Hematologic Problems Flashcards
what is Hemolytic anemia?
Symptoms?
caused by high rates of RBC destruction. Many diseases and conditions can cause the body to destroy its red blood cells. Hemolysis is the premature destruction of erythrocytes. A hemolytic anemia will develop if bone marrow activity cannot compensate for the erythrocyte loss.
Mild hemolysis can be asymptomatic while the anemia in severe hemolysis can be life threatening and cause angina and cardiopulmonary decompensation.
many types of hemolytic anemia.
can be inherited or acquired.
Difference between these anemias:
Normochromatic
Hypochromatic
Macrocytic
Normochromic - (normocytic) normal RBC color, indicating normal amount of hemoglobin. caused by sudden blood loss, prosthetic heart valves, sepsis, tumor, long-term disease, aplastic anemia, or deficiency of the hormone erythropoietin caused by kidney failure. Invasion of bone marrow by cancer cells carried by the bloodstream.
- Hypochromic - (Microcytic) anemia is caused by iron deficiency, lead poisoning, blood disorder called thalassemia, or inflammation.
- Macrocytic - (Macrocytic/ or hyperchromic) anemia results from chemotherapy, folate deficiency, or vitamin B12 deficiency
Inherited anemias (5)
- Sickle cell anemia
- Thalassemias
- Hereditary Spherocytosis
- Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency
- Pyruvate Kinase Deficiency
What is Sickle cell anemia?
body makes abnormal hemoglobin.
RBCs have a sickle, or crescent, shape.
Sickle cells don’t last as long as healthy red blood cells and usually die after 10 - 20 days. The bone marrow can’t make new RBCs fast enough to replace the dying ones.
incurable disease that is often fatal by middle age because of renal failure, infection, pulmonary failure, and/or stroke.
Thalassemias
Thalassemias -inherited blood disorders in which the body doesn’t make enough of certain types of hemoglobin. This causes the body to make fewer healthy RBCs than normal. Thalassemias most often affect people of Southeast Asian, Indian, Chinese, Filipino, Mediterranean, or African origin or descent.
Polycythemia
above normal in the number of RBCs in the circulating blood, usually accompanied by an increase in hemoglobin and volume of packed red cells.
Polycythemia can develop in the presence of certain types of tumors and as the result of the action of adrenocortical secretions.
What are 2 kinds of hemolytic anemia and describe
Intrinsic: inherited defects - sickle cell, thalassemia
Extrinsic: (acquired) not born with a defect but anemia is caused by autoimmune, infection, medication, cancer, etc…With acquired hemolytic anemias, RBCs may be normal. However, some other disease or factor causes the body to destroy RBCs and remove them from the bloodstream.
The destruction of the RBCs occurs in the bloodstream or, more commonly, in the spleen.
Autoimmune hemolytic anemia (AIHA).
immune system makes antibodies that attack red blood cells. AIHA accounts for half of all cases of hemolytic anemia. AIHA may come on very quickly and become serious. Having certain diseases or infections can raise risk for AIHA.
Examples include:
• Autoimmune diseases, such as lupus • Cytomegalovirus • Chronic lymphocytic leukemia • Non-Hodgkin's lymphoma and other blood cancers • Epstein-Barr virus • Mycoplasma pneumonia • Hepatitis • HIV AIHA also can develop after blood and marrow stem cell transplant.
What are symptoms of thalassemia minor and major?
The patient has mild thalassemia frequently asymptomatic with microcytosis (small cells) and hypochromia (pale cells).
Thalassemia major is life-threatening in which growth, both physical and mental, can be retarded. Patient is pale and displays other general symptoms of anemia. The symptoms develop in childhood by 2 years of age and can cause growth and developmental deficits. Jaundice from the hemolysis of RBCs is prominent.
pronounced splenomegaly, since spleen continuously tries to remove the damaged red cells. Hepatomegaly and cardiomyopathy may occur from iron deposition. Cardiac complications from iron overload, pulmonary disease, and hypertension also contribute to early death. Endocrinopathies (hypogonadotrophic hypogonadism) and thrombosis may also be complications of the disease.
Treatment of thalassemia
Thalassemia minor requires no treatment because the body adapts to the reduction of normal hemoglobin. Thalassemia major is managed with blood transfusions or exchange transfusions in conjunction with oral deferasirox (Exjade), or deferiprone (Ferriprox) or deferoxamine (Desferal) (chelating agents that bind to iron) is given IV or subcutaneously to reduce the iron overloading (hemochromatosis) that occurs with chronic transfusion therapy. Folic acid is given if there is evidence of hemolysis. Zinc supplementation may be needed, since zinc is reduced with chelation therapy. Ascorbic acid supplementation may be needed during chelation therapy, since it increases urine excretion of iron. Other than during chelation therapy, ascorbic acid should not be taken because it increases the absorption of dietary iron. Iron supplements should not be given. Because RBCs are sequestered in the enlarged spleen, thalassemia major may be treated by splenectomy.
Megaloblastic anemias:
caused by impaired DNA synthesis.
presence of large RBCs. When DNA synthesis is impaired, defective RBC maturation results. The RBCs are large (macrocytic) are referred to as megaloblasts. Macrocytic RBCs are easily destroyed because they have fragile cell membranes.
