Differential Diagnosis
- Single most likely diagnosis
- Sepsis due to perforated viscus or severe gastrointestinal infection: The patient's presentation with severe sepsis, abdominal pain, nausea/vomiting, and a positive C. difficile test, along with imaging findings of diffuse small bowel wall thickening and mesenteric tethering, suggests a severe gastrointestinal infection that may have led to perforation or severe sepsis.
- Other Likely diagnoses
- Inflammatory bowel disease (IBD) with complications: The patient's imaging findings, such as diffuse small bowel wall thickening and mesenteric lymph node enlargement, could be consistent with IBD, such as Crohn's disease. The presence of ascites and SBP may indicate complications of IBD.
- Gastrointestinal ischemia: The patient's abdominal pain, nausea/vomiting, and imaging findings could also suggest gastrointestinal ischemia, which may be related to the patient's severe sepsis or other underlying conditions.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Abdominal aortic aneurysm or other vascular emergencies: Although less likely, an abdominal aortic aneurysm or other vascular emergencies, such as mesenteric ischemia or infarction, could present with similar symptoms and would be deadly if missed.
- Intra-abdominal malignancy with perforation or obstruction: A malignancy, such as a gastrointestinal cancer, could cause similar symptoms and imaging findings, and would be critical to diagnose and treat promptly.
- Rare diagnoses
- Ehlers-Danlos syndrome with gastrointestinal involvement: This rare genetic disorder can cause gastrointestinal symptoms, including abdominal pain and bowel perforation, although it is less likely in this case.
- Whipple's disease: A rare, systemic bacterial infection that can cause gastrointestinal symptoms, including abdominal pain, diarrhea, and weight loss, although it is unlikely given the patient's presentation and imaging findings.