Hematologic disorders

Question 1

Anemia Cause: Chronic low volume blood loss

Answer 1

• from erosive gastritis, menorrhagia, GI malignancy, resulting in IDA
• iron from RBCs is wasted with blood loss as it cannot be recylced
• cliniclly sig blood loss could be as little as a few ml/d

Question 2

Anemia Cause: reduced RBC production

Answer 2

• Nutritional defecit: B12, folic acid, iron deficiency
• Anemia of chronic disease - inflammatory disease
• Bone marrow suppression
• reduced erythropoietin production (chronic renal failure)
• Use of meds that prevent micronutrient absorption (PPI used >8 wks (b12 and iron), metformin (b12 malabsorption))

Question 3

Anemia Cause: Premature Destruction

Answer 3

Hemolysis, shortened RBC life span - normally 90-120 days
* mechanism in anemia of chronic disease
* uncommon etiology in primary care

Question 4

Anemia Cause: Acute blood loss

Answer 4

• in adult >1L acute blood loss before sig drop in hgb
• uncommon in primary care
• presentation : dizziness, tachycardia, lowered BP

Question 5

MCV

Answer 5

• mean corpucular volume - size of RBC- remains stable over the lifespan of cell
• Microcytic MCV<80
• Normocytic MCV= 80-96
• Macrocytic MCV >96

Question 6

MCH/MCHC

Answer 6

• mean cell hemoglobin/mean cell hemoglobin concentration
• refers to the color of the cell relative to the amnt of hemoglobin in the cell
• PALE CELLS = SMALL CELLS
• normochromic = normal color MCHC 31-37
• Hypochromic = Pale MCHC <31

Question 7

RDW

Answer 7

• RBC didtribution width
• index of variation in RBC size
• Normal 11.5-15%
• Abnormal >15% - indicates new cells differ in size when compared to older cells
• likely earliest indicator of evolving microcytic or macrocytic anemia
• as more micorcytic or macrocytic cells develop the RDW increases

Question 8

Reticulocyte Percentage

Answer 8

• number of young RBCs
• Body’s normal response to anemia to produce more RBCs
• Normal 1-2%
• Normal response to anemia = reticulocytosis >2%

Question 9

Normochromic, normocytic, NL RDW

Answer 9

• MCV 80-96, normal color, not variable in size
• Cause: Anemia of chronic disease, chronic kidney disease, Acute blood loss
  cells are made with sufficient iron, vitamin B12, folate, and other micronutrients (if NL size, color and RDW, then iron, b12, and folate defficiency is r/o)
• Treatment: treat underlying cause

Question 10

Microcytic, Hypochromic, elevated RDW

Answer 10

*MCV <80, pale, RDW >15%
* Common Cause: Iron deficiency or plumbism (lead toxicity)
* Small cells due to insufficient hemoglobin production r/t low iron, with new cells smaller than old cells.
* Next step: ferritin for estimate of iron stores, lead testing is suspected exposure (esp young children)

Question 11

Microcytic, hypochromic, NL RDW

Answer 11

• MCV <80, pale, normal RDW
• Most common cause: Alpha/beta thalassemia minor (trait)
• ethnic groups at risk for Alpha: Asian, African ancestry (AAA)
• Ethnic groups at risk for beta: African, Medeterranean, Middle Eastern (BAMME)
• Inherited genetic variaton - usually increased RBCs to compensate for uniformly small pale cells.
• Next step: Hemoglobin electrophoresis for evaluation of hempglobin varriants

Question 12

Macrocytic, normochromic, elevated RDW

Answer 12

• MCV >96, normal color RDW >15%
• Most common cause: Vit B 12 defficiency esp pernicious anemia, folate defficiency anemia
• MCV is usually very high if B12 deficient
• Abnormally large cells due to altered RNA:DNA ratio. Normochromic since iron levels are normal. New cells larger than old cells.
• Next step: Serum B12, and RBC folate

Question 13

Drug induced macrocytosis without anemia

Answer 13

• common cause: alcohol excess
• > 5drinks/day in men
• > 3 drinks per day wmn
• can also be casued by antiepilectic drugs
• MCV >96
• Next step: reversable when exessive alcohol intake stops
• not a reason to stop antiepileptic drugs

Question 14

Anemia Treatment

Answer 14

• Determine etilology and treat underlying cause
• replace needed micronutrients, iron, b12, folate
• Epoetin alpha (EPO) as indicated - induces erythropoesis. helpful in severe anemia, particulary in advancing renal failure. EPO is deminshed in CKD begining when GFR <49

Question 15

WBC DIfferntial

Answer 15

total WBC 6000-10,000, leucocytosis: >10,000 = anticipated response in sig bacterial infection
* Nobody Likes My Edcational Background
* Neutrophils 60% Bacterial infect
* Lymphocytes 30% Viral infect
* Monocyte 6% Debris, recovery phase of infection
* Eosinophil 3% Allergens, paracites (worms, wheezes, weird diseases)
* Basophil 1% ANaphylaxis