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| Hematologic disease | |
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| Specialty | Hematology  |
Hematologic diseases are disorders which primarily affect the blood and blood-forming organs. Hematologic diseases include rare genetic disorders, anemia, HIV, sickle cell disease and complications from chemotherapy or transfusions.
Leukemia is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called blasts or leukemia cells. Symptoms may include bleeding and bruising, bone pain, fatigue, fever, and an increased risk of infections. These symptoms occur due to a lack of normal blood cells. Diagnosis is typically made by blood tests or bone marrow biopsy.
Hematology is the branch of medicine concerned with the study of the cause, prognosis, treatment, and prevention of diseases related to blood. It involves treating diseases that affect the production of blood and its components, such as blood cells, hemoglobin, blood proteins, bone marrow, platelets, blood vessels, spleen, and the mechanism of coagulation. Such diseases might include hemophilia, sickle cell anemia, blood clots (thrombus), other bleeding disorders, and blood cancers such as leukemia, multiple myeloma, and lymphoma. The laboratory analysis of blood is frequently performed by a medical technologist or medical laboratory scientist.
Hemolysis or haemolysis, also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid. Hemolysis may occur in vivo or in vitro.
Anemia or anaemia is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin or hemoglobin abnormalities. The name is derived from Ancient Greek ἀν- (an-) 'not', and αἷμα (haima) 'blood'. When anemia comes on slowly, the symptoms are often vague, such as tiredness, weakness, shortness of breath, headaches, and a reduced ability to exercise. When anemia is acute, symptoms may include confusion, feeling like one is going to pass out, loss of consciousness, and increased thirst. Anemia must be significant before a person becomes noticeably pale. Symptoms of anemia depend on how quickly hemoglobin decreases. Additional symptoms may occur depending on the underlying cause. Preoperative anemia can increase the risk of needing a blood transfusion following surgery. Anemia can be temporary or long term and can range from mild to severe.
A myelodysplastic syndrome (MDS) is one of a group of cancers in which immature blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may include fatigue, shortness of breath, bleeding disorders, anemia, or frequent infections. Some types may develop into acute myeloid leukemia.
Tumors of the hematopoietic and lymphoid tissues or tumours of the haematopoietic and lymphoid tissues are tumors that affect the blood, bone marrow, lymph, and lymphatic system. Because these tissues are all intimately connected through both the circulatory system and the immune system, a disease affecting one will often affect the others as well, making aplasia, myeloproliferation and lymphoproliferation closely related and often overlapping problems. While uncommon in solid tumors, chromosomal translocations are a common cause of these diseases. This commonly leads to a different approach in diagnosis and treatment of hematological malignancies. Hematological malignancies are malignant neoplasms ("cancer"), and they are generally treated by specialists in hematology and/or oncology. In some centers "hematology/oncology" is a single subspecialty of internal medicine while in others they are considered separate divisions. Not all hematological disorders are malignant ("cancerous"); these other blood conditions may also be managed by a hematologist.
In medicine (hematology), bleeding diathesis is an unusual susceptibility to bleed (hemorrhage) mostly due to hypocoagulability, in turn caused by a coagulopathy. Therefore, this may result in the reduction of platelets being produced and leads to excessive bleeding. Several types of coagulopathy are distinguished, ranging from mild to lethal. Coagulopathy can be caused by thinning of the skin, such that the skin is weakened and is bruised easily and frequently without any trauma or injury to the body. Also, coagulopathy can be contributed by impaired wound healing or impaired clot formation.
Primary myelofibrosis (PMF) is a rare bone marrow blood cancer. It is classified by the World Health Organization (WHO) as a type of myeloproliferative neoplasm, a group of cancers in which there is activation and growth of mutated cells in the bone marrow. This is most often associated with a somatic mutation in the JAK2, CALR, or MPL genes. In PMF, the bony aspects of bone marrow are remodeled in a process called osteosclerosis; in addition, fibroblast secrete collagen and reticulin proteins that are collectively referred to as (fibrosis). These two pathological processes compromise the normal function of bone marrow resulting in decreased production of blood cells such as erythrocytes, granulocytes and megakaryocytes, the latter cells responsible for the production of platelets.
