Anemias and Iron Deficiency Overview

Anemia Overview

• Anemia characterized by decreased hemoglobin (Hgb) or red blood cell (RBC) volume leading to reduced oxygen capacity in blood.
• Normal hemoglobin levels:
  • Men: 13.5-17.5 g/dL
  • Women: 12-16 g/dL
  • Severe anemia: Hgb <8 g/dL.
• Symptoms vary:
  • Acute: tachycardia, hypotension, palpitations, angina, lightheadedness.
  • Chronic: fatigue, weakness, dyspnea, vertigo, pallor, sensitivity to cold.

Iron Metabolism and Deficiency

• Serum iron normal range: 50-150 µg/dL; <30 µg/dL indicates iron deficiency anemia (IDA).
• Iron absorption occurs mainly in the proximal small intestine; daily intake is 15 mg for men and 11 mg for women.
• Body stores roughly 3-4 grams of iron, primarily for RBC production; 1 gram stored as ferritin.
• Common causes of IDA include inadequate dietary intake, blood loss (GI hemorrhage, heavy menses), decreased absorption (PPIs, Celiac disease), and increased needs (pregnancy, growth spurts).

Iron Supplementation and Dosing

• Oral iron supplements include Fe sulfate, Fe fumarate, Fe gluconate, carbonyl iron, polysaccharide iron complex.
• Elemental iron content varies:
  • Fe sulfate: 20%
  • Fe fumarate: 33%
  • Ferric maltol (Accrufer): 100%
• Adverse drug reactions (ADRs) from oral iron: constipation, dark stools, nausea.
• Drug interactions (DDI) affecting iron absorption: antacids, PPIs, H2RAs, tetracycline—take iron 2 hours before or 4 hours after. Vitamin C enhances absorption.

Intravenous Iron Therapy

• IV iron options:
  • Iron sucrose (Venofer)
  • Ferumoxytol (Feraheme)
  • Iron dextran (INFeD).
• Indications: CKD on hemodialysis, intolerable oral iron, rapid iron loss.
• Risks: potential for anaphylaxis, particularly with INFeD; administer slowly to avoid hypotension.

Vitamin B12 and Folate Function

• Vitamin B12 (cyanocobalamin):
  • Dosage: IM 100-1000 mcg; also available orally.
  • Functions in RBC production and neurologic function; deficiency can lead to neurologic issues.
  • DDI: chloramphenicol, colchicine may reduce absorption.
• Folate (Vitamin B9):
  • Roles in DNA synthesis and RBC formation.
  • Dosage administered IM or orally; potential to cause bronchospasm and skin reactions.
  • Caution with high doses (>10 mg/day) can lead to seizures.

Normocytic Anemia and Treatment

• Normocytic anemia may result from chronic diseases, blood loss, or insufficient erythropoiesis requiring erythropoietin-stimulating agents (ESA).
• ESA can elevate blood pressure and increase risks for stroke and heart failure.

Beta Thalassemia Management

• Treatment involves erythroid maturation agents like Relozyl (luspatercept-aamt).
• Mechanism: binds to TGF-β ligands to modify signaling pathways elevated in thalassemia.
• Usage with caution as there’s a risk of increased bleeding with excessive vitamin C.

Neutropenia and Thrombocytopenia Treatments

• Drug options available for treating neutropenia and thrombocytopenia vary with distinct mechanisms of action and side effects.

Coagulation Disorders

• Treatments for coagulation disorders must address underlying mechanisms; drugs may have significant ADRs and monitor for efficacy.

Summary of Important Points

• Iron's transport and metabolism are crucial for maintaining hemoglobin levels.
• Deficiency may arise from various dietary, physiological, and medical conditions.
• Neutropenia and thrombocytopenia require specific therapeutic considerations tailored to individual patients’ needs.

Anemia Overview

• Anemia is defined by decreased hemoglobin (Hgb) or red blood cell (RBC) volume, leading to reduced oxygen binding capacity of the blood.
• Normal Hgb levels:
  • Men: 13.5-17.5 g/dL
  • Women: 12-16 g/dL
  • Severe anemia: Hgb < 8 g/dL.
• Symptoms of anemia:
  • Acute: Tachycardia, hypotension, palpitations, angina, lightheadedness.
  • Chronic: Fatigue, weakness, dyspnea, vertigo, pallor, sensitivity to cold.

Types of Anemia

• Normocytic Anemia:
  • Related to conditions causing decreased RBC production, such as chronic kidney disease (CKD).
• Microcytic Anemia:
  • Often due to iron deficiency anemia (IDA), characterized by ↓ serum iron (<30 µg/dL) and low mean corpuscular volume (MCV).
• Macrocytic Anemia:
  • Caused by deficiencies in Vitamin B12 or folate (B9), indicated by high MCV.

