Differential Diagnosis
The patient's symptoms of diarrhea, lower abdominal cramping, and blood- and mucus-tinged stools, along with the presence of tender gangliform-type masses, suggest an inflammatory bowel disease. Here's a categorized differential diagnosis:
Single most likely diagnosis
- D. regional enteritis (Crohn's disease): The presence of blood- and mucus-tinged diarrhea, abdominal cramping, and the specific finding of tender gangliform-type masses (likely representing inflamed lymph nodes or granulomas) are consistent with Crohn's disease, a type of inflammatory bowel disease that can affect any part of the gastrointestinal tract.
Other Likely diagnoses
- E. ulcerative colitis: Although the pattern of symptoms could also suggest ulcerative colitis, another form of inflammatory bowel disease, the presence of perianal disease (as suggested by the rectal tenderness and blood-tinged examining finger) and the specific locations of the tender masses might be less typical for ulcerative colitis, which primarily affects the colon and rectum.
- C. malabsorption syndrome: Given the chronic nature of the diarrhea and the potential for malabsorption in inflammatory bowel diseases, malabsorption syndrome could be considered, especially if there are signs of nutritional deficiencies.
Do Not Miss
- Infectious colitis: Although the patient has not traveled outside the contiguous United States, infectious causes of colitis (e.g., Clostridioides difficile, Salmonella, Shigella) must be considered due to the potential for severe complications if not treated promptly.
- Colon cancer: Although less likely in a 28-year-old, any cause of chronic blood-tinged diarrhea warrants consideration of colon cancer, especially if there's a family history or other risk factors.
Rare diagnoses
- A. celiac disease: While celiac disease can cause chronic diarrhea, it typically does not cause blood- and mucus-tinged stools. However, it's a consideration in chronic gastrointestinal symptoms.
- B. irritable bowel syndrome (IBS): IBS can cause chronic abdominal pain and alterations in bowel habits but does not typically cause blood-tinged stools, making it less likely in this scenario.
- Other rare inflammatory or autoimmune conditions: Conditions like Behçet's disease or eosinophilic gastroenteritis could be considered but are much less common and would require additional specific findings for diagnosis.