Splenic hemorrhage is a potentially life threatening situation. The abdominal cavity is a potential significant space that could contain a significant amount of blood. If a large amount of blood is lost into this space, the abdominal wall musculature is stretched and abdominal distension will be noted. Abdominal distension also may cause discomfort and pain, leading to increased agitation and stress. The rapid expansion of the abdomen may also cause pressure on the diaphragm, and thus, a decreased ability to breath comfortably.
Rapid blood loss into the abdomen will also lead to a decrease in blood pressure and tissue perfusion. This may lead to shock. As continued blood is lost, the decrease in circulating red blood cells may lead to acute (sudden) anemia. Pale mucus membranes are commonly observed. If veterinary care is not immediately available, rapid blood loss may lead to death. A slower blood loss is more common and will allow for more time to seek veterinary care.
Chronic (long standing) or intermittent blood loss generally occurs more slowly, and more subtle clinical signs might be present. If the blood loss is slow, the body can reabsorb the free blood. Thus, animals may only have a small amount of blood present in the abdominal cavity. These animals may not present as an emergency, but they still may have a serious underlying disease process. Making the diagnosis of a splenic hemorrhage is critical in establishing an underling cause.
If the animal has normal clotting parameters, the bleeding into the abdomen will often stop on it's own. Blood clots form and stop the bleeding. Sometimes an animal will collapse due to the acute blood loss and then slowly recover due to clot formation and the body's own compensatory mechanisms. These animals appear pale and weak initially, but with time, they slowly become stronger and their mucus membranes again become pink. Owners may describe intermittent episodes of weakness followed by spontaneous recovery. Blood clots can, however, be dislodged especially with increased movement or manipulations. If blood clots are dislodged, the bleeding may start again.
Causes Trauma. The most common traumatic injury causing a splenic hemorrhage occurs when an animal is hit by a car. Severe splenic trauma may cause a rapid death if the bleeding is significant. Most of the time, bleeding occurs more slowly and there is time to seek emergency care. In addition to damage to the spleen, the liver may also be affected. The bleeding may be mild or severe, but most of the time it will stop without intervention. Other causes of trauma include gun and knife wounds that pierce the spleen.
Tumors. Tumors of the spleen may erode a blood vessel or simply rupture causing an acute bleed. The most common tumor is a hemangiosarcoma, which is a tumor of blood vessels. These tumors are aggressive and malignant and are commonly found on the spleen or liver. Golden retrievers and German shepherd dogs are two breeds at increased risk of getting this tumor. A hemangioma is the benign form, but it is not as commonly seen. Hemangiosarcoma is a common tumor in dogs, but it is rare in cats. In cats they usually involve the spleen, mesentery, liver or gastrointestinal tract.
Hematomas. Hematomas are formed by broken blood vessels that cause blood to accumulate in the spleen and are a common cause of splenic hemorrhage. They may be caused by previous trauma, or more commonly nodular regeneration, which is excessive production of splenic tissue. Hematomas may be quite large and are indistinguishable from hemangiosarcomas at surgery.