Anemia and its classification

It is a very common blood disorder derived from Greek word meaning lack of blood. Enemy as a medical condition in which red blood cells or hemoglobin level is lowered in blood. It is more common in females than males and during development till ages as in children adolescence and during puberty pregnancy and lactation.

As oxygen carrying capacity of blood is lowered due to decrease in amount of haemoglobin person's ability of doing work is affected. 

According to WHO hemoglobin<11gm/dl and hematocrit<33%  is termed as anaemia.

Causes / risk factors

1.  Age and sex

It is more common in women of reproductive age group during puberty pregnancy lactation and in children during puberty or adolescence period when there is Rapid growth of body.

2.  Family history

 Some type of anemia have genetic predisposition for family history of Hemolytic anaemia, Thalassemia, Sickle Cell anemia etc.

3.  Diet

Nutritional anemia is common in developing countries diet lacking in iron Folic acid vitamin B12 Vitamin C produces anemia.

4.  Blood loss 

Loss of blood due to some acute injury or due to some hemorrhagic disease or internal bleeding leads to anemia example peptic ulcer, piles, worm infestation etc.

5. Occupation 

Exposure to some chemicals may cause anemia like aniline dyes lead poisoning etc.

6. Drug-induced 

Injection of some drugs may cause hemolysis or may cause bone marrow suppression leading to anemia example aspirin rifampicin and chloramphenicol etc.

 #Signs and Symptoms

○ General symptoms

1. Fatigue

2. Lassitude

3. Breathlessness on exertion

4. Palpitation

5.  Dizziness

 6. Tinnitis

 7. Throbbing in head and ears

 8. Headache

 9. Dimness of vision

10. Insomnia

11. Paraesthesia in toe and fingers

12. Angina

13. Intermittent claudication of the legs

○General signs

1. Pallor of skin mucous membrane conjunctiva Palm of hand and feet

2. Tachycardia

3. Cardiac dilation (ventricular hypertrophy)

4. Systolic flow murmurs

5. Edema

6. Koilonychias ( iron deficiency anemia)

7. Jaundice (hemolytic anemia)

8. Signs of heart failure

 9. Pica (craving for non digestible food items like mud wood paper grass hair etc)

10. Restless leg syndrome (iron deficiency anemia)

• Signs and symptoms of anemia mostly depend on the type of anemia, causes,onset, duration, progress and severity.

*Mild anemia of longer duration with slow progression produce less sign and symptom and are due to dietary deficiency is chronic hemolytic anemia chronic blood loss and chronic diseases

*Severe anemia is produced due to acute onset Rapid progression in short duration and is due to acute blood loss acute leukemia acute haemolysis infiltrative bone marrow diseases etc. 

○ Classification of  Anemia

Anemia is broadly classified as-

1. Morphological classification on the basis of red blood cell morphology

2. Pathophysiological classification on the basis of etiology

3. On the basis of severity it is of three types by WHO

○ Morphological classification of Anemia

 Peripheral blood smear reveals the morphology of RBCs on the basis of morphological changed and RBC they are subdivided into three types:

1. Microcytic anemia-

○ Usually hypochromic with MCV <80fL. 

○ Iron deficiency

○ Thalassemia

○ Sideroblastic anemia

○ Anemia of chronic disease

2.  Normocytic Anemia-

○ Usually normochromic with MCV 80-100fL

○ Acute blood loss

○ Hemolytic anemia

○ Bone marrow failure

○ Hypothyroidism

3. Macrocytic Anemia-

○ Usually hypochromic with MCV >100fL

○ Megaloblastic anemia due to vitamin B12 deficiency of Folic acid deficiency

○ Liver diseases

○ Alcoholism

○ Aplastic anemia

○ Pathophysiological classification

On the basis of causes anemia is classified into three categories-

1.  Anemia due to blood loss

2. Anemia due to impaired red cell production

3. Anemia due to increased red cell destruction (hemolytic anemia)

# Anemia due to blood loss

1. Acute blood loss example accident, injury, surgical hemorrhage etc.

2. Chronic blood loss example peptic ulcer, hemorrhoids, ulcerative colitis, piles, worms infestation, menorrhagia, metrorrhagia etc.

# Anemia due to impaired red cell production

1.  Abnormal bone marrow

a.   Aplastic anemia

b.   Myelopathis

c.   Bone marrow infiltration

2.  Dietary deficiency disease

a.  Vitamin B12 or Folic acid deficiency

b.  Iron deficiency

3.  Stimulation factor deficiency

a.  Chronic diseases

b.  Hypopituitarism

c. Renal failure

d.  Congenital

# Anemia due to increased red cell destruction

1. Intrinsic (intracorpuscular) abnormalities

a.  Hereditary

○ Membrane abnormality, spherocytosis, elliptocytosis.

○ Enzyme deficiencies-G6PD deficiency, pyruvate kinase and hexokinase deficiencies.

○ Disorders of hemoglobin (Hemoglobinopathies)- deficient globin synthesis-Thalassaemia. abnormal globin Sickle Cell anemia

b.  Acquired

Paroxysmal nocturnal hemoglobinuria

2. Expensive (extra corpuscular) abnormalities-

a. Antibody-mediated 

Isohemogglutinins  blood transfusion reaction, Erythroblastosis Fetalis. Autoantibodies idiopathic drug-related SLE. 

b. Mechanical trauma

○ Microangiopathic hemolytic anemia's- TTP, DIC, defective cardiac valves.

○ Infections-malaria

○ Cardiac surgeries and hemodialysis

○ On the basis of severity- it is of three types by WHO

1.  Mild anemia:  Hb 9-11gm/dl

2.  Moderate anemia:  Hb 7-9gm/dl

3.  Severe anemia:  Hb< 7gm/dl