6/10 - ICR: Anemia

Question 1

What is anemia and what do we use to determine it?

Answer 1

Anemia is generally defined as a decrease in the number of Red Blood Cells (RBC), hemoglobin or both. Although Hematocrit (HCT) is often used, it should be noted that this is a calculated (Roughly, HCT = Hgb x 3) rather than measured value. Hemoglobin (Hgb), therefore, is the preferred laboratory test in clinical practice.

Question 2

Racial/Ethnic differences in Anemia

Answer 2

– In general, individuals of African descent including African Americans tend to have lower hemoglobin and thus hematocrit values than Caucasians.

Question 3

Exercise on blood values

Answer 3

conditioning by aerobic exercise tends to lower the hemoglobin (and hematocrit) by increasing the plasma volume and increasing erythrocyte 2,3-DPG synthesis.

Question 4

Blood changes during pregnancy

Answer 4

(Both plasma volume and red blood cell mass increase during gestation, though there is a greater expansion of plasma volume relative to red cell mass leading to a modest fall in hemoglobin levels in healthy pregnant women. The greatest disproportion between the rates at which plasma and red cells are increased occurs during the late second to early third trimester. There is also a drop in the mean corpuscular volume (MCV) during pregnancy with average MCV being 80-84 in the third trimester

Question 5

Oxygen (02) DELIVERY formula

Answer 5

02 Delivery = Cardiac Output X 02 Carrying Capacity

Question 6

What causes the symptoms we see in Anemia?

Answer 6

These are directly related to the degree of reduction in 02 delivery and/or the intensity or chronicity of compensatory increases in cardiac output needed to maintain the O2 delivery

Question 7

O2 DELIVERY INSUFFICIENT (REDUCTION IN O2 DELIVERY) leads to anoxia or lack of oxygen. The symptoms we will see when this is the culprit:

Answer 7

Symptoms may include fatigue, irritability, confusion or difficulty focusing, poor academic performance, decreased exercise tolerance, dyspnea on exertion, angina (see also topic 6 on chest pain), claudication, or dizziness/fainting spells

Question 8

. CARDIAC OUTPUT INCREASE symptoms include:

Answer 8

Symptoms of palpitations (rapid heartbeat) with or without associated chest pain. On examination, one finds tachycardia (pulse rate above 100 per minute) cardiac murmurs (from increased flow), or bruit.

Question 9

Nuclear problems lead to a larger RBC. What 3 conditions will cause this?

Answer 9

a. megaloblastic anemia - missing a vitamin needed for the production of DNA
b. myelodysplastic anemia - abnormal nuclear development of the cell
c. chemotherapy induced anemia – impaired nuclear division

Question 10

Cytoplasmic issues will lead to smaller RBCs. What 2 conditions do we associate with this?

Answer 10

a. iron deficiency anemia – impaired/limited generation of heme in. the cytoplasm
b. abnormal hemoglobin – impaired/limited generation of globin for the cytoplasm

Question 11

What is HCT

Answer 11

HEMATOCRIT (HCT) is the percentage of blood sample occupied by RBC

Question 12

RDW?

Answer 12

RED CELL DISTRIBUTION WIDTH (RDW) is a measure of the “scatter” or distribution in the size of the RBC population. A high RDW means that there is more than one population of RBCs

Question 13

Reticulocyte count

Answer 13

RETICULOCYTE COUNT measures the number of RBC released by bone marrow. Reticulocytes contain residual RNA, seen as blue stranding material in the cell when prepared with a special stain. Their life span (before losing the RNA and becoming like other RBC) is one day.

Question 14

ARC?

Answer 14

The normal range of reticulocytes is 25,000-125,000/ul. Normal or low reticulocytes in the setting of anemia indicates an inadequate marrow response. The ARC can be used to categorize anemia as either hyperproliferative (>100,000/uL) or hypoproliferative (

Question 15

Stages of Iron deficiency and the lab values we associate with them (3)

Answer 15

Stage I is a loss of storage iron, manifested by a low serum ferritin.
Stage II is caused by a loss of circulating iron, manifested by a low serum iron and high TIBC, and
Stage III is decrease Hb production, characterized by a gradual development of microcytosis (a low MCV) and a proportional decrease in Hb.

Question 16

Non-heme tissue iron loss leads to 4 classic symptoms, what are they?

Answer 16

a. headache
b. tongue burning
c. pica (clay, chalk), pagophagia (ice)
d. nocturnal leg cramping (restless legs)

Question 17

What signs do we see on exam that indicate iron deficiency?

Answer 17

Signs

a. glossitis (rapid turnover of epithelial cells)
b. stomatitis
c. angular cheilitis

Question 18

Why is B12 important, and what happens with a deficiency? What stage of the cell cycle is affected?

Answer 18

A. ETIOLOGY B12 is necessary for DNA synthesis. B12 deficiency can develop either through lack of dietary intake or through impaired absorption of B12 from the GI tract. Cells in the marrow become arrested in the S-phase of DNA synthesis and desynchronization of nuclear and cytoplasmic maturation leads to increased size of RBCs.

Question 19

Discuss how B12 gets absorbed

Answer 19

1. B12 - gastric R binder
2. B12 - R binder complex dissociates in duodenum via pancreatic proteases
3. Parietal cells (in stomach) make Intrinsic Factor (IF) which combines with B12
4. B12-IF complex absorbed in the distal ileum

Question 20

Symptoms of B12 deficiency

Answer 20

a. Symptoms related to the anemia in general
b. Diarrhea (B12 also needed for enteric cells, their impaired growth can cause malabsorption)
c. Burning tongue
d. Paresthesias/numbness/loss of dexterity
e. Impaired memory/Dementia
f. Irritability/Personality changes

Question 21

Signs of B12 deficiency

Answer 21

a. Glossitis - smooth, beefy red tongue
b. Neurological
- Early findings - loss of vibratory and position sense (Romberg test), some may present with Lhermitte’s syndrome, a shock-like sensation that radiates to the feet during neck flexion
- Late findings - weakness, spasticity, clonus, paraplegia

Question 22

Morphology of B12 deficiency

Answer 22

On peripheral blood smear, red blood cells become larger ( larger MCV) and often oval in shape, and neutrophils become hypersegmented (5 or more lobes). Patients can also develop leucopenia and thrombocytopenia.

Question 23

A 28-year of woman of Greek ancestry in the 2nd trimester of pregnancy is noted to have a hypochromic, microcytic anemia on routine lab testing. She has had two uncomplicated full-term pregnancies in the past 3 years. Her highest hemoglobin prior to her first pregnancy was 10.8 g/dl. Her blood counts reveal a hemoglobin of 8.0 g/dL, MCH of 26, and MCV 72 fL.
In managing this patient’s anemia, which additional information is most relevant?
A) Red cell count, serum iron, ferritin, and total iron binding capacity?
B) Hemoglobin electrophoresis
C) Serum folate and vitamin B12 level
D) Plasma volume, BUN, and creatinine

Answer 23

Of the choices given, the most valuable differentiating tests are the red blood cell count (low in iron deficiency, normal in thalassemia) and the iron studies, especially the serum ferritin (low in iron deficiency and high in thalassemia). In this setting, iron deficiency is the most likely diagnosis because of the frequent pregnancies, particularly if she has not taken iron supplementation and/or has heavy menstrual flow.