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Hematology

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  1. Hematology

  2. Anemia • deficiency of red blood cells and/or hemoglobin • reduced ability of blood to transfer oxygen to the tissues, and this causes hypoxia

  3. Three main classes • excessive blood loss (acutely such as a hemorrhage or chronically through low-volume loss • excessive red blood cell destruction (hemolysis) • deficient red blood cell production

  4. Signs and symptoms • weakness or fatigue. • sometimes shortness of breath • severe anemia prompts the body to compensate by markedly increasing cardiac output, leading to palpitations and sweatiness; lead to heart failure in elderly • Pallor (pale skin and mucosal linings) : only notable in severe anemia, not a reliable sign

  5. Diagnosis • Complete blood count (CBC) • Blood smear • Reticulocyte count • Mean corpuscular volume (MCV) • Mean corpuscular hemoglobin (MCH) • Mean corpuscular hemoglobin concentration (MCHC)

  6. Deficient red blood cell production • iron deficiency anemia • pernicious anemia • folate deficiency anemia

  7. Excessive red blood cell destruction (hemolysis) • G-6-PD deficiency anemia • Thalassemia

  8. Iron deficiency anemia • most common type of anemia • microcytic anemia • dietary intake or absorption of iron is insufficient • hemoglobin, which contains iron, cannot be formed

  9. Diagnosis • complete blood count (CBC) : low hemoglobin or hematocrit • low MCV, MCH or MCHC • a peripheral blood smear : microcytic anemia • low serum ferritin, a low serum iron level • elevated serum transferrin and a high total iron binding capacity (TIBC).

  10. Treatment • If the cause is dietary iron deficiency, iron supplements, usually with iron sulfate, • Oral iron supplements (ferrous sulfate) 300 mg three times a day • The hematocrit should return to normal after 2 months of iron therapy, but the iron should be continued for another 6 to 12 months to replenish the body's iron stores

  11. Prevention of complications • Detection and referral for diagnosis and treatment

  12. Pernicious anemia • a type of autoimmune anemia • Antibodies are directed against intrinsic factor or parietal cells which produce intrinsic factor • Intrinsic factor is required for vitamin B12 absorption, so impaired absorption of vitamin B12 can result • vitamin B12 malabsorption, and vitamin B12 deficiency

  13. Folate deficiency anemia • Deficiency in daily intake or absorption

  14. Diagnosis • complete blood count (CBC) : low hemoglobin or hematocrit • High MCV, MCH • macrocytic anemia • low levels of serum vitamin B12

  15. Treatment • Vitamin B12 (hydroxycobalamin or cyanocobalamin) injected intramuscularly generally 1000 to 2000 mcg daily • Folic acid orally 1 mg daily

  16. Potential problem • Infection • Bleeding • Delayed healing

  17. Prevention of complications • Detection and medical treatment (early detection and treatment can prevent permanent neurologic damage)

  18. Glucose-6-phosphate dehydrogenase deficiency • hereditary, sex-linked enzyme defect that results in the breakdown of red blood cells when the person is exposed to the stress of infection or drugs

  19. Causes, incidence, and risk factors • primary effect is the reduction of the enzyme G-6-PD in red blood cells, causing destruction of the cells, called hemolysis. • hemolysis leads to anemia • disorder are not normally anemic and display no evidence of the disease until the red blood cells are exposed to an oxidant or stress.

  20. Drugs : • antimalarial agents • sulfonamides (antibiotic) • aspirin • nonsteroidal anti-inflammatory drugs (NSAIDs) • nitrofurantoin • quinidine • quinine • others

  21. Symptoms • Fatigue • Paleness • Shortness of breath, rapid heart rate • Yellow skin color (jaundice) • Dark urine • Enlarged spleen Note: Severe hemolysis may cause hemoglobinuria (hemoglobin in the urine).

  22. Treatment • cause is an infection, it should be treated. • cause is a drug, the offending agent should be stopped

  23. Potential problem • Accelerated hemolysis of RBC • Prevention of complications • control infection • avoid drugs : antibiotics, aspirin • often increased sensitivity to sulfa drugs, aspirin , chloramphenicol

  24. Emergency care • Having hemolytic crisis : conservative control of pain and infection

  25. Thalassemia • inherited disease of the red blood cells, classified as a hemoglobinopathy • genetic defect results in synthesis of an abnormal hemoglobin molecule • blood cells are vulnerable to mechanical injury and die easily • Prevalence : 3-14 % in Thailand

  26. Classification • according to which chain of the globin molecule is affected: • α thalassemia, the production of α globin is deficient • β thalassemia the production of β globin is defective

  27. Alpha (α) thalassemias • involve the genes HBA1 and HBA2 • inherited in an autosomal dominant • connected to the deletion of the 16p chromosome

  28. α thalassemias result in excess β chain production in adults and excess γ chains in newborns • excess β chains form unstable tetramers that have abnormal oxygen dissociation curves. four genetic loci for α globin • The more of these loci that are deleted or affected by mutation, the more severe will be the manifestations of the disease

  29. All four loci are affected • infants are dead at birth with hydrops fetalis, born alive die shortly after birth • edematous and have little circulating hemoglobin • tetrameric γ chains (hemoglobin Barts). • homozygous inheritance of an alpha thalassemia trait, type 1.

