Anemia II Flashcards
Normochromic, Normocytic anemia with increased reticulocyte count
- prior or recent hemorrhage
- recent hemolysis
Normochromic, Normocytic anemia with normal reticulocyte count and normal bone marrow
- anemia of chronic disease
- hypothyroidism
- liver disease
What are the two causes of megaloblastic anemia
- B12 deficiency
- folate deficiency
falsely elevated MCV due to
- large number of reticulocytes (larger RBC)
- RBC clumping mimicking larger RBC
Cause of megaloblastic anemias
defective DNA synthesis results in disordered RBC maturation resulting in larger RBCs
Where does B12 come from
diet
- daily requirement is 1-2ug
How is B12 absorbed
- B12 (cobalamin) is bound to intrinsic factor in the somach
- colbalamin is released from the Cobalamin-IF complex in the ileum where it is absorbed
what cells produce intrinsic factor
gastric parietal cells
What is pernicious anemia
- autoimmune
- autoantibodies against the gastric parietal cells impair IF secretion
- deficiency of intrinsic factor which causes B12 malabsorption and megaloblastic anemia
What are some other conditions that cause B12 deficiency
- ileal disease or resection
- bacterial overgrowth
- intestinal parasites
Clinical presentation
- typical symptoms of anemia
- glossitis, jaundice, splenomegaly
- neuro findings: decreased vibratory and position sense, ataxia, paresthesias, confusion
B12 deficiency anemia
Peripheral smear
- hypersegmented neutrophils (> 5 lobes)
- anisocytosis (size)
- poikilocytosis (shape)
- macro-ovaocytes (large, oval RBC)
- could be B12 deficiency anemia or folate deficiency anemia
positive schilling test
- detects antibodies to IF
- test for pernicious anemia
elevated serum methylmalonic acid and homocysteine levels are common with which anemia
pernicious anemia
treatment of pernicious anemia
- Parenteral vitamin B12
- daily injections of 1000 ug for 1 week
- then weekly injections x 1 month
- then monthly injections for life
- ***Do not treat with folic acid alone
where does folic acid come from
- diet
- fresh, leafy vegetables
dailey requirement of folic acid normally? pregnancy?
- daily requirement 200 ug/day
- 400-800 ug/day in pregnancy
- **half life of 3 weeks
folate deficiency occurs in what conditions
- alcoholism
- end of pregnancy
- anticonvulsant therapy
Homocysteine levels and serum methylmalonic acid levels in folid acid deficiency
- Homocysteine levels elevated
- serum methylmalonic acid normal
treatment of folate deficiency
- 1 mg folic acid orally daily
- 5 mg folic acid in patients with malabsorption
Hemolysis
destruction of RBCs
bone marrow cannot compensate for RBC survival time less than what?
- 20 days…up to 5 times less than normal
- ** nml survival time=120days
clinical presentation
- usual features of anemia: pallor, SOB
- jaundice
- gallstones
hemolytic anemia
patients with hemolytic anemia are at an increased risk of infection with?
- salmonella
- pneumococcus (give vaccine)
intravascular hemolysis
destruction of RBC within the blood stream
extravascular hemolysis
destruction of RBC in the spleen
lab findings
- elevated reticulocyte count (polychromasia)
- peripheral smear
- immature RBC’s nucleated RBCs
- possible schistocytes (fragmented RBCs)
- unconjugated biliruben increased
- elevated serum LDH: Lactate dehydrogenase
- plasma hemoglobin increased
Hemolytic anemia
what lab value is low in intravascular hemolysis
serum haptoglobin
- mucoprotein produced in the liver which binds hemoglobin that has been released from lysed RBC
polychromasia
reticulocytosis
G6PD deficiency can cause intravascular hemolysis. what would you see in peripheral smear
Heinz bodies
common causes of intravascular hemolysis
- fragmentation syndromes
- mechanical heart valve
- G6PD deficiency
- paroxysmal nocturnal hemoglobinuria
positive osmotic fragility test is indicative of what disease
hereditary spherocytosis
common causes of extravascular hemolysis
- hereditary spherocytosis
- sick cell anemia
- autoimmune hemolytic anemia
- incompatible blood transfusion
- drug induced
positive coombs test is indicative of
autoimmune hemolytic anemia
- usually causes by IgG autoantibody
presentation
- normal MCV but smaller surface area
- RBCs have dense, globular appearance and lack central pallor
- RBC are poorly deformable and trapped in splenic sinusoids and phagocytized by splenic macrophages
hereditary spherocytosis
treatment of hereditary spherocytosis
-
splenectomy
- restores RBC life span back to normal
- give pneumococcal vaccine
- delay splenectomy until adulthood
sickle cell anemia is what type of genetic disorder
autosomal recessive: need HbSS to show symptoms
In sickle cell disease, when do RBC become sickle shaped
when deoxygenated
- dehydration
- hypoxia
- high altitude
- intense exercise
when do signs and symptoms of sickle cell disease develop
age 4-6 months with change from fetal hgb to adult hgb
aplastic crisis
sudden decrease in hemoglobin seen in chronic hemolysis
what is the most common feature of sickle cell disease
-
pain crisis: vaso-occlusive ischemic tissue injury
- pain in back, ribs, limbs lasting 5-7 days
diagnosis of sickle cell
hemoglobin elecrophoresis reveals HbS
peripheral smeal of sick cell disease
- a few sickled RBC
- howell-jolly bodies
Why are RBCs normochronic and normocytic in sickle cell anemia
it is an anemia of chronic disease
treatment of sickle cell disease
- analgesics, fluids and oxygen in painful crisis
- hydroxyurea to decrease incidence of painful crisis
- suppresses bone marrow function of all cell lines
peripheral smear seen with autoimmune hemolytic anemia
- polychromasia
- spherocytosis: sphere-shaped RBC
- nucleated red cell
treatment of hemolysis
- corticosteroids
- splenectomy is frequently advised
- folic acid supplementation
most antibodies to RBC are directed against?
the ABO/Rh blood grouping antigens
aplastic anemia
acquired abnormality of bone marrow stem cells
- >50% idiopathic
- 20% drug exposure
- 10% viral illness
what is the hallmark feature of aplastic anemia
pancytopenia
- anemia (reticulocytopenia)
- leukopenia
- thrombocytopenia
** bone marrow shows absense of precursor of these cells
treatment of aplastic anemia
bone marrow transplant or immunosuppressive tx
