Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Synonyms and keywords: Internal bleed
Internal bleeding is bleeding occurring inside the body.
Internal bleeds are usually called hemorrhages, even though the term is general to all kinds of bleeds. A hemorrhage can occur near the colon due to large bowel movements.
A minor case of internal bleeding is ecchymosis (a bruise): blood expands under the skin, causing discoloration.
It may be caused by high blood pressure (by causing blood vessel rupture) or other forms of injury, especially high speed deceleration occurring during an automobile accident, which can cause organ rupture. Also, internal bleeding can be caused by hitting or running against a sharp object in that area. Some diseases may also cause internal bleeding, such as the Filovirus Ebola. This infection, together with similar infections such as the Marburg virus, is fortunately rare. The most common cause of internal bleeding is carcinoma (cancer), either of the gastro-intestinal tract or of the lung, or more rarely of other organs such as the prostate, pancreas or kidney. Peptic ulceration and non-malignant inflammatory conditions of the colon (large bowel) remain, at least in the high-stress environment of Western Society, significant and indeed increasingly common conditions.
Natural History, Complications and Prognosis
Depending on where it occurs (e.g. brain, stomach, lungs), internal bleeding can be a serious medical emergency, potentially causing death if not given a proper treatment quickly.
Internal bleeding can be serious for two reasons:
- The blood can compress organs and cause their dysfunction (as can occur in hematoma).
- When it does not stop spontaneously, the loss of blood will cause hemorrhagic shock, which can lead to brain damage and death.
Medical investigation is necessary to identify internal bleeding. The external signs are general signs of hypovolemic shock (see the article about shock for more information).