Hypochromic Anemias Flashcards
Name 3 classifications of Anemia
- Disorders of Iron metabolism
- Disorders of Heme Synthesis (sideroblastic anemias)
- Disorders of Globin Synthesis
List 2 types of Disorders of iron Metabolism
- Iron deficiency anemia
- anemias of chronic disease
List 3 causes of iron deficiency anemia
- decreased dietary iron
- blood loss
- impaired iron transport
List 2 causes of anemia of chronic disease
- chronic inflammatory disease
- malignant disorders
List 3 types of disorders of Heme synthesis (Sideroblastic Disease)
- Heretitary sideroblastic anemias
- idiopathic sideroblastic anemias
- Secondary sideroblastic anemias
List three causes of secondary sideroblastic anemia
- drug induced
- alcohol induced
- lead poisoning
List 3 disorders of globin synthesis
- β thal
- α thal
- other thalessemias
List the functions of iron
- formation of heme in hgb and myoglobin
- components of cytochromes, catalses , myeloperoxidase
- enzyme activator in some reactions
State the total body iron in normal adults
total iron in adults 2-5 grams
males: 3.5g
females 2.3g
list 3 iron compartments and the distribution in each
- Heme {enymes, Hgb, myoglobin} 80%
- Transport: transferrin 0.1%
- Storage: spleen, liver etc 20%
List 3 factors which influence iron absorption
- serum iron concentration (inverse relationship)
- amount in diet (direct)
- pH in gut (acid pH enhances absorption)
Describe transferrin
transferrin is a β-globulin which carries two Fe3+ / molecule
Function of transferrin
transports iron in plasma from macrophages to developing normoblasts in bone marrow
Define transferrin saturation
the % of iron binding sites on transferrin which are occupied by iron
describe ferritin
main storage form of iron
is the water soluble and labile storage form found in nucleated rbcs, intestinal mucosal cells, blood plasma and in macrophages mostly in liver and spleen
this form is not visible under Perl’s Prussian blue stain
Describe hemosiderin
a type of storage iron
less labile than ferritin and is water insoluble
formed in macrophages by polymerization and processing of many ferritin molecules into large, dense aggregates
visible on Perl’s Prussian blue
Describe the excretion of iron
there is NO normal physiologic mechanisms designed to excrete iron
How is iron lost in a normal person
Fe is lost in small amounts each day
men and postmenopausal women: feces by desquamation, perspiration, and minute hemorrhages for a total loss of about 1mg/day
fertile but non pregnant females: due to menstrual loss 2mg/day
Pregnant women: diversion of iron to fetus loss = 3mg/day
Dietary requirements of iron
men and post menopausal women: 10mg
infants and children: 5 mg
menstruating women: 20 mg
Pregnant women: 30 mg
list the 5 main causes of Fe Deficiency
- Chronic bleeding (most frequent cause)
- decreased absorption of irom
- dietary deficiency
- increased requirements for iron
- decreased or abnormal transferrin (rare)
Describe iron deficiency anemia
Fe deficiency results in decreased heme formation in nRBC and hypochromia and microcytosis of mature rbc
Define hypochromia
rbcs with increases size of central pallor indicating they contain less Hgb than normal
Define microcytosis
more cell divisions that occur while waiting for the cell to fill up with hgb which results in cells that are smaller than normal
Three stages of the development of iron deficiency
- iron depletion: iron stores are reduced by not absent
- iron deficiency: iron stores are depleted to almost zero, the serum iron and transferring sat are decreased, and TIBC is increased
- Iron deficiency anemia: hgb decreased with hypo and micro
List the lab findings in iron deficiency anemia
Peripheral blood:
- hgb: ↓
- hct: ↓
- rbc count: normal
- rbc indices: MCV, MCH, MCHC all ↓
- RDW: ↑
- RBC Morphology: micro hypo in mild cases plus in severe cases can get ovalocytes and target cells
- Retic count: normal or sl ↑
- WBC count/morph: normal or sl ↑ due to chronic bleeding
- Plt count/morph normal or sli ↑ (chronic bleed)
Serum Chemistries:
- Iron assay: ↓
- TIBC: ↑
- Transferrin Sat:↓
- Ferritin: ↓
- sTfR (soluble transferrin receptor): ↑
- FEP (free erythrocyte protoporphyrin): ↑
Define Thalassemia
group of disorders in which the rate of synthesis of a specific type of polypetide chain (α or β) used in globin production is decreased
seen as micro hypo anemia
Define Sideroblastic anemia
anemia caused by a biochemical abnormalities in the sythesis of heme in developing red cells
Note: not due to a lack of Fe
Most cases involve abnormal enzyme functions in the synthesis of heme.
Iron accumulates in these because less than normal amts of protoporphyrin IX is formed.
What are 2 major categories of Sideroblastic anemias:
- Refractory sideroblastic anemias
(poor response to therapy)
inherited and idiopathic
- Secondary sideroblastic anemia
- due to vit B6 (pyridoxine) deficiency: required for coenzyme in first rx of heme synthesis
- due to drugs toxins chemicals etc: inhibit heme synthesis eg: lead poisoning
What are the lab findings in Sideroblastic anemia
- Ringed sideroblasts in bone marrow (nRBC containing prussian blue staining, iron loaded mitochondria and siderotic granules)
- Hypochromia and normocytic, macrocytic or morphology
- Basophilic stippling and possible pappenheimer bodies
- increased serum iron, transferrin sat and serum ferritin; TIBC is usually normal or decreased
- Monocytosis seen sometimes
Define Anemia of Chronic Disease
sometimes anemia is seen in chronic inflammatory diseases eg:
- chronic infection
- autoimmune disorders,
- renal failure
- chronic leukemias
- endocrine disorders
Morphology: normochromic and normocytic
Causes of Anemia of Chronic Disease
- An inflammatory blockage of the release of iron stores from macrophages in the liver and spleen due tot he action of cytokines associated witht eh inflammatory response. the inability to release iron stores results in usually mild accumulation of iron in the storage areas and a deficiency of iron inside the developing red cells
- increased hemolysis of circulating red cells
- decreased erythropoietin production
What are the lab findings in Anemia of Chronic Disorders?
- hypochromia or normochromia
- normocytic
- decreased iron and transferrin saturation
- Normal or increased storage iron
- Serum ferritin is normal or increased
- Serun sRfR is normal
- Hgb rarely less than 90g/L
- MCV is usually slightly low or low normal (75-80fL)
