Chapter 12: Summaries Flashcards
Name three causes of anemia.
Blood loss (hemorrhage), increased red cell destruction (hemolysis) and decreased red cell production (erythropoiesis).
Name three forms (morphology) of anemia.
Microcytic, macrocytic and normocytic.
What causes microcytic anemia? What are characteristics?
Microcytic anemia occurs due to iron deficiency or thalassemia. Microcytic anemia means that red blood cells are smaller and are present in lower numbers than normal.
What causes macrocytic anemia? What are characteristics?
It occurs due to folate or vitamine B12 deficiency. Red blood cells are bigger and are present in lower numbers than normal.
What causes normocytic anemia? What are characteristics?
Red blood cells have a normal size, but have abnormal shapes. It is due to hereditary spherocytosis or sickel cell disease.
What are clinical manifestations of acute anemia?
Shortness of breath, organ failure, shock.
What is a general clinical manifestation of chronic anemia?
Pallor and fatigue/lassitude
What clinical manifestations are there during anemia when it is caused by hemolysis?
Jaundice and gallstones.
What clinical manifestations are there during anemia when it is caused by ineffective erythropoiesis?
Iron overload, heart and endocrine failure.
What clinical manifestations are there during severe and congenital anemia?
Growth retardation, bone deformities due to reactive marrow hyperplasia.
What two diseases can lead to hemolytic anemia?
Hereditary Spherocytosis and Sickle Cell Anemia.
What is Hereditary Spherocytosis?
It is an autosomal dominant disorder caused by mutations that affect the red cell membrane skeleton. This causes a loss of membranes and with that the formation of spherocytes. These are phagocytosed and removed in the spleen.
What is Sickle Cell Anemia?
It is an autosomal recessive disorder where a mutation in β-globin causes deoxygenated hemoglobin to self-associate into long polymers that distort the red cells.
What is the consequence of distorted red blood cells in Sicke Cell Anemia?
The distorted red blood cells block vessels. This causes pain crises and tissue infarction.
Where does blockage of vessels and tissue infarction mostly occur in Sickle Cell Anemia?
In the marrow and spleen.
Patients with Sickle Cell Anemia are at high risk for … and …
bacterial infections and stroke
What is Thalassemia?
It is an autosomal codominant disorder caused by mutation in α- or β-globin. This reduces synthesis of hemoglobin which results in microcytic and hypochromic (red blood cells are paler) anemia.
What is Glucose-6-Phosphate Dehydrogenase
(G6PD) Deficiency?
An X-linked disorder caused by mutations that destabilize G6PD, making red cells susceptible to oxidant damage.
What is Immunohemolytic Anemia caused by?
It is caused by antibodies against either normal red cell constituents or antigens modified by haptens (small molecules that elicit an immune response only when attached to a large carrier such as a protein).
What happens upon antibody binding in Immunohemolytic Anemia?
It results in red cell opsonization and extravascular hemolysis. But can also result in complement fixation and intravascular hemolysis (less common).
How can the parasite malaria cause anemia?
The parasite causes chronic hemolysis of variable severity.
Why is falciparum malaria fatal?
Because of the propensity of infected red cells to adhere to small vessels in the brain (cerebral malaria).
Name three kinds of anemia of diminished erythropoiesis.
Iron deficiency anemia, anemia of chronic inflammation and megaloblastic anemia.
What is the cause and result of iron deficiency anemia?
It is caused by chronic bleeding or inadequate iron intake which results in insufficient hemoglobin synthesis and hypochromic, microcytic red cells.
