Iron-deficiency anemia

Iron-deficiency anemia
Name	Iron-deficiency anemia
Caption	A blood film showing characteristic pale, small red blood cells.
Field	Hematology
Symptoms	Fatigue, pallor, shortness of breath
Complications	Heart failure, Developmental delay
Causes	Blood loss, poor diet, Malabsorption
Diagnostic	Complete blood count, Serum ferritin
Treatment	Iron supplements, Blood transfusion
Frequency	~1.2 billion globally
MedlinePlus	000584
EMedicineSubj	med
EMedicineTopic	1188
MeshID	D018798

Iron-deficiency anemia is a prevalent hematological disorder characterized by a reduction in hemoglobin due to insufficient bodily iron stores. It is the most common type of anemia worldwide, affecting individuals across all demographics but with higher prevalence in certain populations. The condition arises from an imbalance between iron loss, often through chronic blood loss, and iron absorption from the diet. Management typically involves addressing the underlying cause and replenishing iron stores through supplementation or dietary changes.

Signs and symptoms

Clinical manifestations are often nonspecific and develop gradually. Common symptoms include profound fatigue, weakness, and generalized pallor, particularly noticeable in the conjunctiva and nail beds. Patients may experience shortness of breath (dyspnea), especially upon exertion, dizziness, and headaches. More specific signs can include koilonychia (spoon-shaped nails), pica (cravings for non-nutritive substances like ice or dirt), and restless legs syndrome. In severe cases, it can precipitate angina or worsen pre-existing cardiovascular conditions, potentially leading to tachycardia and heart failure. In children, it is associated with irritability and developmental delay.

Causes

The primary cause is chronic blood loss, which depletes the body's iron reserves needed for erythropoiesis. In adults, this is frequently due to gastrointestinal bleeding from sources like peptic ulcer disease, colorectal cancer, or hemorrhoids. In women of reproductive age, menorrhagia (heavy menstrual bleeding) is a major contributor. Other causes include inadequate dietary intake of bioavailable iron, as seen in strict vegetarian or vegan diets, and conditions that impair absorption. Malabsorption syndromes such as celiac disease, atrophic gastritis, or previous bariatric surgery (e.g., Roux-en-Y gastric bypass) can significantly reduce iron uptake. Chronic use of medications like nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin can also induce gastritis and bleeding.

Diagnosis

Diagnosis is confirmed through laboratory testing, beginning with a complete blood count (CBC), which typically reveals microcytic, hypochromic red blood cells, a low mean corpuscular volume (MCV), and reduced hemoglobin and hematocrit levels. Key iron studies include a low serum ferritin, which is the most specific indicator of depleted iron stores, elevated total iron-binding capacity (TIBC), and low serum iron. A peripheral blood smear examined by a pathologist often shows the characteristic pale, small erythrocytes. To identify a source of bleeding, further investigations such as colonoscopy, esophagogastroduodenoscopy (EGD), or fecal occult blood test may be warranted, especially in older adults or those with alarming symptoms.

Treatment

First-line treatment involves oral iron supplementation, typically with ferrous sulfate, ferrous gluconate, or ferrous fumarate, often accompanied by ascorbic acid (vitamin C) to enhance absorption. Treatment must continue for several months to replenish stores and correct the anemia. For patients who cannot tolerate or absorb oral iron, or in cases of severe deficiency, intravenous iron formulations such as ferric carboxymaltose or iron sucrose are administered. In acute, life-threatening anemia, a blood transfusion may be necessary. Crucially, treatment must address the underlying etiology, such as managing menorrhagia with hormonal therapy or surgically correcting a bleeding ulcer. Follow-up testing with a CBC is essential to monitor response.

Epidemiology

It is a global public health issue, affecting an estimated 1.2 billion people according to the World Health Organization (WHO). Prevalence is highest among young children, adolescent girls, and women of reproductive age, particularly in low-income and middle-income countries where nutritional deficiencies and parasitic infections like hookworm are common. In the United States, data from the Centers for Disease Control and Prevention (CDC) indicate it affects approximately 5% of women and 2% of men. Certain populations, including pregnant women, individuals with chronic kidney disease (especially those on dialysis), and patients with congestive heart failure, are at significantly increased risk.

Prevention

Preventive strategies focus on ensuring adequate iron intake and managing risk factors. Public health initiatives include dietary diversification, food fortification programs (such as fortifying wheat flour or infant formula), and nutritional education. For high-risk groups, routine screening with a CBC is recommended; for instance, the American Academy of Pediatrics advises screening infants at 12 months. Prophylactic iron supplementation is standard for all pregnant women as per guidelines from the American College of Obstetricians and Gynecologists. Controlling helminthic infections through mass deworming campaigns in endemic regions and promoting early diagnosis and treatment of conditions causing chronic blood loss are also critical preventive measures.

Category:Hematology Category:Nutritional deficiencies