Anaemia Flashcards
What is blood comprised of and what are their functions?
Plasma - serum and clotting factors.
Serum = water, nutrients, minerals, hormones, gases, antibodies, enzymes, waste.
Cells - erythrocytes, leucocytes, thrombocytes.
What is anaemia?
Decrease in levels of circulating red blood cells, due to increased loss or decreased production of RBCs.
What is regenerative anaemia?
Name an example of the cause.
When new erythrocytes are produced.
(normal erythropoiesis occurs)
Haemorrhage
Haemolysis
What is non-regenerative anaemia?
Name an example of the cause.
No/limited new production of erythrocytes.
(erythropoiesis is reduced)
Viral, neoplastic, CRF, toxins/drugs
What is the aetiology of acute haemorrhage?
Bleeding from damaged tissues.
External haemorrhage – cuts, lacerations, sudden severe epistaxis
Internal haemorhage – post surgical, organ damage eg trauma to liver, spleen, rupture of internal blood vessels post RTA, neoplasia – bleeding tumour tissue
What is the aetiology of chronic haemorrhage?
Chronic GI bleeding – ulcerated or inflamed GI tract, parasites
Chronic urinary bleeding – renal or bladder in origin
Heavy ectoparasite burden
Recurrent epistaxis of a less dramatic nature
What is the pathophysiology of both acute and chronic haemorrhage?
Excessive acute blood loss leads to:
- Decreased blood volume
- Decreased oxygen carrying capacity of blood
- Immature red blood cells released into the circulation
- In chronic haemorrhage there may be secondary iron deficiency anaemia as the body uses up its iron store
What is the aetiology of haemolytic anaemia?
Immune mediated (autoimmune/Hereditary)
Toxaemia (lead, copper, onion, paracetamol)
Some drugs (TMPS, penicillins)
Incompatible blood transfusion
Mycoplasma hemofelis
Babesia canis (Mediterranean)
Possible link to recent vaccination
What is the pathophysiology of haemolytic anaemia?
Destruction of red blood cells by the animals immune system OR due to parasites or toxins eventually leading to reduced circulating red cell volume
Bone marrow attempts to respond producing a regenerative anaemia releasing immature cells from bone marrow
Spherocytes (red cells that have been partially phagocytosed) may be seen in the circulation
In some cases haemolysis may lead to increased bilirubin in the animals blood»_space;> jaundice
What is the aetiology of non-regenerative anaemia?
- Leukaemias, FIV, FeLV
- Lymphosarcoma, myleoma
- Myelofibrosis, myelodysplasia
- Toxaemia, effecting the bone marrow
- Renal failure – decreased erythropoietin production
- Malnutrition – iron deficiency
- Some drugs – stilboestrol, PBZ
- Radiation
What are the clinical signs of general anaemia?
Pale mucous membranes (normal CRT)
Weakness, exercise intolerance
Murmur
Tachycardia
Dyspnoea
Collapse
Inappetent
Petechiation
Haemorrhage
Jaundice ( if haemolysis present the patient may be pale and jaundiced)
What are the diagnostic techniques for anaemia?
- History and clinical signs
- PCV*
- Reticulocyte count*
- MCV, MCHC
- Blood smear - Rbc morphology,* heinz bodies – toxins
- Hb level
- Coomb’s test, Agglutination – to diagnose the presence of IMHA
- Bone marrow biopsy – non-regenerative anaemia
- Test for FeLV, FIV, Mycoplasma, FIA
- Faecal occult blood
What PCV reading would indicate anaemia in a dog?
25%
