What Causes Internal Bleeding?
Internal bleeding may be caused by the following conditions:
- Damage to a blood vessel that can't easily be repaired by the body's internal mechanisms;
- not enough clotting factors in the blood to make the repair; or
- medications that are taken to prevent abnormal clotting.
Most people appreciate that injuries occur when great force is applied to the body. Falling from a height or being involved in a car accident may cause compression or deceleration forces that can damage the organs in the body without necessarily lacerating or cutting the skin. External bleeding is easy to recognize. Internal bleeding may be more difficult to appreciate.
Damaged Blood Vessels
Damage to the blood vessels occurs due to trauma. The amount of internal bleeding that occurs depends upon the severity of the force applied, the blood vessel that is injured, and the condition of the patient prior to injury. For example, a person taking warfarin (Coumadin), a medication that inhibits blood from clotting, will likely have more bleeding from the same amount of force due to trauma than a person whose clotting factors are working normally.
Blood vessel walls may be weakened because of chronic high blood pressure, which can cause them to dilate and form aneurysms that are at higher risk of bleeding because of weak vessel walls. However some aneurysms may also be congenital (present from birth). Regardless, the aneurysms are at risk for leaking or rupturing, and depending upon their location, may have devastating consequences. For example, an aneurysm of a cerebral artery (those that supply blood to the brain) may bleed and cause ahemorrhagic stroke; while a patient may bleed to death due to an aortic aneurysm that ruptures, causing severe internal bleeding into the abdominal cavity.
Orthopedic injuries almost always cause internal bleeding. Bone marrow is where blood cell production takes place and it has a generous blood supply. When a bone breaks, significant bleeding may be expected. Long bones like the humerus (upper arm bone), femur (thigh bone), and pelvic bones can cause the body to lose 10% or more of its blood supply.
Compression injuries occur when an external force is applied to the body and an organ is compressed between two hard surfaces. For example, if a football player is tackled, the force of the tackle may compress the spleen between the ribs and the backbone enough to make it rupture and bleed. Or imagine a weight falling on a foot compressing the tissues and the bones of the foot between the weight and the ground; there is potential for bleeding because blood vessels have ruptured.
Deceleration injuries occur when the moving body is stopped very quickly. When traveling in a vehicle; an individual is moving with the speed of the car. If the car hits a wall, the speed becomes zero very quickly. A classic deceleration injury can occur when a rapidly moving human body strikes a stationary object (chest hits a steering wheel when the vehicle hits a tree), causing the moving aorta to hit the chest wall and rupture causing fatal internal bleeding. Different parts of the body will stop at different times and the difference in the deceleration may cause organs to shift and the blood vessels that are attached to tear. If a person hits their head in a fall, the brain may fall for a fraction of a second longer than the skull that initially hits the ground. This can cause the arteries that run on the surface of the brain to tear and bleed forming epidural or subdural hematomas.
Some individuals have inherited bleeding disorders that cause spontaneous bleeding. Minimal trauma or even no apparent injury can cause internal bleeding. The most common bleeding disorders are Von Willebrand's disease and hemophilia.
Clotting factors are manufactured in the liver and any damage to the liver will increase bleeding risk. While viral infections may cause hepatitis leading to liver failure, alcohol abuse is the most common reason for the liver to fail. Aside from the lack of clotting factors in the blood, liver failure or cirrhosis can also cause blood to flow abnormally in the liver or portal system, which leads to the formation of swollen veins in the esophagus and other parts of the body. Called varices, these veins have the tendency to spontaneously weaken and bleed.
Medications are often prescribed to "thin" the blood to prevent blood clots from forming or for treating blood clots that have already occurred. Common reasons for prescribing medications such as warfarin (Coumadin) and heparin (medications that inhibit clotting factor function) include atrial fibrillation, deep venous thrombosis, and pulmonary embolism. Clopidogrel (Plavix), dipyridamole (Persantine), and prasugrel (Effient) are medications that inhibit platelet function and are often used to prevent heart attack, stroke, and peripheral vascular disease.
Aspirin is an over-the-counter (OTC) medication that is commonly recommended to prevent heart attack and stroke. It works by inhibiting platelets that help blood to clot and can be a risk factor for internal bleeding.
Alcohol, smoking, aspirin, ibuprofen and other nonsteroidal antiinflammatory medications can cause irritation of the lining of the esophagus, stomach, and intestine thus predisposing individuals to internal bleeding.
What Are Some Other Causes of Internal Bleeding?
Bleeding in pregnancy is never normal, though not uncommon in the first trimester and is a sign of a threatened miscarriage. Early on in pregnancy, the concern is that of ectopic pregnancy (tubal pregnancy), where the fetus implants in the Fallopian tube. As the placenta grows, it erodes through the tube and may cause fatal bleeding. Bleeding after 20 weeks of pregnancy may be due to placenta previa or placental abruption and emergent medical care should be accessed. Placenta previa describes the situation where the placenta attaches to the uterus close to the cervical opening and may cause painless vaginal bleeding. Abruption occurs when the placenta partially separates from the uterus wall and causes significant pain with or without bleeding from the vagina.
Depending upon the type of procedure and amount of blood loss, bleeding may occur as an expected result or as a complication of surgery. After cutting into tissue, the surgeon attempts to make certain all bleeding has stopped before the skin is closed and the operation completed. Sometimes, internal sutures can break or tissue can stretch and bleeding may restart. Often, nothing more than observation is needed, however in some situations, the surgeon may need to explore the surgical site for the cause of bleeding and repair it.
Often, the cause of internal bleeding may be a combination of many factors. The potential for internal bleeding depends upon an individual's underlying medical condition(s), medications being taking, and the injury or illness present.