L19 - Basic Anemias Part 1

Where are erythrocytes (RBCs) produced?

RBCs are produced in the bone marrow and then released into the bloodstream.

What is the life cycle of an erythrocyte?

Approximately 120 days.

Why is RBC deformability important?

RBCs must deform to travel through small blood vessels and capillaries.

What happens to RBC components when RBCs are broken down?

Globin is broken down for amino acid reuse, iron leaves the heme groups, and transferrin binds the liberated iron.

What is the function of transferrin?

Transferrin transports iron → carries iron to the bone marrow for HGB production and to the liver for storage.

Why is iron important?

Iron is essential for hemoglobin (HGB) formation.

What is the difference between ferric (Fe3+) and ferrous (Fe2+) iron?

Ferric Fe3+ is the most notable dietary form; it must be reduced to ferrous Fe2+, which is the form required for proper absorption.

How does vitamin C help iron absorption?

Vitamin C helps reduce ferric iron (Fe3+) → ferrous iron (Fe2+), the form required for absorption.

What are reticulocytes?

Immature RBCs circulating in the blood; they represent newly produced RBCs.

What does an increased reticulocyte count suggest?

Increased reticulocytes suggest a bone marrow response, which can occur in various anemic states.

What can a depressed reticulocyte count suggest?

A depressed count may suggest decreased bone marrow production, including malignant/cancerous conditions; drugs may also contribute.

What is hemoglobin (HGB)?

The oxygen-carrying component of RBCs.

What is the structure of hemoglobin?

4 globin polypeptide chains + 4 heme groups = 1 HGB molecule.

What is hematocrit (HCT)?

The packed erythrocyte volume; the ratio of RBC volume to whole blood expressed as a percentage.

Which is more consistently reliable for assessing bleeding status: HGB or HCT?

Hemoglobin (HGB); HCT can be affected by changes in fluid status.

What does CBC stand for?

Complete Blood Count.

What major components are evaluated on a CBC?

RBCs, reticulocytes, HGB, HCT, platelets, MCV, MCHC, and WBCs.

What is the Rule of 3 for HGB and HCT?

HCT ≈ HGB × 3; HGB ≈ HCT ÷ 3. Example: HGB 9 → HCT 27%.

What is MCH?

Mean Cell Hemoglobin = the weight/amount of HGB in the average RBC.

What is MCHC?

Mean Cell Hemoglobin Concentration = measurement of HGB concentration within RBCs.

What do hypochromic and hyperchromic mean?

Hypochromic = low HGB content/color; hyperchromic = high HGB content/color.

What does MCV measure?

Mean Cell Volume measures RBC size and is used to classify anemia.

What MCV indicates microcytic anemia?

MCV <80 fL = microcytic.

What MCV indicates normocytic anemia?

MCV 80–100 fL = normocytic.

What MCV indicates macrocytic anemia?

MCV >100 fL = macrocytic.

What type of anemia is associated with iron deficiency?

Microcytic anemia → MCV <80 fL.

What type of anemia is associated with chronic kidney disease?

Normocytic anemia → MCV 80–100 fL.

What deficiencies are associated with macrocytic anemia?

Vitamin B12 deficiency and folate deficiency → MCV >100 fL.

What laboratory values generally decrease in anemia?

RBCs ↓, HGB ↓, and HCT ↓.

What is erythropoietin (EPO)?

A hormone that stimulates RBC production in the bone marrow.

Where is most erythropoietin produced?

The kidneys synthesize approximately 90% of circulating EPO.

What stimulates EPO secretion?

Hypoxia/low oxygen.

How does the EPO response maintain blood physiology?

↓ Oxygen → kidneys release EPO → bone marrow/erythroid tissue increases RBC production → ↑ red cell mass → ↑ HGB concentration.

Why can kidney disease cause anemia?

Diseased kidneys produce insufficient EPO → decreased stimulation of RBC production.

At what CrCl does the lecture state anemia begins to develop?

CrCl <50 mL/min.

What are the characteristic symptoms of iron deficiency anemia?

Fatigue, pica, restless legs syndrome, headache, exercise intolerance, exertional dyspnea, and weakness.

What is pica?

Craving/eating non-food substances; a classic presentation of iron deficiency anemia.

What is pagophagia?

Ice craving/chewing ice; a form of pica strongly associated with iron deficiency anemia. KNOW THIS.

What should be evaluated when assessing a patient for anemia?

Symptoms + CBC + RBC indices (MCH, MCV, MCHC) + reticulocyte count + iron parameters + occult blood.

What iron parameters are evaluated in anemia?

Serum iron, TIBC, TSAT, and serum ferritin.

What does occult blood testing assess?

Hidden blood, such as blood in the stool or urine, which may indicate blood loss contributing to anemia.

What does serum ferritin reflect?

Total iron stores.

