extravasation

This term is used almost exclusively in medical and clinical contexts to describe the accidental escape of fluids into the interstitial space. It carries a high degree of technical formality and is typically associated with adverse events, such as the leakage of vesicant drugs from an intravenous catheter, which can lead to severe tissue damage.

While it describes a physical process of leakage, it is distinct from "hemorrhage," which specifically refers to the escape of blood. Extravasation is a broader term that encompasses any fluid, including saline, contrast media, or chemotherapy agents, and emphasizes the movement of the substance outside its intended vessel or duct.