Differential Diagnosis for Chronic Diarrhea
Single Most Likely Diagnosis
- Irritable Bowel Syndrome (IBS): This is often the most common cause of chronic diarrhea due to its high prevalence and the fact that it can present with a variety of gastrointestinal symptoms, including chronic diarrhea, without an identifiable cause.
Other Likely Diagnoses
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic diarrhea due to inflammation in the gastrointestinal tract.
- Gastroesophageal Reflux Disease (GERD): Although more commonly associated with heartburn, some patients with GERD may experience diarrhea.
- Lactose Intolerance: The inability to digest lactose can lead to chronic diarrhea in individuals who consume lactose-containing products.
- Small Intestine Bacterial Overgrowth (SIBO): An overgrowth of bacteria in the small intestine can lead to malabsorption and chronic diarrhea.
- Celiac Disease: An autoimmune reaction to gluten can cause chronic diarrhea and malabsorption in affected individuals.
Do Not Miss Diagnoses
- Colorectal Cancer: Although less common, colorectal cancer can present with chronic diarrhea and would be catastrophic if missed.
- Thyroid Disorders: Hyperthyroidism can cause chronic diarrhea due to increased motility of the gastrointestinal tract.
- Neuroendocrine Tumors: Certain tumors, like VIPomas, can produce hormones that lead to severe, chronic diarrhea.
- Infectious Causes: Chronic infections such as giardiasis or chronic parasitic infections can cause diarrhea and must not be overlooked.
Rare Diagnoses
- Whipple's Disease: A rare, systemic bacterial infection that can cause chronic diarrhea among other symptoms.
- Short Bowel Syndrome: A condition that results from a significant loss of intestinal tissue, leading to malabsorption and chronic diarrhea.
- Congenital Diarrheal Disorders: Rare genetic conditions that affect the intestines and can cause chronic diarrhea from birth.
- Eosinophilic Gastroenteritis: A rare condition characterized by eosinophilic infiltration of the gastrointestinal tract, which can cause chronic diarrhea.