Anemias Flashcards
Ratio of Hgb to Hct
1:3
Ex. Men: Hgb 14-18, Hct 40-50%
MCV
Mean corpuscular volume
-normal is 80-100
MCH
Mean corpuscular Hemoglobin
Avg mass of Hgb per RBC”how much color?”
- Low MCH/MCHC = hypchromic
- Normal MCH/MCHC = normochromic
- High MCH/MCHC = hyperchromic
RDW
Red cell distribution width
Normal is 11-15%
Causes of increased RBC count
- Dehydration
- COPD
- Polycythemia vera
Signs of Anemia
Early:
- pallor
- tachycardia
- hypotension
- orthostatic changes
Late:
- glossitis
- chelitis
- Jaundice (hemolytic anemia, indirect bili)
- koilonchia
What is the best indicator of iron deficiency anemia
low ferritin (<12ng/mL)
Signs of Fe Deficiency Anemia
- Pica
- Dysphagia (Plummer-Vinson Syndrome)
- Restless leg syndrome
- Glossitis
How long do you give ferrous sulfate 325mg in Fe deficiency anemia?
give until corrected.
Continue 3-6 months after corrected
Thalassemia
- microcytic (low MCV)
- hypochromic
- Normal RDW**
- HIGH ferritin
- Target cells*
- Poikilocytosis
Dx: hemoglobin electrophoresis
Tx: transfusions, avoid iron supplements.
- Folic acid supplemention
- Consider removing spleen
What can make MCV falsely big?
- reticulocytes
2. RBC clumping
What are two characteristic findings on peripheral blood smear for megaloblastic anemias (ex. Folate deficiency, B12 deficiency)
- Hypersegmented neutrophils
2. Macro-ovalocytes
Macrocytic anemia with reticulocyte elevation
-Hemorrhage
or
-Hemolysis
Where is folate absorbed in the small bowel?
Jejunum
Folic acid deficiency: causes
- alcoholism
- hemodialysis
- anticonvulsants
Folic acid deficiency: clinical features
- anemia sx
- glossitis
- NO neurologic abnormalities
What labs will help you tell if folic acid deficiency is the issue?
elevated homocysteine
normal methylmalonic acid
B12 Deficiency
- only available in diet
- MC cause is inability to absorb (needs intrinsic factor [made by parietal cells])
-B12 absorbed in the ileum
Pernicious Anemia
- type of B12 deficiency
- Autoimmune destruction of parietal cells so, absent gastric acid and intrinsic factor
Pernicious anemia: clinical features
- atrophic gastritis –>increased risk for gastric CA
- Neurologic findings (decreased vibration sense, ataxia, parethesias, confusion)
B12 deficiency labs
Positive schilling test
or
Antibodies to IF (pernicious anemia)
Elevated methylmalonic acid and homocysteine levels
Hemolytic anemia: Labs
-Elevated reticulocyte count**
- Increased unconjugated bilirubin (indirect)
- Elevated LDH (lactic acid dehydrogenase)
- Low haptoglobin
Hemolytic anemia: peripheral smear
- reticulocytes
- schistocytes
Haptoglobin
protein produced in the liver that binds to hemoglobin that has been released from lysed RBCs
so, more lysing the less free haptoglobin
Hemolytic anemia: clinical features
- anemia sx
- jaundice
- gallstones (bilirubin stones)
- increased risk of infection with salmonella and pneumococcus**
(infection with parvovirus B19 can lead to transient aplastic crisis)
Micro versus Macroangiopathic hemolytic anemia
Macro - from prosthetic heart valve
Micro - from fibrin strands in the vessels
G6PD Deficiency
- X-linked recessive disorder
- More common in black males and Mediterranean men
- Fava bean is common trigger**
G6PD Deficiency: Labs
During episode:
- Increased reticulocytes
- Increased serum bilirubin
- Low G6PD
Peripheral smear:
- Heinz bodies (denatured hemoglobin)
- Bite cells
G6PD: Tx
- self limited
- Avoid oxidative drugs
Hereditary Spherocytosis
- Autosomal dominant
- Normal MCV, but smaller surface area, dense, globe appearance (no central pallor)
- Poorly deformable, so get stuck in spleen and get phagocytized by splenic macrophages
- Chronic hemolysis creates need for increased folate
Hereditary Spherocytosis: Dx and Tx
clinical manifestion:
- splenomegaly
- jaundice
Dx: Osmotic fragility test
Tx: remove the spleen (in adulthood if possible)
-Give PNA vaccine
Sickle Cell Disease: General
- Autosomal recessive
- HbSS (sickle cell disease)
- HbS + Hb A (sickle cell trait)
Sickle cell disease: clinical features
- symptoms start at 4-6 months with change from fetal hemoglobin to adult hemoglobin
- INCREASED susceptibility to infection
Symptoms precipitated by dehydration, hypoxia, high altitude, intense exercise
Sickle cell disease: more clinical features
- chronic hemolysis (bilirubin rises)
- Vaso-occlusive ischemic tissue injury
- PAIN CRISIS** (MC feature of disease)
- osteonecrosis of femoral and humeral heads from bone infarcts
- Splenic infarcts lead to functional asplenism
- leg ulcers
Sickle cell disease: labs
- Reticulocyte count is elevated**
- Hgb electrophoresis shows HbS*** (best test to confirm diagnosis)
Peripheral smear:
-Howell-jolly bodies (nuclear remnants usually removed by the spleen)
Sickle cell disease: Tx
-Hydroxyurea (suppresses bone marrow to decrease incidence of painful crises)
- PNA vaccine
- Folate supplementation
Autoimmune Hemolytic Anemia: general
- antibodies adhere to surface of RBC
- Complexed antibody and cell are phagocytized leaving –>spherocytes*
Autoimmune hemolytic anemia: Labs/peripheral smear
- Polychromasia
- spherocytosis
- (+) Coombs test**
Incompatible blood transfusion
- Antibodies to ABO/RH blood group antigen
- (+) Coombs test**
Treatment for hemolytic anemias
- Folic acid supplementation**
- Splenectomy (to consider)
Anemia of Chronic Disease
- normocytic, normochromic
- normal or increased ferritin
- Fe and TIBC are low in setting of inflammation
Myelodysplastic Syndrome: Tx
bone marrow biopsy*
Sideroblastic anemia: general
Marrow doesn’t use iron for heme synthesis very well
Bone marrow: ringed sideroblasts** (these are produced instead of healthy RBCs)
Ringed sideroblasts
- seen in sideroblastic anemia
- they are erythroblasts with perinuclear iron-engorged mitochondria
- subtype of myelodysplastic syndrome
Sideroblastic anemia: Dx
Marked anisocytosis
Marked poikilocytosis
Systemic iron overload**
BMbx: ring sideroblasts
Sideroblastic anemia: Tx
treat underlying cause
If Congenital sideroblastic anemia…
-Pyridoxine (vitamin B6)
What is the most common cause of aplastic anemia?
idiopathic
Aplastic Anemia: clinical features
Pancytopenia**
Aplastic Anemia: Tx
bone marrow transplant
When are helmet cells seen on peripheral smear?
hemolytic anemias
