Differential Diagnosis for Chronic Nausea, Vomiting, Intermittent Bloody Diarrhea, and Abdominal Pain

Single Most Likely Diagnosis

• Inflammatory Bowel Disease (IBD): This includes conditions like Crohn's disease and ulcerative colitis, which are known for causing chronic abdominal pain, diarrhea (often bloody), nausea, and vomiting due to inflammation in the gastrointestinal tract.

Other Likely Diagnoses

• Irritable Bowel Syndrome (IBS): Although IBS typically does not cause bloody diarrhea, some variants can present with bloody stools. It's known for causing abdominal pain, changes in bowel habits, and nausea.
• Gastroesophageal Reflux Disease (GERD): Can cause nausea and vomiting, and while less commonly associated with bloody diarrhea, it can lead to abdominal pain.
• Gastritis or Peptic Ulcer Disease: These conditions can cause abdominal pain, nausea, vomiting, and in some cases, bloody stools if there is significant mucosal erosion or ulceration.

Do Not Miss Diagnoses

• Intestinal Ischemia: A condition where there's insufficient blood flow to the intestines, which can lead to abdominal pain, nausea, vomiting, and bloody diarrhea. It's critical to diagnose promptly as it can lead to severe complications or death.
• Infectious Colitis: Certain bacterial, viral, or parasitic infections can cause severe gastrointestinal symptoms, including bloody diarrhea. Missing these diagnoses can lead to severe dehydration, sepsis, or death.
• Gastrointestinal Cancer: Although less common, cancers of the stomach, small intestine, or colon can present with these symptoms. Early detection is crucial for treatment and survival.

Rare Diagnoses

• Eosinophilic Gastroenteritis: A rare condition characterized by eosinophilic infiltration of the gastrointestinal tract, leading to symptoms like abdominal pain, nausea, vomiting, and diarrhea.
• Whipple's Disease: A rare, systemic bacterial infection that can cause malabsorption, weight loss, abdominal pain, and diarrhea.
• Celiac Disease: An autoimmune reaction to gluten, leading to small intestine damage and symptoms that can include abdominal pain, diarrhea, and nausea, although bloody diarrhea is less common.

Each of these diagnoses has a different approach to management and treatment, emphasizing the importance of a thorough diagnostic workup to determine the underlying cause of the patient's symptoms.