What is Hemophilia A?
Hemophilia is a condition that causes longer and extreme bleeding that can happen either spontaneously or after minor injuries. It is a hereditary disorder, meaning it’s passed down through families, and it affects how blood clots in the body. Specifically, Hemophilia A, often referred to as classical hemophilia, is due to a lack or shortage of something called factor VIII. This lack can result in prolonged and severe bleeding, which can occur on its own or due to injuries.
What Causes Hemophilia A?
Hemophilia A is a bleeding disorder caused by a trait or gene that is passed down through families in a pattern called X-linked recessive. This means it mainly affects males, and it’s tied to the X chromosome. Hemophilia A means that someone is missing or has low levels of a blood protein called clotting Factor VIII. This is a crucial protein that helps the blood to clot and stop bleeding by forming a patch (or thrombin) where blood vessels get damaged.
Women who carry the Hemophilia A gene won’t typically have any symptoms of the disorder, but they could have lower than normal amounts of Factor VIII. These carriers will pass on the hemophilia gene to half their sons, who will have the disorder. Men with Hemophilia A will not pass the condition to their sons, but their daughters will carry the hemophilia gene.
Risk Factors and Frequency for Hemophilia A
Hemophilia A is a common hereditary disorder that affects the body’s ability to control bleeding. It’s linked to the X chromosome and is found in one out of every 5000 males. This condition makes up 80% of all hemophilia cases. Globally, over 400,000 males have Hemophilia A, though many are undiagnosed, particularly in developing countries.
Signs and Symptoms of Hemophilia A
Hemophilia is a genetic disorder where blood does not clot properly. This problem often shows up early on in life for severe cases. However, if it’s mild or moderate, signs might be noticed later on, often after some sort of accident or injury. For two-thirds of hemophiliacs, doctors confirm the diagnosis after a baby boy is born, and it is found that his mother carries the related gene. For about one-third of these patients, symptoms that include spontaneous bleeding or bleeding after minor trauma, often lead to the diagnosis.
The usual signs of Hemophilia include spontaneous bleeding in the brain (especially in newborns), heavy bleeding after surgeries like circumcision, unexplainable pain and swelling in the joints (hemarthrosis), unusual bruising once a child starts moving around, and noticeable bleeding under the skin or inside muscles, even without any significant injury. When babies are learning to move around, they may get extensive bruising and bleeding from minor falls, which can sometimes be mistaken for child abuse.
In teenagers and adults, the most common issue encountered is hemarthrosis. Continual episodes of hemarthrosis can eventually damage the joint cartilage causing painful deformity known as Charcot joints. The most serious and immediate risk of hemophilia is a brain bleed or intracranial hemorrhage. This can cause serious, long-lasting neurological issues.
Testing for Hemophilia A
If there is a family history of Hemophilia or if someone is bleeding excessively relative to their injury, a diagnostic test for Hemophilia may be done. This would involve checking whether force of clotting, known as activated partial thromboplastin time, takes longer than normal. You can suspect Hemophilia if a normal blood count and clot formation time are accompanied by an increased activated partial thromboplastin time. These results often lead to an evaluation of clotting factors VIII and IX.
Checking the concentration of Factor VIII in the blood is key when diagnosing, classifying, and treating Hemophilia A. This is because the treatment and outlook of the person depend on whether they’re deficient of Factor VIII. Majority of people with this condition usually have an extended activated partial thromboplastin time, but having a normal result doesn’t mean that they don’t have a mild form of Hemophilia A. In Hemophilia A, the level of Factor VIII usually determines the severity of bleeding.
Factor VIII concentration is expressed in international units per mL volume, or as percentages of the normal amount, which range between 50% to 150%. In severe Hemophilia A, Factor VIII concentration may not be measurable, making it less than 0.01 international units/mL or less than 1%. A person with this extreme deficiency will bleed spontaneously. Those with moderate or mild Hemophilia A, with Factor VIII concentration ranging from 0.02 to 0.05 international units/mL (2% to 5%) or 0.06 to 0.40 international units/mL (6% to 40%), are likely to bleed significantly more than usual following a minor injury.
Treatment Options for Hemophilia A
When a patient with severe Hemophilia A, a blood clotting disorder, experiences acute bleeding, treatment should start immediately, often before patient assessment is complete. The treatment includes giving a synthetic version of “factor VIII” — a protein vital for blood clotting.
Here’s how the dosage is determined:
* Frequency of factor VIII = desired percentage of the factor x weight (kg) x 0.5
In cases of severe, potentially life-threatening bleeding, the goal is to achieve 100% of the needed factor VIII level. For less severe bleeding, the aim is to reach 30-50% of the desired factor VIII level. If known, the patient’s natural factor VIII levels should be taken into account when deciding how much to give. Enhanced safety measures have made factor VIII replacement products safer from transmitting viruses such as HIV and hepatitis C.
There are also other additional medications that can help manage bleeding caused by Hemophilia A, like desmopressin, tranexamic acid, and epsilon aminocaproic acid. Desmopressin can be given intravenously, under the skin (subcutaneously), or through the nose (intranasally), and works by stimulating the release of factor VIII and von Willebrand’s factor (involved in blood clotting) from cells lining the blood vessels.
Patients with severe Hemophilia A may also receive regular infusions of Factor VIII to help prevent unexpected bleeding. The aim is to change severe Hemophilia A into a milder form by maintaining a basic level of factor VIII above 1% of the normal amount. This preventive treatment is recommended for children with hemophilia after their first or second episode of joint bleeding, to prevent damage to their joints and maintain normal muscle and bone function. Patients with mild or moderate Hemophilia A can also receive factor VIII or desmopressin to prevent bleeding, especially before surgery or in the event of injury.
What else can Hemophilia A be?
These are various medical conditions that can be responsible for certain symptoms:
- Acquired Hemophilia (a rare, non-inheritable form of hemophilia)
- Ehlers-Danlos Syndrome (a group of inherited disorders that affect your connective tissues)
- Factor XI Deficiency (a rare genetic disorder that affects the blood’s ability to clot)
- Glanzmann Thrombasthenia (a bleeding disorder resulting from platelet dysfunction)
- Haemophilia C (a mild form of hemophilia affecting both sexes)
- Haemophilia Type B (also known as Christmas disease, a less common form of hemophilia)
- Physical Child Abuse (physical harm inflicted on a child by a caregiver)
- Platelet Disorders (conditions where platelets don’t work the way they should, causing bleeding or clotting issues)
- Von Willebrand Disease (a lifelong bleeding disorder caused by problems with the blood clotting protein von Willebrand factor).
Understanding these conditions can help healthcare providers determine the right diagnosis and treatment.
