Classifications of Anaemia | Haematology

In this article we will discuss about the classification of anaemia.

1. Anaemias due to Deficiency of Haemopoietic Principles:

A. Anaemia due to deficiency of iron:

This is the commonest type of anaemia encountered in our country. It is widely prevalent in all ages and sexes as well asin all parts of India. General incidence of iron deficiency anaemia varies according to the economic and social status of the individual. Its incidence is higher in the poorer section of the society though it is also met with in the higher income group.

In India incidence varies from place to place. In the South, 25-50 per cent of pregnant women during the last trimester of pregnancy and approximately 50 per cent of infants and young children suffer from iron deficiency anaemia. In Gujarat, in a village community of 1441 people, 29.55 per cent were found to be suffering from iron deficiency anaemia whilst in a survey of low income group at Poona, 51.43 per cent showed a similar type of anaemia, whereas a similar study from Kerala showed that 14.2% of the females were suffering from iron deficiency anaemia.

A study from New Delhi showed that out of 71 children, 51 were suffering from manifestations of hypochromic anaemia. In view of its widespread incidence a detailed discussion on the iron metabolism and its disorders is considered necessary.

Iron Metabolism and its Disorders:

(a) Body Iron Content:

There are about 4 to 5 gms of iron in the adult human body. About two-thirds of it are found.in the red cells. One ml of red cell contains approximately 1 mgm of iron, so that an adult has about 2 gms of iron in the red cell mass. About 0.15 gm is present as myoglobin and respiratory enzymes.

Stored of iron are found in the reticulum cells of liver, spleen and bone marrow and the amount varies from 0 to 1 g or more. Stored iron is in two forms in the body, ferritin and haemosidorrin. Plasma iron forms only a small proportion of the total (3-4 mgm).

Plasma iron functionally is of great importance since all iron exchange takes place through this pool. Iron is always bound to transferrin, a β₁-globulin to prevent the toxic reaction of unbound iron and its precipitation at the PH of body fluids. Transferrin acts as a transfer protein carrying iron to and from various tissues without itself being utilised or assimilated. Iron is continuously circulating through plasma bound to transferrin and major part of this iron is derived from the daily destruction of about 20 ml of red cells which liberates 20 mgm of iron.

There is also a further 10-15 mgm of iron derived from stores and tissues carried through plasma daily. Plasma iron is rapidly removed by the active haemopoietic tissues in the bone marrow but part goes to stores and new tissue formation. There is an increase in iron absorption when erythropoiesis is stimulated by bleeding, haemolysis or by high altitude.

(b) Body Iron Balance:

Iron metabolism occurs within a closed system in the body. Iron is conserved by the body, the small amount lost daily is made good by absorption from the gut.

(i) Iron Loss:

Faecal loss:

Faecal loss is about 0.4 to 0.5 mgm daily. Urinary loss—is normally less than 0.1 mgm daily. These urinary losses are uninfluenced by body iron content. Urinary iron losses may be greatly increased by the use of iron chelators.

Skin loss:

Skin loss losses from growth of hair, nails and from desquamation of epithelial cells have been estimated at 1-5 mg daily. It has also been suggested that in hot humid climate of tropical countries, thermal sweating may account for several milligrams of iron loss daily but this has not been supported by isotope studies.

Menstrual iron loss:

Menstrual iron loss an additional daily loss of about 0.8 mgm of iron is incurred by a menstruating woman.

Thus basal losses of body iron in man amount to less than 1.0 mgm daily. In females, it is about 1.5 mgm daily.

Pregnancy:

Pregnancy Total iron requirement during pregnancy is as follows—Foetal need is about 280 mgmof iron. Expanding maternal red cell mass requires about 200 mgm of iron and a further 125 mgm of ironfor blood loss and placenta during delivery. Although, basal iron losses are offset by amenorrhoea, to this must be added an average daily loss of 162-370 mgm of iron throughout pregnancy.

Thus total iron requirement is about 800 mgm; since after delivery mother’s red cell mass comes down to normal level again, which permits 140 mgm of iron becoming available to her, the total iron outlay during pregnancy is around 650 mgm.

(ii) Iron Absorption:

This is the principal means of body iron regulation. Mechanism of absorption is complex and still is not well understood.

Many factors are known to influence iron absorption and they are:

(a) Luminal factors,

(b) Systemic factors and

(c) Mucosal cell factors.

(a) Luminal factors:

Dose—depends on the amount of iron presented.

Valency—ferrous iron is much more readily absorbed than ferric.

Substances increasing absorption—are reducing agents like Vit C orally, Succinic acid orally as well as intravenously increas’es iron absorption. Iron chelates with fructose and combines with aminoacids such as histidine and cysteine and gets readily absorbed.

Substances decreasing absorption—are those which form insoluble compound with ferric iron like dietary phytates, phosphates, iron chelators such as desferrioxamina. Food iron absorption—an average diet contains approximately 10-20 mgm of iron per day mostly in organic form but there is some in inorganic form also. Iron is widely distributed in vegetables and meat, concentration being higher in the latter.

11 to 14 per cent of dietary iron is absorbed. Liver iron is well absorbed, iron in egg yolk, spinach and rice is less well absorbed and still less in wheat and soyabeans.,It is difficult to define the precise role of dietary iron deficiency in the etiology of a condition so multifactorial as iron deficiency anaemia.

There is apparently no co-relation between dietary iron and iron deficiency anaemia. The availability of food iron for absorption depends not only on its form in the natural state but also in the case with which digestion releases iron containing compounds from the foods and the presence of iron-binding substance in food which may increase or decrease iron absorption.

Stomach and iron absorption—Importance of stomach in iron absorption could be seen from the fact that the incidence of gastric atrophy and achlorhydria is higher in patients with this type of anaemia than in normal people. It is well established that hydrochloric acid is an important factor in its absorption.

