Differential Diagnosis for Case 8

The patient presents with acute onset of diffuse abdominal pain, watery diarrhea, fatigue, dizziness, palpitations, and a history of pseudomembranous colitis. The following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • C. difficile infection: This is the most likely diagnosis given the patient's history of pseudomembranous colitis, the presence of watery diarrhea, and the detection of C. difficile toxin in the stool. The patient's symptoms and laboratory findings are consistent with a C. difficile infection.

• Other Likely Diagnoses

  • Inflammatory bowel disease (IBD): Although less likely given the patient's age and presentation, IBD (such as ulcerative colitis or Crohn's disease) could cause similar symptoms, including abdominal pain, diarrhea, and blood in the stool.
  • Gastroenteritis: Other forms of gastroenteritis, caused by viral or bacterial pathogens, could also present with similar symptoms, although the absence of fever and the specific stool findings make this less likely.
  • Ischemic colitis: Given the patient's age and symptoms of abdominal pain and diarrhea, ischemic colitis is a possibility, although the presence of C. difficile toxin and the patient's history make this less likely.

• Do Not Miss Diagnoses

  • Toxic megacolon: A complication of severe colitis (including C. difficile infection), toxic megacolon is a life-threatening condition that requires prompt recognition and treatment.
  • Sepsis: Although the patient's blood cultures are negative, the presence of fever, tachycardia, and abdominal pain could indicate sepsis, particularly if the patient's condition worsens.
  • Bleeding disorder or gastrointestinal bleeding: The presence of occult blood in the stool necessitates consideration of a bleeding disorder or gastrointestinal bleeding as a potential cause of the patient's symptoms.

• Rare Diagnoses

  • Microscopic colitis: A condition characterized by chronic watery diarrhea, microscopic colitis is less common and may be considered if other diagnoses are ruled out.
  • Whipple's disease: A rare, systemic bacterial infection that can cause diarrhea, abdominal pain, and weight loss, Whipple's disease is an unlikely but possible diagnosis if other causes are excluded.
  • Eosinophilic colitis: A rare condition characterized by eosinophilic infiltration of the colon, eosinophilic colitis could present with similar symptoms, although it is much less common than other diagnoses.