12_Anemia

Anemia Overview

Definition:

Anemia is defined as a reduction of red cell volume or hemoglobin concentration below the normal range for age in healthy individuals. It can lead to insufficient oxygen transport to the body's tissues, resulting in various health complications.

Classification of Anemias

Anemia can be classified based on the underlying cause:

1. Inadequate Intake

   • Deficiency of specific factors:

     • Iron deficiency: The most common cause of anemia, particularly in children and pregnant women, often resulting from inadequate dietary intake or absorption issues.

     • Vitamin B12 deficiency: Often due to inadequate dietary intake (especially in vegetarians) or malabsorption syndromes, leading to megaloblastic anemia.

     • Folic acid deficiency: Resulting from inadequate intake, absorption issues, or increased demand (e.g., pregnancy).

2. Production Issues

   • Bone Marrow related anemia: Disorders that affect the bone marrow, leading to reduced production of red blood cells.

   • Congenital pure red cell anemia: Genetic disorders impacting the production of red blood cells.

   • Anemia of infection: Occurs secondary to chronic disease states such as renal failure or cancer, which inhibit erythropoiesis.

   • Ineffective erythropoiesis: Syndromes that disrupt the normal erythropoiesis process, such as congenital dyserythropoietic anemia.

3. Hemolytic Anemias

   • RBC defects: Conditions such as hereditary spherocytosis and elliptocytosis that alter the red blood cell membrane structure.

   • Enzyme defects: Enzymatic deficiencies, such as G6PD and pyruvate kinase deficiency, lead to increased red blood cell fragility and hemolysis.

   • Defect in Hb synthesis: Genetic conditions affecting hemoglobin, including Hemoglobin S (sickle cell disease), Hemoglobin C, Hemoglobin D, and Thalassemias.

   • Immunologic Issues: Such as Rh incompatibility and ABO incompatibility causing hemolysis.

4. Blood Loss

   • Blood loss due to various causes, including gastrointestinal bleeding, heavy menstrual periods, or prolonged breastfeeding in infants.

Symptoms to Assess

When evaluating a patient for anemia, key symptoms to inquire about include:

• Fever and night sweats: May suggest underlying infection or malignancy.

• Weight loss: Can be indicative of chronic disease or malignancy.

• Jaundice and dark urine: Often related to hemolysis.

• Nosebleeds: Indicating possible platelet issues or blood clotting disorders.

• Melena: Suggestive of upper GI bleeding.

• Family history of anemia: Provides insight into possible inherited conditions.

• Use of certain drugs: Some medications, such as anti-epileptics, can contribute to blood dyscrasias.

• Gastrointestinal symptoms: Including diarrhea or symptoms of malabsorption that could point to underlying causes of anemia.

Anemia in Infancy

Physiological Anemia:Newborns typically present with higher hemoglobin at birth, followed by physiological anemia around 2-3 months as fetal hemoglobin is replaced with adult hemoglobin. Premature infants often have a more pronounced anemia due to lower erythropoietin levels and decreased red blood cell mass.

Megaloblastic Anemia:Characterized by the presence of megaloblasts in the bone marrow and macrocytes in the blood, often due to deficiencies in folic acid or vitamin B12.

• Folic Acid Deficiency:

  • Causes: Insufficient intake, absorption challenges, increased metabolic requirements, or accompanying conditions.

  • Onset: Common in infants around 4-7 months.

• Vitamin B12 Deficiency:

  • Causes: Inadequate intake, defective absorption (issues with intrinsic factor), gastrointestinal diseases, drug interactions, or congenital transport disorders.

  • Age of onset: Typically manifests between 9 months and 10 years.

  • Lab findings: Present as macrocytic anemia with pancytopenia and hypersegmented neutrophils, often accompanied by megaloblastic changes in the bone marrow.

Clinical Manifestations of Anemia

Common symptoms and findings in anemia may include:

• Failure to thrive: Especially critical in infants and young children.

• Generalized weakness: Lethargy and fatigue common due to inadequate oxygenation of tissues.

• Glossitis: Inflammation of the tongue commonly associated with nutritional deficiencies.

• Anorexia: Poor appetite contributing to nutritional deficiencies.

• Pallor: Notable paleness, often examined through oral mucosa and conjunctiva.

• Jaundice: Indicative of hemolytic processes, detected through skin and scleral examination.

• Neurological manifestations: Such as ataxia, paresthesia, and hyporeflexia, particularly linked to vitamin B12 deficiency.

