Hematology – Blood Disorders
When something is wrong with your blood, it can affect your total health. That is why it is important for you to know about some of the common blood disorders that may affect you. People may be affected by many different types of blood conditions and blood cancers. Common blood disorders include:
Talking to your doctor is the first step to take if you believe you may have a blood condition.
Anemia is the most common blood disorder. According to the National Heart, Lung, and Blood Institute, anemia affects more than 3 million Americans.
Red blood cells carry hemoglobin, an iron-rich protein that attaches to oxygen in the lungs and carries it to tissues throughout the body. Anemia occurs when you do not have enough red blood cells or when your red blood cells do not function properly.
When you have anemia, your body lacks oxygen, so you may feel tired or weak. Other symptoms might include:
- Shortness of breath
- Fast or irregular heartbeat
- Pounding or “whooshing” in your ears
- Cold hands or feet
- Pale or yellow skin
- Chest pain
Many people are at risk for anemia because of poor diet, intestinal disorders, chronic diseases, infections, and other conditions. Women who are menstruating or pregnant and people with chronic medical conditions are most at risk for this disease. The risk of anemia increases as people grow older. People who engage in vigorous athletic activities, such as jogging or basketball, may develop anemia as a result of red blood cells breaking down in the bloodstream.
Many forms of anemia can be easily treated by eating foods rich in iron (such as dark green leafy vegetables, red meat, fortified cereals, eggs, and peanuts) and/or taking dietary supplements. Other types can be treated by addressing the underlying cause.
Some common types of anemia are:
- Iron-deficiency anemia is the most common type of anemia. It happens when you do not have enough iron in your body. Iron deficiency is usually due to blood loss but may occasionally be due to poor absorption of iron. Pregnancy and childbirth consume a great deal of iron and thus can result in this form of anemia. People who have had gastric bypass surgery for weight loss or other reasons may also be iron deficient due to poor absorption.
- Vitamin-deficiency anemia may result from low levels of vitamin B12 or folate (folic acid), usually due to poor dietary intake. Pernicious anemia is a condition in which vitamin B12 cannot be absorbed in the gastrointestinal tract.
- Aplastic anemia is a rare form of anemia that occurs when the body stops making enough red blood cells. Common causes include viral infections, exposure to toxic chemicals, drugs, and autoimmune diseases.
- Hemolytic anemia occurs when red blood cells are destroyed in the bloodstream or in the spleen. Hemolytic anemia may be due to mechanical factors (leaky heart valves or aneurysms), infections, autoimmune disorders, or inherited abnormalities in the red blood cell. Inherited abnormalities may affect the hemoglobin or the red blood cell structure or function. Examples of inherited hemolytic anemias include some types of thalassemia and low levels of enzymes such as pyruvate kinase. The treatment will depend on the cause.
- Sickle cell anemia is an inherited hemolytic anemia in which the hemoglobin protein is abnormal, causing the red blood cells to be rigid and unable to flow through small blood vessels.
Anemia caused by other diseases Some diseases can affect the body’s ability to make red blood cells. For example, some patients with kidney disease develop anemia because the kidneys are not making enough hormones to signal the body to make red blood cells. Chemotherapy used to treat various cancers often impairs the body’s ability to make new red blood cells, and anemia often results from this treatment.
Bleeding disorders are a group of conditions that result when the blood cannot clot properly. In normal clotting, platelets 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, 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 heart attack and stroke, the inability to form clots can be very dangerous as well, as it can result in excessive bleeding.
Hemophilia is perhaps the most well-known bleeding disorder, although it is relatively rare. It affects mostly males.Â Many more people are affected by von Willebrand disease, the most common bleeding disorder in America. Von Willebrand disease can affect both males and females. You can find information on other bleeding disorders by following the links at the bottom of this page.
Bleeding disorders such as hemophilia and von Willebrand disease result when the blood lacks certain clotting factors. These diseases are almost always inherited, although in rare cases they can develop later in life if the body forms antibodies that fight against the blood’s natural clotting factors. Individuals and pregnant women with a family history of bleeding disorders should talk to their doctors about detection and treatment. Symptoms of bleeding disorders may include:
- Easy bruising
- Bleeding gums
- Heavy bleeding from small cuts or dental work
- Unexplained nosebleeds
- Heavy menstrual bleeding
Hemophilia is a rare, typically inherited, bleeding disorder that can range from mild to severe, depending on how much clotting factor is present in the blood. Hemophilia is classified as Type A or Type B, based on which type of clotting factor is lacking (factor VIII in Type A and factor IX in Type B). Hemophilia results from a genetic defect found on the X chromosome. Women, who have two X chromosomes, can pass the disease onto their sons but will be not be affected by the disease unless both X chromosomes have the defective gene; this is very rare. On the other hand, males, who have one X and one Y chromosome, will be affected by hemophilia if their one X chromosome has the defective gene.
Because blood does not clot properly without enough clotting factor, any cut or injury carries the risk of excessive bleeding. In addition, people with hemophilia may suffer from internal bleeding that can damage joints, organs, and tissues over time.