The ingested iron is liberated from food by peptic digestion and becomes bound to chelators which with the help of HCL keep it in soluble form. Iron is absorbed in the duodenum and jejunum. Regulation of iron absorption takes place in this portion of the intestine. There is a significant impairment of non-haem iron absorption in patients with histamin fast achlorhydria. Gastric acid also may influence iron absorption through lowering of pH.

(b) Systemic factors modifying iron absorption:

Body iron stores:

Body iron stores a decrease of body iron induces increased iron absorption from the alimentary tract. This may occur in iron deficiency state without anaemia. Conversely, iron absorption is diminished if states of iron overload.

Erythropoietic activity:

Iron absorption increases with increased erythropoietic activity which occurs during bleeding, haemolysis or staying in high altitudes. Similarly, iron absorption is reduced when erythropoiesis is depressed.

Plasma transferrin level:

There is a correlation between unsaturated transferrin levels and iron absorption.

Humoral factors:

Recent investigations suggest that there is a heat stable humoral factor which regulates iron absorption.

(c) Mucosal cell factors:

After iron has been taken up by the mucosal cells, it is either bound to an. intracellular protein resembling transferrin which carries across the mucosal cell to plasma or it is incorporated into ferritin in the epithelial cells. Iron requirement of the body regulates the iron absorption.

Precise mechanism is still speculative. It could be a messenger iron from plasma that is incorporated in the epithelial cell, which in turn will synthesize ferritin and prevent the absorption of unnecessary iron which is eventually shed in the G.I. tract.

The cells in iron deficiency have no ferritin and in iron repletion body has abundant ferritin. The function of the ferritin is to trap absorbed iron into mucosal cells. In iron deficiency states with no intestinal ferritin, iron would pass unhindered into the body; conversely in iron overload, iron would be held back in the cell and be shed with it into the intestinal lumen at the end of its three-day life span. Recent experiments show that the synthesis of muscosal ferritin is controlled by the amount of iron in body iron stores.

In man, there are two stages of iron absorption from the gut, viz., a rapid stage starting 10 minutes after administration of an oral dose and lasting 3 to 4 hours and subsequent slow plasma phase lasting several hours. Absorbed iron is transported in the plasma bound to transferrin.

The latter circulates in interstitial spaces and exchanges iron with all cells of the body. Normally transferrin iron is delivered to developing red cells. Iron liberated from transferrin and not taken up by young red cells, is incorporated into an intracellular exchangeable pool of low molecular weight complexes.

This pool plays a vital role in the regulation of iron absorption and is in equilibrium with body iron pools. After having considered the salient points in the iron metabolism, it would now be proper to discuss various types of iron deficiency anaemia and their management.

(i) Chronic Nutritional Hypochromic Anaemia:

It is the commonest type of anaemia in this country. Its widespread incidence is well recognised in all strata of the society but it is seen mostly in women, children and infants and in men belonging to the low socio-economic group.

Causes of iron deficiency:

Iron absorption may be inadequate which in turn may be due to low iron content in the diet or to an impairment of intestinal absorptive mechanism. On the other hand, loss of iron through haemorrhage may occur at a greater rate than replacement from a normal diet by a normal absorption mechanism. In women of the child-bearing age, this anaemia is seen more frequently because of enhanced demand for iron resulting from menstrual blood loss, foetal requirement and lactation.

There may be insufficiency of iron in the diet also. Other causes in the country in both sexes are helminthiasis, especially ankylostomiasis, malabsorption syndrome, tropical sprue, parasprue, steatorrhoea and gastrointestinal bleeding. Gastrectomy is also responsible for iron deficiency anaemia.

Clinical features:

The symptoms are gradual and progressive unless treated. The general clinical features of anaemia already described (vide supra) will be seen along with other evidences of nutritional deficiencies like glossitis, angular stomatitis, koilonychia and dysphagia. The glossitis is usually referred to as chronic atrophic glossitis because of atrophy of the papillae and mucous membrane, makes the tongue smooth and glazed.

The atrophy begins at the edges and later affects the whole tongue. Koilonychia or nail changes are seen as brittleness, dryness, flattening and thinning followed later on by concavity (spoon-shaped nail). Dysphagia occurs in severe cases. Post-cricoid dysphagia is the least common consequence of iron deficiency. This is occasionally associated with the presence of an oesophageal web.

In a long-standing case, sometime spleen can become palpable. Hypochlorhydria or achlorhydria is commonly present. Paresthesias may be complained of but no definite C.N.S. findings are detected. A combination of glossitis, dysphagia and anaemia is called Plummer-Vinson syndrome (Kelly-Paterson syndrome).

Blood examination shows a hypochromic, microcytic anaemia with an M.C.H.C. value less than 31%. Anisocytosis and poikilocytosis are present but not marked. Bone marrow shows normoblastic reaction. Serum iron level is low. Iron binding capacity (T.I.B.C.) is invariably raised. A raised T.I.B.C. is a useful diagnostic criterion since the only other disease in which it may be raised is viral hepatitis.

T.I.B.C. is frequently reduced below normal in infection, neoplasm and rheumatoid arthritis and this helps to distinguish anaemia in these diseases from those due to iron deficiency. Percentage of transferrin that is bound to iron (i.e. serum iron concentration to T.I.B.C. expressed as a percentage) is a very useful index for the diagnosis of iron depletion.

Diagnosis:

The differential diagnosis from other types of anaemia can be arrived at from the blood examination. Peripheral smears immediately suggest the diagnosis which is confirmed by an M.C.H.C value less than 31%, low serum iron level, high T.I.B.C. and a reduced transferrin saturation. A value of 16 per cent or lower for the transferrin indicates lack of iron stores.

(ii) Hypochromic Anaemia in Infancy and Childhood:

Iron deficiency is frequently found between the ages of 6 months and 5 years, the highest incidence being at the age of 12 months. There are two factors which predispose to iron deficiency in infancy, name y, inadequate iron stores at birth and inadequate amount of iron in the diet. Prolonged milk feeding especially breast-fed and artificially fed infants become anaemic due to iron deficiency.