  30. three loci are affected, Hemoglobin H disease results • in blood, both hemoglobin Barts (tetrameric γ chains) and hemoglobin H (tetrameric β chains) • noticed in childhood or in early adult life, when the anemia and splenomegaly • usually due to compound heterozygous inheritance of alpha thalassemia type 1 and type 2 traits.

  31. two of the four α loci are affected, alpha thalassemia trait, type 1 results • Two α loci permit nearly normal erythropoiesis • mild microcytic hypochromic anemia • deletion of one of the two α loci on chromosomes

  32. one of the four α loci is affected, alpha Minor or alpha+ thalassemia trait or alpha thalassemia trait, type 2 results • minimal effect. • Three α-globin loci are enough to permit normal hemoglobin production • no anemia or hypochromia • called α thalassemia carriers.

  33. Beta (β) thalassemias • mutations in the gene on chromosome 11 • inherited in an autosomal dominant • excess α chains are produced, but these do not form tetramers • bind to the red blood cell membranes producing membrane damage • at high concentrations have the tendency to form toxic aggregates

  34. severity of the damage depends on the nature of the mutation • individual has two β globin alleles • mutations (βo) prevent any formation of β chains • (β+) allow some β chain formation to occur

  35. β thalassemia major or Cooley's anemia : both have mutations, a severe microcytic, hypochromic anemia • Untreated, this results in death before age twenty • Treatment : • periodic blood transfusion • splenectomy (splenomegaly) • transfusion-caused iron overload • Cure is possible by bone marrow transplantation.

  36. Thalassemia minor (sometimes referred to as β thalassemia trait) : only one β globin allele mutation • results mild anemia with microcytosis • Symptoms include weakness and fatigue • most cases β thalassemia minor may be asymptomatic and may be unaware • Detection usually involves counting the mean corpuscular volume (size of red blood cells) and noticing a slightly decreased mean volume than normal.

  37. Thalassemia intermedia • condition intermediate between the major and minor forms • often normal life but may need occasional transfusions e.g. at times of illness or pregnancy • depends on the severity of their anemia.

  38. Treatment and complications Thalassemia Major and Intermedia • receive frequent blood transfusions that lead to iron overload. Iron chelation treatment is necessary • Untreated thalassemia Major eventually leads to death usually by heart failure, therefore birth screening is very important • bone marrow transplant

  39. Thalassemia Intermedia • patients vary in treatment needs depending on the severity of their anemia Thalassemia Minor • not life threatening, can affect quality of life due to the effects of a mild to moderate anemia

  40. Diagnosis • complete blood count (CBC) : low hemoglobin or hematocrit • low MCV or MCHC • a peripheral blood smear : hypochromic microcytic anemia • increase serum iron level

  41. Prevention of complications • Detection and referral for diagnosis and treatment • Severe anemia : hemoglobin, hematocrit before dental treatment • Severe anemia : • Hematocrit < 15 % - blood transfusion • Splenectomy : infection • Antibiotic prophylaxis before dental surgery

  42. Leukemia • cancer of the blood or bone marrow characterized by an abnormal proliferation of blood cells, usually white blood cells (leukocytes)

  43. Symptoms • Damage bone marrow, by displacing the normal marrow cells with increasing numbers of malignant cells, • results in a lack of platelets, which are important in the blood clotting process. • people with leukemia may become bruised, bleed excessively, or petechiae

  44. White blood cells, which are involved in fighting pathogens, may be suppressed or dysfunctional, putting the patient at the risk of developing infections • red blood cell deficiency leads to anaemia, which may cause dyspnea

  45. Diagnosis • blood tests • bone marrow biopsy

  46. Related symptoms • Fever, chills, and other flu-like symptoms • Weakness and fatigue • Loss of appetite and/or weight • Swollen or bleeding gums • Neurological symptoms (headache)

  47. Acute vs. chronic • Leukemia is clinically and pathologically split in to its acute and chronic forms

  48. Acute leukemia • characterized by the rapid growth of immature blood cells • bone marrow unable to produce healthy blood cells • Acute forms of leukemia can occur in children and young adults

  49. Immediate treatment in acute leukemias • rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. • If left untreated, the patient will die within months or even weeks

  50. Chronic leukemia • excessive buildup of relatively mature, but still abnormal white blood cells • progress months to years • the cells are produced at a higher rate than normal cells, resulting in many abnormal white blood cells in the blood. • mostly occurs in older people, but can occur in any age group