Patho: Chapter 23 (RBC Disorders)

What is anemia?

An abnormally low number of circulating RBCs, too little hemoglobin, or both.

What causes anemia?

• Blood loss (bleeding)

• Hemolysis (destruction of RBCs)

• Impaired RBC production

What is sickle cell disease?

An autosomal recessive inherited disorder in which abnormal hemoglobin S (HbS) leads to chronic hemolytic anemia, pain, and organ failure.

What causes sickle cell disease?

• Inherited autosomal recessive disorder

• Point mutation in the beta chain of hemoglobin

• Substitution of valine for glutamic acid

• Production of abnormal hemoglobin S (HbS)

What are the characteristics/manifestations of sickle cell disease?

• RBCs become sickled when deoxygenated

• Jaundice

• Pain

• Organ failure

• Chronic hemolytic anemia

• May lead to pigment gallstones

• May lead to acute chest syndrome

• May lead to stroke

• May lead to damage to the liver, spleen, heart, kidneys, eyes, and bones

What is the hemolytic disease of a newborn?

A disorder in which maternal antibodies destroy the RBCs of an Rh-positive infant.

What causes hemolytic disease of a newborn?

• Rh-positive infant born to an Rh-negative mother

• Mother has anti-Rh antibodies from a previous Rh-positive infant or Rh-positive transfusion

• Maternal antibodies cross the placenta and attack the infant’s RBCs

• Hemolysis of the infants RBCs occurs

What are the characteristics/manifestations of hemolytic disease of a newborn?

• Hemolysis (destruction of RBCs)

• Severe anemia

• May lead to severe brain damage if bilirubin levels become too high

What is thalassemia?

A group of inherited disorders of hemoglobin synthesis that cause decreased production of either the alpha or beta globin chains of hemoglobin.

What causes thalassemia?

• Inherited disorder of hemoglobin synthesis

• Decreased production of alpha or beta globin chains

What are the characteristics/manifestations of thalassemia?

• Decreased hemoglobin production

• Anemia

• Impaired RBC production

• May lead to hemolysis

What are the two types of thalassemia?

• Alpha thalassemia

• Beta Thalassemia

What is Alpha thalassemia?

Insufficient synthesis of alpha globin chains

What is Beta thalassemia?

Insufficient synthesis of beta globin chains

When a person has their stomach removed, why do they suffer from Vitamin B12 deficiency-Pernicious anemia?

The stomach produces intrinsic factor, which is required for vitamin B12 absorption. Without intrinsic factor, vitamin B12 cannot be absorbed, leading to vitamin B12 deficiency-Pernicious anemia.

Why does iron deficiency lead to anemia?

Iron is needed to make hemoglobin, which is in RBCs. Without iron, hemoglobin and RBCs cannot be made.

What is polycythemia?

An abnormally increased total RBC count with a hematocrit greater than 50%.

What are the types of polycythemia?

• Primary polycythemia

• Secondary polycythemia

What is primary polycythemia?

A neoplastic (abnormal) disease of the bone marrow characterized by an absolute increase in RBCs, WBCs, and platelets

What causes primary polycythemia?

Neoplastic (abnormal) disease of the bone marrow

What are characteristics of primary polycythemia?

• Increased total RBC count

• Increased WBC count

• Increased platelet count

• Hematocrit greater than 50%

What is secondary polycythemia?

An increase in RBC concentration due to increased erythropoietin.

What causes secondary polycythemia?

• Hypoxia

• Increased erythropoietin released by the kidneys

• High altitude

• Chronic Heart Disease

• Chronic Lung Disease

• EPO-secreting tumors

What are the characteristics of secondary polycythemia?

• Increased EPO levels

• Increased RBC concentration

• Hematocrit greater than 50%

If someone lives at a high altitude or has chronic lung disease or heart disease, can they get secondary polycythemia?

Yes

A nurse is monitoring a client with anemia and low oxygen levels. The nurse knows that which condition stimulates the secretion of erythropoietin?

Hypoxia

Which condition stimulates erythropoietin secretion?

Hypoxia

Which of the following refers to increased RBC count and a hematocrit greater than 50%

Polycythemia

If someone lives at a high altitude or has chronic lung disease, they can get secondary polycythemia.

True