In humans, the presence of damaged blood vessels normally triggers the formation of blood clots to prevent blood loss. However, there are instances when blood clots can abnormally develop in the veins and arteries due to certain medical conditions, genetic variations, drugs and other contributing factors, according to the National Heart, Lung and Blood Institute.
Blood clots typically form when flowing blood encounters ruptured blood vessels, which cause the platelets and plasma proteins in the blood to coagulate. This process stems the flow of blood that could be potentially dangerous if there is profuse bleeding. During clot formation, the platelets, which are a major blood cell type, congeal into small blood clumps around the injured area. The plasma proteins, known as clotting factors, initiate the production of fibrin, which is a protein that binds the clumps together. The body usually degrades the blood clot at the first sign of healing, as stated by the American Society of Hematology.
The normal clotting process can be drastically altered due to a variety of reasons. These occurrences pose serious health risks. Underlying diseases and conditions, such as atherosclerosis, diabetes, cardiac failure, atrial fibrillation, vasculitis, antiphospholipid antibody syndrome, bone marrow disorders, thrombocythemia and metabolic syndrome are known to trigger abnormal clotting within the blood vessels. Medications, including heparin, birth control pills and hormone replacement therapy, can also induce irregular blood clotting. Other contributing factors that may result in the formation of dangerous blood clots include smoking, HIV treatments, dehydration and implanted devices.