Macrocytic Anemia Flashcards
Anemia is defined as?
dec RBC count, HGB, HCT or O2 carrying capacity of blood
Anemia is NOT what?
specific diagnosis - purely abnormal lab test result that signifies and underlying cause
An expansion of plasma volume that results in dilutional anemia is called?
spurious anemia
What are some causes of spurious anemia?
- hydremia of pregnancy (physiologic)
- congestive heart failure
- overhydration (excessive IV fluids)
Shortness of breath (esp with exertion), fatigue, weakness, palpitations, dizziness, syncope are all symptoms of?
anemia
What happens to the mucocutaneous membranes of anemic patients?
pallor
What happens cardiovascularly in anemic patients?
hyperdynamic circulation: tachy, bounding pulse, systolic flow murmur
What is kolionychia? Which anemia is it associated with?
concave (“spoon-shaped”) brittle nails
iron deficienc anemia
Which anemias are leg ulcers indicative of?
sickle cell anemia, hemoglobinopathies
What causes bone deformities in some anemic patients?
expansions of medularry cavity due to erythroid hyperplasia
How do the bone deformities look on x-ray?
“hair-on-end” appearance
What types of anemias will result in bone deformities?
thalassemia, sickle cell anemia
Loss of vibratory and position sense in associated with?
B12 megaloblastic anemia
What are some initial major adaptations to anemia?
- cardio: tachy and inc stroke volume
- HGB-O2 dissociation curve: right shift due to inc 2,3-DPG - O2 loses affinity
What are some following marrow responses to anemia?
erythroid hyperplasia with reticulocytosis (erythroid production can increase 8-fold)
____ reflects ability of the marrow to produce and deliveer RBCs to the peripheral blood (aka?)
is it a part of the routine CBC?
reticulocyte count; effective erythropoiesis
NO
What stain is needed to see reticulocytes and how does it work?
supravital stain - precipitates ribosomal RNA as a reticulin network
Polychromatic erythrocytes are visible with what smear? What does an increase indicative of?
Wright-Stained smear; polychromasia
Reticulocytes are the same cells as?
polychromatic RBCs
What does a decrease/normal reticulocyte count with anemia implies?
lack of appropriate marrow response - determine cause
What value is normal reticulocytes?
0.5-1.5% (percent of circulating RBCs) or
50-165 x 103 cells/microliter
An inc in retic count implies what?
increase production and delivery of RBCs in response to anemia
may be adequate OR insufficient depending on degree of anemia
How do we correct reticulocyte count?
Decrease in RBC production resuts in?
hypoproliferative anemia
A decrease or “normal” corrected RC is indicative of? (in relation to hypoproliferative anemia)
- aplastic anemia
- myelophthisic anemia
Define myelophthisic anemia.
replacement of marrow by fibrosis, tumor, etc
What’s maturation defect?
RBCs produced by die in the marrow - aka ineffective erythropoiesis
A decrease or “normal” corrected RC is indicative of? (in relation to maturation defect)
- megaloblastic anemia
- myelodysplastic syndromes
What results when the bone marrow effectively produce and deliver RBCs to peripheral blood?
hyperproliferative anemia
What kinds of peripheral destruction can occur in hyperproliferative anemia?
hemolysis or hemorrhage
Increased corrected retic count can be indicative of?
hyperproliferative anemia
treated nutritional anemia
MCV 80 – 100 fL
*MCV being an average*
normocytic
MCV <80 fL
microcytic
MCV >100 fL
macrocytic
What are the 2 major types of macrocytic anemias?
megaloblastic vs non-megaloblastic anemia
What are some causes for megaloblastic anemia?
- B12, folate deficiency
- drugs - folate antagonists (methotrexate), chemotherapeutic agents, antiretroviral drugs
What are some causes of non-megaloblastic anemias?
- hemolysis, hemorrhage (reticulocytosis)
- alcoholism, liver disease
What’s the pathogenesis of megaloblastic anemia?
What’s the source of B12?
foods of animal origin: meat, liver, fish, dairy (NOT found in veg, frits, cereals)
normal body stores last 3-4 years
How is B12 absorbed in the body?
What are the causes of B12 deficiency?
- malabsorption
- dietary deficiency (rare in U.S.) - strict vegans and their breast-fed infants
- drugs- nitrous oxide exposure
What can lead to malabsorption of B12?
- pernicious anemia - lack of intrinsic factor
- surgical: gastrectomy (total or partial), resection of terminal ileum
- inflammatory bowel disease
- tropical sprue and gluten - sensitive enteropathy
- blind loop syndrome - bacterial overgrowth competing for B12
- fish tapeworm (diphyllobothrium latum)
- an autoimmune chronic atrophic gastritis
- results in hypo-/achlorhydria
- average age = 60 years
- most common in persons of N. european descent
- increased risk of gastric carcinoma
- significant assocation with other autoimmune diseases (grave”s, hashimoto’s)
pernicious anemia (PA)
Define autoimmune chronic atrophic gastritis.
anti-parietal and anti-intrinsic factor antibodes destroy gastric parietal cells and intrinsic factor production
- found in leafy greeen veg, fruits, cereals, dairy products, and liver
- heat labile and destroyed by cooking (unlike what?)
- where absorbed?
folate
B12
in upper SI (duodenum and jejunum)
What’s the most common cause of folate deficiency?
inadequate dietary intake since body stores in liver only lasts 3-4 months
What are some clinical signs and symptoms of folate deficiency?
similar to those in B12 deficiency except lack of neurological features typically seen in B12 deficiency
- symptoms: weakness and sore tongue; glossitis may be painful, smooth, and atrophic or beefy red; angular cheilosis
- physical exam: pallor with mild jaundice (“lemon-yellow” skin)
- neurological impairment: may present with this with no anemia or macrocytosis
megaloblastic anemia
What causes the neurological impairments sometimes seen in megalobastic anemia? reversible or irreversible?
B12 deficiency! (unreleated to degree of anemia)
irreversible
What are the neuropathologic changes that can occur in B12 deficiency?
- demyelination of dorsal and lateral columns of spinal cord - affecting both sensory and motor pathways - subacute combined degeneration
- peripheral neuropathy: parethesias (“pins and needles”) in LE; reduced vibration and position sense in extremities
- uncoordinated gait: difficulty walkng and loss of balance
What’s the B12/Folate pathophysiology?
What are the 3 key reactins B12 is essential for?
What’s the peripheral blood morphology in megaloblastic anemia?
- RBC: macro-ovalocytes
- WBC: hypersegmented neutrophils- one of first to appear and among last to disappear after therapy
- platelets: decreased - thrombocytopenia
What’s the bone marrow morphology in megaloblastic anemia?
- erythroid hyperplasia with megalobastic change (nuclear/cytoplasmic dysynchrony)
- giant bands and metamyelocytes
