Bone marrow is responsible for the production and constant replenishment of red blood cells (RBCs), white blood cells (WBCs), and platelets. Aplastic anemia results when the bone marrow is not able to replenish blood cells. This happens when the part of the normal bone marrow is replaced by adipose tissue and therefore the required number of WBCs, RBCs, and platelets are not produced resulting in decreased total number of these cells in the blood. RBCs have several vital functions in the body, including carriage of oxygen and removal of waste carbon dioxide. WBCs are essential for fighting infections and foreign particles, whereas platelets are required for clotting the blood and preventing hemorrhage. All symptoms seen in aplastic anemia directly relate to the functions of these cells. In most cases of aplastic anemia, all three types of cells are affected. If left untreated, this condition can lead to death in severely affected dogs. Some common symptoms seen with aplastic anemia are recurrent infections, fever, tiny (Petechial) hemorrhage, blood in urine, nosebleed, Black-colored feces, pale mucous membrane, weakness, and lethargy
