Bruises are the bluish or brownish patches that mostly develop after trauma in living organisms with warm blood. They are the result of extravasation of blood outside the lumen of blood vessels, especially platelets within an area of the body -mostly skin and muscles-. Almost all humans including you and I have experienced bruises, whether from being hit by a punch, after injections or even one discovered without a memory of trauma.
Where do bruises come from?
Bruises occur due to the flow of blood from blood vessels after their rupture. Such rupture is almost always due to trauma, even minor trauma that is experienced in every day life and their medical term is “contusions.” Most contusions form on exposed surfaces of our bodies especially our arms and legs and vary from small almost unnoticeable spots to large patches several centimeters across. When the blood escapes from the injured blood vessels, it causes inflammation, and one of the so-called cardinal signs of inflammation is “Rubor” or red colour. Therefore, immediately after the injury, the area is reddish and swollen. After a few hours, the bruise starts to be well defined and bluish. The reason for the bluish discolouration is the chemical change of haemoglobin found in red blood cells, where it loses its oxygen and becomes “reduced” or “deoxygenated’. After a few days, the bruise becomes green then yellow or light brown and then eventually disappears. This is also due to the degradation of haemoglobin into biliverdin -which is green- then to bilirubin -which is yellow-, such changes can help doctors roughly estimate the age of a bruise. The primary source of extravasation of blood is stopped within minutes by the action of our blood vessels, clotting mechanisms and platelets, and the bruise is eventually absorbed into the surrounding tissue.
When to worry about bruises in adults?
As mentioned above, bruises, in general, are a physiological response to trauma and active circulation. In fact, dead people don’t bruise, and the last bruise can be used to determine the time of death -along with other 100 or so forensic signs-. Therefore, the mere presence of bruises should not call for concern; on the other hand, some factors can indicate a more serious condition that requires the assistance of a doctor:
○ Multiple bruises
If there is no memory of trauma at these sites, the presence of bruises should call for concern, and a visit to the physician may be necessary.
○ Large bruises
Although bruises vary in size, the presence of large bruises can be alarming, and a bruise that is more than a few centimetres -even after trauma- can indicate a problem in the mechanisms of coagulation.
○ Muscular bruises
Muscle bruising has the same mechanism as bruises of the skin, but the force that causes the rupture of a blood vessel inside a muscle needs to be considerably stronger, and even though muscle contusion by itself is not hazardous and the risk of complications is very low, the trauma that caused the contusion could have caused muscle rupture or broken bones. The primary way to differentiate pain severity is the degree of functional limitation. A patient with a ruptured muscle can never move that body part, while in the case of contusions, the range of movement is only reduced and associated with pain.
○ Bruises over joints following trauma
If a joint is tender and painful after trauma with a bruise, it may be necessary to seek medical care, as it can indicate a broken bone, and an X-ray is mandatory in such cases.
○ If associated with bleeding
Contusions in themselves only indicate trauma. However, if they are multiple and associated with bleeding from minor trauma or spontaneously whether in the form of bloody vomiting, bloody defecation, bleeding per nose, heavy menses, or blood in urine, it could point out to a problem in coagulation or platelet function.
○ Bruises that don’t go away
Following trauma or spontaneously, bruises are absorbed into the surrounding tissue by the action of cells called macrophages or “big eaters.” The persistence of a bruise means that the source isn’t controlled and that it leaks at a rate that exceeds the ability of macrophages to absorb; this can be found in many blood coagulation disorders.
What causes easy bruising?
Causes of easy bruising are diverse, and the best way to categorize them is to classify them according to the dysfunctional mechanism that eventually led to their development and/or persistence:
• Platelet disorders
Blood platelets “clog” and temporarily patch small defects of any vessel wall after trauma, so they are responsible for the initial cessation of bleeding. They also function to activate the coagulation pathway, which eventually leads to the healing of the defect. Platelet disorders can either be a problem of quantity or quality:
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- Thrombocytopenia: Thrombocytopenia is a general medical term that indicates a decrease of platelet count, they can be as a reaction to infections, a side effect of some drugs or due to failure of the bone marrow to produce enough platelets, thrombocytopenia can also be due to an enlarged spleen, a condition known as hypersplenism. In young females, the presence of thrombocytopenia may necessitate looking for autoimmune diseases as systemic lupus, especially if it is associated with fertility problems or pregnancy complications. If thrombocytopenia cannot be attributed to a cause, it is diagnosed as immune thrombocytopenic purpura, which is an immune-mediated disease where the body produces antibodies that destroy and prevent the formation of new platelets, it develops after acute viral infection in most cases.