Low birth weight, nutritional anaemia in mother, infections in infants and intestinal malabsorptions are some other etiological factors which lead to iron deficiency. Clinical features are similar to those of adults, but are not easy torecogmse. Anaemia leads to impairment of general health and vitality and an increased incidence of infection.

Iron Depletion without Anaemia:

In recent years, this state has been well documented. The diagnosis of this stage can be made when the Hb concentration is within the normal range but the serum iron concentration is below normal and transferrin saturation is below 16 per cent. In pregnant women, the depletion of iron stores is the rulerather than the exception. It is generally agreed, however, that iron depletion without anaemia does not cause symptoms and there are no good reasons to treat these people with iron.

Treatment of Iron Deficiency Anaemias:

In iron deficiency anaemia, there is a depletion of the body’s usually considerable iron reserves. As a consequence, the iron through intestinal tract is rapidly absorbed. Ferrous salts are more effective than ferric salts. Treatment should start with oral administration of ferrous sulphate (600 mgm) which contains 120 mgm of elemental iron daily in 3 daily doses after meals.

This is the cheapest and safest method. To replenish the depleted body stores, administration of iron should continue for 4-6 months after the haemoglobin has become normal. Patient should be warned that the stool will be black. If the response to this dose is not adequate, then the following should be considered.

(a) The patient has not taken the tablets:

One of the common reasons advanced by patients that the tablets cause gastro-intestinal symptoms such as pain, diarrhoea or constipation. These patients who cannot tolerate the ferrous sulphate, other types of preparations like ferrous carbonate, chloride, fumarate, gluconate or succinate can be tried. All these preparations are equally effective.

(b) That patient has malabsorption syndrome:

In such patient iron may be injected I.M. or I.V. in dose of 100-250 mgm daily. Ferrvenin is suitable for the I.V. route whilst Imferon and Jactofer (iron sorbitalcittic acid) are efficient and well tolerated by I.M. route. Another preparation, Iron Polymaltose (Ferrum Hausmann) has also been used for parenteral therapy. In order to cut down the hospital stay and to avoid repeated injection to pregnant women especially within a limited time that is available before labour or operation, many workers have tried giving infusion of total dose of iron in one sitting (T.D.I.). But because of many side effects which have been reported, treatment by T.D.I. should not be taken lightly.

Total amount of iron required can be-calculated as:

(Normal Hb — patients Hb) x 0.255

= gm. Iron required.

(c) That initial dose was incorrect or that B₁₂ or folate deficiency is also present. It should be remembered that there is a high incidence of overt or latent folic acid deficiency in pregnancy and this usually manifests when haemoglobin level reaches 7-8 gms per cent. Some Indian firms have brought out intramuscular iron preparations combined with folic acid.

(d) If the iron deficiency was due to haemorrhage, the bleeding may still continue from the gut.

A rise of 1% Hb level per day is expected and in an average case blood level is restored in 4 to 8 week’s time. The purpose of the treatment with iron is not only to restore the red cell volume to normal but also to replenish iron stores. The former is easy but the latter is difficult. If the patient absorbs 10 per cent of 120 mgm iron ingested each day as ferrous sulphate then it will take approximately three months to raise the iron stores to about lg.

In practice it has been found that the percentage of iron absorbed is often less than this and the patient should therefore be persuaded to continue taking iron for 6 months. Failure rate with oral iron therapy is high because of not taking the tablets regularly. Iron medication should be supplemented by a well-balanced diet.

There are a large number of iron and folic acid preparations in the market. These are costly and should not be used in pure iron deficiency anaemias. The addition of trace elements like copper, manganese and cobalt is of no clinical value. When the Hb is below 5 g per 1-00 ml. it is normally advisable to keep the patient in bed. Whether to transfuse blood or not will be decided on the clinical condition of the case.

In infants the treatment of iron deficiency anaemia requires the administration of a liquid iron preparation as well as introduction of iron containing food in the diet. The dose should be about 6 mgm iron per mg body wt. daily.

(iii) Post Haemorrhagic Iron Deficiency Anaemia:

It may be acute or chronic.

Acute:

Sudden loss of a large volume of blood more than 1 litre due to trauma or bleeding can lead to haemodilution during the recovery phase which is reflected by a fall in Hb level and red cell count. When the circulating blood volume is partially restored, the acute symptoms of shock subside. During convalescence, general symptoms and signs of anaemia may be present.

During recovery, the red cells are formed more rapidly than Hb and the M.C.H.C. falls unless adequate iron is available. Treatment consists of bed rest, blood transfusion of adequate amount to restore the blood volume and combat the oligaemic shock. The cause of the blood loss should be sought and treated. Iron, afterwards, should be given.

Chronic:

Anaemia results from repeated loss of small amounts of blood. Common causes are bleeding peptic ulcer, piles, carcinoma, ankylostomiasis or menorrhagia. Frequent medication with aspirin can also cause alimentary bleeding. Frequent and persistent blood loss can cause a progressive fall in Hb.

The clinical and haematological features are similar to those found in chronic nutritional hypochromic anaemia. In addition, the clinical features of the causative disorder will be present. Treatment is to arrest the source of blood loss by appropriate measures where possible and the administration of iron and a good diet.

(iv) Sideroblastic Anaemia:

Abnormal utilisation of iron with failure of haem synthesis by the marrow may cause a refractory anaemia. In this condition, there is a peripheral blood picture of chronic iron deficiency anaemia with excessive accumulation of iron containing granules in the erythroblasts and reticulocytes of the bone marrow and haemosiderosis of the liver and other tissues.

The condition may be congenital or acquired. The congenital form is sex-linked and found in boys. Iron therapy does not help. The secondary type may be caused by drugs such as isoniazid or be associated with chronic general diseases. Some cases respond to treatment with pyridoxine, Vit C and folic acid. Those who do not respond to above therapy, blood transfusion is the only treatment which should be given very cautiously to avoid transfusion siderosis.

