Haematology 3

Question 1

ANAEMIAS OF DECREASED RED CELL PRODUCTION

Answer 1

NON REGENERATIVE.
Can be PRIMARY- hypoplastic/aplastic.
SECONDARY- nutritional deficiency
- inflammatory disease
- chronic renal failure

Question 2

NUTRITIONAL DEFICIENCY ANAEMIA

Answer 2

eg. protein deficiency- starvation.
-Mineral deficiencies- iron, copper, cobalt.
-Vitamin deficiency- B12, folate.
The above SELDOM cause anaemia in domestic species, APART FROM IRON.

Question 3

IRON DEFICIENCY ANAEMIA

Answer 3

Seen in veterinary medicine.
Iron is an essential component of haem.
-> iron deficiency interferes with Hb production.
HYPOCHROMIC MICROCYTES are produced.

CAUSES- Decreased iron intake (eg. fast growing large breed puppies, suckling piglets)
- Chronic blood loss (eg. GI ulceration/neoplasia, inflammatory GI disease, parasites, clotting disorders)

Question 4

HYPOCHROMIC MICROCYTES

Answer 4

Small cells (microcytes) with large areas of central pallor due to decreased Hb concentration and thus decreased staining abilities (hypochromic)

Question 5

ANAEMIA OF INFLAMMATION

Answer 5

A mild to moderate NON REGENERATIVE anaemia.
may be due to a longstanding process- infectious, malignant or other.
FUNCTIONAL iron deficiency (to inhibit bacteria etc)

Some cytokines may inhibit erythropoeitin production, or bone marrow progenitor cells directly.

Question 6

ANAEMIA SECONDARY TO RENAL DISEASE

Answer 6

Functional marrow failure is caused by decreased EPO levels (non functioning kidneys cannot produce EPO)
There are other potential factors- anaemia of inflammation.
-Uraemic toxins affect red blood cells and bone marrow.
NORMOCYTIC NORMOCHROMIC ANAEMIA- Cells are of normal size and normal colour; they contain normal levels of HB, there are just fewer of them due to decreased production.

Question 7

PRIMARY HYPOPLASTIC/APLASTIC ANAEMIAS

Answer 7

Caused by primary marrow dysfunction- CELLULARITY OF BONE MARROW IS DECREASED.
May involve multiple cell lines (erythrocyte, granulocytes, platelets)- APLASTIC.
Or, may only affect red cell line- PURE RED CELL APLASIA.

Question 8

PURE RED CELL APLASIA

Answer 8

Only red cell line is affected. 
Causes:
-Immune mediated
-Infectious
-Vaccine related
-EPO replacement therapy
-Pre-leukaemic conditions.

Question 9

CLASSIC APLASTIC ANAEMIA

Answer 9

Affects several cell lines. 
Causes:
-Idiopathic
-Drugs, chemicals
-Radiation
-Infectious agents.
PANCYTOPAENIA develops- reduction/absence of ALL cell lines.

Question 10

PANCYTOPAENIA

Answer 10

Reduction or absence of all cell lines.
Development is usually gradual, starting with cells with shorter lifespans.
(granulocytes first, platelets, then erythrocytes.
SELECTIVE DEPRESSION of one or two lineages may occur.

eg. Bracken poisoning in cattle.
Oestrogen, sulphadiazine.
Ehrlichia, parvovirus, FeLV
Bleeding calf syndrome (newly recognised)

Question 11

POLYCYTHAEMIA/ERYTHROCYTOSIS

Answer 11

An abnormally increased red cell mass:
-Increased red cells
-Increased haematocrit/PCV
-Increased Hb. 
Like the opposite of anaemia!

Can be absolute or relative.
ABSOLUTE polycythaemias can be PRIMARY or SECONDARY.

Question 12

PRIMARY ABSOLUTE POLYCYTHAEMIA

Answer 12

NOT controlled by EPO. 
aka. POLYCYTHAEMIA VERA. 
Uncontrolled expansion of red cell mass. 
Chronic myeloproliferative disorder. 
Rare in animals.

Question 13

SECONDARY ABSOLUTE POLYCYTHAEMIA

Answer 13

IS controlled by EPO.

Excess EPO production is seen; this can be APPROPRIATE or INAPPROPRIATE.

Question 14

RELATIVE POLYCYTHAEMIA

Answer 14

MOST COMMON FORM OF POLYCYTHAEMIA.
Increased RBCs/PCV/HB concentration seen due to DECREASED PLASMA VOLUME.
eg. due to dehydration.

or seen due to SPLENIC CONTRACTION in exciteable/stressed animals (dogs and horses only).
This form is TRANSIENT.

Question 15

EXCESS EPO PRODUCTION

Answer 15

Seen in secondary absolute polycythaemia.

Question 16

APPROPRIATE EXCESS EPO PRODUCTION

Answer 16

Hypoxia is fundamental stimulus to EPO production and thus erythropoeisis.
Causes of chronic hypoxia include- CV disease
- Chronic respiratory disease.

Question 17

INAPPROPRIATE EXCESS EPO PRODUCTION

Answer 17

Seen in kidney neoplasms or non-neoplastic disorders (eg. cysts), and in other, NON RENAL neoplasms.

Question 18

POLYCYTHAEMIA CLINICAL SIGNS

Answer 18

RELATIVE- signs of dehydration (tacky mucous membranes, sunken eyes, increased skin tent).

ABSOLUTE- neurological (hyperviscosity of blood)

• Weakness
• Cyanosis/hyperaemia
• Signs attributed to underlying process if secondary absolute polycythaemia eg. chronic lung disease etc.