94. Iron deficiency anemia - etiology, pathogenesis, clinical manifestations.

Iron deficiency anemia – etiology, pathogenesis, and clinical manifestations.

Iron deficiency anemia is a microcytic, hypochromic anemia caused by insufficient iron availability, leading to reduced hemoglobin synthesis and impaired oxygen transport.

Etiology

1. 1 Increased iron loss

• Chronic blood loss (most common cause):
• Gastrointestinal bleeding (peptic ulcers, colon cancer, hemorrhoids, gastritis).
• Heavy menstrual bleeding (menorrhagia).
• Repeated blood donations.
• Parasitic infections:
• Hookworm (Ancylostoma, Necator ).

1. 2 Decreased iron intake

• Malnutrition, poor diet.
• Strict vegetarian or vegan diet without adequate iron sources.

1. 3 Decreased iron absorption

• Celiac disease.
• Post- gastrectomy.
• Chronic diarrhea.
• Helicobacter pylori infection (can reduce gastric acidity and impair iron absorption).

1. 4 Increased iron requirements

• Pregnancy and lactation.
• Rapid growth periods (infancy, adolescence).

Pathogenesis

1. 1 Negative iron balance:

• Iron loss or increased need exceeds intake/ absorption.

1. 2 Depletion of iron stores:

• First, ferritin (storage form) decreases.

1. 3 Reduced serum iron and transferrin saturation:

• Less iron transported to developing erythroblasts.

1. 4 Decreased hemoglobin synthesis:

• RBCs produced are smaller (microcytic) and contain less hemoglobin (hypochromic).

1. 5 Impaired oxygen delivery to tissues:

• Tissue hypoxia → anemia symptoms.

Clinical manifestations

General anemia symptoms

• Fatigue, weakness.
• Dyspnea on exertion.
• Dizziness, headache.
• Palpitations, tachycardia.

Skin and mucous membranes

• Pallor (skin, mucosae).
• Dry skin, brittle hair.

Epithelial (specific) changes

• Koilonychia (spoon- shaped nails).
• Glossitis (smooth, sore, red tongue).
• Angular cheilitis (fissures at corners of the mouth).
• Dysphagia due to esophageal webs (Plummer-Vinson syndrome).

Pica

• Craving for non- nutritive substances (clay, ice, starch).