Content Reviewers:Antonella Melani, MD, Lisa Miklush, PhD, RNC, CNS, Jannah Amiel, MS, BSN, RN, Jodi Berndt, PhD, RN, CCRN-K, PCCN-K, CNE, CHSE, Gabrielle Proper, RN, BScN, MN
James West is a 14-year-old male client with a history of hemophilia type A. He was brought to the emergency department, or ED, by his grandmother, Mrs. West, after falling off his skateboard.
James states that he was wearing a helmet and protective pads over his elbows and knees but that he fell onto his buttocks while learning a new skateboarding trick.
He says that it hurts to sit down or bend his left leg at the hip. Hemophilia is a group of genetic bleeding disorders caused by deficiencies in various coagulation factors.
Normally, after a tissue injury, there’s an immediate constriction of the blood vessel to limit the amount of blood flow and loss.
First off in the blood there’s a set of clotting factors, most of which are proteins synthesized by the liver, and usually these are inactive and just floating around the blood.
The coagulation cascade starts when one of these proteins gets activated. This active protein then activates the next clotting factor, and so on.
Now, the coagulation cascade can get started in two ways. The first way is called the extrinsic pathway, and it starts when tissue factor gets exposed by the injury of the endothelium.
The tissue factor turns inactive factor VII into activated factor VIIa. Together, the tissue factor and the newly formed factor VIIa form a complex that turns factor X into active factor Xa.
Factor Xa, with factor Va as a cofactor, turns factor II, also called prothrombin, into factor IIa, also called thrombin.
Thrombin then turns factor I or fibrinogen, into factor Ia or fibrin, which precipitates out of the blood at the site of injury.
On the other hand, the intrinsic pathway starts when platelets near the blood vessel injury activate factor XII into factor XIIa.
Next, factor XIIa activates factor XI to factor XIa, which further activates factor IX to factor IXa.
Finally, factor IXa and factor VIIIa work together to activate factor X to factor Xa, and from that point, both the extrinsic and intrinsic pathways basically converge on a single final path called the common pathway.
Now, the most important risk factor for hemophilia is having a family history of hemophilia; and there are three main types: A, B, and C.
The most common one is hemophilia A, which is caused by mutations of the F8 gene, leading to deficiency of factor VIII; while hemophilia B is caused by mutations in the F9 gene, which leads to deficiency of factor IX.
Both hemophilia A and B are X-linked recessive, so they almost exclusively affect males, while females are only carriers.
On the other hand, hemophilia C is caused by mutations in the F11 gene coding for factor XI, and is an autosomal recessive disorder, meaning it can affect both males and females.
Now, all hemophilias present with the same signs and symptoms. The severity depends on the baseline factor activity, represented as a percentage of normal activity.
Having 5 to 40% of normal factor activity is defined as mild hemophilia and typically presents with excessive bleeding after surgical or dental procedures, as well as heavy menstrual bleeding.
Activity between 1% to 5% refers to moderate hemophilia, which presents with symptoms such as easy bruising, even after very minor trauma.
Finally, activity less than 1% is defined as severe hemophilia and unfortunately, most clients have this form of the disease.
Clinical features associated with severe hemophilia are typically present since birth, and include cephalohematoma, which is bleeding under the scalp due to pressure on the fetal head during delivery; as well as excessive bleeding from circumcision.
Other important clinical features that are commonly seen in clients with hemophilia include nosebleeds, ecchymosis, muscle hematomas, and hemarthrosis, or bleeding within the joint space, which is common in young children once they start walking and falling.
Repeated episodes of hemarthrosis can eventually lead to synovitis and arthropathy, which can be further complicated by joint deformation, leading to restricted range of motion and chronic pain.
Clients affected by hemophilia can also develop some life-threatening complications, such as internal bleeding, which can often be retroperitoneal, gastrointestinal, and urinary.
Now, diagnosis of hemophilia is usually based on clinical presentation, family history, and lab tests, including a platelet count, which is usually normal, as well as a normal prothrombin time or PT, since the extrinsic pathway is not involved, and a prolonged activated partial thromboplastin time or aPTT, since the intrinsic pathway is affected.
Finally, the hemophilia type can be confirmed via tests to look at specific factor activities, as well as genetic testing to identify the mutated gene.
The treatment of hemophilia includes transfusion of the deficient clotting factor.
Additionally, antifibrinolytics can be used to prevent severe blood loss in surgical procedures or during menstrual bleeding.