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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, or a reduction in the amount of hemoglobin. The name is derived from Ancient Greek: ἀναιμία anaimia, meaning 'lack of blood', from 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.
Reticulocytes are immature red blood cells (RBCs). In the process of erythropoiesis, reticulocytes develop and mature in the bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells. Like mature red blood cells, in mammals, reticulocytes do not have a cell nucleus. They are called reticulocytes because of a reticular (mesh-like) network of ribosomal RNA that becomes visible under a microscope with certain stains such as new methylene blue and Romanowsky stain.
Hereditary spherocytosis (HS) is a congenital hemolytic disorder, wherein a genetic mutation coding for a structural membrane protein phenotype leads to a spherical shaping of erythrocytic cellular morphology. As erythrocytes are sphere-shaped (spherocytosis), rather than the normal biconcave disk-shaped, their morphology interferes with these cells' abilities to be flexible during circulation throughout the entirety of the body - arteries, arterioles, capillaries, venules, veins, and organs. This difference in shape also makes the red blood cells more prone to rupture under osmotic and/or mechanical stress. Cells with these dysfunctional proteins are degraded in the spleen, which leads to a shortage of erythrocytes resulting in hemolytic anemia.
Hemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels or elsewhere in the human body (extravascular). This most commonly occurs within the spleen, but also can occur in the reticuloendothelial system or mechanically. Hemolytic anemia accounts for 5% of all existing anemias. It has numerous possible consequences, ranging from general symptoms to life-threatening systemic effects. The general classification of hemolytic anemia is either intrinsic or extrinsic. Treatment depends on the type and cause of the hemolytic anemia.
The mean corpuscular volume, or mean cell volume (MCV), is a measure of the average volume of a red blood corpuscle. The measure is obtained by multiplying a volume of blood by the proportion of blood that is cellular, and dividing that product by the number of erythrocytes in that volume. The mean corpuscular volume is a part of a standard complete blood count.
Red blood cell distribution width (RDW), as well as various types thereof, is a measure of the range of variation of red blood cell (RBC) volume that is reported as part of a standard complete blood count. Red blood cells have an average volume of 80-100 femtoliters, but individual cell volumes vary even in healthy blood. Certain disorders, however, cause a significantly increased variation in cell size. Higher RDW values indicate greater variation in size. Normal reference range of RDW-CV in human red blood cells is 11.5–15.4%. If anemia is observed, RDW test results are often used together with mean corpuscular volume (MCV) results to determine the possible causes of the anemia. It is mainly used to differentiate an anemia of mixed causes from an anemia of a single cause.
Megaloblastic anemia is a type of macrocytic anemia. An anemia is a red blood cell defect that can lead to an undersupply of oxygen. Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis. Megaloblastic anemia has a rather slow onset, especially when compared to that of other anemias. The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically vitamin B12 deficiency or folate deficiency. Loss of micronutrients may also be a cause.
Microcytic anaemia is any of several types of anemia characterized by smaller than normal red blood cells. The normal mean corpuscular volume is approximately 80–100 fL. When the MCV is <80 fL, the red cells are described as microcytic and when >100 fL, macrocytic. The MCV is the average red blood cell size.
Anemia of chronic disease (ACD) or anemia of chronic inflammation is a form of anemia seen in chronic infection, chronic immune activation, and malignancy. These conditions all produce elevation of interleukin-6, which stimulates hepcidin production and release from the liver. Hepcidin production and release shuts down ferroportin, a protein that controls export of iron from the gut and from iron storing cells. As a consequence, circulating iron levels are reduced. Other mechanisms may also play a role, such as reduced erythropoiesis. It is also known as anemia of inflammation, or anemia of inflammatory response.
Macrocytosis is the enlargement of red blood cells with near-constant hemoglobin concentration, and is defined by a mean corpuscular volume (MCV) of greater than 100 femtolitres. The enlarged erythrocytes are called macrocytes or megalocytes. As a symptom its cause may be relatively benign and need no treatment or it may indicate a serious underlying illness.
Sideroblastic anemia, or sideroachrestic anemia, is a form of anemia in which the bone marrow produces ringed sideroblasts rather than healthy red blood cells (erythrocytes). In sideroblastic anemia, the body has iron available but cannot incorporate it into hemoglobin, which red blood cells need in order to transport oxygen efficiently. The disorder may be caused either by a genetic disorder or indirectly as part of myelodysplastic syndrome, which can develop into hematological malignancies.
