Differential Diagnosis
The patient's symptoms of intermittent diarrhea, severe cramping abdominal pain, and occasional constipation, without fever or weight loss, suggest a functional gastrointestinal disorder. Here is a categorized differential diagnosis:
- Single most likely diagnosis
- Irritable Bowel Syndrome (IBS): This is the most likely diagnosis given the patient's symptoms of intermittent diarrhea, abdominal pain, and constipation, which are characteristic of IBS. The absence of fever, weight loss, and blood in the stool also supports this diagnosis.
- Other Likely diagnoses
- Infectious gastroenteritis (post-infectious IBS): The patient's recent travel to Mexico could have exposed her to infectious agents that cause gastroenteritis, which can sometimes lead to post-infectious IBS.
- Lactose intolerance or other food intolerances: These conditions can cause similar symptoms, such as diarrhea, abdominal pain, and bloating, especially if the patient consumes lactose or other offending foods.
- Do Not Miss
- Inflammatory bowel disease (IBD): Although less likely, IBD (e.g., Crohn's disease, ulcerative colitis) can present with similar symptoms and must be considered to avoid missing a potentially serious condition.
- Celiac disease: This autoimmune disorder can cause chronic diarrhea, abdominal pain, and malabsorption, and it is essential to rule it out due to its potential for long-term complications.
- Giardiasis: Given the patient's travel history, giardiasis is a possibility, especially if she has been exposed to contaminated water or food.
- Rare diagnoses
- Microscopic colitis: A rare condition characterized by chronic, watery diarrhea, which can be caused by various factors, including infections, medications, or autoimmune disorders.
- Bile acid diarrhea: A condition where the body produces too much bile acid, leading to chronic diarrhea, which can be caused by various factors, including gastrointestinal surgery or certain medications.
- Small intestine bacterial overgrowth (SIBO): A condition where excessive bacteria in the small intestine can cause diarrhea, bloating, and abdominal pain, which can be related to various factors, including anatomical abnormalities or motility disorders.