pathological condition of haematopoietic system. Helpful for veterinary science students, veterinarians and pathologists.

1. By-
Dr Abhijeet Anan Panda
M.V.Sc, Veterinary pathology

2. Definition:-
 Anemia is defined as the reduction in the quality and
or number of erythrocytes below normal for that
particular age, species, breed and geographic location.

3. Clinical signs
 Depends on the degree of anemia, the duration and the
underlying cause.
 In acute blood loss, the animal usually presents with
tachycardia, pale mucous membranes, bounding or weak
peripheral pulses and hypotension. If hemolysis is present,
the animal may be icteric. Animals with chronic anemia
have had time to accommodate, and their clinical
presentation is usually more indolent with vague signs of
lethargy, weakness, and anorexia.
 Splenomegaly, abdominal distention, and/or heart
murmur may be present, depending on the underlying
cause of anemia.

4. Pale oral mucous
membrane
Pale ocular
mucous membrane
Icteric mucous
membrane

5.  ‘Anaemia’ can be conveniently grouped
as :-
 Production low, but destruction normal-
i)Dyshemopoietic anemias
 Production normal but destruction excessive -
i)Hemolytic anemias
ii) Hemorrhagic anemias

6. Dyshemopoietic anaemias
 Anaemies in which there is defect in the formation of
erythrocytes
 The defect may lie in the formation of stroma protein
or in the formation of Hb etc.
 Porphyrinopathies : Porphyrins are necessary for the
normal synthesis of heme. If certain enzymes are
lacking, then heme is not synthesized.

7. A. Diminished stroma protein formation
 Blood picture- macrocytic and normochromic or hypochromic.
 Bone marrow is megaloblastic showing numerous megaloblasts
and giant metamyelocytes.
 Dietetic deficiency of Extrinsic factor: Cobalt-cyanocobalamine
 Dietetic deficiency of Folic acid
 Deficiency of the intrinsic factor ( an enzyme secreted by gastric
mucosa)
 Failure to store the Erythrocyte Maturation Factor
 Failure to use the Erythrocyte Maturation Factor
 Hypopituitarism

8. B. Diminished hemoglobin formation:
 Blood picture- normocytic or microcytic and hypochromic.
 Dietetic deficiency of iron: can occur due to
i) Deficient intake
ii) Detective absorption
 Dietetic deficieney of copper
 Dietetic defciency of ascorbic acid
 Dietetic deficiency of pyrydoxine or nicotinic acid or
riboflavin
 Deficiency of Thyroxine

9. C. Toxic inhibition
 Blood picture- normochromic and microcytic
 Chemical Poisons: Nitrogen mustard, Folic acidd
antagonists, Streptomycin, chloromycetin Metals like
Bismuth, Arsenic and Gold, Benzol, hair dyes, insecticides.
 Chronic interstitial Nephritis
 Oesophagastomiasis
 chronic infections like Tuberculosis, Brucellosis and
Rheumatic fever
 Ionising radiation

10. D. Aplastic anemia:
 Blood picture- normochromic and normocytic
 This occurs due to aplasia of bone marrow where there is
utter inactivity
 Classification-
 i) Primary or idiopathic : rather rare.
 ii) Secondary
 A) exhaaustion- chronic haemorrhages due to GI parasites,
neoplasm, vit C & K deficiency
 B) Toxic – radiation, chemical poisoning
 C) metabolic- in sows suffering from protein malnutrition
during pregnancy

11. E. Myelophthisic anemia:
 There is replacement of bone marrow by other tissues.
 Since in this disease immature forms of granulocytes are found
in the peripheral blood, it is also known as leuco-erythroblastic
anemia. This condition is found in-
1. Secondary metastasis of other tumors- lymphatic leukemia in
dog and cat.
2. Osteodystrophies- where the myeloid tissue is replaced by
connective tissue
3. Primary tumors of the reticulo-endothelial system- Nieman-
Pick Disease , Hodgkin’s Disease etc.