Megaloblastic Anaemia:

Occurs due to deficiency of Vit B₁₂ or folic acid or both. Deficiencies of both vitamin B₁₂ and folate produce identical changes in cells of bone marrow and peripheral blood. Normal erythropoiesis is changed to a megaloblastic character. In the peripheral blood, red cells are macrocytic. The megaloblasts in the marrow are larger and have a fine reticular structure of the nucleus than normal red cell precursors.

Causes of megaloblastic anaemia are:

(i) Due to lack or defective production of intrinsic factor as in Addisonian pernicious anaemia. Total or partial gastrectomy also leads to a deficiency of Vit B₁₂.

(ii) Poor nutrition or diet leading to nutritional megaloblastic anaemia where chief deficiency being folic acid.

(iii) Resection, short circuit or disease of small intestine.

(iv) Blind loop syndrome or jejunal diverticulosis where there is an abnormal growth of bacteria which utilises Vit B₁₂ leading to its deficiency.

(v) Pregnancy where there is a higher requirement of folic acid and at the same time patient suffers from anorexia and vomiting pari passu with a low food intake.

(vi) Due to drugs like methotrexate and cytosine arabinoside which interferes with dihydrofolate reductase system or DNA synthesis or anticonvulsant drugs like phenytoin sodium or pirimidone.

B. Vit B₁₂ and Folic Acid Deficiency Anaemia:

Vit B₁₂ acts as a co-enzyme and helps in the synthesis of methionine. Although Vit B₁₂ is required for the proper functioning of every cell, signs and symptoms of deficiency are usually seen in haematological, gastrointestinal and neurological systems. Vit B₁₂ is produced entirely by intestinal bacteria and none is present in plants.

Man gets this Vit B₁₂ also by eating animal food. Vit Bi₂ is absorbed through distal half of small intestine after combining with the intrinsic factor. Intrinsic factor is produced in the stomach by the parietal cells which produce HCL. Daily requirement of Vit B₁₂ is about 3-5 _Mg and the normal diet contains an excess of Vit B₁₂.

This vitamin is mainly stored in the liver and an average healthy adult has a total body content of about 3 mgm. Loss of Vit B₁₂ takes place through desquamation of epithelium and through excretion in bile. Rate of loss of Vit B₁₂ is approximately 0.1 per cent of the total body content each day.

The factors which cause deficiency of Vit B₁₂ are failure to secrete the intrinsic factor and a failure to absorb Vit B₁₂ as a result of abnormalities of ileum. Folic acid or pteroylglutamic acid is absorbed mainly in the proximal half of the small intestine and is converted into an active form (tetrahydrofolate) in the body by reduction.

The active form acts as a co-enzyme in the purine and pyrimidine synthesis for the formation of DNA and RNA. The chief cause of folate deficiency in pregnancy is greatly increased DNA and RNA synthesis associated with growth of fetus, placenta and uterus and increased red cell volume of mother. Folate requirements increase three times during pregnancy.

Several other factors also play a part in the production of folate deficiency in pregnancy like anorexia and vomiting along with a reduced food intake- Folate deficiency also occurs in malabsorption syndrome where it is associated with iron and Vit B₁₂ deficiencies. Failure to absorb folate may occur in regional ileitis or resection of jejunum where it is absorbed chiefly.

(i) Nutritional Megaloblastic Anaemia & Megaloblastic Anaemia of Pregnancy:

This is seen commonly in tropical countries including India due to dietary deficiency mainly of folic acid. The anaemia is made worse during pregnancy. The disease is most common in second and third decades. Though folic acid deficiency is the main causative factor, in some of the cases Vit B₁₂ also may be required thereby causing a dual deficiency anaemia.

Symptoms are mostly due to anaemia. Diarrhoea and vomiting may occur but are usually due to an inter current infection to which subjects are particularly liable. Sore tongue is relatively uncommon and C.N.S. symptoms have not been described. Oedema of the feet and ankle, a low blood pressure, cardiac haemic murmurs and fever are common. Blood changes—The anaemia is megalocytic.

The R.B.C. count is reduced more than haemoglobin, so the colour index, M.C.H., M.C.V., all are high whilst the M.C.H.C. is normal. There may be some thrombocytopenia, sometime there is leucopenia. In uncomplicated cases, serum iron is normal or high and T.I.B.C. is depressed and the bone marrow haemosiderin is increased. The bone marrow is megaloblastic. There may be giant metamyelocytes, hypersegmented granulocytes and twin nucleated granulocytes. Megakaryocytes are usually reduced and show depression of platelet formation.

Treatment:

Folic acid in doses of 15 mgm to 20 mgm or more a day is the treatment of choice and causes a rapid and satisfactory response. Some cases need both Vit B₁₂ and folic acid for complete recovery. Relapses should be prevented by providing adequate diet containing 100 g of protein preferably derived from meat, fish or eggs.

(ii) Megaloblastic Anaemia Due to Pathological Conditions of G.I. Tract:

It is seen in tropical sprue and para sprue, and idiopathic steatorrhoea. The anaemia in these conditions is due to failure of absorption of folate or Vit B₁₂ or both.

Anaemia can also occur subsequent to resection or short circuiting of a large segment of the small intestine. Vit B₁₂ is only absorbed from the lower portion of the ileum whereas folate is mainly absorbed through proximal half of small intestine.

Clinical picture is mainly that of the underlying condition along with general symptoms of anaemia. Achlorhydria is uncommon. Folate level in the blood and urine is measured by means of microbiological assay after giving a large dose of folic acid orally.

Vit B₁₂ absorption is measured by giving the fasting patient a small dose of Vit B₁₂ labelled with radioactive cobalt. A large dose of non-radioactive Vit B₁₂ is injected two hours after and urine is collected for 24 hours. Radioactivity of urine is then measured. In normal subjects more than 16 per cent of the oral dose should be excreted in urine. In P.A., when the radioactive B₁₂ is given with an intrinsic factor, excretion is more than 16 per cent whereas in a malabsorption case, the result is low due to the diseased ileum. In tropical sprue and para sprue, folic acid therapy produces excellent response.

