Bleeding disorders are a group of conditions that result when the blood cannot clot properly. In normal clotting, platelets, a type of blood cell, stick together and form a plug at the site of an injured blood vessel. Proteins in the blood called clotting factors then interact to form a fibrin clot, essentially a gel plug, which holds the platelets in place and allows healing to occur at the site of the injury while preventing blood from escaping the blood vessel. While too much clotting can lead to conditions such as heart attacks and strokes, the inability to form clots can be very dangerous as well, as it can result in excessive bleeding. Bleeding can result from either too few or abnormal platelets, abnormal or low amounts of clotting proteins, or abnormal blood vessels.
Bleeding disorders fall into two main categories: inherited and acquired. Inherited bleeding disorders have a genetic predisposition and involve a deficiency of coagulation factors. Acquired bleeding disorders can be caused by conditions that an individual may develop at any point during their lifetime. These can be broader in range and dependent on comorbid conditions. The focus of this discussion will be on congenital coagulopathies; acquired bleeding disorders will be considered to be outside the scope of the information presented here.
Types of Bleeding Disorders
There are numerous different bleeding disorders, but the following are the most common ones:
- Hemophilia A and B – are conditions that occur when there are low levels of clotting factors in your blood. It causes heavy or unusual bleeding into the joints. Though hemophilia is rare, it can have life-threatening complications.
- Factor II, V, VII, X, or XII deficiencies – are bleeding disorders related to blood clotting problems or abnormal bleeding problems.
- Von Willebrand’s disease – is the most common inherited bleeding disorder. It develops when the blood lacks the von Willebrand factor, which helps the blood to clot.
Specific bleeding disorders include
- Acquired platelet function defects
- Congenital platelet function defects
- Disseminated intravascular coagulation (DIC)
- Prothrombin deficiency
- Factor V deficiency
- Factor VII deficiency
- Factor X deficiency
- Factor XI deficiency (hemophilia C)
- Glanzmann disease
- Hemophilia A
- Hemophilia B
- Idiopathic thrombocytopenic purpura (ITP)
- Von Willebrand disease (types I, II, and III)
Inherited bleeding disorders include the following
- Combined deficiency of the vitamin K–dependent clotting factors (VKCFDs) – caused by a problem with clotting factors II, VII, IX, and X.
- Hemophilia A – a condition in which you are missing clotting factor VIII or have low levels of clotting factor VIII. Hemophilia A is the most common type of hemophilia.
- Hemophilia B – a condition in which you are missing clotting factor IX or have low levels of clotting factor IX.
- Hemophilia C – a rare condition also known as factor XI deficiency.
- Von Willebrand disease (VWD) – the most common inherited bleeding disorder. The different types of VWD are numbered based on how common the condition is and how severe the symptoms are. For example, VWD 1 is the most common, and symptoms are usually mild, and VWD 3 is uncommon with symptoms that are usually severe.
- Other inherited bleeding disorders – include other factor deficiencies, such as I, II, V, V + VIII, VII, X, XI, or XIII deficiencies. These rare bleeding disorders are named by the clotting factor causing the problem.
- Hereditary hemorrhagic telangiectasia – is a rare inherited condition in which your blood vessels get tangled in different parts of the body, which can lead to bleeding.
Acquired bleeding disorders
Pathophysiology
Bleeding disorders may present in correlation with their severity, and some may be undetected until a major trauma or surgery occur. Patients with a severe form of hemophilia In hemophilia, categorized as less than 1% of normal plasma levels, will often present with 20 to 30 episodes of epistaxis a year, excessive bleeding after minor traumas or into muscles and joints (hemarthrosis). Diagnosis usually occurs within the first two years of life and can be immediately evident after circumcision. Newborns can also present with intracranial hemorrhages, cephalohematoma or umbilical cord bleeding immediately following delivery.[rx] Those with a more moderate form of the disease (6 to 30% of normal levels) may only bleed excessively after surgery or a major trauma.
