What would cause you to bleed from your mouth while sleeping?

Rightdx.com see ENT: Bleeding diathesis carcinoma, squamous cell of head and neck - bleeding from the mouth crown placement dental caries dental cleaning dentures hantavirosis - bleeding from the mouth hemophilia idiopathic thrombocytopenic purpura leukemia pancytopenia periodontal disease plaque post tonsillectomy bleeding root canal stomatitis thrombocytopenia tonsillar abscess tooth extraction.