Autoimmune hemolytic anemia (AIHA) occurs when antibodies directed against the person's own red blood cells (RBCs) cause them to burst (lyse), leading to an insufficient number of oxygen-carrying red blood cells in the circulation. The lifetime of the RBCs is reduced from the normal 100–120 days to just a few days in serious cases. The intracellular components of the RBCs are released into the circulating blood and into tissues, leading to some of the characteristic symptoms of this condition. The antibodies are usually directed against high-incidence antigens, therefore they also commonly act on allogenic RBCs. AIHA is a relatively rare condition, with an incidence of 5–10 cases per 1 million persons per year in the warm-antibody type and 0.45 to 1.9 cases per 1 million persons per year in the cold antibody type. Autoimmune hemolysis might be a precursor of later onset systemic lupus erythematosus.
Mean platelet volume (MPV) is a machine-calculated measurement of the average size of platelets found in blood and is typically included in blood tests as part of the CBC. Since the average platelet size is larger when the body is producing increased numbers of platelets, the MPV test results can be used to make inferences about platelet production in bone marrow or platelet destruction problems.
Paroxysmal cold hemoglobinuria (PCH) or Donath–Landsteiner hemolytic anemia (DLHA) is an autoimmune hemolytic anemia featured by complement-mediated intravascular hemolysis after cold exposure. It can present as an acute non-recurrent postinfectious event in children, or chronic relapsing episodes in adults with hematological malignancies or tertiary syphilis. Described by Julius Donath (1870–1950) and Karl Landsteiner (1868–1943) in 1904, PCH is one of the first clinical entities recognized as an autoimmune disorder.
GATA-binding factor 1 or GATA-1 is the founding member of the GATA family of transcription factors. This protein is widely expressed throughout vertebrate species. In humans and mice, it is encoded by the GATA1 and Gata1 genes, respectively. These genes are located on the X chromosome in both species.
Reticulocytopenia is the medical term for an abnormal decrease in circulating red blood cell precursors (reticulocytes) that can lead to anemia due to resulting low red blood cell (erythrocyte) production. Reticulocytopenia may be an isolated finding or it may not be associated with abnormalities in other hematopoietic cell lineages such as those that produce white blood cells (leukocytes) or platelets (thrombocytes), a decrease in all three of these lineages is referred to as pancytopenia.
Cold autoimmune hemolytic anemia caused by cold-reacting antibodies. Autoantibodies that bind to the erythrocyte membrane leading to premature erythrocyte destruction (hemolysis) characterize autoimmune hemolytic anemia.
Clonal hypereosinophilia, also termed primary hypereosinophilia or clonal eosinophilia, is a grouping of hematological disorders all of which are characterized by the development and growth of a pre-malignant or malignant population of eosinophils, a type of white blood cell that occupies the bone marrow, blood, and other tissues. This population consists of a clone of eosinophils, i.e. a group of genetically identical eosinophils derived from a sufficiently mutated ancestor cell.
Transient myeloproliferative disease (TMD) occurs in a significant percentage of individuals born with the congenital genetic disorder, Down syndrome. It may occur in individuals who are not diagnosed with the syndrome but have some hematological cells containing genetic abnormalities that are similar to those found in Down syndrome. TMD usually develops in utero, is diagnosed prenatally or within ~3 months of birth, and thereafter resolves rapidly and spontaneously. However, during the prenatal-to-postnatal period, the disease may cause irreparable damage to various organs and in ~20% of individuals death. Moreover, ~10% of individuals diagnosed with TMD develop acute megakaryoblastic leukemia at some time during the 5 years following its resolution. TMD is a life-threatening, precancerous condition in fetuses as well as infants in their first few months of life.