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Blood Disorders

Biology of Blood
Symptoms and Diagnosis of Blood Disorders
Anemia
Bleeding Due to Abnormal Blood Vessels
Bleeding Due to Clotting Disorders
Blood Clotting Process
- How Blood Clots
- Bruising and Bleeding
Blood Transfusion
Excessive Clotting
- Excessive Clotting

Iron Overload
Leukemias
Lymphomas
Myeloproliferative Disorders
Plasma Cell Disorders
Platelet Disorders
Spleen Disorders
- Overview of the Spleen
- Enlarged Spleen
White Blood Cell Disorders

Blood performs various essential functions as it circulates through the body. It delivers oxygen and essential nutrients (such as fats, sugars, minerals, and vitamins) to the body's tissues. It carries carbon dioxide to the lungs and other waste products to the kidneys for elimination from the body. It transports hormones (chemical messengers) to allow various parts of the body to communicate with each other. Also, it carries components that fight infection and stop bleeding.

Blood DisordersSections (A-Z)

Anemia

Anemia is a condition in which the number of red blood cells or the amount of hemoglobin (the protein that carries oxygen in them) is low.

Overview of Anemia
Anemia Due to Excessive Bleeding
Iron Deficiency Anemia
Vitamin Deficiency Anemia
Anemia of Chronic Disease
Aplastic Anemia
Autoimmune Hemolytic Anemia
Sickle Cell Disease
Hemoglobin C, S-C, and E Diseases
Thalassemias

Biology of Blood

Blood is a complex mixture of plasma (the liquid component), white blood cells, red blood cells, and platelets. The body contains about 5 to 6 quarts (about 5 liters) of blood. Once blood is pumped out of the heart, it takes 20 to 30 seconds to make a complete trip through the circulation and return to the heart.

Overview of Blood
Components of Blood
Formation of Blood Cells
Effects of Aging on the Blood

Bleeding Due to Abnormal Blood Vessels

Blood vessel disorders that cause bleeding result from blood vessel defects, typically causing red to purple discoloration of the skin or bruising but seldom causing serious blood loss. Bleeding may be a result of connective tissue disorders, vitamin deficiencies, blood protein abnormalities , defective blood vessels, or conditions that cause blood vessel inflammation. Bleeding under the skin may also be more common among older people ( senile purpura ).

Overview of Blood Vessel Disorders
Autoerythrocyte Sensitization
Protein Disorders Causing Blood Vessel Disorders
Hereditary Hemorrhagic Telangiectasia
Purpura Simplex

Bleeding Due to Clotting Disorders

(See also How Blood Clots .)

Overview of Blood Clotting Disorders
Disseminated Intravascular Coagulation (DIC)
Hemophilia
Clotting Disorders Caused by Circulating Anticoagulants
Uncommon Inherited Clotting Disorders

Blood Clotting Process

Hemostasis is the body's way of stopping injured blood vessels from bleeding. Hemostasis includes clotting of the blood. Too much clotting can block blood vessels that are not bleeding. Consequently, the body has control mechanisms to limit clotting and dissolve clots that are no longer needed. An abnormality in any part of this system that controls bleeding can lead to excessive bleeding or excessive clotting, both of which can be dangerous. When clotting is poor, even a slight injury to a blood vessel may lead to severe blood loss. When clotting is excessive, small blood vessels in critical places can become clogged with clots. Clogged vessels in the brain can cause strokes, and clogged vessels leading to the heart can cause heart attacks. Pieces of clots from veins in the legs, pelvis, or abdomen can travel through the bloodstream to the lungs and block major arteries there (pulmonary embolism).

How Blood Clots
Bruising and Bleeding

Blood Transfusion

A blood transfusion is the transfer of blood or a blood component from one person (a donor) to another (a recipient).

Overview of Blood Transfusion
Blood Donation Process
Blood Products
Special Blood Donation Procedures
Precautions and Adverse Reactions During Blood Transfusion

Excessive Clotting

Excessive clottong (thrombophilia) occurs when the blood clots easily or excessively.

Excessive Clotting

Iron Overload

Iron is essential for life, so the body usually tightly controls iron absorption from food and recycles the iron from red blood cells. People lose small amounts of iron every day, and even a healthy diet contains only a small amount of iron. Thus, people rarely have too much iron in their body. Causes of excess iron in the body (iron overload) include the following:

Overview of Iron Overload
Hemosiderosis
Hemochromatosis
Secondary Iron Overload

Leukemias

Leukemias are cancers of white blood cells or of cells that develop into white blood cells.