It should be given I,M. for first two or three days and orally in a dosage of 20 mgm a day thereafter. Vit B₁₂ should also be given. Iron may also become necessary. If anaemia is due to resection or short circuiting of a large segment of small intestine, then the primary deficiency is Vit B₁₂ which should be administered in large doses.

(iii) Addisonian Pernicious Anaemia:

It is uncommon in our country but is the commonest type of megaloblastic anaemia in Western countries. It is due to failure of secretion of the intrinsic factor. This disease affects the females more than males between the ages of 40 and 65 years.

Clinical manifestations:

It is commonly observed that degree of anaemia is quite considerable before the patient consults the doctor. In addition to the symptoms due to anaemia, patient complains of soreness of tongue and occasional diarrhoea. Four most common presenting symptoms are weakness, dyspnoea, paraesthesia and sore tongue. Apart from pallor, the most common sign is atrophic glossitis. Fever is seen in some percentage (22%) of cases and spleen is seldom enlarged.

In about 7% of cases, neurological features are also seen. The usual syndrome described is sub-acute combined degeneration of the cord as posterior and lateral columns are both affected. Dementia may also occur. Gastric analysis invariably shows achlorhydria which is histamine or pentagastrin fast.

Peripheral blood shows a macrocytic anaemia. M.C.V. is increased and M.C.H.C. is normal. There is marked anisocytosis and poikilocytosis. Serum bilirubin is raised. There is leucopenia, reduction involving the granulocytes which are mature, some having more lobes than five in their nuclei (hypersegmented). There is also thrombocytopenia.

Treatment:

Hydroxycobalamine should be given in a dose of 1000 microgram two to three times a week in the first week and then once a week until blood count becomes normal. Then 100-1000 fig µm daily once a month for the patient’s lifetime.

If sub-acute combined degeneration of cord is present, then patient should be given 1000 microgram of Vit B₁₂ twice weekly for about six months and then switching over to monthly injections.

It is important that a patient of pernicious anaemia is given a maintenance therapy of Vit B₁₂, 1000 microgram every four to eight weeks for the rest of his life. Oral B₁₂—intrinsic preparation is not recommended for the treatment of P.A.

Megaloblastic anaemia due to drugs:

Drugs as earlier stated interfere with the dihydrofolate reductase mechanism. Therefore, folic acid should be given for treatment. When anticonvulsant drugs are given, simultaneous folic acid therapy should also be given to the patient.

(iv) Megaloblastic Anaemia in Infancy:

Infants whose diet is deficient in proteins, folate and ascorbic acid and who are suffering from infection and diarrhoea may become anaemic which is megaloblastic or dimorphic in character. In India, this type of anaemia in infants is due to protein calorie malnutrition. This anaemia responds to folic acid along with a good high protein diet.

2. Anaemias due to Excessive Haemolysis:

Whenever there is an increased destruction of red cells, haemolytic anaemia results. This anaemia may be due to an intracorpuscular defect or due to an extracorpuscular abnormality. Anaemia will occur if destruction exceeds the regeneration of red cells.

In this condition there will be an increased reticulocytosis and an increase in serum bilirubin level. Peripheral smear will show schistocytes and nucleated red cells. There may be microspherocytes. Target cells may be seen in cases of haemoglobinopathies. Osmotic fragility may be increased in some cases. Antiglobulin test will be positive in acquired haemolytic anaemias.

Classification of Haemolytic Anaemia:

1. Intracorpuscular defects:

Hereditary spherocytosis

Hereditary ovalocytosis or elliptocytosis

Haemoglobinopathies like sickle cell anaemia, thalassaemia,

E-thalassaemia and other disorders like HbC, HbD, HbH

G-6-PD deficiency or other enzyme deficiency

Paroxysmal nocturnal haemoglobinuria

2. Extracorpuscular abnormality:

Extracorpuscular abnormality (infective, toxic, allergic or associated with other diseases)

Immune acquired haemolytic anaemia (warm or cold) types

Haemolytic disease of the new-born

Drug induced haemolytic anaemia

Incompatible blood transfusion

Due to burns, lead or infection

Hereditary Elliptocytosis or Ovalocytosis:

It is an inherited autosomal disorder where the red cells are elliptical or oval. It is not a common disorder and produces mild symptoms of haemolytic anaemia. Spleen is often palpable. Splenectomy often results in a clinical cure.

Haemoglobinopathies or Abnormal Haemoglobin Disorders:

Adult haemoglobin—A (α₂ β₂) comprising 98 per cent of total Hb consists of four polypeptide chains, two alpha and two beta chains. There is also 1 to 3 per cent A₂ in adult blood consisting of two alpha and 2 delta chains (α₂ β₂). Hb A is written as α^A₂ β^A₂. In foetus, the Hb F has two alpha chains and two gamma chains (α₂ β₂). There are 141 amino acids in alpha chain and 146 amino acids in beta chain.

There are 3 types of Hb disorders that one meets with:

(i) There is an alteration in the amino acid sequence or structure of the polypeptide chain as in sickle cell anaemia,

(ii) The amino acid sequence is normal, but the rate of production is impaired or absent as in thalassaemias,

(iii) There is persistence of Hb F in the adult life. More than 100 varieties of haemoglobinopathies have been described but most of them are rare. In India commonest haemoglobinopathy is thalassaemia and in West Bengal, E-thalassaemia. Sickle cell anaemia has been described amongst tribals and aborigines of India. Other haemoglobin disorders like D, J, L. Q and M have also been described. We will only consider thalassaemia as it is the commonest and sickle cell anaemia because of its importance amongst tribal population.

Thalassaemia:

It is commonest haemoglobinopathy in India. In eastern part, it is E-thalassaemia and in western India it is β-thalassaemia or sickle cell-thalassaemia or a combination with other Hb disorders. In all of them, there is a decreased rate of synthesis of beta chains. Heterozygotes are called thalassaemia minor and the homozygotes, thalassaemia major.

