Differential Diagnosis for 42-year-old Female with RLQ Pain, Diarrhea, Facial Flushing, and Wheezing

• Single Most Likely Diagnosis
  • Carcinoid Syndrome: This condition is characterized by flushing, diarrhea, wheezing, and abdominal pain due to a neuroendocrine tumor secreting serotonin and other substances. The symptoms match closely with those presented, making it a strong candidate for the single most likely diagnosis.
• Other Likely Diagnoses
  • Irritable Bowel Syndrome (IBS): While IBS primarily causes abdominal pain and changes in bowel habits, some patients may experience extraintestinal symptoms like flushing. However, wheezing is less commonly associated with IBS.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause abdominal pain, diarrhea, and systemic symptoms. Though less common, extraintestinal manifestations can include skin and respiratory symptoms.
• Do Not Miss Diagnoses
  • Appendicitis: Although the classic presentation of appendicitis is abdominal pain, nausea, vomiting, and fever, atypical presentations can occur, especially in adults. The presence of RLQ pain necessitates considering appendicitis to avoid missing a potentially life-threatening condition.
  • Intestinal Obstruction: This is a medical emergency that can present with abdominal pain, vomiting, and changes in bowel habits. While diarrhea is less typical, the combination of symptoms warrants consideration to prevent missing a serious condition.
  • Mesenteric Ischemia: This condition involves insufficient blood flow to the intestines and can present with severe abdominal pain out of proportion to physical examination findings, diarrhea, and potentially systemic symptoms due to bowel ischemia.
• Rare Diagnoses
  • Mastocytosis: A condition characterized by the accumulation of mast cells in one or more organs, which can lead to a variety of symptoms including flushing, diarrhea, abdominal pain, and respiratory symptoms due to the release of histamine and other mediators.
  • Eosinophilic Gastroenteritis: A rare condition involving eosinophilic infiltration of the gastrointestinal tract, which can cause abdominal pain, diarrhea, and potentially systemic symptoms including respiratory issues due to eosinophilia.
  • Neuroendocrine Tumors (other than Carcinoid): Other neuroendocrine tumors, like VIPomas or glucagonomas, can cause distinct syndromes with diarrhea, flushing, and abdominal pain, though they are less common than carcinoid syndrome.