12. HEMOLYTIC ANEMIAS
 In this condition intravascular destruction of erythrocytes
occurs.
 Anemia is normochromic and macrocytic becoming
hypochromic and microcytic as the iron Stores are used up
 Causes-
 1) Abnormal auto-antibodies the presence of which may be
 A. Primary or idiopathic. or
 B. Secondary due to
i) Malignant disease-lymphatic neoplasms; ovarian tumors,
Gastro-intestinal carcinoma.
ii) Collagen diseases- disseminated lupus erythematosis.
iii) Viral disease - infectious mononucleosis

13.  2. Abnormal iso-antibodies: Due to the presence of
hemolysins in the plasma which is produced by
 A) incompatible blood transfusion
 B) injection of blood products
 C) pregnancy- blood group antigens of the foetus pass to the
dam which does not possess these antigens.
 3. Toxic
 A) Chemicals:
 i) Copper poisoning
 ii) Onion poisoning
 iii) Poisoning by castor seeds
 iv) Phenothiazine poisoning
 v) Naphthalene poisoning
 vi) lead poisoning
 vii) Hypersensitivity to certain drugs like sulphanilamide,
quinine etc
 viii) snake venom

14.  B) Post-parturient hemoglobinuria
 C) infection
a) Protozoa- Anaplasmosis, Babesiosis, Ehrlichia canis.
b) Bacteria- Leptospira, Clostridia, Streptococci and
Staphylococci.
c)Viruses -Equine infectious anemia, feline infectious
anemia.
 D. Hypersplenism
 E. Cold hemoglobinuria in calves

15. HEMORRHAGIC ANEMIAS
 In this condition extravascular destruction of
erythrocytes occurs.
 The types are determined by
 l. the amount of blood lost.
 2. the rate at which the blood is lost
 3. the diet controlling the balance between blood loss
and production

16.  A. Acute haemorrhagic anaemia
 Injury
 sweet clover poisoning
 Warfarin poisoning
 bracken fern poisoning.
 B. Chronic hemorrhagic anemia
 blood sucking worms; Hemonchus, Fasciola ,
Bunostomum. in cattle and sheep, Strongyles in horses,
Ancylostomes in dogs.
 Ectoparasites - ticks, lice and fleas
 Protozoa- Coccidiosis in dogs
 Hemorrhagic diseases- Chronic bovine hematuria

17.  C. Purpura and hemorrahagic diseases
 Purpura is accumulation of blood, under the skin due to
spontaneous rupture of the capillaries.
 1. Vascular disorders ;
i. Purpuric infections : This is found in various diseases
characterised by petechial hemorrhages . eg. Hemorrhagic
septicemia, Anthrax etc. The Cause is injury to the capillaries
and venules by the toxins. In viremic diseases endothelium is
directly damaged due to the multiplication of the virus in the
endothelial cells eg. Infectious canine hepatitis and hog
cholera
ii. Allergic purpura or purpura hemorrhagica : -This is a
symptom of post-infectious toxemia as in Strangles, fistulous
withers, poll evil and emphysema of guttural pouches.

18.  iii. Congenital purpura: Purpura may develop in the foetus.
The mechanism is suggested to be similar to the one found
in erythroblastosis foetalis. lso-agglminins formed
against platelets in the mother pass into the foetus via
placenta and produce thrombocytopenia.
iv. Senile purpura: in human beings
v. Vitamin C deficiency : Hemorrhages occur due to
increased capillary permeability and capillary
fragility since cement substance of capillary wall is not
synthesized. However this condition may not be met with
in animals since vitamin C is synthesized in their gut.

19.  2. Impaired Clotting mechanism:
a) Thrombocytopenia
b) haemophilia
c)prothrombin deficiency due to liver diseases,
Deficiency of Vit K, Impaired absorption of Vitamin K,
Poisoning by dieoumarin and Warfarin
d) Presence of Circulating anticoagulants
3) Mouldy corn poisoning in cattle and swine
4) Epistaxis in horse