Differential Diagnosis for Vomiting Black

• Single most likely diagnosis:
  • Gastrointestinal bleeding (upper GI bleed), specifically from a source such as ulcers or varices, which can cause the vomit to appear black due to the digestion of blood.
• Other Likely diagnoses:
  • Ingestion of substances that can cause black vomit, such as activated charcoal or certain medications.
  • Gastroesophageal reflux disease (GERD) with associated bleeding.
  • Peptic ulcer disease without significant bleeding but with some blood in the stomach.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
  • Massive upper GI bleed from any cause (e.g., varices, ulcers, malignancy), which requires immediate medical attention.
  • Malignancy in the upper GI tract, which could cause bleeding leading to black vomit.
  • Aortic-enteric fistula, a rare but potentially fatal condition where there's a connection between the aorta and the intestine, leading to GI bleeding.
• Rare diagnoses:
  • Ingestion of black substances not commonly associated with medical treatment, such as certain dyes or pigments.
  • Rare bleeding disorders that could lead to GI bleeding.
  • Certain infections that could cause black vomit, such as a fungal infection in immunocompromised patients.