There is a wide spectrum of severity in thalassaemia ranging from normal haemoglobin concentration on one hand to still birth on the other. In thalassaemia minor, disability is much less whereas in major, manifestation of disease could be very great, though there is a wide variability in manifestations. In β-thalassaemia, there is little or no Hb A, there is an increase in A₂ which helps in the diagnosis and also that of Hb F.

Patients of thalassaemia major are very anaemic and depend entirely on packed red cell transfusion for survival. Because of persistent bone marrow hyperplasia, there is osteoporosis, may be even pathological fracture, head bossing, prominent malar eminences giving rise to Mongoloid facies.

Patients are often stunted, puberty is greatly delayed but they are normally intelligent. Mild jaundice may be present. Splenomegaly is an important sign and it could be large enough to cause abdominal distension and discomfort.

They are susceptible to infection. Leg ulcer and gallstones can occur. X-ray of skull shows hair-on-end appearance. Extramedullar haemopoiesis can occur which causes spinal cord compression. Liver is enlarged much later but more quickly if splenectomy is carried out early.

Blood picture often is similar to severe iron deficiency anaemia. Target cells are seen in fair number. Normoblasts (esp. late variety) are present. Osmotic fragility shows increased resistance. Bone marrow aspiration shows normoblastic hyperplasia.

Diagnosis is confirmed by Hb electrophoresis.

Treatment:

Repeated packed red cell or washed red cell transfusion is the mainstay of the treatment. Iron deposition which was seen in earlier years producing ultimately haemosiderosis, could be avoided by using iron chelating agent like desferrioxamine. Present trend is to keep the haemoglobin at a higher level of 10-12 gm/dl to allow proper development.

Splenectomy may be considered when it is huge and causing mechanical difficulties or hypersplenism. Splenectomy should only be considered after the age of 6 years. As there is folic acid deficiency it is advisable to give folic acid in higher dosage along with other members of Vitamin B Complex group.

Sickle Cell Haemoglobinopathies:

The importance of Hb-S is for its clinical severity. In homozygous Hb-S, the sickle cell anaemia, most patients die in infancy or within first 10 years of life. It is seen amongst the aboriginal tribes of India, especially those of Nilgiri Hills of south India like Irules, Kothas, Kurumba and Toda aboriginals. It is also seen in aboriginals of Orissa, central India, Gond, Goshti of western India. Tribal groups from Gujarat, U.P., Bastar district of Madhya Pradesh also show sickle cell trait.

Clinical manifestation is uncommon during first six months of life. When the foetal haemoglobin gets replaced, clinical symptoms develop which is evident as anaemia and jaundice in early childhood. Repeated debilitating crises lasting 5 to 7 days are usually associated with shock and prostration and may simulte a perforation of abdominal organ or other surgical emergencies localising either in abdomen or bones or joints. Spleen is often enlarged in early stages but may shrink later on due to repeated infarction. Bacterial infection is the commonest cause of early childhood morbidity and mortality.

The hand-foot syndrome is due to micro-infection of medulla of the carpal and tarsal bones. Overlying skin is tender and swollen with a rise in temperature. The lesion is symmetrical and healed without therapy but may recur. When pooling of blood suddenly occurs in the spleen, splenic sequestration syndrome in the form of oligaemic shock occurs. Blood transfusion can only save the life.

There may occur cerebral, pulmonary or vascular accidents due to occlusion of vessels by sickled cells. Aplastic crises can occur due to sudden cessation of marrow activity due to an infection. Gallstone and leg ulcer are common. Liver is often enlarged, spleen in adult is not palpable. Cardiac complications are common; skeletal X-rays show often rarefaction and osteoporosis. Aseptic necrosis of femoral or humoral head may occur due to repeated bone infection and may cause severe arthritis.

Blood Picture:

Anaemia is often severe due to reduction of red cell life span. The anaemia is normocytic normochromic. There may be elongated cells in the smear or sickle cells. Cover slip preparation confirms sickling. Hb electrophoresis confirms the diagnosis.

Treatment of sickle cell anaemia consists of proper management, especially, of painful crises by complete rest, use of analgesics, early treatment by appropriate antibiotics and partial exchange transfusion. No specific treatment has yet been evolved for sickling disorder, though urea in high doses and cyanates have been tried to prevent sickling. Cyanate therapy shows some success in this field but has the drawback of several toxic symptoms and is still in the trial stage.

G-6-P D Deficiency:

(Glucose-6-Phosphate dehydrogenase deficiency):

It is an inherited disorder which is transmitted by a sex-linked gene of intermediate dominance. Males are always full reactors and intermediate expression is seen in a female when she is heterozygous.

Amongst Indians, 5 to 9 per cent are G-6-PD deficient. Whenever any oxidising drug like aspirin, quinine, Chloromycetin, sulphonamide group, primaquin or any such drug is taken, oxidised Hb cannot be reduced back due to the absence of the enzyme G-6-PD. Such oxidised red cells are unstable and break down producing an acute haemolytic episode.

The severity of the haemolytic episode, in general, is related to the dose of the drug. Patient may become jaundiced. The haemolytic episode is self-limiting. When the incriminating drug is withdrawn, the haemolysis stops. New-borns, who are G-6-PD deficient, may have severe degrees of jaundice necessitating even exchange transfusion. Such cases may be mistaken for Rh incompatibility. Predisposing factor in them is mostly some infection, bacterial or viral.

Laboratory test for diagnosis:

Common screening tests for G-6-PD deficiency are brilliant cresyl blue dye test or methaemoglobin reduction test.

Other enzyme deficiencies like pyruvate kinase producing haemolytic anaemia have also been reported, but they are very rare.