What does TSAT reflect?

The amount of iron immediately available for hemoglobin synthesis.

How is transferrin saturation (TSAT) calculated?

TSAT (%) = (Serum Iron ÷ TIBC) × 100.

What happens to TIBC in iron deficiency?

TIBC ↑.

What happens to TIBC in malnourished states?

TIBC ↓.

What TSAT goal is given in the lecture?

TSAT >20%.

What laboratory findings indicate absolute iron deficiency?

TSAT <15% AND serum ferritin <15 ng/mL.

If serum iron = 40 and TIBC = 400, what is the TSAT?

TSAT = (40 ÷ 400) × 100 = 10%.

What oral iron products should you recognize?

Ferrous gluconate, ferrous sulfate, and ferrous fumarate.

Are oral iron products equally efficacious?

Yes; differences are mainly in dosing, elemental iron content, and tolerability.

Do you need to memorize the elemental iron amounts of the oral iron products?

No; the lecture notes say to know the oral products, not the elemental iron amounts.

When is oral iron indicated?

Less severe iron deficiency.

What are the major disadvantages of oral iron?

Dose-dependent GI side effects and decreased adherence due to poor tolerability.

What is a common adverse effect of oral iron?

Constipation.

What can be recommended for iron-induced constipation according to the lecture?

Docusate.

What are advantages of oral iron?

Appropriate for less severe iron deficiency and typically has a lower acquisition cost.

When is IV iron indicated?

More severe iron deficiency.

What is an advantage of IV iron over oral iron?

Improved GI tolerability because IV iron bypasses the GI tract.

What are disadvantages of IV iron?

Requires infusion monitoring, is more expensive, and requires personnel/equipment for possible allergic or infusion reactions.

What IV iron products should you recognize?

Iron dextran, ferric gluconate, iron sucrose, and ferumoxytol.

Which IV iron requires a test dose before the first dose?

Iron dextran.

Why is a test dose required with iron dextran?

For SAFETY, not efficacy.

Does ferric gluconate require a routine test dose?

No; a test dose may be recommended with a complicated allergy history.

Does iron sucrose require a routine test dose?

No; a test dose may be recommended with a complicated allergy history.

Does ferumoxytol require a routine test dose?

No; a test dose may be recommended with a complicated allergy history.

What is an important counseling/clinical point for ferumoxytol?

Ferumoxytol may impact the visibility of some images on an MRI scan.

When should IV iron be avoided during pregnancy according to the lecture?

AVOID IV iron during the 1st trimester because safety data are not established.

During which pregnancy trimesters can IV iron be used according to the lecture?

2nd and 3rd trimesters.

How do oral and IV iron compare?

Oral = less severe iron deficiency, GI side effects, cheaper. IV = more severe iron deficiency, bypasses GI tract, better GI tolerability, requires monitored infusion.

What product from the lecture could be recommended for low iron levels?

Vitron-C → iron + vitamin C; vitamin C helps convert Fe3+ → Fe2+ for absorption.

What medication class can cause GI bleeding and potentially contribute to anemia?

NSAIDs.

Why are ibuprofen, Motrin, and Advil a concern when taken together?

They are all ibuprofen products; using multiple products can increase NSAID exposure and risk of GI bleeding.

Why is NSAID use especially concerning in a patient with blood in the stool?

NSAIDs can cause GI bleeding, which may contribute to blood loss and anemia.

Why is oxycodone concerning in a patient already experiencing constipation?

Oxycodone can cause or worsen constipation.

A patient has HGB 9 g/dL and HCT 27%. Does this follow the Rule of 3?

Yes. 9 × 3 = 27%.

A patient has an MCV of 72 fL. What type of anemia is present?

Microcytic anemia (<80 fL) → iron deficiency anemia is a major consideration.

A patient has an MCV of 90 fL. What type of anemia is present?

Normocytic anemia (80–100 fL) → chronic kidney disease is an example.

A patient has an MCV of 110 fL. What type of anemia is present?

Macrocytic anemia (>100 fL) → consider vitamin B12 or folate deficiency.

A patient reports fatigue, weakness, exertional dyspnea, and constantly chewing ice. What condition should you suspect?

Iron deficiency anemia; pagophagia/ice craving is a classic presentation.

A patient has less severe iron deficiency and can tolerate GI effects. Which route of iron is preferred?

Oral iron.

A patient has more severe iron deficiency. Which route of iron is preferred?

IV iron.

A patient has significant GI intolerance to oral iron. Why might IV iron be beneficial?

IV iron bypasses the GI tract and therefore has improved GI tolerability.

A patient receiving IV iron requires a test dose before the first administration. Which drug is being used?

Iron dextran.

A patient receiving IV iron is scheduled for an MRI. Which drug should raise concern?

Ferumoxytol because it may affect the visibility of some MRI images.