Von Willebrand factor (vWF) is a glycoprotein produced in endothelial cells and megakaryocytes that is responsible for facilitating platelet binding after injury of the endothelial surface occurs. Von Willebrand disease is a common congenital bleeding disorder in which there is a deficiency or dysfunction of vWF. Factor VIII levels can be affected as well. The disease presents similarly to that of a platelet abnormality and can exhibit variable clinical symptomatology from mild mucocutaneous bleeding of the nose or gingiva or menorrhagia to hemarthrosis in more severe cases. The disease categorized into three types. Type I is the most common, representing 60 to 80% of cases. Type 1 von Willebrand disease is a heterozygous deficiency in which there may be only 20% to 40% of normal levels of vWF in addition to a reduction in Factor VIII levels. Patients with Type I von Willebrand disease can present with mild clinical symptoms like a propensity for easy bruising, mucosal bleeding or menorrhagia.[rx] Medications that inhibit prostaglandin and thromboxane synthesis may significantly exacerbate symptoms and can often aid in initial diagnosis.[rx] Type 2 von Willebrand disease is less common, representing approximately 17% of the reported cases, and is characterized by a qualitatively abnormal vWF which can also be associated with thrombocytopenia and decreased Factor VIII. There are four distinct subtypes within the Type 2 category. Type 2A lacks a normal vWF multimer because of abnormal proteolysis or reduced secretion of the factor. Type 2B is a mutation that causes the vWF to be hyperactive and have an increased binding affinity to platelets causing the creation of complexes that are quickly cleared from the circulation, ultimately resulting in thrombocytopenia.[rx] Type 2M possesses a decreased platelet binding ability to vWF with depleted factor levels, and Type 2N exhibits a decrease in binding of vWF to Factor VIII. Type 3 is the rarest and the most severe form of the disease representing approximately 3% of the cases, where there are markedly diminished levels of vWF and FVIII.
Causes of Bleeding Disorders
Hemophilia, an x-linked heredity disorder, is diagnosed by an abnormal concentration of Factor VIII or IX. Approximately one-third of cases arise from a spontaneous mutation. Von Willebrand disease, with an autosomal dominant inheritance pattern, has variable penetrance and clinical symptoms can vary from person to person. The most severe pathology occurs in homozygotes.[rx] Neither bleeding disorder has a predilection for a specific race.
Symptoms of Bleeding Disorders
Symptoms of bleeding disorders may include:
- Easy bruising
- Bleeding gums
- Heavy bleeding from small cuts or dental work
- Unexplained nosebleeds
- Heavy menstrual bleeding
- Bleeding into joints
- Excessive bleeding following surgery
- Bleeding into joints, muscles and soft tissues
- Excessive bruising
- Prolonged, heavy menstrual periods (menorrhagia)
- Unexplained nosebleeds
- Extended bleeding after minor cuts, blood draws or vaccinations, minor surgery or dental procedures
According to the CDC
Signs and symptoms of a bleeding disorder
- Heavy bleeding during menstruation (period) that can include
- Bleeding that lasts longer than 7 days from the time bleeding starts until the time it ends;
- Flooding or gushing of blood that limits daily activities, such as work, school, exercise, or social activities;
- Passing clots that are bigger than a grape; and
- Soaking a tampon or pad every hour or more often on the heaviest day(s).
- A diagnosis of “low in iron” or having received treatment for anemia.
- Symptoms of easy or frequent bleeding can include
- Nosebleeds that occur for no apparent reason and last longer than 10 minutes or that need medical attention
- Easy bruising that occurs with no physical injury;
- Excessive bleeding after a medical procedure or dental extraction; and
- History of muscle or joint bleeding with no physical injury.
- Having one or more of the bleeding symptoms above and a family member with a bleeding disorder, such as von Willebrand disease or hemophilia.
or
- Blood in urine or stool
- Excessive bleeding that does not stop with pressure and may start spontaneously, such as with nosebleeds, or bleeding after a cut, dental procedure, or surgery
- Frequent, large bruises
- Heavy bleeding after giving birth
- Heavy menstrual bleeding, which includes menstrual bleeding that often lasts longer than seven days or requires changing sanitary pads or tampons more than every hour
- Petechiae, or bleeding under the skin causing tiny purple, red, or brown spots
- Redness, swelling, stiffness, or pain from bleeding into muscles or joints, which is particularly common with inherited hemophilia
- Umbilical stump bleeding that lasts longer than what is typical for newborns—about one to two weeks after the umbilical cord is cut—or that does not stop
Diagnosis of Bleeding Disorders
To diagnose a bleeding disorder and whether it may be inherited or acquired, your doctor may order one or more of the following tests.
- A complete blood count (CBC) – to measure many different parts of your blood, such as the number of blood cells and platelets. If the number of platelets is too low, you may have a platelet disorder instead of a clotting factor disorder.