In the past, people with hemophilia were treated with transfusions of factor VIII obtained from donor blood, but by the early 1980s these products were discovered to be transmitting blood-borne viruses, including hepatitis and HIV. Thanks to improved screening techniques, and a major breakthrough that enabled scientists to create synthetic blood factors in the laboratory by cloning the genes responsible for specific clotting factors, today’s factor-replacement therapies are pure and much safer than ever before.
Von Willebrand disease is an inherited condition that results when the blood lacks von Willebrand factor, a protein that helps the blood to clot and also carries another clotting protein, factor VIII. It is usually milder than hemophilia and can affect both males and females. Von Willebrand disease is classified into three different types (Types 1, 2, and 3), based on the levels of von Willebrand factor and factor VIII activity in the blood. Type 1 is the mildest and most common form; Type 3 is the most severe and least common form.
With early diagnosis, people with von Willebrand disease can lead normal, active lives. People with mild cases may not require treatment, but should avoid taking drugs that could aggravate bleeding, such as aspirin and ibuprofen, without first consulting with a doctor. More serious cases may be treated with drugs that increase the level of von Willebrand factor in the blood or with infusions of blood factor concentrates. It is important for people with von Willebrand disease to consult with their doctors before having surgery, having dental work, or giving birth, so that proper precautions can be taken to prevent excessive bleeding. You may be referred to a hematologist, a doctor who specializes in the treatment of blood disorders.
Blood clotting, or coagulation, is an important process that prevents excessive bleeding when a blood vessel is injured. Platelets (a type of blood cell) and proteins in your plasma (the liquid part of blood) work together to stop the bleeding by forming a clot over the injury. Typically, your body will naturally dissolve the blood clot after the injury has healed. Sometimes, however, clots form on the inside of vessels without an obvious injury or do not dissolve naturally. These situations can be dangerous and require accurate diagnosis and appropriate treatment.
Clots can occur in veins or arteries, which are vessels that are part of the body’s circulatory system. While both types of vessels help transport blood throughout the body, they each function differently. Veins are low-pressure vessels that carry deoxygenated blood away from the body’s organs and back to the heart. An abnormal clot that forms in a vein may restrict the return of blood to the heart and can result in pain and swelling as the blood gathers behind the clot. Deep-vein thrombosis (DVT) is a type of clot that forms in a major vein of the leg or, less commonly, in the arms, pelvis, or other large veins in the body. In some cases, a clot in a vein may detach from its point of origin and travel through the heart to the lungs where it becomes wedged, preventing adequate blood flow. This is called a pulmonary (lung) embolism and can be extremely dangerous.
Arteries, on the other hand, are muscular, high-pressure vessels that carry oxygen- and nutrient-rich blood from the heart to other parts of the body. When your doctor measures your blood pressure, the test results are an indicator of the pressure in your arteries. Clotting that occurs in arteries is usually associated with atherosclerosis (hardening of the arteries), a deposit of plaque that narrows the inside of the vessel. As the arterial passage narrows, the strong arterial muscles continue to force blood through the opening, and the high pressure can cause the plaque to rupture. Molecules released in the rupture cause the body to overreact and form an unnecessary clot in the artery, potentially leading to a heart attack or stroke. When the blood supply to the heart or brain is completely blocked by the clot, a part of these organs can be damaged as a result of being deprived of blood and its nutrients.
The risk factors for developing a venous clot are different from those for an arterial clot, and people at risk for getting one are not necessarily at risk for getting the other. Different risk factors or events can cause unnatural clotting; however, each factor may initiate clotting in a different way. There are molecules in your system that signal your body to let it know when, where, and how quickly to form a clot, and genetics plays a role in how quickly your body reacts to these signals. Certain risk factors, such as obesity, slow the flow of blood in the veins, while others, such as age, can increase the body’s natural ability to clot. Even certain medications can affect how quickly your blood clots. The following factors increase your risk of developing a venous blood clot:
- Immobility (including prolonged inactivity, long trips by plane or car)
- Oral contraceptives
- Certain cancers
- Certain surgeries
- Age (increased risk for people over age 60)
- Inherited clotting disorders (family members who have had clots)
- Chronic inflammatory diseases
The risk factors for arterial clots can be modified through changes in lifestyle or by medical treatment:
- Lack of physical activity
- High blood pressure
- High cholesterol
In addition to knowing your risk factors, it is also important to be aware of the symptoms of blood clots, which vary depending upon where the clot is located:
- Heart: chest pain, often radiating down the left arm and accompanied by shortness of breath, and sweating
- Brain: visual disturbances, weakness, seizures, speech impairment
- Arm or Leg : sudden pain, swelling, tenderness
- Lung: sharp chest pain, rapid pulse, bloody cough, shortness of breath, sweating, fever
- Abdomen: severe abdominal pain, vomiting, diarrhea
Blood clots are among the most preventable types of blood conditions. There are several ways to decrease your chances of developing a blood clot, such as controlling your risk factors when possible. If you think you may be at risk because of genetic or behavioral factors, talk with your doctor. Also, make sure your doctor is aware of all the medications you are taking and any family history of blood clotting disorders.
Resource: American Society of Hematology - http://www.hematology.org/Patients/Blood-Disorders/Anemia/5225.aspx