Diseases of the lymphoid and myeloid systems

Question 1

What are some things that might stimulate the immune system?

Answer 1

• Physiologic leukocytosis (‘fight or flight’)
  ◦ Epinephrine
• Physiologic stress (‘stress leukogram’)
  ◦ Corticosteroid (including exogenous)
• Iatrogenic antigenic stimulation (vaccines)
• Inflammation
• Infection
• Parasites / foreign bodies

Question 2

What response would you see on a leukogram following a fight or flight response lasting approx 30 min?

Answer 2

• mild neutrophilia (mature cells, no left shift)
• lymphocytosis

Question 3

What are the characteristics of a stress leukogram?

Answer 3

• neutrophilia
• lymphopaenia
• monocytosis
• eosinopaenia

Question 4

When might you not see a stress leukogram?

Answer 4

• Imagine you are presented with a very poorly, collapsed dog
• Whilst waiting for biochemistry results, you review the haematology
  ◦ This very sick dog…has no stress leukogram
• This dog may have hypoadrenocorticism (Addisonian crisis)
  ◦ Insufficient cortisol is being produced to stimulate a stress leukogram

Question 5

What are causes of chylous effusions? How is it treated?

Answer 5

• rupture (e.g. trauma) or obstruction (e.g. neoplasia) of thoracic duct or other major lymphatic vessel
• Often idiopathic, site of leak not always determined

ligation of the thoracic duct
◦ will form collateral system
◦ thoracocentesis can be therapeutic as well as diagnostic

Question 6

What’s so bad about mast cell tumours? What breeds are most susceptible?

Answer 6

boxers, labradors, golden retrievers, staffies, boston terriers, pugs

Question 7

How do we grade MCTs?

Answer 7

• Evaluation of proliferative activity per high power field:
  ◦ Mitotic index
  ◦ Multinucleated cells
  ◦ Atypical nuclei (shape and size)
  ◦ Guided by anisokaryosis

Question 8

What are the 2 forms of feline MCTs?

Answer 8

• cutaneous form
• visceral form
  
  • spleen, LN, liver
  • intestine

Question 9

What are the stages of lymphoma?

Answer 9