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
• At sea level, anemia is diagnosed with the following hemoglobin levels (g/L):           

• 	Mild	Moderate	Severe
  Men (≥15 years old)	110-129	80-109	<80
  Women (non-pregnant, ≥15 years old)	110-119	80-109	<80
  Women (pregnant)	100-109	70-99	<70
  Children (12-14 years old)	110-119	80-109	<80
  Children (5-11 years old)	110-114	80-109	<80
  Children (6 months - 4 years old)	100-109	70-99	<70

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 (GI) 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
• Helminthiasis in pregnant women from low- and middle-income countries

Anemia

• Primary symptoms include: Dyspnea (exertional or at rest), fatigue, palpitations, headache, faintness or lightheadedness, tinnitus, anorexia, 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