Heme #1: Microcytic Anemias Flashcards

1
Q

MCC of anemia worldwide is _________

Etiologies include…

Risk factors include

A

-Iron deficiency anemia

-Chronic blood loss MCC in US: menstruation, Colon cancer, hookworms in resource-poor countries
-decreased absorption (diet) MCC worldwide: Celiac, H. Pylori, bariatric surgery

-increased metabolic requirements: children, pregnant, lactating women
-cow milk ingestion in young children < 1 year old

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2
Q

Why does iron deficiency anemia occur (Patho)?

Symptoms of iron deficiency anemia

A

-Decreased RBC production due to lack of iron and decreased iron stories (ferritin).

-Pasophagia (craving for ice), Pica (craving for starch, clay), koilonychia (spooning of nails), angular chelitis, tachycardia, glossitis, pallor, poor concentration, irritability, restless legs syndrome

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3
Q

What do the labs for iron deficiency anemia show?
-CBC
-Iron studies

What is the definitive diagnostic for IDA?

A

-CBC: microcytic hypochromic anemia. Increased RDW.
-Iron studies: decreased ferritin***, increased TIBC (transferrin), decreased transferrin saturation, decreased serum iron.

Bone marrow biopsy: absent iron stores (definitive), but rarely done.

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4
Q

What is the treatment for iron deficiency anemia and what are some recommendations to taking the medication/supplement?

A

-Iron replacement (ferrous sulfate orally).
-Take with Vitamin C (ascorbic acid), with water or orange juice, and on an empty stomach. Give 2 hours before or 4 hours after ingestion of antacids.
-RBC transfusion if severe

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5
Q

What is microcytic?
What is normocytic?
What is macrocytic?

A

-Micro: < 80
-Normo: 80-100
-Macro: > 100

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6
Q

Lead Poisoning Anemia
-Patho
-Risk Factors (who MC in)
-Sources

A

-Patho: Lead poisons enzymes causing cell death. Shortens life span of RBCs, inhibits enzymes needed for heme synthesis.

-RF: MC in children (<6 years old)

-Sources: inhalation of environmental lead (paint chips or lead dust) especially if the house was built prior to the 1970’s.

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7
Q

Symptoms of lead poisoning anemia
-think specific symptoms

A

-Neuro: ataxia, fatigue, concentration, learning problems, peripheral neuropathy (wrist or foot drop), encephalopathy

-Intermittent abdominal pain, vomiting, loss of appetite, constipation.

-Burton’s line: thin, blue-black line at base of gums in adults

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8
Q

What do diagnostics for lead poisoning anemia show?
-Peripheral smear/CBC
-Lead
-Iron studies
-Radiographs

A

-Microcytic hypochromic anemia with basophilic stippling (dots of denatured RNA seen in RBCs). Ringed sideroblasts in bone marrow.
-Serum lead levels > 10 mcg/dL (capillary fingerstick)
-Normal/High serum iron, decreased TIBC
-Lead lines: linear hyperdensities at metaphyseal plates in children

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9
Q

Management for lead poisoning anemia
-Mainstay
-Mild (44 or lower)
-Moderate (45-69)
-Severe (70 or higher)
–without encephalopathy
–with encephalopathy

A

-Removal of source of lead
-Mild: outpatient follow up and lifestyle changes
-Mod: Succimer
-Severe w/o: Succimer + calcium disodium edetate
–with enceph: Dimercaprol + calcium disodium edetate

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10
Q

How does Succimer work for lead poisoning anemia?

A

-Forms water soluble chelates, and therefore, increases urinary excretion of lead.

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11
Q

What is thalassemia?

Normally after what age is adult Hgb the predominant Hgb produced?

When should you suspect a thalassemia?

A

decreased production of globin chains

After 6 months of age

Microcytic anemia with normal/increased serum iron or no response to Fe treatment

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12
Q

Alpha Thalassemia
-What is it?
-MC in what population?
-Explain 1-4 abnormal alleles and presentation

A

-Decreased alpha-globin chain production. 4 genes determine it.
-MC in SE Asians

-Alleles
–1 abnormal: silent carrier, asymptomatic
–2: Minor (trait)
–3: Intermedia (like B-Thalassemia Major)
–4: Hydrops Fetalis: stillbirth: Hgb Barts (gamma tetramers)

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13
Q

Diagnostics for Alpha Thalassemia and what do they show?

