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.
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.
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.
The symptoms of internal bleeding depend upon the circumstances. Sometimes it is the location of the bleeding and not the amount that makes the difference. Sometimes it is the amount of blood that is lost and sometimes it is a combination of the two.
Shock may occur if there is enough blood lost to decrease the amount of blood within the circulatory system. The signs and symptoms of shock may include rapid heartbeat, low blood pressure, cool and sweaty skin, and decrease mental function or confusion.
Most healthy people can lose 10% to 15% of their blood supply and show minimal signs of shock. This blood loss is the equivalent of donating a pint of blood. Symptoms become more severe as more blood is lost.
Children, the elderly, and those taking certain medications may not exhibit classic signs and symptoms and medical care providers may need to maintain a higher level of suspicion when looking for internal bleeding.