Normocytic / Normochromic Anemias

The spleen is responsible for the "pitting process" for red blood cells (RBCs). In this process, the spleen removes damaged or old RBCs from circulation. The spleen contains specialized cells called macrophages that engulf and break down these RBCs, removing any waste or harmful substances in the process. This process helps maintain the quality and functionality of RBCs in the bloodstream. The liver, kidney, and lymph nodes do not play a direct role in the pitting process for RBCs.

Hereditary spherocytosis is a disorder characterized by the presence of spherical-shaped red blood cells that are more fragile and prone to rupture. This increased fragility is due to a defect in the proteins that help maintain the shape and stability of the red blood cell membrane. As a result, these cells are more susceptible to osmotic stress and are more likely to burst when exposed to a hypotonic environment. Iron deficiency anemia, hereditary elliptocytosis, and hereditary stomatocytosis do not typically exhibit an increase in osmotic fragility.

Sickle cell disorders are hereditary, meaning they are passed down from parents to their children through genes. They are also intracorpuscular, which means that the defect occurs within the red blood cells themselves. This defect causes the red blood cells to have an abnormal shape, resembling a sickle or crescent, which can lead to various health problems.

The amino acid substitution responsible for sickle cell anemia is valine being substituted for glutamic acid at the sixth position of the B-chain. This substitution causes a change in the structure of hemoglobin, leading to the formation of abnormal sickle-shaped red blood cells. These cells have a reduced ability to carry oxygen and can cause blockages in blood vessels, leading to various complications associated with sickle cell anemia.

Howell-Jolly bodies are small nuclear remnants that are normally removed by the spleen. In patients who have undergone splenectomy, these nuclear remnants may be seen in the peripheral blood smear. Therefore, Howell-Jolly bodies are a red cell inclusion that may be observed in the peripheral blood smear of a patient postsplenectomy.

Aplastic anemia is a condition characterized by a decrease in the production of red blood cells, white blood cells, and platelets in the bone marrow. This results in a decrease in the number of these cells in the peripheral blood, leading to a condition called pancytopenia, which is the presence of low levels of all three types of blood cells. Therefore, peripheral blood pancytopenia is a common finding in aplastic anemia.

Reticulocytosis refers to an increase in the number of reticulocytes, which are immature red blood cells. This usually occurs in response to increased red cell regeneration, such as during recovery from anemia or after blood loss. It is a normal physiological response to replenish the red blood cell population. In contrast, neoplastic processes, aplastic anemia, and inflammation are not typically associated with reticulocytosis. Therefore, the correct answer is red cell regeneration.

The morphological classification of anemias is based on RBC indices. RBC indices are laboratory measurements that provide information about the size, shape, and hemoglobin content of red blood cells. These indices include mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). By analyzing these indices, healthcare professionals can determine the specific type of anemia a patient may have, such as microcytic, normocytic, or macrocytic anemia.

Bite cells are red blood cells that have been damaged by phagocytes in the spleen. This occurs in G6PD deficiency, which is an inherited condition that affects the red blood cells. G6PD deficiency leads to a decrease in the activity of the enzyme glucose-6-phosphate dehydrogenase, making the red blood cells more susceptible to oxidative damage. This damage causes the formation of Heinz bodies, which are removed by phagocytes, resulting in the characteristic appearance of bite cells.

Microangiopathic hemolytic anemia is characterized by the presence of schistocytes (fragmented red blood cells) and nucleated red blood cells. Schistocytes are formed when red blood cells are damaged as they pass through narrowed blood vessels, leading to their fragmentation. Nucleated red blood cells are immature red blood cells that are released into circulation prematurely due to increased destruction of red blood cells. These findings indicate the presence of an underlying condition that causes damage to the small blood vessels, leading to the destruction of red blood cells and the release of immature red blood cells into circulation.

