Fibrinogen is a protein produced in the liver that plays a central role in the body’s ability to stop bleeding. It acts as a precursor to fibrin, forming the mesh-like structure that stabilizes blood clots and promotes hemostasis. When blood vessels are injured, fibrinogen is converted into fibrin, which helps to form a strong clot. Low levels of fibrinogen, known as hypofibrinogenemia or afibrinogenemia, can impair this clotting process, leading to an increased risk of bleeding.
Identifying Low Fibrinogen
Low fibrinogen levels are identified through specific blood tests, often prompted by symptoms of unusual bleeding. Common tests include the fibrinogen activity assay, which measures how well fibrinogen functions in forming a clot. Additional tests like prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin time (TT) are also used. Their results can indicate fibrinogen levels below 100 mg/dL. Symptoms that might lead to such testing include easy bruising, prolonged bleeding from minor cuts, or excessive bleeding following injury or surgery.
Common Causes of Low Fibrinogen
Low fibrinogen levels can stem from inherited genetic conditions or acquired medical issues. Inherited forms include afibrinogenemia, where fibrinogen is completely absent, and hypofibrinogenemia, characterized by reduced amounts of the protein. Dysfibrinogenemia is another inherited type where the liver produces normal amounts of fibrinogen, but it does not function correctly, potentially leading to both bleeding and clotting issues.
Acquired causes are more common and can result from various health problems. Liver disease often leads to low fibrinogen because the liver produces this protein. Conditions like disseminated intravascular coagulation (DIC) cause low fibrinogen due to its rapid consumption during widespread clotting, which paradoxically can also lead to bleeding. Severe bleeding from trauma or surgery can deplete fibrinogen levels due to excessive loss. Certain medications, such as asparaginase, and some nutritional deficiencies can also contribute to reduced fibrinogen.
Direct Treatment Approaches
Direct treatment for low fibrinogen involves supplementing the protein or enhancing the body’s natural clotting mechanisms. Fibrinogen concentrate, a purified product derived from human plasma, is a treatment option, particularly for congenital deficiencies and severe acquired cases. It provides a concentrated source of functional fibrinogen, directly increasing circulating levels to improve clotting ability. This concentrate offers quicker administration compared to other blood products, as it does not require thawing or blood type matching.
Cryoprecipitate, another blood product, is used to treat low fibrinogen. It is prepared from fresh frozen plasma and contains fibrinogen, Factor VIII, Factor XIII, and von Willebrand factor. Cryoprecipitate is administered when fibrinogen levels are below 80-100 mg/dL, especially in acquired deficiencies related to major hemorrhage or DIC. While effective, it delivers a smaller amount of fibrinogen per unit volume compared to fibrinogen concentrate, often requiring larger volumes for adequate replacement.
Fresh Frozen Plasma (FFP) provides a broad range of clotting factors, including fibrinogen. FFP is used when multiple clotting factor deficiencies are present, such as in certain liver diseases or DIC, though it contains a lower concentration of fibrinogen than cryoprecipitate or concentrate. Large volumes of FFP may be necessary to significantly raise fibrinogen levels, which can carry a risk of volume overload. Antifibrinolytic agents, such as tranexamic acid (TXA) and aminocaproic acid, prevent the breakdown of existing blood clots. These medications stabilize the clot by inhibiting plasmin, an enzyme that dissolves fibrin, thereby reducing bleeding, especially in inherited bleeding disorders.
Addressing Underlying Health Issues
Treating low fibrinogen requires addressing the underlying health condition, especially for acquired forms. For individuals with liver disease, improving liver function can enhance the natural production of fibrinogen. This may involve managing the specific liver condition, such as cirrhosis or hepatitis, to restore its synthetic capacity.
In cases of disseminated intravascular coagulation (DIC), the focus is on treating the root cause of the widespread clotting and bleeding. This could involve managing severe infections, trauma, or certain cancers that trigger DIC. Discontinuing or adjusting medications, such as asparaginase, is necessary if they are identified as the cause of low fibrinogen. When severe bleeding is the underlying issue, controlling the source of hemorrhage is important to stop the ongoing consumption of fibrinogen and other clotting factors.
Ongoing Management and Monitoring
Long-term management of low fibrinogen involves monitoring fibrinogen levels and overall bleeding risk. Individuals with chronic conditions or congenital deficiencies require regular assessments to guide their care. Healthcare providers will also advise on lifestyle adjustments, such as avoiding non-steroidal anti-inflammatory drugs (NSAIDs), which can increase bleeding risk, and implementing strategies to minimize injury.
For those with inherited forms of low fibrinogen, genetic counseling can provide information about the condition, its inheritance patterns, and implications for family planning. Patient education is a process, empowering individuals to understand their condition and recognize symptoms that require medical attention. Open communication with healthcare providers ensures that care plans are personalized and adjusted as needed, optimizing long-term outcomes and quality of life.