Differential Diagnosis

The patient's symptoms of mucous with mild blood, fever, and loose bowel movements after traveling on an airline suggest a gastrointestinal infection. Here is a differential diagnosis organized into categories:

• Single most likely diagnosis
  • Traveler's diarrhea (likely caused by a bacterial or viral pathogen): The patient's symptoms of diarrhea, mucous with mild blood, and fever after traveling are consistent with traveler's diarrhea. The fact that the symptoms resolved and then left him with loose bowel movements also fits with this diagnosis.
• Other Likely diagnoses
  • Viral gastroenteritis: The patient's symptoms of fever, diarrhea, and mucous with mild blood could be caused by a viral infection such as norovirus or rotavirus.
  • Bacterial gastroenteritis (e.g. Salmonella, Shigella, or Campylobacter): These bacteria can cause diarrhea, fever, and bloody stools, and are commonly acquired through contaminated food or water while traveling.
• Do Not Miss
  • Inflammatory bowel disease (IBD) flare: Although the patient has a history of IBS, it's possible that he has underlying IBD (e.g. ulcerative colitis or Crohn's disease) that is being exacerbated by the infection.
  • Infectious colitis (e.g. Clostridioides difficile): This bacterial infection can cause severe diarrhea, fever, and bloody stools, and is a potentially life-threatening condition if not treated promptly.
• Rare diagnoses
  • Parasitic infection (e.g. Giardia or amoebiasis): These infections can cause diarrhea, fever, and bloody stools, but are less common than bacterial or viral causes.
  • Food poisoning (e.g. from contaminated food or water): Although less likely, food poisoning from toxins such as Staphylococcus aureus or Bacillus cereus could cause the patient's symptoms.