The electrophoretic result consistent with a diagnosis of sickle cell trait is Hgb A: 60%, Hgb S: 40%, Hgb A2: 2%. This is because sickle cell trait is characterized by the presence of both hemoglobin A and hemoglobin S. In this result, the percentage of hemoglobin A is higher than hemoglobin S, which is consistent with sickle cell trait. Additionally, the presence of a small amount of hemoglobin A2 is also consistent with sickle cell trait.

In sickle cell disease, the anemia is usually characterized by normocytic, normochromic red blood cells. This means that the red blood cells are of normal size and have a normal amount of hemoglobin. This type of anemia is different from microcytic anemia, where the red blood cells are smaller than normal, and hypochromic anemia, where the red blood cells have a decreased amount of hemoglobin. Normocytic, normochromic anemia in sickle cell disease is a result of the destruction of red blood cells due to the abnormal sickle-shaped hemoglobin.

Autoimmune hemolytic anemia is the correct answer because it is a condition characterized by the destruction of red blood cells by the immune system. In this condition, the immune system mistakenly identifies red blood cells as foreign and produces antibodies against them, leading to their destruction. Spherocytes are small, round red blood cells that lack central pallor and are commonly seen in autoimmune hemolytic anemia. These abnormal cells result from the removal of a portion of the cell membrane during the destruction process.

Hemolytic anemia is characterized by the destruction of red blood cells, leading to a decrease in the number of circulating red blood cells. Methemoglobinemia, hemoglobinuria, and hemoglobinemia are all associated with hemolytic anemia. Methemoglobinemia occurs when there is an abnormal form of hemoglobin that is unable to carry oxygen efficiently. Hemoglobinuria is the presence of hemoglobin in the urine, which can occur when red blood cells are destroyed. Hemoglobinemia is the presence of free hemoglobin in the blood, also indicating red blood cell destruction. Increased haptoglobin, on the other hand, is not associated with hemolytic anemia. Haptoglobin is a protein that binds to free hemoglobin in the blood and removes it, so increased levels of haptoglobin would actually be a response to hemolysis, not a sign of hemolytic anemia itself.

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Hgb C disease is a genetic disorder characterized by the presence of Hgb C crystals, target cells, and lysine substituted for glutamic acid at the sixth position of the B-chain. These are typical findings in individuals with Hgb C disease. However, fast mobility of Hgb C at pH 8.6 is not a characteristic feature of this condition. The mobility of Hgb C is slower compared to normal hemoglobin, which can be observed on electrophoresis at pH 8.6. Therefore, the absence of fast mobility of Hgb C at pH 8.6 is the correct answer.

Chloramphenicol is most often implicated in the development of aplastic anemia. This antibiotic has been associated with a rare but serious side effect called aplastic anemia, which is a condition where the body stops producing enough new blood cells. It is important to monitor patients closely when using chloramphenicol and consider alternative antibiotics when possible to minimize the risk of this severe adverse reaction.

Hemolytic uremic syndrome (HUS) is a condition characterized by the destruction of red blood cells, leading to various symptoms. Hemorrhage refers to bleeding, thrombocytopenia is a low platelet count, and hemoglobinuria is the presence of hemoglobin in the urine. However, reticulocytopenia is not a characteristic of HUS. Reticulocytes are immature red blood cells, and a decrease in their count indicates a decrease in the production of new red blood cells. In HUS, the destruction of red blood cells occurs, but it does not necessarily affect the production of new ones, hence reticulocytopenia is not observed.

Paroxysmal cold hemoglobinuria (PCH) is a rare autoimmune hemolytic anemia characterized by the destruction of red blood cells. The antibody associated with PCH is Anti-P. This antibody binds to the P antigen on red blood cells and activates complement, leading to the destruction of the cells. Anti-P is commonly found in individuals with syphilis or other infections, and it is often associated with cold exposure. Anti-I, Anti-i, and Anti-M are not specifically associated with PCH.

Autosplenectomy is the process in which the spleen shrinks and becomes non-functional. In sickle cell disease, the abnormal sickle-shaped red blood cells can become trapped in the small blood vessels of the spleen, leading to infarction and subsequent shrinkage of the organ. This makes sickle cell disease the most likely condition for autosplenectomy to occur. Thalassemia major, Hgb C disease, and Hgb SC disease do not typically cause autosplenectomy.

