Immune Mediated Diseases

Question 1

Acquired causes of immunodeficiency

Answer 1

Failure of passive transfer
Chronic infections e.g. FIV
Inflammatory or neoplastic disease
Drugs
Malnutrition
Toxins
Stress

Question 2

Major haemolymphatic immune mediated diseases (3)

Answer 2

Immune mediated haemolytic anaemia/IMHA
Immune mediated thrombocytopaenia/IMTP
Immune mediated neutropenia (rare)

Question 3

Major endocrine immune mediated diseases (2)

Answer 3

Hypothyroidism
Hypoadrenocorticism

Question 4

Major cutaneous immune mediated diseases (3)

Answer 4

Canine dermatomyositis
Discoid lupus erythematosus
Pemphigus-pemphigoid complex

Question 5

Major NMSK immune mediated diseases (3)

Answer 5

Polyarthritis (erosive and non-erosive)
Myasthenia gravis
Polymyositis/polyneuritis

Question 6

Major CNS immune mediated diseases (2)

Answer 6

Meningitis of unknown origin/MUO
Granulomatous meningoencephalitis/GME

Question 7

Major gastrointestinal immune mediated diseases (2)

Answer 7

Inflammatory bowel disease/chronic enteropathy
Pancreatitis

Question 8

Major renal immune mediated diseases

Answer 8

Glomerulonephropathies (there are many)

Question 9

Major immune mediated disease with multi-systemic involvement (1)

Answer 9

Systemic lupus erythematosus/SLE

Question 10

Hypersensitivity reaction involved in IMHA/IMTP

Answer 10

Type 2 (antibody mediated)

Question 11

Is immune mediated disease more common in cats or dogs?

Answer 11

Cats

Question 12

Infectious causes of secondary IMHA (5)

Answer 12

Mycoplasma haemofelis
Babesia canis
FIP
FeLV
Chronic bacterial infection

Question 13

What disease is administration of TMPS (antibiotic) and methimazole (hyperthyroid medication) a trigger for?

Answer 13

Secondary IMHA

Question 14

Neoplastic cause of secondary IMHA

Answer 14

Splenic haemangiosarcoma

Question 15

What disease can be caused by a snake bite or bee trigger?

Answer 15

Secondary IMHA

Question 16

Clinical signs of IMHA

Answer 16

Hepatomegaly
Jaundice
Anaemia

Question 17

What is a marker of IMHA in a blood smear?

Answer 17

Spherocytes (also present after a blood transfusion)
Small, densely staining RBCs that lack central pallor

Question 18

How do you distinguish rouleaux formation from agglutination?

Answer 18

Auto-agglutination test

Question 19

Haematology findings in IMHA

Answer 19

Low PCV (<20%)
Moderate to marked anaemia (regenerative response depends on magnitude, if presented early may be pre-regenerative)

Question 20

Is there a left shift in IMHA?

Answer 20

Yes

Question 21

Role of Coombe’s test in IMHA and which test tube should be used?

Answer 21

Identifies antibody on the surface of red blood cells, useful if no autoagglutination/spherocytes/regenerative anaemia
EDTA

Question 22

What is commonly seen on urinalysis in IMHA?

Answer 22

Signs consistent with bilirubinuria or haemoglobinuria

Question 23

Why should a urine sediment analysis and culture be done for animals with suspected/confirmed IMHA?

Answer 23

In case UTI is a trigger

Question 24

What are two important diagnostic steps to rule out trigger factors in IMHA?

Answer 24

Diagnostic imaging (thoracic and abdominal radiography/ultrasound)
Infectious diseases screening (travel history?)

Question 25

Two major focus points in treatment of IMHA

Answer 25

Treat underlying disease (ensure no infectious causes before immunosuppression) Immunosuppression (glucocorticoids, azathioprine, mycophenolate mofetil, cyclosporin, leflunomide)

Question 26

What is the main risk of death in IMHA and how should you prevent it?

Answer 26

Thromboembolic disease

Question 27

Signalment in IMHA

Answer 27

Young to middle aged dogs Inherited predisposition in cocker spaniels, springer spaniels and poodles

Question 28

Signalment in primary IMTP

Answer 28

Middle aged female dogs Cocker spaniels, Old English sheepdogs, GSDs and poodles

Question 29

Pathophysiology of secondary IMTP

Answer 29

Antibodies target non-self antigens absorbed onto surface of platelets or immune complexes bound to platelets

Question 30

Clinical signs of IMTP

Answer 30

Petechiae Ecchymoses Haematomas Epistaxis Gingival bleeding Malaena/haematochezia from GIT bleeding Retinal haemorrhage/hyphaema/anterior uveitis

Question 31

Laboratory findings in IMTP

Answer 31

Low platelet count (automated or manual, check for clumping) Biochemistry profiles and coagulation tests often normal Concurrent anaemia/other cell line reductions could indicate bone marrow disease

Question 32

What infectious disease is shown here that is causing secondary IMTP?

Answer 32

Leishamiasis

Question 33

What infectious disease is shown here that is causing secondary IMTP?

Answer 33

Babesia

Question 34

On a blood smear, below which value of platelets in one view would you suspect IMTP?

Answer 34

5

Question 35

Acute treatment of IMTP

Answer 35

Transfusion to improve oxygen delivery if clinical signs indicate

Question 36

Long term treatment of IMTP

Answer 36

Immunosuppression with prednisolone initially Ideally move onto azathioprine, cyclosporine or mycophenolate mofetil

Question 37

Causes of death in IMTP

Answer 37

Severe life threatening haemorrhage (could be in GI tract so look for malaena) Small but catastrophic breed (CNS/lung)

Question 38

First coagulation parameter affected by warfarin

Answer 38

Prolonged prothrombin time (PT)