Anemia%20-%20iron-deficiency Signs and Symptoms

Anemia

• A condition wherein the blood has low levels of red blood cells (RBC), hemoglobin (oxygen-carrying pigment in whole blood) or hematocrit (intact RBC in the blood) making it insufficient to address the physiologic needs of the body
• Based on WHO, anemia is defined as having the following hemoglobin concentrations¹:
  • Men (≥15 years old): <13 g/dL
  • Women (non-pregnant, ≥15 years old): <12 g/dL
  • Women (pregnant): <11 g/dL in the 1st and 3rd trimesters, declines by 0.5 g/dL in the 2nd trimester
  • Children (12-14 years old): <12 g/dL
  • Children (5-11 years old): <11.5 g/dL
  • Children (6 months - 4 years old): <11 g/dL

Anemia - Iron-Deficiency

• Anemia due to low iron stores in the body
• Reduced availability of iron is the most important cause of anemia due to impaired erythropoiesis
• Most common nutritional disorder worldwide and accounts for more than half of anemia cases
• Most common cause of microcytic anemia although almost half of patients have normocytic erythrocytes
• High prevalence among children during rapid growth and erythroid expansion especially in premature and low birth weight babies, in toddlers and those in preschool and pregnant women
• It causes impaired cognitive development in preschool-aged children, and diminished work productivity and quality of life and cognitive and behavioral problems in adults
• Among pregnant women, it is associated with increased risk of low birth weight, prematurity and maternal morbidity
• Development and rapidity of progress depend on the individual’s iron stores, which are, in turn, dependent upon age, sex, rate of growth, and the balance between iron absorption and loss
• Absolute iron deficiency is when the iron stores in the bone marrow and other parts of the monocyte-macrophage system in the liver and spleen are absent, resulting into iron being unavailable for normal or increased rates of erythropoiesis
• Functional iron deficiency is when there is insufficient availability of iron for incorporation into erythroid precursors despite normal or increased body iron stores
  • Usually due to anemia of inflammation or use of erythropoiesis-stimulating agents

¹Values for the definition of anemia may vary between countries. Please refer to available guidelines from local health authorities.

Causes of Anemia

• Normocytic anemia when RBC morphology is unremarkable 
  • Blood loss - most common cause
  • Decreased RBC production due to low RBC production or destruction of precursors of RBC within the bone marrow, eg chronic disease
  • Increased RBC destruction, eg hemolysis
• Macrocytic anemia wherein the RBC is larger than the nucleus of a small lymphocyte on a peripheral smear due to:
  • Megaloblastic causes: Folate and vitamin B12 deficiency, human immunodeficiency virus (HIV) infection, rare inborn errors of metabolism, myelodysplastic syndrome or congenital dyserythropoietic anemia
  • Nonmegaloblastic causes: Marked reticulocytosis, aplastic anemia, abnormal nucleic acid metabolism of erythroid precursors interfering with nucleic acid synthesis, abnormal RBC maturation, other causes such as Down syndrome, alcohol abuse, liver disease and hypothyroidism
• Microcytic anemia when RBCs appear smaller due to the following pathologic processes:
  • Reduced iron availability/iron-deficiency anemia
  • Acquired disorders of heme synthesis, eg thalassemia 
  • Reduced globin production
  • Rare congenital disorders including sideroblastic anemias, porphyria, and defects of iron absorption transport, utilization and recycling
  • Inflammation or chronic disease
  • Lead poisoning

Etiology of Anemia - Iron-Deficiency

• Blood loss (overt) - most common and important cause
  • Menstrual blood loss - common cause in premenopausal women
  • Gastrointestinal blood loss - common cause in men and postmenopausal women
• Inadequate iron intake (eg elderly, malnutrition, vegan diet, alcoholism)
• Iron malabsorption may be due to:
  • Intestinal mucosal disorders (most commonly celiac disease)
  • Impaired gastric acid secretion
  • Gastrectomy and gastric/intestinal bypass procedures
  • H pylori colonization
• Increase in iron demand (eg rapid growth in children, menstruation, pregnancy, lactation) 
• Increase in iron loss (eg frequent epistaxis) 
• Occult bleeding 
• Congenital iron deficiency (iron-refractory iron-deficiency anemia)
• Intravascular hemolysis
• Pulmonary hemosiderosis
• Response to Erythropoietin treatment
• Chronic diseases and genetic disorders (eg chronic hematuria) 
• Frequent blood donations

Anemia

• Primary symptoms include: Dyspnea (exertional or at rest), fatigue, palpitations, headache, faintness or lightheadedness, tinnitus, anorexia, gastrointestinal (GI) disturbances, loss of libido
• Symptoms of severe anemia include: Lethargy, confusion, tachycardia, retinal hemorrhage that may lead to life-threatening complications such as congestive heart failure, angina, arrhythmia and/or myocardial infarction
• Symptoms can be due to decreased oxygen delivery to tissues and in patients with acute and marked bleeding, the added insult of hypovolemia

Anemia - Iron-Deficiency

• Commonly asymptomatic
• Usual symptoms include paleness, weakness, headache, irritability and varying degrees of fatigue, dyspnea and exercise intolerance