- A partial thromboplastin time (PTT) test – also called an activated PTT (aPTT), to measure how long it takes blood to clot. It can help determine whether certain clotting factors are involved.
- A prothrombin time (PT) test – is another test to measure how long it takes blood to clot. It measures clotting factors that the PTT test does not.
- A mixing test – to help determine whether the bleeding disorder is caused by antibodies blocking the function of clotting factors, such as with autoimmune disorders or acquired hemophilia.
- Von Willebrand factor (vWF) tests – to measure the amount of von Willebrand factor, whether the factors are working correctly, or which type of VWD you have.
- Clotting factor tests – also called factor assays or a coagulation panel, to determine whether certain clotting factors are missing or show up at lower levels than normal, which can indicate the type and severity of the bleeding disorder. For example, if you have very low levels of clotting factor VIII, you may have hemophilia A.
- A Bethesda test – to look for antibodies to factor VIII or IX
- Factor XIII antigen and activity assays – to look for factor XIII deficiency
- Genetic testing – to determine if particular genes may be causing the bleeding disorder. Your doctor may refer you or your child to a specialist in genetic testing.
For some bleeding disorders, such as hemophilia, the clotting factor test can tell you how severe the disorder is. Below are possible results from testing for hemophilia A:
- Severe hemophilia A: <1% of factor VIII detected
- Moderate hemophilia A: 1% to 5% of normal factor VIII levels
- Mild hemophilia A: 6% to 30% of normal factor VIII levels
For hemophilia A, the amount of factor VIII is measured and compared to normal amounts. If you have mild hemophilia, you would have 30% or less of the factor VIII levels that a person without a bleeding disorder would have. If you have moderate hemophilia, you would have less than 6% of normal factor VIII levels. If you have severe hemophilia, there would be no detectable levels of factor VIII.
Hemophilia – While mild hemophilia may only present after a traumatic injury or surgery, those with a moderate to severe form of the disease may exhibit hallmark characteristics such as mucosal or gingival bleeding, easy bruising, and hematoma formation. The concern is when there is bleeding into joints, particularly in the ankles, knees, and elbows, referred to as hemarthrosis. Hemarthrosis can initiate an inflammatory process to occur in which the joints become painfully swollen and eventually limit motion.[rx] There is potential for the perpetuation of a vicious cycle whereby the joints are damaged resulting in synovitis, and an area for subsequent bleeding can occur. Over time hemophilic arthropathy occurs with joint narrowing, bone cysts and a decreased range of motion. Bleeding into muscle tissue from minor traumas can result in anemia and compression of vital structures and nerves leading to compartment syndrome. Bleeding less frequently occurs in the urinary and gastrointestinal tracts. These patients are at significant risk of intracranial bleeds which would be a life-threatening emergency. Hemophilia can present in infancy with cephalohematoma formation after vaginal birth and with significant bleeding after circumcisions.
Von Willebrand Disease – Von Willebrand disease can exhibit clinical signs and symptoms starting in childhood with a history of easy bruising and bleeding. While patients with a very mild version of the disease may not have clinical symptoms at all, patients with vWF that is qualitative or quantitatively low may present with a predisposition to mucosal bleeding and episodic epistaxis. Women with von Willebrand disease may have significant menorrhagia which is often a presenting sign of the illness, precipitating a workup and eventual diagnosis.[rx] These patients can also go unrecognized until undergoing major surgery or experiencing a traumatic injury.
Laboratory Evaluation for Bleeding Disorders
Laboratory testing is essential for diagnosing bleeding disorders. However, the specific panels necessary for an accurate diagnostic evaluation are not standardized and may vary significantly between hospitals and regions. Routine laboratory analysis for clotting disorders starts with platelet count, prothrombin time (PT), partial thromboplastin time (aPTT), the international normalized ratio (INR), and bleeding time. The platelet count should not only have a sufficient quantity (normal = 150000 to 500000/ml) but must also be functional. The bleeding time assesses the function of the platelets. Bleeding times can be delayed in a patient with vWF deficiency or from specific medications that interfere with platelet function (NSAIDs, aspirin, and valproic acid). PT (normal = 11.5 to 14s) represents the function of coagulation factors II, V, VII, and X which are the hepatically synthesized vitamin K dependent factors. The PT and INR will be affected by patients taking warfarin as it interferes with the synthesis of vitamin K dependent factors. The INR (normal= 0.8 to 1.2) is a ratio that is used to estimate the percent of functional clotting factors. For example, an INR of between 2 to 3 correlates approximately to 10% of active clotting factors present. It is necessary to have at least 30% of the clotting factors present for normal coagulation. Partial thromboplastin time (normal = 25 to 40s) measures the efficacy of von Willebrand Factor and factors VIII, IX, XI, and XII.[rx]
Hemophiliacs will have an elevated aPTT and a normal PT/INR, bleeding time and platelet count. The aPTT, a measure of the intrinsic pathway, will be elevated as a result of low levels of FVIII. An elevated aPTT should prompt investigation by looking at individual factor levels, specifically Factor VIII and IX.[rx] When evaluating specific factor levels, the amount of factor present will determine the severity of the disease. When the diagnosis is suspected, emphasis must also focus on family history including maternal male family members.
