Table of Contents
- Hematoma facts
- What is a hematoma?
- What causes a hematoma?
- What conditions cause a hematoma?
- What are other conditions that cause hematomas?
- What are the different types of hematomas?
- What are epidural and subdural hematomas?
- What are intracerebral and scalp hematomas?
- What are ear and nasal hematomas?
- What are intramuscular and subungual hematomas?
- What are subcutaneous and intra-abdominal hematomas?
- What are the symptoms of a hematoma?
- How does a hematoma resolve?
- When should I call a doctor about a hematoma?
- How is a hematoma diagnosed?
- What is the treatment for a hematoma?
- What are the complications of a hematoma?
- Can hematomas be prevented?
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What is a hematoma?
A hematoma is an abnormal collection of blood outside of a blood vessel. It occurs because the wall of a blood vessel wall, artery, vein, or capillary, has been damaged and blood has leaked into tissues where it does not belong. The hematoma may be tiny, with just a dot of blood, or it can be large and cause significant swelling.
The blood vessels in the body are under constant repair. Minor injuries occur routinely and the body is usually able to repair the damaged vessel wall by activating the blood clotting cascade and forming fibrin patches. Sometimes the repair fails if the damage is extensive and the large defect allows for continued bleeding. If there is great pressure within the blood vessel, for example, a major artery, the blood will continue to leak through the damaged wall and the hematoma will expand.
Blood that escapes from within a blood vessel is very irritating to the surrounding tissue and may cause symptoms of inflammation including pain, swelling, and redness. Symptoms of a hematoma depend upon their location, their size, and whether they cause associated swelling or edema.
Hematomas may occur anywhere in the body. Regardless of how a hematoma is described or where it is located, it remains a collection of clotted blood outside of a blood vessel.
Longo, Dan, et al. Harrisons's Principles of Internal Medicine. 18th ed. McGraw-Hill, 2011.