Nutritional Anemia: Causes, Classification, and Clinical Insights

Nutritional Anemia: Causes, Classification, and Clinical Insights

Question. Classify anemia and discuss Nutritional Anemias.

Answer. Classifiation of Anemia

Etiological Classifiation of Anemia(By lea and Febiger, 1981)

1. Loss of blood:

• Acute posthemorrhagic anemia
• Chronic posthemorrhagic anemia.

Nutritional Anemia: Causes, Classification, and Clinical Insights

2. Excessive destruction of red blood corpuscles:

1. Extracorpuscular causes:

• Antibodies
• Infections like malaria
• Splenic sequestration and destruction
• Associated diseases like lymphomas
• Drugs, chemical and physical agents
• Trauma to RBC.

Causes of Nutritional Anemia and Its Classification

2. Intracorpuscular hemolytic diseases:

Hereditary

• Disorders of glycolysis
• Faulty synthesis or maintenance of reduced glutathione
• Qualitative or quantitative abnormalities in the synthesis of globulin
• Abnormalities in RBC membrane
• Erythropoietic porphyria.

Nutritional Anemia Types and Symptoms

Acquired

• Paroxysmal nocturnal hemoglobinuria
• Lead poisoning

Impaired blood production resulting from defiiency of substances essential for erythropoiesis:

• Iron defiiency
• Defiiency ofvarious B vitamins: Vitamin B12 and folic acid (pernicious anemia and megaloblastic anemia); pyridoxine responsive anemia
• Protein defiiency
• Possibly ascorbic acid defiiency.

Inadequate production of mature erythrocytes:

Defiiency of erythroblast

1. Atrophy ofbone marrow: Aplastic anemia

• Chemical or physical agents
• Hereditary
• Idiopathic.

2. Isolated erythroblastopenia

• Thymoma
• Chemical agents
• Antibodies.

Infitration ofbone marrow:

• Leukemia, lymphomas
• Multiple myeloma
• Carcinoma, Sarcoma
• Myelofirosis.

Endocrine abnormalities:

• Myxedema
• Addison’s disease
• Pituitary insuffiency
• Sometimes hyperthyroidism.
• Chronic renal failure.
  Chronic inflmmatory disease:
• Infectious
  Non­infectious including granulomatous and collagen disease.
• Cirrhosis of liver.

Morphological Classifiation of Anemia

Based on the red cell size, hemoglobin content and red cell indices, anemias are classifid into 3 types:

1.Microcytic, hypochromic: MCV, MCH, MCHC are all reduced, e.g. in iron defiiency anemia and in certain noniron defiient anemias (sideroblastic anemia, thalassaemia,anemia of chronic disorders).

2.Normocytic, normochromic: MCV MCH, MCHC are all normal, e.g. after acute blood loss, hemolytic anemias,bone marrow failure, anemia of chronic disorders.

3.Macrocytic: MCV is raised, e.g. in megaloblastic anemia due to defiiency of vitamin B12 or folic acid.

Nutritional Anemias

Following are the nutritional anemias:

• Iron defiiency anemia
• Macrocytic anemia.

1. Due to increased blood loss:

• Gastrointestinal: Peptic ulcer, piles, hookworm manifestation,
• Carcinoma of stomach, acute erosive gastritis, ulcerative colitis
• Lung: Due to hemoptysis
• Renal: Haemoglobinuria and hematuria
• Uterine: Menorrhagia, post menopausal uterine bleeding.
• Nose: Epistaxis

2. Due to increased body demands:

• In adolescence
• During prematurity
• In pregnancy and lactation.

3. Due to inadequate dietary intake:

• In low socioeconomic status
• In elder patients with loss of teeth
• Anorexia of pregnancy.

4. Decreased absorption:

• In achlorhydria
• In patients with malabsorption
• In cases with gastrectomy.

Macrocytic Anemia
Macrocytosis is the rise in mean cell volume or red cells above the normal range. It is due to vitamin B12 defiiency or folic acid defiiency.

Macrocytic Anemia Etiology

1. Vitamin B12 defiiency

• Inadequate intake:
• In strict vegetarians
• In poor diet.

Due to malabsorption:

• Gastric:
• Pernicious anemia
• Congenital intrinsic factor defiiency
• Gastrectomy.
• Small intestinal disease:
• Topical and Non­topical sprue
• Crohn’s disease
• Fish tapeworm.
• Increased requirement
• In pregnancy.

Macrocytic Anemia Folic acid defiiency

1. Inadequate intake

• Infancy
• Old age
• Poverty
• Alcoholism
• Kwashiorkor.

2. Malabsorption

• Coeliac Disease
• Topical sprue
• Congenital folate malabsorption.

3. Increased utilization or loss

1. Physiological

• Prematurity
• Pregnancy and lactation.

2. Pathological

• Blood disorders
• Malignancy
• Dialysis.

3. Anti­folate Drugs

• Methotrexate
• Pyrimethamine
• Trimethoprim
• Anti­convulsant drugs.

Macrocytic Anemia Clinical Features

• Due to anemia: Shortness of breadth, anemia and pallor.
• Gastrointestinal: Diarrhea, loss of weight and apetite
• Neurological: Vitamin B12 neuropathy and neural tube defects due to defiiency of folic acid.
• Gonadal dysfunction: It is due to deficiency of both Vitamin B12 and folic acid
• Epithelial cell changes: Glossitis and other epithelial surfaces show cellular abnormalities.

Macrocytic Anemia Investigations

1. Vitamin B12 Defiiency:

• Hemoglobin levels are decreased below normal range.
• Mean corpuscular volume is raised.
• Peripheral blood fim examination reveals macrocytosis, poikilocytosis and hypersegmentation of the neutrophils
• Bone marrow examination reveals hypercellular marrow with megaloblastosis, giant metamyelocytes and platelets
• Serum iron and serum ferritin levels are raised.
• Schilling’s test is positive.

2. Folic acid defiiency:

• Serum folate levels are low
• Red cell folate levels are low
• Figlu test is positive.

Macrocytic Anemia Treatment

Vitamin B12 Defiiency:

• Hydroxycobalamine 1000 µg IM is given, i.e. 6 injections in 2 to 3 weeks.
• Since rapid regeneration of blood deplete marrow iron stores, so ferrous sulphate 200 mg daily is given after starting the therapy.
• Maintenance dose of 500–1000 μg IM is given for every 3 months.

Folic acid defiiency:

• InitiallyFolicacid 5 mg daily orally for 4 months is given.
• Maintenance dose is 5 mg folic acid once a week.