Diagnosis of von Willebrand disease is represented by increased bleeding time and a decrease in vWF levels as measured by the ristocetin cofactor collagen binding, in addition to a history of bleeding and positive family history of von Willebrand disease. The recommendation is that patients are tested at least three times before making the official diagnosis as vWF levels are subject to fluctuate, changing with stress, pregnancy, exercise, and inflammatory processes. There are also some subtle differences in vWF levels based on gender and blood type.[rx] Von Willebrand disease requires factor multimer assays to diagnose the specific subtype of the disease. Additionally, the aPTT may be mildly elevated in approximately 50% of patients with von Willebrand disease second to low levels of factor VIII.
Treatment of Bleeding Disorders
The mainstay treatment of hemophilia is factor replacement, either prophylactically or need-based. Recombinant-derived Factor VIII and IX concentrates are available and prevent the risk of viral transmission.[rx] Recombinant Factor VIII increases the plasma concentration by 2% for every 1 IU/kg, and recombinant factor IX produces an increase of 0.8% for every 1IU/kg given. The goals of correction are to achieve a 50% plasma value for the management of bleeding risks such as surgery and 100% correction in the setting of major trauma. These levels should be obtained 30 minutes before the onset of surgery and maintained for 2 to 7 days after surgery. The timing of subsequent doses is determined based on factor half-life which is typically 8 to 12 hours.
The treatment of von Willebrand disease consists of desmopressin (DDAVP) or cryoprecipitate. DDAVP will enhance the release of vWF in patients with Type 1 von Willebrand disease. DDAVP is a synthetic derivative of antidiuretic hormone that acts on type 2 vasopressin receptors. It works by stimulating the release of vWF from endothelial cells by way of signaling through the cyclic adenosine monophosphate pathway which prompts the release of Weibel-Palade bodies into the endothelial cells and eventually into the plasma.[rx] Additionally, DDAVP works on the renal collecting duct as an anti-diuretic. It reduces the amount of water that is eliminated in the urine potentially causing dilutional hyponatremia; therefore, patients should have fluid restriction maintained while receiving this medication.[rx] DDAVP administered intravenously (0.3mcg/kg) will increase plasma Factor VIII and VWF levels by 3 to 5 times their baseline within 30 to 60 minutes after administration. DDAVP can also be administered subcutaneously (0.3 mcg/kg) or at fixed intranasal doses which is convenient for prophylactic treatment at home. DDAVP administration is expected to raise levels to 30 to 50% in patients with a baseline of 10% factor activity which may be sufficient for low-risk procedures but may require further supplementation to increase vWF to adequate levels needed for trauma or major surgery. Patients with a baseline of 20% factor level receiving DDAVP can see levels rise to 60 to 100% which would be suitable for most surgical procedures. Approximately 10% of patients within the Type 1 category may fail to respond to DDAVP; therefore, the recommendation is that patients undergo a trial of DDAVP administration at diagnosis or before its clinical need. Patients with Type 2 and 3 von Willebrand disease typically require replacement products consisting of Factor VIII and vWF. It is also important to note that patients with Type 2a and 3 will not respond to DDAVP as the former possesses dysfunctional vWF and Type 3 lacks releasable stores of vWF. Type 2b should never be given DDAVP, as it is contraindicated due to its potential thrombogenicity.[rx]
Replacement Products
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There is a human plasma-derived concentrate of Factor VIII with an even higher concentration of vWF. This product has been the subject of extensive study and deemed to be the safest option for factor replacement as it has undergone a pasteurization process to inactivate any blood-borne viruses. It has approval from the Food and Drug Administration (FDA) for the treatment and prevention of bleeding disorders in adult patients with Hemophilia A, as well as adult and pediatric patients with von Willebrand disease.[rx]
Factor VIII replacement with human plasma-derived concentrate of Factor VIII requires a simple weight-based calculation. The patient’s weight (in kg) is multiplied by the desired percent level of Factor VIII, assuming that starting levels are 0. That number then gets multiplied by the volume of distribution, which is approximately 0.5.[rx] Thus, the dose of human plasma-derived concentrate of Factor VIII = weight in kg x desired Factor VIII level x 0.5. For a 60kg female, with a target goal of 50% Factor VIII level: 60 x 50 x 0.5 = 1500 units of Factor VIII.
