Differential Diagnosis for Bad Odor Stool
Single Most Likely Diagnosis
- Malabsorption: This is often the most common cause of bad odor stool. Conditions such as celiac disease, pancreatic insufficiency, or lactose intolerance can lead to the malabsorption of nutrients, resulting in foul-smelling stools.
Other Likely Diagnoses
- Gastrointestinal Infections: Infections caused by bacteria, viruses, or parasites can alter the normal gut flora, leading to changes in stool odor.
- Dietary Factors: Consuming certain foods like garlic, onions, or cruciferous vegetables can cause stool to have a stronger odor.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause inflammation in the gut, leading to changes in stool consistency and odor.
Do Not Miss Diagnoses
- Cancer: Although less common, certain types of cancer, such as colorectal cancer, can cause changes in stool odor due to the tumor's effect on the bowel.
- Infectious Diarrhea: Certain infectious causes of diarrhea, such as Clostridioides difficile (C. diff), can be severe and require prompt treatment.
Rare Diagnoses
- Short Bowel Syndrome: A condition where a significant portion of the small intestine is missing or not functioning, leading to malabsorption and potentially foul-smelling stools.
- Trimethylaminuria: A rare genetic disorder that affects the body's ability to break down trimethylamine, a compound found in certain foods, resulting in a strong fish-like odor in urine, sweat, and stool.