8/4- Approach to Anemia Flashcards

1
Q

What are reticulocytes?

A

Young RBCs just released from the bone marrow

  • Typically 1% of RBCs
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2
Q

When will reticulocytes be high?

A
  • Blood loss
  • Premature destruction of RBC (hemolysis)
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3
Q

In hemolysis, the % of reticulocytes roughly tells you what?

A

In hemolysis the % of reticulocytes roughly correlates with red blood cell life span

  • The higher the reticulocyte count (retic) the shorter the red cell life span.
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4
Q

How long does it take a reticulocyte to mature?

A

1 day

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5
Q

What is the lifespan of a RBC?

A

120 days

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6
Q

CBC normal values (will be provided on tests)?

A
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7
Q

Mean normal values for hemoglobin?

A

Note that adult men have a hB that is about 1.5 g/dL higher than women

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8
Q

What is anemia (basic def)?

A

Reduction in the RBC mass

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9
Q

Classification of anemia based on mechanism?

A

1. Physiologic- due to expanded plasma volume– anemia of pregnancy

2. Hypoproliferative- due to decreased bone marrow production– reticulocyte low count

3. Proliferative- due to blood loss or hemolysis– reticulocyte high count

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10
Q

What basic labs may help in approaching anemia?

A

- CBC, reticulocyte count, peripheral blood smear

  • Comprehensive metabolic panel (CMP) for electrolytes (Na, K, Cl, CO2, Ca) and renal function (BUN, creatinine), and liver function (total protein, albumin, ALT, AST, alkaline phosphatase, total and direct bilirubin)
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11
Q

Symptoms and signs of anemia?

A

- Mild anemia: asymptomatic

- Breathlessness and fatigue

  • Pallor: shunting away from the skin (nail beds, conjunctivae, and buccal mucosa)
  • Tachycardia: severe anemia, pulse at rest is elevated, palpitations

- Systolic flow murmur

  • Other findings depending on the cause
  • Pounding headache with exertion
  • Dizziness and syncope
  • Insomnia, inability to concentrate and disorientation
  • Angina, claudication, heart failure
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12
Q

What important family history should be explored when considering anemia?

A
  • Anemia
  • Cholecystectomy and splenectomy at a young age (hereditary hemolytic disease)
  • Ethnicity
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13
Q

What is this showing?

A

Pallor

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14
Q

What is this showing?

A

Retinal hemorrhages in severe anemia

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15
Q

Other things to look at on physical exam for anemia?

A
  • Scleral icterus and jaundice
  • Lymph node enlargement
  • Splenomegaly
  • Hepatomegaly
  • Petechiae, ecchymoses, hematomas
  • FOB (fecal occult blood)
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16
Q

Blood tube: Purple or lavender

A

Purple or lavender: EDTA—strong calcium chelator—CBC, reticulocyte counts

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17
Q

Blood tube: Red

A

Red: no anticoagulant, the blood clots and there may be a separator—serum is then available for electrolytes, antibodies, etc

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18
Q

Blood tube: Blue

A

Blue: citrate a week calcium chelator—you can add back calcium so that you can do clotting assays for PT, aPTT etc

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19
Q

Blood tube: Green

A

Green: heparin –for flow cytometry

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20
Q

Equation for packed cell volume?

A

Packed cell volume = hematocrit = RBC x MCV

(MCV = mean cellular volume)

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21
Q

Equation for MCH (mean cellular hemoglobin)?

A

MCH = Hb/RBC

22
Q

Equation for MCHC (mean cellular hemoglobin concentration)?

A

MCHC = Hb/PCV

23
Q

What can be measured on a CBC?

A
  • RBC
  • MCV (by impedance or forward scatter)
  • Hematocrit (when spun in centrifuge)
  • Hemoglobin
  • RDW (red cell size distribution width)
24
Q

What is RDW?

A

Red cell size Distribution Width

  • Measurement of heterogeneity of RBC size
  • The higher the RDW, the wider the cell distribution is
25
Q

What is corrected reticulocyte count?

A

The % multiplied by the patient’s hematocrit divided by 45 (normal hematocrit)

26
Q

What is absolute reticulocyte count?

A

Absolute is % reticulocytes x RBC

27
Q

When is a PBS (peripheral blood smear) typically ordered for review?

A

If there is an abnormal value resulting from the specimen on CBC

28
Q

What is this?

A

Peripheral blood smear: normal

  • RBCs close but not touching
  • Central pallor only 1/3 to 1/2 of diameter
  • Some normal platelets are seen
29
Q

What is this?

A

Reticulocytes

  • Methylene blue stain aggregates RNA and ribosomes in very young RBCs and shows a reticular pattern
30
Q

What is RPI?

A

Reticulocyte production index

  • RPI = Hct/45 x retic/MF

(MF = maturation factor or shift correction factor)

31
Q

What factor can be used to correct/adjust reticulocyte count?

A

The reticulocytes are usually presented as a percent of the red blood cell count

  • This can be adjusted to reflect the degree of anemia (overcounts retics) and the stress of anemia—higher EPO allows younger red cells to come out earlier and last longer as reticulocytes.
32
Q

What are “shift” reticulocytes?

A

Anemia and stress with higher EPO allow younger RBCs to come out earlier and last longer as reticulocytes.

Very young reticulocytes are larger and are called “shift” reticulocytes because they are coming out of the marrow sooner that usual.

  • The normal reticulocyte exists for about a day
  • The red cell life span is about 120 days so about 1 % of the red cells are turning over—so the normal reticulocyte count is about that.
33
Q

What is the normal range of the absolute reticulocyte count is ___?