Alphanate is another commercially available, virally inactivated product with Factor VIII and ristocetin cofactor activity essential for vWF support. The FDA has approved its use for both adults and children with Hemophilia A or von Willebrand disease who require treatment or prevention of spontaneous or trauma-related bleeding, including surgery.
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Factor IX concentrate is a commercially available product and has been subject to various purification techniques to eliminate the risk of viral transmission during its administration. These products have FDA approval for use in the setting of prevention and control of bleeding in patients with a factor IX deficiency.[rx]. Dosing of Factor IX concentrate = weight in kg x desired factor level x volume of distribution (which is 1 for Factor IX). For a 60kg female with a target goal of 100% Factor IX level: 60 x 100 x 1 = 6000 units.
Allogenic Replacement Therapy
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Fresh frozen plasma (FFP) contains Factor VIII and vWF, but large volumes are needed to obtain adequate factor levels (20 to 25mL/kg).
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Cryoprecipitate is a human plasma-derived product containing high levels of Factor VIII, vWF and fibrinogen (Factor I). It comes packaged in small volumes, so multiple bags are often required to obtain the adequate level of the factor desired. Virus inactivation is not routinely applied to these products therefore virally inactivated replacement products are considered a safer alternative to FFP and cryoprecipitate. The absence of factor IX in cryoprecipitate negates its use in Hemophilia B.
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Platelet transfusions are necessary when bleeding continues despite normal Factor VIII levels. Platelets can transport and localize the vWF from the site of the vascular injury.
Antifibrinolytic Acid Therapy
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Aminocaproic acid is a synthetic analog of lysine used to control or prevent hemorrhage. It competitively reduces the conversion of plasminogen to plasmin thereby inhibiting fibrinolysis and promoting clot formation. It is typically administered as an intravenous infusion during a surgical procedure but is also available in an oral form for home use in patients with bleeding disorders. It is available as a mouthwash or a tablet for oral bleeding, recurrent epistaxis or menorrhagia. This agent is FDA approved in the treatment of patients with bleeding disorders and is often useful as an adjunct therapy in patients with coagulopathic potential.
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Tranexamic acid is a synthetic medication made from lysine which acts by competitively inhibiting plasminogen activation and is considered more potent than aminocaproic acid. At higher concentrations, it can act as a non-competitive inhibitor of plasmin. It has ten times the potency of aminocaproic acid and is FDA approved for use in patients with bleeding disorders. It is available in intravenous and oral formulations. The oral preparation can also help in the treatment of recurrent minor bleeding issues that occur at home and in preparation for dental work.[21]
Hormonal Treatments
Oral contraceptives such as oral progestins and depot medroxyprogesterone have been shown to be effective in women with Type 1 von Willebrand disease with menorrhagia by significantly elevating circulating vWF levels. While the exact mechanism of estrogens’ influence on vWF is not entirely understood, it is hypothesized to occur as a result of its lipophilic nature, allowing it to penetrate the cytoplasm of the nuclear receptors thereby increasing gene transcription of the various clotting proteins.[rx]
According to
Medicines to treat bleeding disorders may include the following.
- Antifibrinolytic agents – such as tranexamic acid, to treat bleeding after childbirth or during procedures such as those involving dental work
- Birth control pills – to treat heavy menstrual bleeding for women with von Willebrand disease
- Desmopressin (DDAVP) – a human-made hormone, to treat minor bleeding in hemophilia or VWD.
- medicines – such as prednisone, to block the production of antibodies in acquired bleeding disorders. Side effects can include infections and diabetes.
- Vitamin K supplement – to treat vitamin K deficiency bleeding
Factor replacement therapy
Bleeding Disorders
References