.
• Rare Diagnoses
  • Whipple's disease: A rare bacterial infection that can cause malabsorption, weight loss, and gastrointestinal symptoms.
  • Abetalipoproteinemia: A rare genetic disorder that affects fat absorption and can cause malabsorption and gastrointestinal symptoms.
  • Immunoglobulin A (IgA) deficiency: A rare immune disorder that can increase the risk of gastrointestinal infections and malabsorption.

Each of these diagnoses should be considered and investigated further to determine the underlying cause of the family's chronic malabsorption issues.