Flashcards in EXAM #1: MICROCYTIC ANEMIA Deck (63):
What is the most important point to remember about anemia?
Anemia is NOT a concluding diagnosis; it is a manifestation of disease
What is the definition of anemia?
Decreased RBC resulting in decreased oxygen carrying capacity
What are the common symptoms of anemia?
What is the normal MCV of RBCs?
What is the definition of microcytic anemia?
Less than 80 fl MCV
What is the rule of thumb for determining the size of a RBC on PBS?
- Lymphocyte nucleus
- Central pallor is roughly 1/3 of the RBC width
What are the hallmark features of microcytosis on PBS?
What is a normal Hb for men?
What is a normal Hb for women?
What is a normal Hct in men?
What is a normal Hct in women?
What is the normal MCH?
Mean Corpusucular Hb
What is the normal MCHC?
Mean Corpusucular Hb Concentration
What is the normal RDW?
Red Cell Distribution Width
*****Note that the smaller the RDW, the more UNIFORM the size*****
What are the three causes of iron deficiency?
1) Inadequate absorption
2) Inadequate utilization
3) Excessive loss******
*****This is the most common cause
How much iron can be absorbed per day?
Where in the body is iron absorbed?
First and second parts of the duodenum
What is the difference between ferrous and ferric iron?
What form of iron is most efficiently absorbed?
Are plants a good source of iron?
- Low in iron to begin with
- Most is Fe+++
What transporter is important for the absorption of Fe++?
Divalent Metal Transporter
What happens to Fe++ once it is absorbed into the enterocyte?
How does iron/ferretin leave the enterocyte?
How is iron transported in the blood?
Plasma transferrin i.e. carrier protein
What blocks the ferroportin transporter?
Hepcidin (made in the liver)
What is the iron cycle?
1) Iron enters the gut and into the circulation
2) Transferrin transports iron in the blood to the bone marrow
3) Bone marrow to makes RBCs
4) Old RBCs are recycled in the spleen and iron is stored
5) Iron is released back into the blood to repeat the cycle
What upregulates hepcidin?
High circulating ferretin
What downregulates hepcidin?
What organ produces EPO? What is the function of EPO?
- Kidneys (renal fibroblasts)
- EPO stimulates erythropoiesis
How much iron is circulating in the RBCs?
How much iron is in iron-containing proteins?
How much iron is transferrin-bound?
How much iron is stored?
Is iron excreted from the body? How is iron lost?
- Most in insensible
- Vascular loss
2) Sequetration/ hematoma
4) Internal loss (GI)
What is the defining laboratory characteristics of iron deficiency anemia?
- Low Hb/ Hct
- Small MCV
- Low ferretin (10 or less)*****
- Low transferrin SATURATION
- TIBC high
What is the most specific lab value for iron deficiency anemia?
Low ferritin, less than 10
What is a normal Serum Fe?
What is a normal TBIC?
What is a normal iron saturation?
What is a normal ferritin?
What is the diagnosis for the underlying cause of anemia in a 50 y/o (or older)?
GI malignancy until proven otherwise
What are the signs of iron deficiency?
Pale palmar crease
How is iron deficiency anemia treat?
1) Find bleeding
2) Stop bleeding
3) Replace blood
- Iron supplement
How is iron supplemented?
PO- max 25mg per day
IV- 500 mg
*****IM is NOT recommended b/c of side effects*****
What is the antibacterial effect of Hepcidin?
Limits Fe-dependent electron transport in bacteria
What are the cytokines that will stimulate the production of hepcidin?
What is Rouleaux formation characteristic of?
ACD--autoimmune induced e.g. RA
What are the characteristics of Anemia of Renal Disease?
Normochromic b/c is is caused by a lack of EPO
How many hb-alpha alleles are on each chromosome? What chromosome?
How many beta alleles are on each chromosome? What chromosome?
How are Thalassemias named?
1) Gene that is deficient
2) null or += all genes or not
What is Hb-H and Hb-barts?
Both are tetramers WITHOUT alpha globin
List the a-thalassemias.
1) aa/aa= normal= Asx.
2) -a/aa= silent carrier= Asx.
3) -a/-a= thalassemia trait= mild
4) --/-a= Hb-H disease= severe
5) --/--= "fetal hydrops"= lethal
Fetal hydrops is INCOMTATABLE WITH LIFE
Differentiate the ppt examples of alpha-Thalassemia.
List the B-thalassemias.
1) B+= trait/ minor= mild
2) B0= major= severe and transfusion dependent
Intermedia= 2x defective genes BUT partially functioning
Outline the pathophysiology of B-Thalassemia.
1) Increased RBC destruction
2) Fe overload in the spleen, marrow, and liver
3) Anemia and hypermetabolic marrow result, BUT the patient is iron overloaded from the destruction of misshaped RBCs
Requires a balance between phlebotomy and transfusion.
Outline the phenotypic characteristics of Beta-Thalassemia.
- Large forehead
- Distended abdomen with slenomegaly and heptaomegaly
Differentiate ppt examples of Beta-thalassemia.
What is sideroblastic anemia?
Anemia with ringed siderblasts i.e. rings of iron around the nucleus
Identify ppt. examples of sideroblastic anemia.
What is the enzyme defieincy of hereditary sideroblastic anemia?
What are the causes of acquired Sideroblastic Anemia?
1) Myelodyplastic Syndrome
3) Drug induced
4) Lead poisoning
5) Cooper deficiency