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Microcytic Anemia

Terms in this set (89)

Question #1 = What is the MCV? *MCV <80 =
Microcytic anemia
**What is in the differential for Microcytic Anemia?
1) Iron Deficiency anemia

2) Thalassemia syndromes

3) Early Anemia of Chronic Disease (ACD)

4) Other rare causes such as Sideroblastic anemia
Question #2 What is the basic mechanism of anemia? If ii is iron deficiency, what can cause it?
1) Blood loss- GI, menses

2) Inadequate absorption- PPI, inflammation

3) Inadequate intake- poverty, fad dieting
Question #3 What else do I know about this patient? So what is the most common cause of anemia worldwide?
Iron deficiency
In the U.S, what causes the majority of Iron deficiency anemia?
Inadequate intake
What population of people is iron deficiency anemia more common?
1) Women- menstruation and pregnancy

2) Children- rapid growth with borderline nutritional status
What is the homeostasis of iron?
1-2 mg in and out on a daily basis (most of which is incorporated into RBCs)
When is the absorption of iron increased?
1) Anemia

2) Hypoxia

3) Increased erythropoiesis

4) Decreased iron stores
When is the absorption of iron decreased?
1) Inflammation

2) Increased iron stores
This is the storage protein for iron within the cells. Excess iron is stored in virtually all cells, but the major repository is the liver.
Ferritin (Serum ferritin is directly related to the amount of iron stored in your body)
This is protein responsible for transporting iron throughout the body, primarily from storage sites to the bone marrow
Transferrin
This is the hormone produced in hepatocytes in response to inflammatory cytokines (primarily Il-6). Inverse relationship to intestinal iron absorption. Hepcidin binds with a cell wall protein called FERROPORTION which is responsible for allowing iron OUT of storage
Hepcidin
This is the insoluble form of iron that is formed when there is an excess of iron in the body.
Hemosiderin (Hemosiderin is frequently absorbed by circulating macrophages (hemosiderin-laden macrophages))
What are the three mechanisms of loss for iron deficiency anemia?
1) INCREASED LOSS (GI blood loss, GU blood loss, Pulm Blood loss, Trauma, etc...)

2) INADEQUATE ABSORPTION (poor bioavailability, antacid therapy/high gastric pH, loss/dysfunction of absorptive enterocytes, bowel resection, inflammatory bowel disease, intrinsic enterocyte defects)

3) Inadequate intake
What are the stages of development for iron deficiency anemia?
Negative iron balance--> Fall in iron stores-->fall in serum iron/transferrin saturation--> hypochromic reticulocytes-->hgb drops--> MCV drops
What are the EARLY signs and symptoms of iron deficiency anemia?
1) Easily fatigued

2) Tachycardia

3) Palpitations

4) Tachypnea on exertion

5) Pallor

6) lightheadedness
What are the SEVERE signs and symptoms of iron deficiency anemia?
1) Angina

2) Dizziness

3) Fainting

4) Tachycardia

5) Cardiac murmurs

Also as shown in the following pictures on the next cards:

6) Mild Glossitis

7) Cheilosis

8) Koilonychia- "spoon nails"

9) Plummer-Vinson Syndrome

10_ Schatzki's Rings
What does mild glossitis look like in severe iron deficiency anemia?
Mild Glossitis
What does Glossitis & Cheilosis (kī-lō'sĭs) look like in severe iron deficiency anemia?
Glossitis & Cheilosis (kī-lō'sĭs)
What does Koilonychia- "spoon nails" [koi-loh-nik-ee-uh] look like in severe iron deficiency anemia?
Koilonychia- "spoon nails" [koi-loh-nik-ee-uh]
What does Plummer-Vinson Syndrome look like in severe iron deficiency anemia?
TRIAD:

