PRACTICAL: Diagnostic techniques

Question 1

Define NAD

Answer 1

No appreciable disease

Question 2

What questions to ask a horse owner if horse has respiratory problem?

Answer 2

• Age, breed
• Management
• Worming
• Vaccination status
• What the owner perceives the problem to be
• How long has it been present
• Is it getting worse or better?
• When does it occur e.g. at rest, exercise, in stable?
• Any associated exercise intolerance?
• Has the horse received any treatment yet?
• Has the horse had this problem before?
• Any other horses on the yard affected?

Question 3

What are the components of a respiratory system exam? 7

Answer 3

• TPR
• Airflow from each nostril
• Facial symmetry
• Submandibular and retropharyngeal LNs
• Palpate larynx
• Auscultate lungs
• Look at breathing pattern/effort

Question 4

Components of CVS exam - 5

Answer 4

• TPR (already done)
• MMs and CRT
• Peripheral pulse – facial or transverse facial
• Jugular pulse height and refill time
• Cardiac auscultation

Question 5

If a cough was due to URT disease what else woul dyou not?

Answer 5

other URT abnormalities on PE (if not then likely to be LRT problem)

Question 6

How can you sample the LRT?

Answer 6

• BALV

- Transtracheal aspirate (via endoscope - most commonly)

Question 7

T/F: All causes of noise at exercise are URT in origin.

Answer 7

True

Question 8

Most common cuases of noise at exercise (adult horses)

Answer 8

• DDSP
• RLN
• Epiglottic entrapment

Question 9

How can you rule out IAD?

Answer 9

tracheal aspirate via endoscope - to rule in or out concurrent subclinical LRT inflammation

Question 10

Dictyocaulus arnfieldi can cause respiratory disease - how can it be killed?

Answer 10

Horses should be given ivermectin every 8 weeks and moxidectin every 12 weeks

Question 11

Why isn’t equine influenza vaccine 100% effective? 3

Answer 11

• antigenic drift
• individual response to vaccine
• short duration of immunity to vaccine in young horses (3-5 months)

Question 12

How big are the submandibular LNs in a normal horse?

Answer 12

broad bean sized (pinch between mandibles at level where caudal headcollar strap lies, if you can’t find them, they are probably normal)

Question 13

When are the retropharyngeal LNs palpable?

Answer 13

above larynx only when enlarged

Question 14

What does asymmetry of the dorsal aspect of the larynx suggest?

Answer 14

muscle atrophy as found in laryngeal hemiplegia (but this is difficult to determine)

Question 15

How sensitive is lung auscultation in detecting lung pathology?

Answer 15

not very sensitive (fat, hairy animals - often no sound heard) IF normal sounds are heard, this doesn’t rule out pathology of lungs.

Question 16

What do Kirschmann spirals indicate?

Answer 16

chronic inflammation

Question 17

What do preserved neutrophils indicate?

Answer 17

active inflammation

Question 18

Describe appearance of mast cells

Answer 18

• smaller than macrophages
• doesn’t have foamy cytoplasm (unlike macrophages)
• bilobed kidney shaped nucleus
• small numbers (<10%) present in normal equine airway

Question 19

Describe the cells in a normal equine tracheal lavage

Answer 19

• usually 80% cells are macrophages and lymphocytes (split in equal numbers)
• normally <10%) mast cells
• ciliated columnar epithelium are a normal finding (dislodged during lavage)

Question 20

What does a tracheal aspirate smear that is densely cellular with a pink background suggest?

Answer 20

abnormal