Iron Deficiency Anemia

Description of the Disease

Iron deficiency anemia is a condition characterized by a reduced number of red blood cells (erythrocytes) and a decreased hemoglobin concentration due to insufficient iron stores needed for red blood cell production (erythropoiesis). Normal hemoglobin levels are approximately 135–160 g/L in men and 120–150 g/L in women. Anemia is generally defined as a hemoglobin concentration below 130 g/L in men and postmenopausal women, and below 120 g/L in premenopausal women. Iron deficiency anemia is the most common type of anemia and occurs more frequently in women.

The main causes of iron deficiency anemia include:

• Inadequate dietary iron intake (for example, in vegetarians).
• Increased iron requirements during pregnancy, breastfeeding, or intense physical activity.
• Reduced iron absorption due to gastrointestinal disorders, such as atrophic hypochlorhydric gastritis or partial gastrectomy.
• Increased iron loss caused by heavy menstrual bleeding, bleeding from gastric or duodenal ulcers, gastrointestinal cancers, esophageal varices, or other sources of chronic blood loss.
• Chronic intravascular hemolysis accompanied by hemoglobinuria.

Symptoms

Early iron deficiency may cause sideropenic symptoms before anemia develops. These include dry, flaky skin, brittle nails, spoon-shaped nails (koilonychia), hair thinning and hair loss, cracks at the corners of the mouth (angular cheilitis), altered taste, and atrophy of the mucosa of the tongue, mouth, throat, and esophagus, which may cause tongue pain and difficulty swallowing.

As anemia develops, symptoms include pallor of the skin and mucous membranes, weakness, fatigue, ringing in the ears (tinnitus), dizziness, shortness of breath during physical activity, and an increased heart rate.

Diagnosis

Diagnosis is based on the patient’s medical history, clinical symptoms, and identification of the underlying cause, particularly chronic blood loss. Evaluation often includes examination of the gastrointestinal tract, intestines, and genitourinary system.

Blood tests typically demonstrate decreased hemoglobin, hematocrit, and red blood cell count. In more severe cases, red blood cell indices—including mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW)—are abnormal. A peripheral blood smear may reveal microcytic, hypochromic red blood cells with variation in size and shape (anisopoikilocytosis).

Bone marrow examination, when performed, shows increased erythropoiesis, reduced numbers of sideroblasts, and depleted or absent iron stores within macrophages. Biochemical tests typically demonstrate low serum iron, increased total iron-binding capacity (TIBC), elevated transferrin with reduced transferrin saturation, and low serum ferritin levels.

Treatment

Treatment focuses on correcting the underlying cause of iron deficiency and replenishing iron stores. Oral iron supplementation is the first-line treatment. Intravenous iron is reserved for patients with impaired gastrointestinal absorption, intolerance to oral iron, or other situations in which oral therapy is ineffective or contraindicated. Intramuscular iron injections may be used when intravenous administration is not feasible, although they are painful and are used infrequently.

Source | Author Doctor Nikas Samuolis, reviewed by Prof. Virginijus Šapoka | Vilnius University | Faculty of Medicine | Head of the Department of Internal Medicine, Family Medicine, and Oncology