Differential Diagnosis for Vomiting with Dark Brown Blood in a 6-Week Pregnant Woman

• Single most likely diagnosis:
  • Gastroesophageal reflux disease (GERD) or gastritis exacerbated by pregnancy and vomiting, leading to minor mucosal bleeding. The dark brown color of the blood suggests it has been partially digested, indicating the bleeding is likely coming from the upper gastrointestinal tract.
• Other Likely diagnoses:
  • Peptic ulcer disease: The stress of pregnancy and the use of anti-nausea medications could potentially contribute to the development or exacerbation of a peptic ulcer, leading to bleeding.
  • Esophageal tear (Mallory-Weiss syndrome): Repeated vomiting can cause a tear in the esophagus, leading to bleeding. The presence of dark brown blood in the vomit could be indicative of this condition.
  • Pregnancy-related hyperemesis: Although the patient's vomiting had decreased with anti-nausea medication, the condition can still cause significant stress on the body, potentially leading to gastrointestinal complications.
• Do Not Miss diagnoses:
  • Ectopic pregnancy with rupture: Although less likely given the initial improvement with anti-nausea medication, any sign of bleeding in early pregnancy warrants consideration of ectopic pregnancy, especially if accompanied by abdominal pain or other concerning symptoms.
  • Placental abruption: This condition involves the placenta separating from the uterus and can cause bleeding. It is a serious condition that requires immediate medical attention.
• Rare diagnoses:
  • Gastric cancer: Although extremely rare in young pregnant women, any instance of gastrointestinal bleeding warrants consideration of malignancy, especially if other symptoms such as weight loss or difficulty swallowing are present.
  • Dieulafoy's lesion: A rare cause of gastrointestinal bleeding due to a mucosal defect with an exposed artery, which could potentially cause the observed symptoms.