Causes of Iron Deficiency Anemia (IDA)

• Inadequate dietary intake (e.g., vegetarian diet, malnutrition).
• Blood loss (e.g., GI hemorrhage, heavy menstrual bleeding, medications like NSAIDs).
• Decreased iron absorption (e.g., due to PPIs, Celiac disease).
• Increased iron requirements (e.g., during pregnancy, lactation, and rapid growth phases).

Iron Supplementation

• Elemental iron conversion in oral supplements varies:
  • Fe sulfate: 20% elemental iron.
  • Fe fumarate: 33%.
  • Antidote for overdose: Deferoxamine (Desferal®).
• Daily iron requirements:
  • Men: 15 mg,
  • Women: 11 mg.
  • Absorption: Men (6%), Women (12%).
• Drug interactions (DDI):
  • Antacids and PPIs decrease iron absorption, necessitating separation before/after intake.
  • Vitamin C enhances iron absorption.

Intravenous Iron

• Common IV iron products:
  • Iron sucrose (Venofer®), Ferumoxytol (Feraheme®), Iron dextran complex (INFeD).
• Indications: CKD patients on dialysis or unable to tolerate oral iron.
• Potential adverse drug reactions (ADRs): Anaphylaxis, hypotension, infusion reactions.

Vitamins B12 and B9 Functions and Deficiencies

• Vitamin B12 (Cyanocobalamin):
  • Essential for DNA synthesis and RBC maturation.
  • Deficiency leads to macrocytic anemia and potential neurologic issues.
  • ADRs: Injection site pain, rash.
• Vitamin B9 (Folate):
  • Crucial for DNA synthesis and amino acid metabolism.
  • Deficiency can lead to similar macrocytic anemia and elevated homocysteine, a risk factor for stroke.
  • ADRs: Bronchospasm, flushing.

Erythropoiesis-Stimulating Agents (ESA)

• Used for normocytic anemia, especially in CKD patients.
• Drugs include Epoetin α (Procrit®, Epogen®) and Darbepoetin α (Aranesp®).
• ADRs: Hypertension, headache, and increased risk of thrombotic events if serum Hgb > 12 g/dL.

Beta-Thalassemia Treatment

• Relozyl® (luspatercept-aamt) utilized as an erythroid maturation agent.
• Adverse effects can include hypertension and stroke.

Treatment for Neutropenia and Thrombocytopenia

• Neutropenia drugs enhance bone marrow production:
  • Filgrastim (Neupogen®): Stimulates neutrophil accumulation.
  • ADRs include bone pain and allergic reactions.
• Thrombocytopenia drugs aim to increase platelet production:
  • Romiplostim (Nplate®), Oprelvekin (Neumega).
  • ADRs include head pain and fluid retention.

Coagulation Disorders

• Issues arise from clotting factor deficiencies (e.g., Hemophilia A/B).
• Treatments include blood factor concentrates, which may carry risks of transfusion reactions and infections.

General Recommendations

• Assess and manage underlying causes of anemia, monitor serum iron, and vitamin levels.
• Advise on diet sources of iron (heme and non-heme) and the importance of supplementation in deficiency states.

Blood Disorder Agents

• Anemia classification includes normocytic, microcytic, and macrocytic based on red blood cell size.

Microcytic Anemia (Iron Deficiency Anemia - IDA)

• Commonly associated with inadequate dietary intake, particularly in diets lacking iron (e.g., vegetarian diets).
• Blood loss can result from gastrointestinal hemorrhage, heavy menstrual periods, or certain medications (NSAIDs, steroids, antiplatelet agents, anticoagulants).
• Iron absorption may be decreased due to medications like proton pump inhibitors (PPIs) or conditions such as Celiac disease, inflammatory bowel disease (IBD), and post-gastric bypass surgery.
• Increased iron requirements are seen during pregnancy, lactation, and periods of rapid growth in infants and adolescents.

Microcytic Anemia (Beta-Thalassemia)

• Indications for treatment include:
  • Anemia in patients who require regular red blood cell (RBC) transfusions.
  • Anemia that does not respond to RBC transfusion.
  • Myelodysplastic syndrome (MDS) or pre-leukemia conditions.

Normocytic Anemia

• The kidney is responsible for producing about 90% of erythropoietin (EPO), a hormone crucial for RBC production.
• EPO stimulates the bone marrow to produce red blood cells.
• A deficiency of EPO typically results in anemia associated with chronic kidney disease (CKD).

Macrocytic Anemia

• Characterized by decreased levels of Vitamin B12 or folate (Vitamin B9), or both.
• Diagnosis involves identifying low hemoglobin (Hgb) levels and high mean corpuscular volume (MCV).
• Intramuscular B12 injections are considered the first-line treatment option.

This quiz explores the various types of anemias, including normocytic, microcytic, and macrocytic, along with their causes and treatments. It also covers important concepts related to iron deficiency anemia (IDA), including iron salts, drug interactions, and IV iron treatments. Additionally, the functions of vitamins B12 and B9 are examined in relation to deficiencies and overdoses.