Spherocytes differ from normal red cells in all of the following except for an increase in deformability. Spherocytes have a decreased surface to volume ratio, meaning they have a smaller surface area compared to their volume. They also lack central pallor, which is the lighter area in the center of normal red cells. Spherocytes also have decreased resistance to hypotonic saline, meaning they are more prone to swelling and bursting in a hypotonic environment. However, they do not show an increase in deformability, which refers to their ability to change shape and squeeze through narrow blood vessels.

Hemoglobin C migrates to the same position as Hgb A2 at pH 8.6.

Autoimmune hemolytic anemia is best characterized by spherocytic red cells. In this condition, the immune system mistakenly attacks and destroys red blood cells, leading to their abnormal shape. Spherocytic red cells are smaller and more spherical than normal red blood cells. This can be observed under a microscope and is a key characteristic of autoimmune hemolytic anemia. Increased levels of plasma C3, decreased osmotic fragility, and decreased unconjugated bilirubin are not specific to autoimmune hemolytic anemia and may be seen in other conditions.

Congenital dyserythropoietic anemias (CDAs) are a group of inherited disorders characterized by abnormalities in the production of red blood cells. One of the key features of CDAs is the presence of bizarre multinucleated erythroblasts, which are immature red blood cells with multiple nuclei. This abnormality can be observed in the bone marrow and is a characteristic finding in CDAs. The other options mentioned in the question, such as cytogenetic disorders, megaloblastic erythropoiesis, and an elevated M:E ratio, may also be present in some cases of CDAs, but the presence of bizarre multinucleated erythroblasts is a more specific and defining feature.

Hereditary pyropoikilocytosis (HP) is a red cell membrane defect that is characterized by the presence of misshapen budding fragmented cells. This means that the red blood cells in individuals with HP have an abnormal shape and tend to break apart into smaller fragments. This can lead to various complications, including anemia, as the fragmented cells are not able to function properly. The presence of misshapen budding fragmented cells is therefore a key characteristic of HP.

In a patient with numerous NRBCs, marked variation of red cell morphology, and pronounced polychromasia, the increased MCV (mean corpuscular volume) can be anticipated. MCV is a measure of the average size of red blood cells, and an increase in MCV indicates the presence of larger-than-normal red blood cells. This can be seen in conditions such as megaloblastic anemia, where there is impaired DNA synthesis leading to larger red blood cells. Therefore, in this case, the increased MCV is an expected finding.

Intravascular hemolysis is not associated with hereditary spherocytosis. Hereditary spherocytosis is a genetic disorder characterized by the presence of spherical-shaped red blood cells that are more prone to premature destruction. The condition is typically associated with increased osmotic fragility, meaning that the red blood cells are more likely to burst when exposed to changes in osmotic pressure. Additionally, hereditary spherocytosis can lead to extravascular hemolysis, where the red blood cells are destroyed outside of the blood vessels, typically in the spleen. However, intravascular hemolysis, which occurs within the blood vessels, is not commonly associated with hereditary spherocytosis.

The major Hgb found in the RBC's of patients with sickle cell trait is Hgb A.

Hypersplenism is a condition characterized by an overactive spleen that destroys blood cells prematurely. Leukopenia refers to a low white blood cell count, which is commonly seen in hypersplenism. This occurs because the spleen removes white blood cells from circulation at a faster rate than normal, leading to a decrease in their numbers. Therefore, leukopenia is a characteristic feature of hypersplenism.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired disorder characterized by the abnormal breakdown of red blood cells. Autohemolysis refers to the destruction of one's own red blood cells. In PNH, the red blood cells are already fragile and prone to breakdown, so the autohemolysis test would not be positive in this condition. On the other hand, glucose-6-phosphate dehydrogenase (G6PD) deficiency, hereditary spherocytosis, and pyruvate kinase deficiency are all conditions that can lead to increased red blood cell destruction, resulting in a positive autohemolysis test.