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Lecture

BIOC33H3 Lecture Notes - Watchful Waiting, Hypercalcaemia, Lymph Node


Department
Biological Sciences
Course Code
BIOC33H3
Professor
Stephen Reid

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Chapter 31: Hematologic Problems
ANEMIA
Anemia is a deficiency in the number of erythrocytes (red blood cells [RBCs]), the quantity of
hemoglobin, and/or the volume of packed RBCs (hematocrit), which can lead to tissue hypoxia.
Hemoglobin (Hb) levels are often used to determine the severity of anemia.
Correcting the cause of the anemia is ultimately the goal of therapy.
Interventions may include blood or blood product transfusions, drug therapy, volume
replacement, oxygen therapy, dietary modifications, and lifestyle changes.
Anemia Caused By Decreased Erythrocyte Production
Iron-Deficiency Anemia
Iron-deficiency anemia may develop from inadequate dietary intake, malabsorption, blood loss,
or hemolysis. Also, pregnancy contributes to iron deficiency because of the diversion of iron to
the fetus for erythropoiesis, blood loss at delivery, and lactation.
The main goal of collaborative care for iron-deficiency anemia is to treat the underlying disease
causing reduced intake (e.g., malnutrition, alcoholism) or absorption of iron. In addition, efforts
are directed toward replacing iron with dietary changes or supplementation.
It is important for a nurse to recognize groups of individuals who are at an increased risk for the
development of iron-deficiency anemia. These include premenopausal and pregnant women,
persons from lowerclass socioeconomic backgrounds, older adults, and individuals
experiencing blood loss.
Thalassemia
Thalassemia is a group of diseases that has an autosomal-recessive genetic basis that involves
inadequate production of normal hemoglobin.
An individual with thalassemia may have a heterozygous or homozygous form of the disease,
based on the number of thalassemic genes the individual has.

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Thalassemia minor requires no treatment because the body adapts to the reduced level of
normal hemoglobin.
The symptoms of thalassemia major are managed with blood transfusions or exchange
transfusions in conjunction with IV deferoxamine to reduce the iron overloading
(hemochromatosis) that occurs with chronic transfusion therapy.
MEGALOBLASTIC ANEMIAS
Megaloblastic anemias are a group of disorders caused by impaired DNA synthesis and
characterized by the presence of large RBCs.
Macrocytic (large) RBCs are easily destroyed because they have fragile cell membranes.
Two common forms of megaloblastic anemia are cobalamin deficiency and folic acid deficiency.
o Cobalamin (vitamin B12) deficiency is most commonly caused by pernicious anemia,
which results in poor cobalamin absorption through the GI tract. Parenteral or
intranasal administration of cobalamin is the treatment of choice.
o Folic acid (folate) is required for DNA synthesis leading to RBC formation and
maturation and therefore can lead to megaloblastic anemia. Folic acid deficiency is
treated by replacement therapy.
Aplastic Anemia
Aplastic anemia is a disease in which the patient has peripheral blood pancytopenia (decrease
of all blood cell types) and hypocellular bone marrow.
Management of aplastic anemia is based on identifying and removing the causative agent (when
possible) and providing supportive care until the pancytopenia reverses.
Anemia Caused By Blood Loss
Acute Blood Loss
Acute blood loss occurs as a result of sudden hemorrhage.
Causes of acute blood loss include trauma, complications of surgery, and conditions or diseases
that disrupt vascular integrity.
Collaborative care is initially concerned with replacing blood volume to prevent shock and
identifying the source of the hemorrhage and stopping the blood loss.

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Chronic Blood Loss
The sources of chronic blood loss are similar to those of iron-deficiency anemia (e.g., bleeding
ulcer, hemorrhoids, menstrual and postmenopausal blood loss).
Management of chronic blood loss anemia involves identifying the source and stopping the
bleeding. Supplemental iron may be required.
Anemia Caused By Increased Erythrocyte Destruction (Hemolytic Anemia)
SICKLE CELL DISEASE
Sickle cell disease is a group of inherited, autosomal recessive disorders characterized by the
presence of an abnormal form of hemoglobin in the erythrocyte.
The major pathophysiologic event of this disease is the sickling of RBCs. Sickling episodes are
most commonly triggered by low oxygen tension in the blood.
With repeated episodes of sickling there is gradual involvement of all body systems, especially
the spleen, lungs, kidneys, and brain.
Collaborative care for a patient with sickle cell disease is directed toward alleviating the
symptoms from the complications of the disease and minimizing end target-organ damage.
There is no specific treatment for the disease.
Acquired Hemolytic Anemia
Extrinsic causes of hemolysis can be separated into three categories: (1) physical factors, (2)
immune reactions, and (3) infectious agents and toxins.
Physical destruction of RBCs results from the exertion of extreme force on the cells.
Antibodies may destroy RBCs by the mechanisms involved in antigen-antibody reactions.
Infectious agents foster hemolysis in four ways: (1) by invading the RBC and destroying its
contents, (2) by releasing hemolytic substances, (3) by generating an antigen-antibody reaction,
and (4) by contributing to splenomegaly as a means of increasing removal of damaged RBCs
from the circulation.
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