4.1. Bleeding
4.1.1. Types of bleeding
Types of bleeding are distinguished depending on their cause, location, time of occurrence, and the anatomic structure of damaged vessel. Causes of bleeding
Mechanical injury to the vascular wall can be open and closed, complete and incomplete.
In most cases it is not difficult to recognize open vascular injuries due to the obvious symptoms of bleeding (blood flow from the wound). However, in small wounds of great vessels or wounds of medium and small vessels, spontaneous coagulation may occur arresting the bleeding. This is made possible by a reflex vascular spasm (as a reaction to injury), with intima screwing in into vessel lumen which leads to wound closing and activation of blood clotting system. However, such bleeding can resume later (especially, after a BP rise associated with administered treatment).
Closed vascular injury poses a greater danger, as difficulties in recognizing it are often a cause of misdiagnosis and delayed treatment. Bleeding into body cavity, as well as intraand intermuscular hematomas can be very significant in volume and lead to severe hypovolemia and hemorrhagic shock.
In incomplete vessel ruptures, the contraction of vessel wall can aggravate the lesion and increase bleeding.
The vascular wall pathology maydevelop as a result of atherosclerosis, purulent colliquation, necrosis, specific inflammation, neoplasm. As a result, the vascular wall is gradually destroyed, eventually leading to a "sudden" erosive hemorrhage. Localization of nidus next to great vessels should alarm the physician about possible bleeding. In some pathological conditions (such as vitamin deficiency, intoxication, sepsis) permeability of vascular wall deteriorates, which leads to diape-detic bleeding, not massive as a rule.