An 85-year-old hypertensive man is evaluated in the emergency department for recent onset epistaxis. His blood pressure is 150/80 mm Hg, and hematocrit is 39%. What is the most likely source of bleeding?

Epistaxis in children and young adults usually arises from the anterior nasal septum (Kiessel bach's plexus). In elderly persons, however, spontaneous rupture of a sclerotic blood vessel in the posterior nasal septum is usually the cause of bleeding, especially in combination with hypertension.