Hematoma

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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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• Hematoma Overview
• Hematoma Causes
• Hematoma Symptoms
• When to Seek Medical Care
• Hematoma Diagnosis
• Hematoma Treatment
• Hematoma Self-Care at Home
• Hematoma Medical Treatment
• Hematoma Follow-up
• Hematoma Prevention
• Hematoma Prognosis
• Synonyms and Keywords
• Author and Editor

Hematoma Overview

A hematoma is a collection of blood, usually clotted, outside of a blood vessel that may occur because of an injury to the wall of a blood vessel allowing blood to leak out into tissues where it does not belong. (heme=blood + oma=tumor or collection). The damaged blood vessel may be an artery, vein, or capillary; and the bleeding may be very tiny, with just a dot of blood or it can be large and cause significant blood loss. It is a type of internal bleeding that is either clotted or is forming clots. Hemorrhage is the term used to describe active bleeding and is often graded on a severity score of one to four (15% to >40% of total blood volume). Hematoma describes bleeding that has already started to become clotted. However, the distinction sometimes is not clear as some hematomas enlarge over time as active bleeding can add to the mass of the hematoma.

Hematomas are often described based upon their location in the body, whether it is in the skull (intracranial: intra=within +cranium=skull), under the fingernail (subungual: sub=underneath + ungual=nail), or in the earlobe.

Hematomas of the skin may also be named based upon their size. Petechiae are tiny dots of blood usually less than 3mm (0.12 inch) while purpura is less than 10mm (0.40 inch) and ecchymosis is greater than 10 mm. Ecchymosis is commonly considered a bruise.

Hematomas form when a blood vessel leaks into surrounding tissue. The injury to a blood vessel wall may occur spontaneously or may be due to trauma. While the word trauma is often thought to be a major injury, it can also refer to minor damage that can occur routinely. The violence of a sneeze or cough may cause blood vessels in the face to break and cause small amounts of bleeding. 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 the bleeding occurs in a tiny capillary blood vessel, only a drop or two of blood may be lost into the surrounding tissue causing petechiae to form. If there is great pressure within the blood vessel, for example a major artery, the blood may continue to leak and cause an expanding hematoma that cause significant blood loss and shock.

Blood that escapes from the blood stream is very irritating and may cause all the symptoms of inflammation including pain, swelling and redness. Symptoms of a hematoma depend upon their location, their size and whether they cause associated swelling, edema or pressure on adjacent structures such as blood vessels and nerves.

Hematoma Causes

Hematomas are usually caused by trauma, whether it is the result of a car accident, a minor bump, a cough, or an unknown event. The blood within blood vessels is continually flowing and therefore does not clot or coagulate. When blood leaves the circulatory system and becomes stagnant, there is almost immediate clotting unless the individual is taking anticoagulation medication to prevent blood clots (these may include aspirin, warfarin [Coumadin], clopidogrel [Plavix) and dipyridamole [Persantine]). The greater the amount of bleeding that occurs, the larger the hematoma.

Blood vessels that are fragile may contribute to hematoma formation. For example, an aneurysm or weakening in a blood vessel wall may gradually cause blood vessel cell walls to come apart from constant exposure to the blood flowing and spontaneously leak.

There are many people who take blood thinners or anti-coagulation medications. Examples include warfarin (Coumadin), aspirin, clopidogrel and prasugrel (Effient). These medications increase the potential for spontaneous bleeding and for allowing hematomas to expand because the body cannot efficiently repair blood vessels and blood continues to leak through the damaged areas.

Occasionally, diseases (for example, autoimmune diseases and bacterial infections) may occur that decrease the number of platelets in the blood stream or their ability to function. The platelets are the cells that help initiate blood clot and fibrin formation. If platelets are inhibited, bleeding can continue and hematomas can develop and expand. Examples of bacterial infections and autoimmune diseases include:

• finger infection,
  
  
• ankylosing spondylitis, and
  
  
• onychomycosis.

All these situations may exist independently to cause a hematoma or two or more may occur together.