Causes of Megaloblastic anemias
Although the overwhelming majority of megaloblastic anemias result from cobalamin (vitamin B12) and folic acid deficiencies,
this type of RBC deformity can also occur from suppression of DNA synthesis by drugs and erythroleukemia (malignant blood disorder characterized by a proliferation of erythropoietic cells in bone marrow).
Cobalamin (Vitamin B12) Deficiency
Normally, a protein termed intrinsic factor (IF) is secreted by parietal cells of the gastric mucosa. IF is required for cobalamin (extrinsic factor) absorption.
Cobalamin is normally absorbed in the distal ileum.
If intrinsic factor is not secreted, cobalamin will not be absorbed
What is aplastic anemia?
And treatment?
Aplastic anemia peripheral blood pancytopenia (decrease of all blood cell types—RBCs,WBCs and platelets) and hypocellular bone marrow.
Severe disease without treatment has 2-6 months survival.
death usually by sepsis.
Bone marrow transplant is best chance for survival.
Causes of acquired aplastic anemia
Approximately 75% of the acquired aplastic anemias are idiopathic and thought to have an autoimmune basis.
• Chemical agents and toxins (e.g., benzene, insecticides, arsenic, alcohol)
• Drugs (e.g., alkylating agents, antiseizure drugs, antimetabolites, antimicrobials, gold)
• Radiation
• Viral and bacterial infections (e.g., hepatitis, parvovirus)
What is neutropenia?
low neutrophil count
A person with neutropenia is susceptible to infection and is at risk for septic shock and death. Even a low-grade fever (above 100.4° F [38° C]) should be considered a medical emergency.
Thrombocytopenia
Low platelets
Thrombocytopenia is manifested by a predisposition to bleeding (e.g., petechiae, ecchymosis, epistaxis).
Platelets below 20,000: at very high risk for bleeding.
Must report below 50,000 to md.
hemolytic anemia
caused by hemolysis of RBCs at a rate that exceeds production. Hemolysis can occur because of problems intrinsic or extrinsic to the RBCs
Difference between intrinsic and acquired hemolytic anemias
Intrinsic hemolytic anemias, which are usually hereditary, result from defects in the RBCs themselves.
Acquired hemolytic anemias,(more common type). In this type of anemia the RBCs are normal, but damage is caused by external factors.
The spleen is the primary site of the destruction of RBCs that are old, defective, or moderately damaged.
Symptoms of hemolytic anemia
general manifestations of anemia in addition to:
Jaundice is likely because the increased destruction of RBCs causes an elevation in bilirubin levels.
Spleen and liver may enlarge because of their hyperactivity, which is related to macrophage phagocytosis of the defective erythrocytes.
Treatment of hemolytic anemia
major focus of treatment is to maintain renal function. When RBCs are hemolyzed, the hemoglobin molecule is released and filtered by the kidneys. The accumulation of hemoglobin molecules can obstruct the renal tubules and lead to acute tubular necrosis.
What is HEMOCHROMATOSIS?
Causes?
- Hemochromatosis is an iron overload disorder.
Primarily caused by a genetic defect.
It may also be caused by liver disease and chronic blood transfusions that are used to treat thalassemia and sickle cell.
Symptoms of HEMOCHROMATOSIS
Early symptoms: fatigue, arthralgia, impotence, abdominal pain, and weight loss.
Later, excess iron accumulates in the liver and causes liver enlargement and eventually cirrhosis. Then other organs become affected, resulting in diabetes mellitus, skin pigment changes (bronzing), cardiac changes (e.g., cardiomyopathy), arthritis, and testicular atrophy.
Laboratory values demonstrate an elevated serum iron, TIBC, and serum ferritin.
Treatment of HEMOCHROMATOSIS
The goal of treatment is to remove excess iron from the body and minimize any symptoms the patient may have. Iron removal is achieved by removing 500 mL of blood each week for 2 to 3 years until the iron stores in the body are depleted. Then blood is removed less frequently to maintain iron levels within normal limits. Iron chelating agents may be used.
Polycythemia
increased numbers of RBCs. The increase in RBCs can be so great that blood circulation is impaired as a result of the increased blood viscosity and volume.
what are some differences between two types of polycythemia:
*primary polycythemia (aka polycythemia vera)
and *secondary polycythemia.
Their etiologies and pathogenesis differ, although their complications and clinical manifestations are similar.
primary polycythemia, or polycythemia vera:
chronic myeloproliferative disorder. Therefore not only are RBCs involved, but also WBCs and platelets, leading to increased production of each of these blood cells.
secondary polycythemia:hypoxia stimulates erythropoietin (EPO) production in the kidney, which in turn stimulates RBC production. The need for oxygen may result from high altitude, pulmonary disease, cardiovascular disease, alveolar hypoventilation, defective oxygen transport, or tissue hypoxia. In hypoxia-independent secondary polycythemia, EPO is produced by a malignant or benign tumor tissue. Splenomegaly does not accompany secondary polycythemia.
What are some serious complications of polycythemia?
most common serious acute complication is stroke secondary to thrombosis.
Hemorrhage can be acute and catastrophic.
Treatment of polycythemia
Phlebotomy is the mainstay of treatment. The aim of phlebotomy is to reduce the hematocrit and keep it less than 45% to 48%. Generally, at the time of diagnosis 300 to 500 mL of blood may be removed every other day until the hematocrit is reduced to normal levels.