The Mentzer index, described in 1973 by William C. Mentzer, is the MCV divided by the RBC count. It is said to be helpful in differentiating iron deficiency anemia from beta thalassemia trait.
Anisocytosis is a medical term meaning that a patient's red blood cells are of unequal size. This is commonly found in anemia and other blood conditions. False diagnostic flagging may be triggered on a complete blood count by an elevated WBC count, agglutinated RBCs, RBC fragments, giant platelets or platelet clumps. In addition, it is a characteristic feature of bovine blood.
The term macrocytic is from Greek words meaning "large cell". A macrocytic class of anemia is an anemia in which the red blood cells (erythrocytes) are larger than their normal volume. The normal erythrocyte volume in humans is about 80 to 100 femtoliters. In metric terms the size is given in equivalent cubic micrometers. The condition of having erythrocytes which are too large, is called macrocytosis. In contrast, in microcytic anemia, the erythrocytes are smaller than normal.
Red blood cell indices are blood tests that provide information about the hemoglobin content and size of red blood cells. Abnormal values indicate the presence of anemia and which type of anemia it is.
Microcytosis or microcythemia is a condition in which red blood cells are unusually small as measured by their mean corpuscular volume.
Anemia is a deficiency in the size or number of red blood cells or in the amount of hemoglobin they contain. This deficiency limits the exchange of O2 and CO2 between the blood and the tissue cells. Globally, young children, women, and older adults are at the highest risk of developing anemia. Anemia can be classified based on different parameters, and one classification depends on whether it is related to nutrition or not so there are two types: nutritional anemia and non-nutritional anemia. Nutritional anemia refers to anemia that can be directly attributed to nutritional disorders or deficiencies. Examples include Iron deficiency anemia and pernicious anemia. It is often discussed in a pediatric context.
Polychromasia is a disorder where there is an abnormally high number of immature red blood cells found in the bloodstream as a result of being prematurely released from the bone marrow during blood formation These cells are often shades of grayish-blue. Polychromasia is usually a sign of bone marrow stress as well as immature red blood cells. 3 types are recognized, with types 1 and 2 being referred to as 'young red blood cells' and type 3 as 'old red blood cells'. Giemsa stain is used to distinguish all three types of blood smears. The young cells will generally stain gray or blue in the cytoplasm. These young red blood cells are commonly called reticulocytes. All polychromatophilic cells are reticulocytes, however, not all reticulocytes are polychromatophilic. In the old blood cells, the cytoplasm either stains a light orange or does not stain at all.
Anemia is a condition in which blood has a lower-than-normal amount of red blood cells or hemoglobin. Anemia in pregnancy is a decrease in the total red blood cells (RBCs) or hemoglobin in the blood during pregnancy. Anemia is an extremely common condition in pregnancy world-wide, conferring a number of health risks to mother and child. While anemia in pregnancy may be pathologic, in normal pregnancies, the increase in RBC mass is smaller than the increase in plasma volume, leading to a mild decrease in hemoglobin concentration referred to as physiologic anemia. Maternal signs and symptoms are usually non-specific, but can include: fatigue, pallor, dyspnea, palpitations, and dizziness. There are numerous well-known maternal consequences of anemia including: maternal cardiovascular strain, reduced physical and mental performance, reduced peripartum blood reserves, increased risk for peripartum blood product transfusion, and increased risk for maternal mortality.
References
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- ↑ Vieth, Julia (2017). "Anemia". Hematology/Oncology Clinics of North America. 31 (6): 1045–1060. doi:10.1016/j.hoc.2017.08.008. PMID 29078923 – via Elsevier Science Direct.
- 1 2 Medical Physiology by Kibble and Halsey p295
- 1 2 Ford, J. (June 2013). "Red blood cell morphology". International Journal of Laboratory Hematology. 35 (3): 351–357. doi: 10.1111/ijlh.12082 . PMID 23480230.
- ↑ "Normocytic anemia". MediGoo - Health Medical Tests and Free Health Medical Information. Retrieved 2020-12-28.