1) Dysphagia

2) Glossitis

3) Iron deficiency anemia

*It most usually occurs in postmenopausal women
What does Schatzki's Rings look like in severe iron deficiency anemia?
Schatzki's Rings
What will be the "iron" levels in BOTH anemia of chronic disease and iron deficiency anemia?
Reduced
What will the "transferrin" level be in anemia of chronic disease?
Reduced to normal
What will the "transferrin" levels be in iron deficiency anemia?
Increased
What will the "transferrin" levels be if a patient has both anemia of chronic disease AND iron deficiency anemia?
Reduced
What will the "transferrin saturation" levels be in BOTH anemia of chronic disease and iron deficiency anemia?
Reduced
What will the "ferritin" levels be in anemia of chronic disease?
Normal to increased
What will the "ferritin" levels be in iron deficiency anemia?
Reduced
What will the "ferritin" levels be if a patient has BOTH anemia of chronic disease and iron deficiency anemia?
Reduced to normal
What are the "soluble transferrin receptors" in anemia of chronic disease?
Normal
What are the "soluble transferrin receptors" in iron deficiency anemia?
Increased
What are the "soluble transferrin receptors" in patients with BOTH iron deficiency anemia and iron deficiency?
Normal to increased
What is the "ratio of soluble transferrin receptor to log ferritin" in anemia of chronic disease?
Low (<1)
What is the "ratio of soluble transferrin receptor to log ferritin" in iron deficiency anemia?
High (>2)
What is the "ratio of soluble transferrin receptor to log ferritin" in patients with BOT anemia of chronic disease AND iron deficiency anemia?
Normal to Increased (≥2)
Anemia of chronic disease vs. iron deficiency anemia chart
**Ferritin shows iron stores (nl=30-250 ng/ml). What is diagnostic of iron deficiency anemia?
Values <30
**Serum iron (Fe++) reflects circulating iron

Normal=40-160mcg/dl

Is Low serum iron diagnostic of iron deficiency?
NO
**Why is low serum iron NOT diagnostic of iron deficiency?
It may change significantly over the course of hours depending on intake and may be elevated in cases of hemolysis
This reflects the trasnferrin's ability to bind more oxygen
Total iron binding capacity (TIBC) (↑ in iron deficiency anemia)

*Normal =200-400mg/dl
This is described as the following:

1) Ratio between free circulating iron and transferrin

2) Not diagnostic by itself, but a helpful discriminator
Transferrin saturation (↓ in iron deficiency anemia)

Normal - 20-50%
This is described as the following:

1) Part of the CBC

2) Usually elevated, but may normalize in long standing iron deficiency
RDW (↑ in iron deficiency anemia)
Does an increased RDW rule out thalassemia?
No
What is the GOLD standard ... but should not be necessary if iron deficiency is the only diagnostic consideration......And it is PAINFUL!
Bone marrow biopsy (last resort)
After Iron Deficiency is established as my diagnosis, what should I do next in an evaluation of potential blood loss?
EGD & colonoscopy ("double dip")
(Esophagogastroduodenoscopy)
What are the specialized tests after endoscopy?
1) SBFT

2) Enteroclysis

3) Pill endoscopy
What is the definitive evaluation of decreased iron absorption?
There isn't one
- Eval often dictated by suspected underlying cause
- Oral iron absorption test
How can I determine the cause of decreased intake of iron?
History
Non-diagnostic workups are NOT UNCOMMON in the work up of iron deficiency anemia, so what must be be done?
Repeat evaluations
What are the principles of iron deficiency therapy?
1) Oral iron is good enough for most

2) IV iron is not a therapy of convenience

3) Do NOT treat empirically with iron
Why should I NOT treat empirically with iron?
Iron will kill a pt w/ a thalassemia
How is iron deficiency treated?
1) Oral replacement- MOST DEFINITELY PREFERRED

2) Intravenous iron- anaphylaxis risks

3) Intramuscular iron- painful and leaves hemosiderin deposits
What is the goal of oral iron replacement therapy?
To deliver at least 100 mg of elemental iron daily
What is the usual dose of oral iron?
Usual dose of 325mg FeSO4 T.I.D. with citric acid delivers ~ 150-200 mg
What are some negative responses to oral iron supplementation?
Constipation, GI upset, dark tarry stools similar to melena.
Because of the negative effects of iron, compliance is a concern. What should be done when prescribing oral iron?
Also prescribe Colasce
What determines the response to oral iron in an anemic patient?
The severity, patient compliance, and whether the cause was corrected
**When will MOST patients show some improvement to oral iron replacement?
2 months
***How long should therapy continue in treating iron deficiency anemia?
Until ferritin returns to normal
When should intravenous iron replacement be used?
Reserved for those who are truly unable to tolerate oral iron with significant anemia
- Theoretical risks for oxidative damage
- Absorption may still be impaired in patients with significant chronic inflammatory states
Who should I consult to with a patient that requires intravenous iron replacement?
Hematology
This route of administration of iron is described as the following:

