ANEMIA Definition :- Anemia is a hematologic condition in which

there is quantitative deficiency of circulating hemoglobin (Hb), often accompanied a reduced number of (erythrocytes) .

Causes of anemia:- Blood loss . Impaired erythropoiesis . Abnormal erythrocyte destruction . Nutritional deficiencies (iron , Cobalamin

(B12), Folate) .

Signs and symptoms :-

Restlessness, headache, dizziness, faintness, tinnitus, diaphoresis, anorexia, nausea, constipation or diarrhea, stomatitis, pallor, shortness of breath, rapid progression to circulatory collapse or shock, tachycardia, cardiac murmurs, angina, and in sever anemia congestive heart failure.

Anemia, which has many causes, is not a single disease entity but a sign of disease .

Anemia is associated with reduction in circulating Hb because of reduced numbers of erythrocytes or less Hb per erythrocyte .

The physiologic result of low circulating Hb is the reduced capacity for blood to carry oxygen .

Pathophysiology :-

CLASSIFICATION OF ANEMIAS :-

Anemia’s may be classified according to :-

1. The morphology of the RBC. # The normocytic, normochromic anemia.

# The macrocytic, normochromic anemia.

# The microcytic, hypochromic anemia.

2. The etiology (pathophysiology). # Increased RBC loss.

# Decreased or defective cell production.

1-In classification of anemia’s by morphology :-

Cytic refers to size of the RBCs and chromic I. The normocytic, normochromic anemia. Ex: acute blood loss, hemolysis.

II. The macrocytic, normochromic anemia. Ex: deficiency states of vitamin B12 and /or folic

acid .

III. The microcytic, hypochromic anemia. Ex: iron-deficiency anemia, sideroblastic states

2-In classification of anemia’s by etiology :-

I. Increased RBC loss . Ex: Bleeding from trauma or ulcers, Destruction of

RBC

II. Decreased or defective cell production

Ex: Any condition affecting the bone marrow function would fall in to this category

MEGALOBLASTIC ANEMIAS• Are Classified morphologically as

macrocytic normochromic .

• Caused by vitamin B12

and folic acid

deficiencies which

result in disordered

DNA synthesis .

Causes of vitamin B12 deficiency 1- Low dietary intake vegans

2- Impaired absorption

* Stomach - pernicious anemia production (Congenital) of intrinsic factor. - Gastroctomy.* Small bowel - ileal disease or resection . - Bacterial overgrowth . - Tropical sprue . - Fish tapeworm .

3- Abnormal metabolism

- Congenital transcobalamin II deficiency . - Nirtous oxide (inactivates B12).

Causes of folate deficiency

1. Nutritinol major cause A. poor intake

Ex: Old age, poor social condition,

starvation, alcohol excess.

B. Poor intake due to anorexia Gastrointestinal disease, e.g. partial gastrectomy,

coeliac disease, crohn’s disease ,or Cancer.

2. Excess utilizationA. physiological

Ex: Pregnancy, Prematurity, Lactation.

Causes of folate deficiency

B. Pathological

Haematological disease with excess red cell production, or malignant disease with increased cell turnover, or inflammatory disease ,e.g. homocystinuria, or haemodialysis or peritoneal dialysis .

3. Malabsorption Occurs in small bowel disease, but the effect is

minor compared with that of anorexia.

4. Antifolate drugs e.g. Methotrexate.

Hematological findings :-

The blood film can point towards vitamin deficiency:

• Decreased (RBC) count and hemoglobin levels • Increased mean corpuscular volume (MCV, >95 fl)

and mean corpuscular hemoglobin (MCH) • The reticulocyte count is normal.• The platelet count may be reduced.• Neutrophil granulocytes may show

multisegmented nuclei ("senile neutrophil"). This is thought to be due to decreased production and a compensatory prolonged lifespan for circulating neutrophils.

Hematological findings :-

• Anisocytosis (increased variation in RBC size) and poikilocytosis (abnormally shaped RBCs).

• Macrocytes (larger than normal RBCs) are present.

• Ovalocytes (oval shaped RBCs) are present. • Bone marrow (not normally checked in a patient

suspected of megaloblastic anemia) shows megaloblastic hyperplasia.

• Howell-Jolly bodies (chromosomal remnant) also present.

Hematological findings :-

Blood chemistries will also show:

• Increased homocysteine and methylmalonic acid in B12 deficiency

• Increased homocysteine in folate defiency

Other method of investegation:-• Bone marrow. • Serum bilirubin .• Serum vitamin B12 .• Sreum folate level

Analysis:- The Schilling test was performed in the past to determine the

nature of the vitamin B12 deficiency, but due to the lack of available radioactive B12, it is now largely a historical artifact.

Vitamin B12 is a necessary prosthetic group to the enzyme methylmalonyl-coenzyme A mutase.

B12 deficiency leads to dysfunction of this enzyme and a buildup of its substrate, methylmalonic acid, the elevated level of which can be detected in the urine and blood.

Since the level of methylmalonic acid is not elevated in folic acid deficiency, this test provides a one tool in differentiating the two.

Analysis:- However, since the test for elevated methylmalonic

acid is not specific enough, the gold standard for the diagnosis of B12 deficiency is a low blood level of B12.

Unlike the Shilling test, which often included B12 with intrinsic factor, a low level of blood B12 gives no indication as to the etiology of the low B12, which may result from a number of mechanisms.

Treatment and prevention of megaloblastic anaemia:-

Treatment depends on the type of deficiency. Blood transfusion is not indicated in chronic anaemia; indeed, it is dangerous to transfuse elderly patients, as heart failure may be precipitated. Folic acid may produce a heamatological response in vitamin B12 deficiency but may aggravate the neuropathy. Large doses of folic acid alone should not be used to treat megaloblastic anaemia unless the serum vitamin B12 level is known to be normal.

Drugs:- For folate deficiency:-

* Folic acid 1mg or 5mg tab.

* Folicum tab. For vitamin B12 deficiency:-

* Twintab cap. 1000µg.

* B1+B6+B12

- Neurobion

- Becezyme

- Vitamin-B complex

- Tri-B