Treatment of Megaloblastic Anemia

Folic Acid: Recommended doses start at 5 mg orally per day, with higher doses considered in congenital deficiencies.Vitamin B12: Initial treatment involves 1 mg intramuscularly daily for 2 weeks, particularly in cases associated with neurological defects. Monthly supplementation should follow the initial course. Subsequent Management: Doses may need adjustment based on individual patient requirements, noting conditions like transcobalamin II deficiency may necessitate increased dosage.

Diagnostic Approach in Case Studies

History Taking: Key focus areas during evaluation should include:

• Nutritional history: Dietary intake of iron, folate, and B12.

• Gastrointestinal symptoms: Possible indicative issues affecting absorption.

• Family history of anemia or blood loss: Important for identifying hereditary conditions.

Basic Investigations to order:

• Hemoglobin levels

• Packed Cell Volume (PCV)

• White Blood Cell (WBC) count

• Platelets

• Mean Corpuscular Volume (MCV)

• Red Cell Distribution Width (RDW)

• Reticulocyte count

Special Cases and Diagnoses

Case Study Example:

Consider a 20-month-old girl presenting with marked pallor. Critical areas of inquiry include:

• Nutritional history to assess dietary intake of essential nutrients.

• Gastrointestinal symptoms to evaluate for malabsorption or bleeding.

• Family history of anemia or related disorders.

Lab Findings may include low hemoglobin levels, abnormal MCV, RDW, and reticulocyte count, leading to possible diagnoses such as:

• Iron deficiency anemia,

• Thalassemia,

• Other specific conditions indicated through lab results (e.g., beta-thalassemia intermedia).

Iron Deficiency Anemia

Epidemiology:Iron deficiency anemia is prevalent in children, with a 5.5% prevalence due to dietary intake disparities or increased requirements during growth phases.

• Requirements

  • Generally recommended is 2 mg/kg/day, peaking at the age of 9-24 months.

• Causes:

  • Poor dietary intake, impaired absorption like in celiac disease, or blood loss due to gastrointestinal conditions or allergies.

Diagnosis of Iron Deficiency Anemia

History and Physical Examination:Assessment of dietary habits, pallor, splenomegaly, and overall health status.Complete Blood Count (CBC):Typically shows decreased hemoglobin, PCV, MCV, MCH, MCHC, increased RDW (>15%).Serum Ferritin:Low ferritin levels (<12 ng/ml) confirm the diagnosis of iron deficiency anemia.Differential Diagnosis: Consider thalassemia, lead poisoning, sideroblastic anemia, chronic infections, or malignancies.

Treatment of Iron Deficiency Anemia

Dietary Interventions:Encourage iron-fortified foods and vitamin C supplements to enhance iron absorption.Oral Iron Supplements:Administered at 6 mg/kg/day divided into three doses for 2-3 months.Monitor Response:Assessment involves initial evaluation of appetite and an increase in reticulocyte counts, followed by hemoglobin levels.

Failure to Respond:If no improvement is noted, evaluate compliance with treatment and investigate possible sources of continued blood loss or underlying diseases.

Parenteral Iron Treatments:Indicated in specific circumstances such as patients with bowel disease or where compliance with oral iron cannot be achieved.

Hemolytic Anemia

Key Indicators of Hemolysis:

• Decreased PCV

• Increased indirect bilirubin

• Increased reticulocytes

• Low haptoglobin levels

• Elevated lactate dehydrogenase (LDH) levels

Types: Hemolytic anemias include spherocytosis, G6PD deficiency, immune hemolytic anemia, and more.

Management Strategies

Blood Transfusions:Closely monitor for reactions, such as allergic or febrile reactions.Splenectomy:May be considered in severe cases of hemolytic anemia to reduce hemolysis.Hydroxyurea Treatment:Indicated for sickle cell disease to reduce the frequency of pain crises.Bone Marrow Transplant:Considered for severe forms of aplastic anemia or specific cancer types.

Genetic Considerations in Blood Disorders

Thalassemias:A group of inherited blood disorders caused by genetic mutations that affect globin synthesis, leading to anemia. Sickle Cell Disease:A genetic disorder resulting from mutations leading to the production of abnormal hemoglobin, which causes vaso-occlusive crises and can lead to severe complications.

Hematological Manifestations of Systemic Diseases

Systemic diseases can manifest as anemia, thrombocytopenia, or leukopenia due to various factors affecting bone marrow function or immune responses, necessitating a broad diagnostic investigation.

Final Considerations

Early detection and treatment are crucial in managing anemias, especially in pediatric populations where growth and development can be severely impacted. Genetic counseling and preventive strategies are essential for conditions like thalassemia and sickle cell disease to minimize morbidity and improve quality of life.

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