- Rarely used as a final replacement alternative but can be effective

- Usually causes extreme pain and hemosiderin deposition in injection area which is often unacceptable to patients
Intramuscular Iron replacement
The following 3 questions will be for Thalassemia
Go!
What is the MCV?
< 80 and often under 70
***What is the mechanism or iron deficiency in Thalassemia?
1) Alpha thalassemia
- Number of deletions of α hemoglobin chains. No substitutes
- Quantitative problem

2) Beta thalassemia
- Type of point mutations, β hemoglobin chains substituted with γ & δ
- Less predictable clinical effects
What else do I know about this patient?
Ethnicity from the malaria belt
**This is defined as:

Heterogeneous, hereditary disorders characterized by defects in the synthesis of one or more of the globin chain subunits of hemoglobin
Thalassemia
**What is Thalassemia usually characterized by?
Significant microcytosis
What population of people are often times afflicted with thalassemia?
May be found in any ethnic group and geographic location given the diversity of modern society, but most commonly traced to Mediterranean basin and equatorial regions of Africa and Asia (15% of population)
This is deletion of genes coded to make α hemoglobin chains
Alpha Thalassemia
**What are the clinical manifestations of Thalassemia?
Microcytosis out of proportion to degree of clinical anemia for thalassemia trait
• Thalassemia: MCV 60; Hct 35
• Iron deficiency: MCV 60; Hct 25
What are Severe thalassemia syndromes more characterized by?
Chronic hemolytic complications
**How is the diagnosis of thalassemia made?
1) Clinical suspicion after iron deficiency is excluded.

2) RDW typically normal

3) Electrophoresis.
• Alpha Thal is normal on electrophoresis
• Beta Thal is abnormal on electrophoresis

4) Genetic testing in complex cases.
**What is the treatment of Mild Thalassemia?
None for mild thalassemia syndromes other than avoidance of unnecessary iron replacement and caution with medications (i.e. sulfa drugs) which may induce an oxidative stress and subsequent hemolysis
What is the treatment of Severe Thalassemia?
Severe thalassemia syndromes require more aggressive treatment to include frequent transfusions, folate supplementation, splenectomy, and bone marrow transplant (when possible)
**What may frequent transfusions for Severe Thalassemia lead to?
Iatrogenic iron overload syndrome which negatively impacts potential success of bone marrow transplant
This is described as the following:

Mostly idiopathic or drug/toxin induced congenital or acquired defects affecting the biosynthesis of heme
Sideroblastic Anemia
T or F. Prevalence of acquired sideroblastic anemia far exceeds hereditary varieties
True
**What often times causes Sideroblastic Anemia?
Drugs and toxins lead this category, propelled largely by the high frequency of alcohol abuse in many societies
**What is at the center of all sideroblastic anemias in which a cause has been determined.
Disturbed mitochondrial metabolism
**What does a Sideroblast show?
Normal iron uptake, but subsequent poor incorporation into heme
What are the drug causes of Sideroblastic Anemia?
1) Ethanol

2) Isoniazid (INH)

3) Cycloserine

4) Chloramphenicol

5) Busulfan
What are the copper chelators that cause Sideroblastic Anemia?
1) Penicillamine

2) Triethylene tetramine dihydrochloride (Trientene)
What are the Toxins that cause Sideroblastic Anemia?
1) Lead

2) Zinc

3) Auto-antibodies
What are the manifestations of Sideroblastic Anemia?
1) Fatigue, decreased tolerance to physical activity, dizziness (usual anemia sx)

2) History of possible toxin or drug exposures

3) BLOOD SMEAR MAY REVEAL BASOPHILIC STIPPLING (ESP W/ LEAD POISONING)

4) Sideroblastic anemia is in the differential of patients with iron def and anemia that is refractory to iron replacement
What is the treatment of Sideroblastic anemia?
R/o reversible causes (EoTH or other drugs/toxins) and d/c the offending agent

Supportive Tx:
• Blood transfusions to maintain an acceptable Hb level
• Trial of pyridoxine 100-200mg PO qd, titrated to 500 mg PO qd
• Folic acid supplementation
• H&H, MCV, and Fe low
• Ferritin Low (most important diagnostic value)
• Transferrin, TIBC, and RDW increased
Iron Deficiency
• MCV low out of proportion to degree of anemia
• RDW typically nl
• Ferritin increased
• Alpha Thal trait electrophoresis is nl
• Beta Thal trait electrophoresis abnormal
Thalassemia
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