Paroxysmal Nocturnal Haemoglobinuria (PNH):

In this condition, there is an acquired defect of the red cell membrane which renders them unusually sensitive to the complement of normal serum. Because of it, there is haemolytic anaemia with haemoglobinuria and also haemosiderinuria along with leucopenia and thrombocytopenia. Haemolytic crises are common with crises of haemoglobinuria, especially during sleep. Increased haemolysis in the night may be due to changes in the pH of blood because of retention of CO₂ during sleep. PNH has definite relationship with aplastic anaemia. Occasionally acute leukaemia following PNH has also been described.

Diagnosis of the disorder is by seeing haemoglobinuria in the urine and confirmation by acid serum test (Ham’s test) and sucrose lysis test. Treatment is to give blood transfusion during the episodes of haemoglobinuria. Because of occasional haemolytic reaction following transfusion, due to the activation of complement by a factor in the donor plasma, it is advisable to give packed red cells or washed packed red cells.

Paroxysmal Cold Haemoglobinuria:

This occurs due to a cold auto-haemolysin and is related to syphilis, often of congenital type. It is usually cured by antisyphilitic treatment.

Acquired Haemolytic Anaemia:

(Immune Haemolytic Anaemia)

There are two types either due to warm or cold agglutinins.

Warm Immune Haemolytic Anaemia:

This is due to warm antibody of Ig G type reacting with red cells at 37° C. It could be either idiopathic or following lymphoma, chronic lymphatic leukaemia, multiple myeloma, acute leukaemia or collagen disorder like S.L.E., Polyarteritis nodosa or Rheumatoid arthritis.

It could also be due to drugs. Patients report with anaemia, hepatosplenomegaly and often mild icterus. Peripheral smear examination shows evidences of haemolytic anaemia, spherocytosis and reticulocytosis. Diagnosis is confirmed by direct antiglobin test (Coomb’s). Treatment is usually with corticosteroids.

In severe cases, most compatible red cell transfusion is given taking into consideration patient’s ABO and Rh group, as cross-matching is difficult. Majority patients achieve remission with a high dose of prednisolone 60 to 100 mgm daily. 30% resistant cases may need splenectomy. Some 10 per cent cases who are resistant tocortico-steroidsand splenectomy, may need cytotoxic drug like cyclophosphamide or imuran to achieve remission.

Cold Immune Haemolytic Anaemia:

This disorder is due to an IgM complement fixing antibody. It acts best at 4°C and leaves the red cell surface at warmer temperature. Normally, it is present in low litres (1:32) but in patients suffering from this anaemia, titre goes up as high as 1:150,000 at 4°C. Because of high litre, it starts acting at body temperature producing haemolytic anaemia.

It was seen classically in Indian soldiers moving from plains to high altitude and very cold climate as Leh. The first symptoms to appear are Raynaud’s phenomenon, acro­cyanosis, especially during the winter. They complain of weakness and dizziness. In some cases, there may be hepatosplenomegaly and in severe cases, icterus. Direct antiglobin test will be positive for complement components but negative for immunoglobulin.

Therefore, the human antiglobulin serum should be a broad-based one with complement antibodies. The test has to be carried out keeping all equipment including syringes at 37° C, otherwise antibodies will be absorbed into red cells at room temperature.

Treatment is unsatisfactory. Patient should be protected from cold and given blood transfusion. If necessary, corticosteroid therapy may be tried but is usually ineffective. Few cases with very high titre may respond.

Haemolytic Disease of New-Born:

(Erythroblastosis foetalis)

This is due to blood group incompatibility, mostly due to ABO group but is also seen due to Rh incompatibility between parents.

In ABO, the mother usually belongs to O group and father belongs to any other group excepting O. In Rh incompatibility, mother is rhesus negative (Rh or D negative) and father is rhesus positive (Rh or D positive). Due to earlier sensitisation either through transfusion or previous child birth, mother forms Rh antibodies which are of IgG type and can cross the placental barrier.

These antibodies combine with Rh positive cells of foetus in utero and cause haemolysis. Usually the first born child escapes any morbidity but subsequent ones may suffer. Very severe haemolysis produces hydrops foetalis or still birth. Less severe one is the cause of erythroblastosis foetalis where the peripheral blood of the neonate shows large number of erythroblasts. Present nomenclature is Haemolytic Diseases of the New-born (HDN). ABO incompatibility in marriage can produce HDN but the morbidity and mortality are less severe than Rh incompatibility.

The baby is born with jaundice, peripheral smear shows erythroblasts and reticulocytosis, Hb is less than normal, serum bilirubin is high and direct antiglobin test is positive. Treatment is by exchange transfusion in all severe cases. In recent years, Rh negative mothers (not sensitised) and primipara are given high titre anti-D immunoglobin intramuscularly within 72 hours of delivery. By adopting this procedure, it has been possible to prevent sensitization of Rh negative mother following child birth.

Acute Haemolytic Anaemia Following Incompatible Blood Transfusion:

A mismatched or incompatible blood may be transfused due to:

(i) Clerical error,

(ii) Technical fault,

(iii) Wrong labelling and

(iv) Nursing error.

Whenever such wrongly matched blood is transfused, patient complains of warm sensation along the vein, severe constriction in the chest, pain in the back and loin. If sufficient quantity has been transfused, then it may lead to haemoglobinuria, oliguria leading to anuria. Immediately on detecting the error or onset of the symptoms, compatible blood should be transfused. Quantity should be twice the amount of incompatible blood transfused. Idea is to prevent renal ischaemia and acute cortical necrosis. Most, if not all, patients, make a miraculous recovery following compatible blood transfusion.

3. Anaemias due to Aplasia or Hypoplasia of the Bone Marrow:

Here the anaemia is due to a failure of bone marrow to regenerate cells. Marrow shows varying degrees of hypocellularity to complete aplasia. The condition is refractory to treatment. In few cases, bone marrow may show normal cellularity or hypercellularity. There may be failure of one or two types of the cell especially affecting the granular series of cells or thrombocytes. When all the cells are affected, pancytopenia results.

