Learning Outcomes
Describe the cellular and fluid components of blood and functions of blood cells (review).
Define anemia and describe the various methods of classifying the anemias.
Describe the manifestations of anemia and the pathophysiology underlying the clinical manifestations.
Compare and contrast the pathophysiology underlying iron deficiency, pernicious and folate deficiency anemias.
Describe the normocytic-normochromic anemias.
Define polycythemia vera and describe its causes and multiple system manifestations related to the increased viscosity and volume of blood.
Describe the different types of alterations in leukocyte function.
Define agranulocytosis and describe its clinical manifestations.
Describe the manifestations of infectious mononucleosis and its complications beyond the immune system.
Classify leukemias as it relates to the maturity of the cells and appearance of the total leukocyte count and differential.
Differentiate the leukemias by manifestations, treatment options and prognosis.
Describe Hodgkin and non-Hodgkin lymphomas, focusing on differential diagnosis, manifestations, treatment and prognosis.
Describe the pathophysiology, clinical manifestations, and treatment of multiple myeloma.
Describe the causes of splenomegaly.
Describe the causes of thrombocytopenia.
Describe the various causes of impaired hemostasis.
Describe the pathophysiology of disseminated intravascular coagulation.
Describe the conditions that predispose an individual to the development of thrombosis.
Definitions: Blood (Disorders of the Hematological System)
Review: Anatomy and Physiology of the Hematological System
Composition of Blood
Critical facts at a glance:
Albumin is the most abundant plasma protein
– Plasma oncotic pressure
o Solutes within blood that holds the fluid within the vessel
o Loss of albumin (or other plasma proteins) causes fluid to leak into the interstitial space
• Manifested as edema
Leukemia = immature cells in blood circulation
Bone marrow contains multiple stages of cellular development and maturation but only mature cells are released into the blood
There are 5-6 million RBC, 9-11 thousand of WBCs and 150-450 thousand of platelets per cubic millimeter
Vacutainers have different colored caps, indicating the type of anticoagulant added to the
container to prevent clotting of the blood sample
– If no anticoagulant were added, the sample would begin to clot once collected
Hemoglobin is a quaternary protein composed of heme + globin (peptide chains).
– Four globin chains; 2 alpha and 2 beta, each chain has heme (iron surrounded by porphyrin ring) in its centre
– RBC has a 120-day life span
– Platelets have 10 day life span
– Some WBCs live for years
Life Cycle of a Red Blood Cell
– Hemoglobin is broken into heme and globin
– Globin is recycled to amino acids
– Heme is broken into iron and biliverdin
– Iron is reused as it goes back the bone marrow through blood circulation via transferrin
– Biliverdin (green) turns into bilirubin (yellow) that goes to the liver
– Bilirubin has three possible outcomes:
1. Some goes with bile to the intestine to help fat digestion; part of which then gets reabsorbed into circulation
2. Some turns into urobilin and is excreted in stool.
3. Some goes straight to the kidney from the liver (via circulation) to be excreted in urine.
Disorders of the Hematological System
Anemia
Reduced number and/or function of erythrocytes
(red blood cells), hemoglobin, hematocrit, or any combination of these
Anemia is a very common pathophysiology worldwide
Etiology
Impaired erythrocyte production
Increased erythrocyte destruction
– Or a combination of both impaired production and increased destruction
Blood loss (acute or chronic)
– Leads to overall decrease in erythrocytes
Anemia may also result with:
– Increased erythrocyte destruction in the spleen
– Impaired bone marrow production (either in producing too few, or poor quality)
– Nutrient deficiencies (i.e. Iron, B12, Folic Acid)
There is a relationship between RBC structure and anemia
– RBCs are 7um biconcave discs, this is the size/shape is required to enable them to stack and move through capillaries
– Low hemoglobin is visible microscopically in a blood smear as a, “pallor sign”, the RBC looks empty, no redness in the middle