A

What is the normal range of the absolute reticulocyte count is between 25,000 - 75,000/uL

34
Q

Example RPI calculation:

Hematocrit of 15 %

Reticulocyte count 7.5 %

A

RPI = Hct/45 X retic/MF

RPI = 15/45 X 7.5/2.5

35
Q

What do RPI values indicate?

A

RPI = 1

RPI < 2- not enough production

RPI >2- hemolysis or blood loss

36
Q

Absolute reticulocyte values for:

  • Severe aplastic anemia:
  • Hypoproliferative anemia:
  • Hemolysis/blood loss:
A

Absolute reticulocyte values for:

  • Severe aplastic anemia: < 20,000/uL
  • Hypoproliferative anemia: < 75,000/uL
  • Hemolysis/blood loss: > 100,000/uL
37
Q

How do you calculate absolute reticulocyte count?

A

RBC x % reticulocytes

38
Q

Hypoproliferative anemia is characterized by what? Categories with examples?

A

Hypoproliferative anemia is accompanied by low reticulocyte counts

  • Normocytic: normal RBC MCV e.g. anemia of chronic renal disease
  • Microcytic: low MCV e.g. iron deficiency
  • Macrocytic: high MCV e.g. B12 deficiency
39
Q

Proliferative anemia is characterized by what? Categories with examples?

A

Proliferative anemia is accompanied by high reticulocyte counts (if there’s been time for the bone marrow to respond)

  • Hemorrhage: red cell morphology normal
  • Hemolysis: RBC morphology often distinctive
40
Q

Marrow and peripheral blood in anemia (picture)

A
41
Q

Hypoproliferative anemia associated with pancytopenia may occur with what diseases/conditions?

A

- Fanconi’s

- Acquired Aplastic anemia

- Myelodysplastic syndrome

- Myelophthisis: fibrosis of the marrow as in myelofibrosis, cancer metastatic to bone (breast, prostate)

- Granulomatous disease: sarcoidosis, tuberculosis (these 2 often have some degree of splenomegaly)

- Megaloblastic anemia

42
Q

Hypoproliferative anemia with anemia alone?

A

- Diamond-Blackfan (can have low WBC or platelet counts, but classically is RBCs only)

- Pure red cell aplasia (Parvo B19, in association with thymoma, collagen; Vascular disease, CLL drugs, idiopathic)

- Anemia of chronic renal failure

- Endocrine disorders

—Hypothyroidism, hypogonadism, Addison’s

- Disorders of hemoglobin synthesis (low MCV)

— Iron deficiency

— Thalassemia

— Sideroblastic anemia

- Anemia of Chronic disease (normal or low MCV)

- Megaloblastic anemia (high MCV)

43
Q

Case)

  • 65 year old man
  • HTN, DM for 20 years
  • Peripheral neuropathy on exam
  • Hb 8.5 Hct 31.5
  • MCV 88 fL
  • Reticulocyte count 1.2 %
  • PBS-normal red blood cells
  • BUN 40 Creatinine 2.5
  • GFR 25 ml/min

Which of the following is most likely present?

A. Low serum iron

B. Low B12 level

C. Low folate level

D. Low erythropoietin level

E. Low testosterone

A

Which of the following is most likely present?

A. Low serum iron

B. Low B12 level

C. Low folate level

D. Low erythropoietin level

E. Low testosterone

44
Q

Anemia of chronic renal failure involves what other characteristics:

  • EPO production:
  • Anemia?
  • Iron:
  • Reticulocytes:
  • RBC morphology:
A

Anemia of chronic renal failure

  • EPO production: Decreased
  • Normochromic normocytic anemia
  • Iron: Normal
  • Reticulocytes: Low
  • RBC morphology: Normal

Does not always correlate with BUN or creatinine

45
Q

With anemia of CRF, pts with ESKD before/on dialysis may have transfusion requirement due to what?

A
  • Decreased RBC production
  • Bleeding
  • Blood loss during hemodialysis
  • Mild hemolysis
46
Q

With anemia of CRF, pts may respond to what?

A

Exogenous EPO

  • May require iron supplementation
  • Improves hematocrit and pts well-being
47
Q

Our patient has a hemoglobin of 8.5 gm/dl

Which of the following is the best target for successful EPO treatment?

A. 9.0

B. 10.0

C. 11.0

D. 12.0

E. 13-14

A

?

48
Q

Results of treatment of anemia of renal failure with EPO?

A
  • Can maintain pts without transfusion
  • Iron is used when EPO is given so that serum iron goes down and storage iron (msrd by ferritin) also goes down as iron is shifted from bone marrow stores to newly made circulating red blood cells
49
Q

Problems with EPO for treatment of anemia?

A
  • If hematocrit rises too quickly: thrombosis
  • Possibly can worsen HTN

- Antibodies to EPO

- Resistance to EPO: Hepcidin, Aluminum toxicity, Parathyroid hormone, Iron deficiency

  • Increased mortality in some cancer patients
  • Blood doping EPO has its legitimate uses, but can be dangerous if used to increase the Hb for endurance events
50
Q

Anemia due to blood loss may result from what conditions?

How much can you donate?

A
  • Trauma
  • GI bleeding
  • Uterine bleeding
  • Retroperitoneal bleading in ICU setting

Can donate 10% of blood volume (500 mL)

51
Q

What are some of the results of greater blood loss?

A

Hypovolemia

  • Postural hypotension
  • Tachycardia at rest
  • Hypovolemic shock (both RBCs and plasma are lost)
  • Hb and hematocrit may be normal
52
Q

Flowchart of anemia

A
  • MCV low is under 80 fL
  • MCV high is > 100 fL