Anaemia and haemolytic conditions

Question 1

What are the 2 types of haemolysis? What clinical signs are associated with each?

Answer 1

Intravascular haemolysis
* Red blood cell destruction occurs in the blood vessels
◦ Cells that are in circulation are affected
* Associated clinical signs:
◦ Haemoglobinaemia (pink/red plasma)
◦ Haemoglobinuria (pink/red urine)
‣ This is because the available haptoglobin (a protein that binds haemoglobin) becomes saturated so excess haemoglobin starts to be excreted in urine
* Haemoglobinuria + haemoglobinaemia + anaemia = intravascular haemolysis*
*assuming poor sampling technique and poor sample handling both ruled out

Extravascular haemolysis
* Red blood cell destruction occurs outside the blood vessels
◦ Cells that are not in circulation are affected
◦ Spleen, liver and bone marrow

• Associated clinical signs:
  ◦ Jaundice (yellow mucous membrane colour)
  ‣ This is because red blood cell destruction is achieved through phagocytosis by macrophages and haemoglobin is not released into circulation (it remains within the macrophage). After red blood cell destruction, unconjugated bilirubin is released by macrophages and taken up by the liver. When the hepatocyte capacity for this process is exceeded, bilirubin accumulates in plasma and causes yellow discolouration of plasma and tissues.
• Less common than intravascular haemolysis in cattle (cf. other species)

Question 2

What are differentials for blood loss anaemia in cattle?

Answer 2

Question 3

What is the aetiology, clinical signs and diagnostics associated with blood loss anaemia?

Answer 3

Question 4

What are the differential diagnoses for intravascular haemolytic anaemia in cattle?

Answer 4

Question 5

What are the differential diagnoses for intravascular haemolytic anaemia in sheep?

Answer 5

Question 6

Haemolytic anaemia diagnostics

Answer 6

• Blood sample
  ◦ Routine haematology
  ◦ Fresh blood smear – important for blood parasites and rbc morphology
• More specific tests
  ◦ Saline (slide) agglutination test
  ◦ Coombs test
• Biochemistry
  ◦ Helps rule in/out some ddx
  ◦ Bilirubin
• Urinalysis
  ◦ Haemoglobinuria

Question 7

How would you treat intravascular haemolytic anaemia?

Answer 7

• First aid treatment as for blood loss anaemia
  ◦ If underlying cause not treated, haemolysis will continue
• Hypophosphataemia
  ◦ Treat with phosphate supplementation
  ◦ Ensure phosphate content in diet is sufficient
• Clostridium haemolyticum
  ◦ High dose penicillin treatment for affected animals
  ◦ Prognosis can be poor -> consider euthanasia
  ◦ Vaccinate herd/flock for prevention
  ◦ Adopt appropriate liver fluke control programmes
• Copper toxicity
  ◦ Take care with copper supplementation
  ◦ Ensure farmers are aware of all sources of supplementation being provided and that these are cumulative
  ◦ Be especially careful with sheep
  ◦ Do not feed cattle concentrates to sheep -> too high in Cu
• Babesia divergens
  ◦ Blood transfusion often needed
  ◦ Imidocarb dipropionate – very long WDP (milk = 504hrs; meat = 213 days)
  ◦ Tick control
  ◦ Calves < 9-12 months old show resistance -> expose when young to develop immunity

Question 8

How would you treat extravascular haemolytic anaemia?

Answer 8

• First aid treatment as for blood loss anaemia
  ◦ If underlying cause not treated, haemolysis will continue
• More specific treatment, prevention and control depend on underlying cause.
  ◦ If IMHA present -> steroids
• Neonatal isoerythrolysis in lambs
  ◦ Do not feed bovine colostrum to lambs
• Mycoplasmas
  ◦ Appropriate antibiotics - Oxytetracycline
  ◦ Consider euthanasia because can become chronic carriers

Question 9

What are differentials for haematuria?

Answer 9

• Haematuria is not very common in cattle or sheep.
• A cause that might affect several cattle in a herd is bracken toxicity- enzootic haematuria
  ◦ This affects sheep to a lesser extent than cattle
• Other causes (affecting individuals rather than groups):
  ◦ Pyelonephritis
  ◦ Urogenital tract trauma (e.g. after calving/lambing).