Differential Diagnosis for Large Bowel Distension with Diarrhea
Single Most Likely Diagnosis
- Irritable Bowel Syndrome (IBS): This condition is characterized by a combination of abdominal pain, bloating, and changes in bowel habits, which can include diarrhea. Large bowel distension can occur due to gas and stool accumulation.
Other Likely Diagnoses
- Infectious Colitis: Infections such as those caused by Salmonella, Shigella, or Campylobacter can lead to diarrhea and large bowel distension due to inflammation and gas production.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic inflammation of the bowel, leading to diarrhea, abdominal pain, and bowel distension.
- Gastroenteritis: Viral or bacterial gastroenteritis can cause acute onset of diarrhea, vomiting, and abdominal pain, potentially leading to large bowel distension.
Do Not Miss Diagnoses
- Toxic Megacolon: A life-threatening condition that can occur in the context of inflammatory bowel disease or infectious colitis, characterized by significant bowel dilatation and potentially leading to perforation.
- Intestinal Obstruction: Although more commonly associated with constipation, certain types of obstruction, especially those involving the distal colon, can present with diarrhea and significant bowel distension.
- Ischemic Colitis: Reduced blood flow to the colon can cause ischemia, leading to abdominal pain, diarrhea, and potentially large bowel distension, which is a medical emergency.
Rare Diagnoses
- Chagas Disease: Caused by Trypanosoma cruzi, this parasitic infection can lead to megacolon, a condition characterized by massive dilatation of the colon, often presenting with chronic constipation but can also have episodes of diarrhea.
- Hirschsprung's Disease: A congenital condition affecting the colon's ability to move stool, typically presenting in infancy but can be diagnosed later in life, leading to chronic constipation and sometimes alternating with diarrhea, with potential for bowel distension.
- Colonic Pseudo-obstruction: A condition where there is impairment of the muscle contractions that move food, fluid, and air through the intestines, leading to severe constipation or diarrhea and significant bowel distension, without any physical obstruction.