Differential Diagnosis for Abdominal Pain with Bloody Stool and High WBC

• Single Most Likely Diagnosis
  • Gastrointestinal Bleeding due to Ulcer: The presence of abdominal pain, high WBC count indicating inflammation or infection, hypokalemia which can be due to gastrointestinal loss, and fecalysis showing bloody red color with numerous RBCs strongly suggests a gastrointestinal bleed. The mention of an X-ray looking like it's filled with fecal material could imply an obstruction or significant constipation, but in the context of these symptoms, a bleeding ulcer is a primary concern.
• Other Likely Diagnoses
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause abdominal pain, bloody stools, and an elevated WBC count. The presence of numerous RBCs in the fecalysis supports this diagnosis.
  • Diverticulitis: This condition can cause abdominal pain, changes in bowel habits, and bloody stools. The high WBC count is consistent with an infectious or inflammatory process.
  • Intestinal Obstruction: While the primary symptoms don't directly point to obstruction, the X-ray description could be interpreted as showing signs of obstruction, especially if there's significant constipation or fecal impaction.
• Do Not Miss Diagnoses
  • Appendicitis: Although the pain is described as generalized, appendicitis can sometimes present with diffuse abdominal pain, especially if the appendix is in an unusual position. The elevated WBC count and abdominal pain make this a critical diagnosis not to miss.
  • Mesenteric Ischemia: This is a life-threatening condition that can cause abdominal pain out of proportion to physical findings, and it might not always present with the classic symptoms. The high WBC count and abdominal pain warrant consideration of this diagnosis.
  • Intussusception: More common in children but can occur in adults, intussusception can cause intestinal obstruction, bloody stools, and abdominal pain. It's a diagnosis that requires prompt intervention.
• Rare Diagnoses
  • Meckel's Diverticulum: A congenital anomaly that can cause gastrointestinal bleeding, especially in younger patients. It's less likely given the generalized abdominal pain but should be considered in the differential, especially if other diagnoses are ruled out.
  • Hemolytic Uremic Syndrome (HUS): Although more commonly associated with renal failure and microangiopathic hemolytic anemia, HUS can cause abdominal pain and bloody diarrhea, particularly in the context of E. coli infections.
  • Ischemic Colitis: This condition can cause abdominal pain, bloody stools, and an elevated WBC count. It's more common in older adults and those with vascular disease.