Overview of Leukemia
Acute Lymphocytic Leukemia
Acute Myelogenous Leukemia
Chronic Lymphocytic Leukemia
Chronic Myelogenous Leukemia
Myelodysplastic Syndrome

Lymphomas

Lymphomas are cancers of lymphocytes, which reside in the lymphatic system and in blood-forming organs.

Overview of Lymphoma
Hodgkin Lymphoma
Non-Hodgkin Lymphomas
Burkitt Lymphoma
Mycosis Fungoides

Myeloproliferative Disorders

In myeloproliferative disorders (myelo = bone marrow, proliferative = rapid multiplication), the blood-producing cells in the bone marrow (precursor cells) develop and reproduce excessively or are crowded out by an overgrowth of fibrous tissue. Typically, these disorders are acquired and not inherited, although rarely there are families in which several members have these disorders.

Overview of Myeloproliferative Disorders
Polycythemia Vera
Myelofibrosis
Thrombocythemia
Secondary Thrombocythemia

Plasma Cell Disorders

Plasma cell disorders are uncommon. They begin when a single plasma cell multiplies excessively. The resulting group of genetically identical cells (called a clone) produces a large quantity of a single type of antibody (immunoglobulin). Plasma cells develop from B cells (B lymphocytes), a type of white blood cell that normally produces antibodies. Antibodies help the body fight infection. Plasma cells are present mainly in bone marrow and lymph nodes. Every plasma cell divides repeatedly to form a clone. The cells of a clone produce only one specific type of antibody. Because thousands of different clones exist, the body can produce a vast number of different antibodies (see Acquired Immunity : Antibodies ) to fight the numerous infectious microorganisms to which the body is exposed.

Overview of Plasma Cell Disorders
Monoclonal Gammopathies of Undetermined Significance (MGUS)
Multiple Myeloma
Macroglobulinemia
Heavy Chain Diseases

Platelet Disorders

Platelets (sometimes called thrombocytes) are cell fragments that circulate in the bloodstream and help blood clot (see How Blood Clots ). Thrombopoietin, primarily produced in the liver, stimulates the bone marrow to make large cells (megakaryocytes), which in turn make platelets from their cytoplasm. Platelets that are not used in clots circulate for 7 to 10 days and are then destroyed. About one third are always stored in the spleen. The platelet count (number of platelets circulating in the bloodstream) can decrease near the end of pregnancy (gestational thrombocytopenia) and increase in response to inflammation (secondary, or reactive, thrombocytosis). Neither of these conditions is serious, and most affected people have no problems resulting from either one.

Overview of Platelet Disorders
Overview of Thrombocytopenia
Immune Thrombocytopenia
Thrombotic Thrombocytopenic Purpura and Hemolytic-Uremic Syndrome
Platelet Dysfunction
Von Willebrand Disease

Spleen Disorders

The spleen, a spongy, soft organ about as big as a person’s fist, is located in the upper left part of the abdomen, just under the rib cage. The splenic artery brings blood to the spleen from the heart. Blood leaves the spleen through the splenic vein, which drains into a larger vein (the portal vein) that carries the blood to the liver. The spleen has a covering of fibrous tissue (the splenic capsule) that supports its blood vessels and lymphatic vessels.

Overview of the Spleen
Enlarged Spleen

Symptoms and Diagnosis of Blood Disorders

Overview of Blood Disorders
Symptoms of Blood Disorders
Medical History and Physical Examination for Blood Disorders
Laboratory Tests for Blood Disorders
Bone Marrow Examination

White Blood Cell Disorders

White blood cells (leukocytes) are an important part of the body’s defense against infectious organisms and foreign substances. To defend the body adequately, a sufficient number of white blood cells must receive a message that an infectious organism or foreign substance has invaded the body, get to where they are needed, and then kill and digest the harmful organism or substance (see White blood cells and see Figure: Lymphatic System: Helping Defend Against Infection ).

Overview of White Blood Cell Disorders
Basophilic Disorders
Eosinophilic Disorders
Lymphocytic Leukocytosis
Lymphocytopenia
Monocyte Disorders
Neutropenia
Neutrophilic Leukocytosis

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Also of Interest

Test your knowledge

Before treatment was available, most people who had acute lymphocytic leukemia (ALL) died within 4 months of the diagnosis. Now, nearly 80% of children diagnosed with ALL can be cured. Which of the following is the main treatment for children diagnosed with ALL?

Radiation therapy Chemotherapy Surgery Stem cell transplantation