About half or more cases of bone marrow failure develop without cause. Rarely there are congenital or familial pancytopaenia in children (Fanconi syndrome), bone marrow failure with thymoma or with paroxysmal nocturnal haemoglobinuria.

Agents responsible for bone marrow depression fall into two categories:

(a) Those which regularly produce bone marrow damage if a sufficient dose is given. They are ionising radiations, radioactive elements, benzene and its derivatives, cytotoxic agents, antimetabolites and other toxic agents like inorganic arsenicals.

(b) Agents occasionally associated with bone marrow damage:

Clinical features:

The symptoms may appear suddenly when marrow aplasia is secondary to radiation or antimitotic treatment. In idiopathic cases the onset is usually insidious, with severe anaemia, weakness, fatigue, dyspnoea, palpitation, pounding headache and fever. Infections become a serious problem associated with severe granulocytopenia.

A low platelet count is frequently attended by bleeding. Lymph nodes and spleen are usually not enlarged but splenomegaly may develop after many transfusions due to transfusion siderosis. Blood picture shows a normochromic normocytic anaemia with low leucocyte and platelet counts but without any nucleated cells or reticulocytosis.

Bone marrow may be hypocellular, normocellular or hypercellular, the latter can be explained on the basis of ineffective haematopoiesis. Serum iron is elevated, iron binding capacity is moderately reduced. Differentiation from subleukaemic leukaemia or myelophthisic anaemia is made by bone marrow examination. This differentiation may be difficult but LAP (leukocyte alkaline phosphatase) stain of peripheral film and chromosomal study for Philadelphia chromosome may be helpful.

Treatment:

Prevention of exposure to a possible toxic agent should be the first aim of treatment. In most instances, however, the evidence on which a drug is incriminated is purely circumstantial. The patient should be advised against the use of hair dyes, insecticides, plant sprays and all drugs except those specifically prescribed. The medication should be kept simple and potential marrow toxic drugs should be avoided.

Supportive care consists of careful mouth hygiene, caution against picking the nose, use of a soft tooth-brush, avoidance of intramuscular or subcutaneous injections, care of arm veins and avoidance of constipation. Antimicrobial therapy should be given for the treatment of specific infections. Blood transfusion should be type specific and given only when Hb level has fallen below 8 gms/d1. Two or three units of blood can be given on successive days after two to three weeks.

The development of transfusion haemosidcrosis and of sensitisation to minor blood groups, leucocytes or platelets is thus postponed as long as possible. Platelet transfusions and corticosteroids help in the haemorrhagic manifestations and in thrombocytopaenia.

Corticosteroids, i.e. prednisolone 20 to 40 mg per day and testosterone preparation like oxymetholone (4-5 mg/kg body weight daily orally) are known to induce remissions in the children and adults.

Oxymetholone should be continued for several months, but the dosage should be halved when there is evidence of remission. Treatment with blood transfusion, oral antibiotics and haematinics should be continued for at least six months before being abandoned.

Splenectomy should be of value if the spleen is enlarged and is destroying cellsat an accelerated rate or if it is depressing the bone marrow function.

In pure red cell aplasia, the use of immunosuppressive drugs like cyclophosphamide, or 6- mercaptopurine may induce a remission. If thymoma is present, thymectomy may help. Bone marrow transplantation should be tried in aplastic anaemia when all other measures have failed.

In some centres, bone marrow transplantation is being carried out earlier because of successful results. Recent results suggest that bone marrow transplantation has become the treatment of choice in cases of aplastic anaemia. Best result is obtained from a twin, otherwise from an HLA matched family member.

As the marrow transplantation is best with immunological problems,’ only centres having the expertise and facilities to manage Graft versus Host reaction should carry out the marrow transplantation. Recent reports suggest successful use of antithymocyte globulin injections in some cases.

4. Symptomatic or Secondary Anaemia:

Most infectious and chronic systemic diseases such as renal or hepatic disease, rheumatoid arthritis, the connective tissue disorders, malnutrition, malignancy, lymphomas, and endocrine deficiencies, are accompanied by anaemia during the course of illness. Usually it is mild, but can be severe in leukaemia and renal failure.

In most cases the anaemia is normocytic and normochromic, occasionally it may be microcytic and also hypochromic. In general, the pathogenesis of anaemia can be explained by a combination of mild haemolytic component with decreased erythropoiesis or relative bone marrow failure. In renal disease, anaemia increases with rise in blood urea above 70 mg/dl though there is no precise correlation with urea retention.

There is reduced span of red cells; sometimes frank haemolytic process occurs when microangiopathy is present. Haemorrhage often makes a contribution terminally but the prime mechanism is marrow failure. The anaemia of hepatic disease is frequently complicated by chronic blood loss and in patients with alcoholic cirrhosis by folate deficiency. After elimination of iron and folate deficiencies, normocytic anaemias remain. Increased plasma volume exaggerates the depression of erythrocyte value by haemodilution.

The anaemia in endocrinopathies is attributed to general hypometabolism. The causes of anaemia in a widespread malignant disease are many and varied. Loss of appetite, malabsorption or blood loss from the G.I. tract or increased haemolysis are some of the factors. Further metastasis in the bone marrow may cause myelophthisic anaemia. The term “myelophthisic anaemia” is applied to those anaemias associated with space occupying lesions of the bone marrow.

The anaemia may be moderate to severe, the white blood cell count may be elevated or depressed; thrombocytopenia may or may not be present. Normoblasts are found in the peripheral blood often in large numbers; young granulocytes may also be seen but are less prominent. Red blood cell survival is shortened, and the anaemia is caused because the bone marrow, although stimulated, does not increase erythrocyte production enough to compensate for the haemolysis.

The old idea that normal marrow is crowded out by the invading cells is no longer tenable. The diagnosis should be suspected whenever there occurs leucoerythroblastic anaemia, i.e. immature red cells and white cells appear in the peripheral blood. The number of nucleated red blood cells present is out of proportion to the degree of anaemia. Treatment and prognosis depend on the causative disorder.