Anemias - understandingphysiology.files.wordpress.com · Anemia It is a common disorder in which...

Anemias

By: Dr Asma Jabeen

Anemia

It is a common disorder in which the hemoglobin content of blood is decreasedbelow normal level.

▪ Decreased production of RBC▪ Increased destruction of RBC▪ Excess loss of blood from body

Classification of Anemia

❑ Morphological classification

❑ Etiological classification

Morphological classification

NormocyticNormochromic

MacrocyticNormochromic

MacrocyticHypochromic

Microcytic Hypochromic

Etiological Classification

HemorrhagicAnemia

Hemolytic anemia

Nutritionalanemia

Aplastic anemia

Anemia of chronic diseases

Hemorrhagic (Blood loss) anemia

▪ Anemia due to hemorrhage▪ Acute or chronic▪ normocytic, normochromic▪ plasma replaces in 1 to 3 days▪ RBC replacement takes 3 to 6 weeks▪ In chronic blood loss, microcytic,

hypochromic

Hemolytic anemia

Occurs due to excess destruction of RBC

▪ Congenital or acquired defect in RBC shape

▪ Liver failure▪ Renal disorder▪ Hypersplenism▪ Burns▪ Infections..malaria, septicemia▪ Agglutinins

➢ Sickle cell anemia

➢ Hereditary spherocytosis

➢ Erythroblastosis fetalis

Examples of hemolytic anemia

Nutritional deficiency anemia

▪ Iron deficiency

▪ Protein deficiency

▪ Vitamin B12 Deficiency

▪ Folic acid deficiency

Iron deficiency anemia

Due to iron deficiency; -in diet-or defect in absorption

RBCs are microcytic and hypochromic

Megaloblastic anemiaLoss of any one of :

Vitamin B12Folic acidIntrinsic factor

Effects: ▪ Slow reproduction of erythroblasts in

bone marrow▪ RBCs grow too large with odd shapes

called megaloblasts▪ Cannot proliferate rapidly to form

normal count

▪ RBCs are oversized, bizarre shapedfragile membranes so rupture easily

Pernicious anemia

➢ The atrophy of stomach mucosa leads to deficiency of vitamin B12 because of lack of intrinsic factor in gastric secretions.

➢ It is one form of megaloblastic anemia

➢ B12 deficiency leads to neurological symptoms

Aplastic anemia

Lack of functioning bone marrow.

▪ Excessive X- ray treatment▪ Gamma ray radiation ▪ Industrial chemicals , insecticides,

benzene in gasoline▪ Drugs , chemotherapy for cancer▪ Autoimmune disorders like lupus

erythematosus

Anemia of chronic disease

Characterized by short life span of redcells caused by

- Disturbance in iron metabolism- Resistance to erythropoietin action

▪ Inflammatory diseases - rheumatoidarthritis

▪ Chronic infections- tuberculosis▪ Cancers of lung and breast

Effects of anemia

Cardiovascular system:

Decreased viscosity of blood

Decreased resistance to flow

Increased blood flow

Increased cardiac output

Peripheralvasodilation due to hypoxia

Clinical features of anemia

Polycythemia

The increase in red blood cell count is

called polycythemia.

PrimaryPolycythemia vera

SecondaryPhysiologicalPathological

Polycythemia vera (Erythremia)

Cause: ▪ Genetic aberration in the hemocytoblasic

cells that produce blood cells▪ No longer stop producing cells even in

excess RBC▪ RBC count: 7 to 8 million/mm3

➢ Increased hematocrit, Increased blood volume

➢ Increased viscosity cause plugging of capillaries ..10 times more viscosity than water

➢ Excess production of WBCs and platelets

Physiological polycythemia

▪ In natives of 14,000 to 17,000 feet due to low atmospheric oxygen

▪ Blood count 6 to 7 millions/mm3

▪ Allow the people to perform high levels of continuous work in unfavorable environment

Secondary polycythemia

▪ Respiratory disorders like emphysema

▪ Chronic carbon monoxide poisoning

▪ Poisoning by chemicals

Effects of polycythemia

▪ Increased viscosity, sluggish blood flow, Decreased venous return but more blood volume - cardiac output almost normal

▪ Blood pressure almost normal

▪ Subpapillary venous plexus gives color to skin ruddy complexion with

bluish tint

PolycythemiaThree Pathophysiological Categories of Polycythemia

1.Relative Polycythemia (Red Blood Cell Mass Normal, Plasma Volume Decreased)

2.Secondary Polycythemia (Red Blood Cell Mass Increased)

3.Polycythemia vera (Red Blood Cell Mass Increased)

Polycythemia

Vera

Secondary Polycythemia

Pathophysiology Stem Cell

Disorder

Tissue hypoxia increasing EPO

production or due to renal or

hepatic disease causing

inappropriate increase in EPO

production

CBC Hct and often

WBC and

platelets are

increased

Only Hct is increased

EPO level Decreased or low

normal

Normal or increased

Treatment Phlebotomy Treatment not required

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