Hemorrhage
| Overview |
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- Hemorrhage refers to the escape of blood from the vasculature and occurs due to disruption of blood vessels. Escaped blood may be completely lost from the body, deposited within interstitial tissues, or accumulate in actual or potential spaces within the body.
| Subtypes |
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- Overview
- Clinical parlance possesses several monickers for subtypes of hemorrhages that help narrow the location and size of hemorrhage
- Hematoma:
- A generic term for localized deposition of blood within a tissue or organ
- Hemorrhages into skin:
- Petechiae: 1-2mm
- Purpura: 3-5mm
- Ecchymoses: 1-2cm
- Hemorrhages into Actual or Potential Spaces:
- GI Bleeding, upper and lower
- Hemothorax
- Hemopericardium
- Hemoperitoneum
- Hemarthrosis
| Clinical Consequences |
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- Overview
- The clinical consequences of hemorrhage depend on a variety of factors including the total amount and speed by which blood is lost as well as the location of loss.
- Volume and Rate
- Small Hemorrhages: Small volume or slow hemorrhage can be handled with fairly minimal effects in most locations of the body
- Major Hemorrhage: Non-minor losses that remain less than 20% of blood volume are generally not life-threatening but require major hemodynamic responses to prevent significant losses in body function (See: Major Hemorrhage - Cardiovascular Homeostasis)
- Catastrophic Hemorrhage: Rapid loss of greater than 20% of blood volume significantly increases the risk of shock
- Location
- Most organs can function effectively even with fairly substantial hemorrhages. However, even small hemorrhages into certain highly sensitive organs such as the brainstem can be life-threatening. If blood is lost to the exterior (this includes GI bleeding) then the iron content of the blood is lost and may result in iron deficiency anemia. However, if blood is lost interstitially then local macrophages can recycle the hemorrhaged erythrocytes and their iron can be re-used.