- Thrombasthenia: Thrombasthenia means “weak” platelets, which is an umbrella of disorders that have a normal platelet count but decreased function. They may be hereditary as Glanzmann’s thrombasthenia or may result as a desired or an undesired effect of a drug, the best example here is Aspirin.
• Coagulation disorders
Coagulation is a complex process that involves the interaction of many mediators and proteins, and when any step of this process is disrupted, consequences will affect the whole pathway. The leading causes of easy bruising that is related to coagulation are:
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- Hemophilia A: Hemophilia A is one of the most common diseases related to coagulation. It results from the absence of factor VIII, which is integral in the coagulation cascade and which appears soon after birth in most cases, patients are mostly males as it is a sex-related genetic disease.
- Hemophilia B: Also known as Christmas disease, it results from the absence of factor IX. Males are also the vast majority of patients.
- Vitamin K deficiency: Vitamin K is one of the fat-soluble vitamins that is produced from the bacteria of our gut and our diet, especially leafy vegetables. Its deficiency has recently been attributed to the rise in the abuse of antibiotics that led to the unwanted elimination of gut bacteria that produce the vitamin.
- Liver disease: The liver is both the filter and the manufacturing plant of our bodies; it produces many proteins that are essential for the functioning of our coagulation as well as most coagulation factors. Any disease that causes liver dysfunction will certainly affect coagulation. These diseases may include alcoholic liver disease, viral hepatitis and fatty liver disease.
- Von Willebrand disease: Like hemophilia, Von Willebrand disease is the congenital absence of a coagulation factor that also functions in the normal adhesion of platelets.
- Drugs: Drugs such as Warfarin and Heparin act through the inhibition of coagulation and are used in many conditions when blood thinning is needed. Patients receiving those drugs include cardiac patients who underwent mechanical valves implantation in their hearts, those with conditions liable to have blood clots like deep vein thrombosis and lupus with pregnancy. The main disadvantage of those drugs is that they must be finely calibrated; otherwise, toxicity will happen, and one of the main signs of toxicity besides bleeding is the development of bruises.
• Cancer
Cancer is a heterogeneous group of diseases that are commonly characterized by the invasion of the surrounding tissue and spread to distal ones. Cancers can cause easy bruising by many mechanisms. Blood cancer or Acute Leukemia can cause thrombocytopenia due to the invasion of bone marrow by malignant cells, metastases from other cancers act by the same mechanism, liver cancer can cause bruising when liver functions are affected. On the other hand, some cancers such as chronic leukemia can cause increased platelet count, but since those platelets are dysfunctional and deformed, their function is null, and bruising can also result.
- Consumption coagulopathy: It is a rare condition that results from the aberrant activation of coagulation when there is no need and is better known as DIC or “Disseminated Intravascular Coagulopathy.” It can result from severe infections, dehydration, bleeding into body cavities, burns or some cancers. When the coagulation factors and platelets are consumed, the blood can’t clot anymore, and bleeding is seen from virtually all sites in the body including the skin.
- Normal bruising of the elderly: In many elderly patients, bruising can result from minor trauma, this is a benign condition that results from the weakness or “atrophy” of the supporting collagen of the skin, which is a normal senile process.
- In females: Many females seek medical care for what they think is easy bruising, and while some diseases that cause easy bruising are more common in females, it is mostly due to a normal variation between males and females owing to sex hormone differences. Females bruise more because they have fewer collagen fibers and a different distribution of fat, compared to men, which results in less support of their blood vessels.