Differential Diagnosis for IBS Diarrhea Prominent
- Single most likely diagnosis
- Irritable Bowel Syndrome (IBS-D): This is the most likely diagnosis due to the presence of diarrhea-predominant symptoms, which is a common subtype of IBS. The diagnosis is often made based on the Rome IV criteria, which include recurrent abdominal pain associated with defecation and changes in stool frequency or form.
- Other Likely diagnoses
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can present with chronic diarrhea, abdominal pain, and weight loss. Differentiation from IBS is crucial, as IBD requires specific treatment and has a different prognosis.
- Infectious gastroenteritis: Bacterial, viral, or parasitic infections can cause acute or chronic diarrhea. A detailed history of travel, exposure to contaminated food or water, and antibiotic use can help identify this diagnosis.
- Small Intestine Bacterial Overgrowth (SIBO): This condition occurs when bacteria overgrow in the small intestine, leading to bloating, gas, and diarrhea. It can be a cause of IBS-like symptoms and should be considered in the differential diagnosis.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Colorectal cancer: Although less common in younger individuals, colorectal cancer can present with changes in bowel habits, including diarrhea. It's essential to rule out this diagnosis, especially in patients with a family history or other risk factors.
- Celiac disease: An autoimmune disorder that causes the immune system to react to gluten, leading to small intestine damage and chronic diarrhea. Missing this diagnosis can result in malabsorption and increased risk of complications.
- Thyrotoxicosis: Hyperthyroidism can cause diarrhea, weight loss, and abdominal pain. Although less common, it's a critical diagnosis to consider due to the potential for severe complications if left untreated.
- Rare diagnoses
- Carcinoid syndrome: A rare condition caused by a neuroendocrine tumor that produces serotonin, leading to diarrhea, flushing, and wheezing.
- Whipple's disease: A rare, systemic bacterial infection that can cause chronic diarrhea, weight loss, and abdominal pain.
- VIPoma: A rare pancreatic tumor that produces vasoactive intestinal peptide (VIP), leading to severe diarrhea, hypokalemia, and dehydration.