A

-Hemoglobin electrophoresis
–1 & 2 gene deletion: normal Hb ratios in adults
–3: HbH (beta chain tetramer) = Heinz bodies
–4: Hgb Barts (gamma tetramers)

-DNA analysis is definitive

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14
Q

What distinguishes alpha from beta thalassemia?

A

Alpha, in 1-2 gene deletions, has normal Hb ratios in adults. In Beta, HgbA is decreased, or little to none.

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15
Q

Explain why the thalassemias are seen as a hemolytic anemia

A

-Beta chain tetramers (Heinz bodies) are produced, which have no oxygen carrying capacity and therefore, the RBCs are destroyed by the spleen.

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16
Q

Symptoms of Alpha Thalassemia Intermedia (Hemoglobin H Disease)

A

-Symptomatic at birth (neonatal jaundice and anemia)
-Anemia symptoms (pallor, fatigue)
-Frontal bossing, maxilla overgrowth (increased bone marrow hematopoeisis)

17
Q

What does a CBC and peripheral smear for alpha thalassemia show?

Hemoglobin electrophoresis?

A

-Microcytic hemolytic anemia (schistocytes, tear drop cells, increased reticulocytes), target cells, increased RBC count, decreased hemoglobin (7-10).
-Hemolysis: increased indirect bilirubin, decreased haptoglobin

-Electrophoresis: presence of HbH (beta chain tetramer)

18
Q

Explain what happens in a hemolytic anemia to indirect bilirubin, haptoglobin, LDH, and reticulocytes.

A

-Haptoglobin decreased: becomes depleted when it binds to free hemoglobin with continued RBC destruction.
-Indirect bilirubin: increased due to RBC destruction, which overwhelms liver’s ability to convert it to direct.
-LDH: increased because it is an enzyme that is released from destroyed RBCs
-Reticulocytes: immature RBCs released due to RBC destruction.

19
Q

Management for alpha thalassemia

A

-Episodic blood transfusions during periods of infection, pregnancy, etc.
-Vitamin C and folate supplementation (helps make RBCs)
-Iron chelating agents (Deferoxamine) to remove excess iron from chronic infusions.
-Bone marrow transplantation is definitive if the patient has major.

20
Q

Beta Thalassemia
-What is it?
-MC in what population?

A

-Decreased production of beta-globin chains, leading to excess alpha chains
-MC in Mediterranean (Greek, Italian, etc.)

21
Q

Symptoms of Beta Thalassema based on abnormal alleles
-Minor (Trait): 1 abnormal
-Major (Cooley’s Anemia): 2 abnmormal

When do symptoms of Major start to occur? Why?

A

Minor: MC type: Asymptomatic or mild anemia

Major: Alpha chains that cannot form tetramers.
–Anemia: severe, chronic. Pallor, dyspnea, mental delays. Hemolytic anemia: Jaundice, hepatosplenomgaly.
–Extremedullary hematopoeisis: bony abnormalities, frontal bossing, hair on end appearance, osteoporosis, abnormal ribs.
–Osteoporosis: by age 10, compression fractures, scoliosis, disc degeneration.
–Endocrine abnormalities due to iron overload: DM, growth failure, hypogonadism
–Enlarged kidneys
–Cardiac dysfunction: heart failure, arryhthmias

Symptoms occur after 6 months of life after fetal hemoglobin replaced with adult.

22
Q

Hemoglobin electrophoresis of Beta Thalassemia
–HgbF vs HgbA
-Minor:
-Major:

What do radiographs of the skull show?

A

Minor: high HgbF and low HgbA
Major: high HgbF and little/none HgbA

Bossing with hair on end appearance (due to extramedually hematopoeisis)

23
Q

Management for Beta Thalassemia
-Minor
-Major

A

-Minor: no treatment needed, genetic counseling

-Major: Frequent transfusions, iron chelating agents, vitamin C and folate supplementation, splenectomy in some cases

24
Q
A