Lecture 12 10/21/24

Question 1

Which resp. viruses are of concern in equine?

Answer 1

-influenza
-EHV
-EVA (equine viral arteritis)
-rhinovirus

Question 2

What are the clinical signs of viral resp. disease in equine?

Answer 2

-high fever (most common)
-dry cough
-submandibular lymphadenopathy
-serous nasal discharge
-rapid spread among susceptible animals
-anorexia and depression
-secondary pneumonia

Question 3

How are resp. viruses diagnosed in equine?

Answer 3

-history/clinical signs
-CBC with leukopenia, lymphopenia, and anemia
-PCR
-virus isolation
-antibody detection

Question 4

How are resp. viruses treated?

Answer 4

-clean, well ventilated, stress-free environments
-monitor for secondary bact. infections
-NSAIDs
-antiviral drugs
-rest

Question 5

Which complications can arise from resp. viruses?

Answer 5

-bact. infections
-pneumonia
-predispose horse to asthma/EIPH
-pleuritis/bronchitis/sinusitis/pharyngitis
-laryngeal hemiplegia
-pharyngeal collapse
-soft palate paresis

Question 6

How is influenza virus prevented?

Answer 6

-intranasal or IM vx every six months
-vx booster 1-2 weeks before potential exposure

Question 7

How is equine herpesvirus prevented?

Answer 7

IM vaccine every six months against the 1 and 4 strains

Question 8

How is equine viral arteritis prevented?

Answer 8

-identification of carrier stallions
-vx of females prior to breeding

Question 9

How is rhinovirus prevented?

Answer 9

IM vx annually

Question 10

What are the steps to physical exam when wanting to evaluate the lower resp tract?

Answer 10

-observation from a distance
-close up examination
-auscultation of lung fields at rest
-rebreathing exam
-percussion

Question 11

What is epistaxis?

Answer 11

blood at the external nares

Question 12

What is exercise induced pulmonary hemorrhage?

Answer 12

strenuous exercise associated with exudation of red blood cells from the pulmonary vasculature into the alveoli and airways of the caudodorsal lung segments

Question 13

Where can epistaxis originate?

Answer 13

-nasal cavity
-paranasal sinuses
-guttural pouch
-pharynx
-larynx
-oral cavity
-lungs

Question 14

What are the differentials for epistaxis?

Answer 14

-nasal trauma
-ethmoid hematoma
-guttural pouch mycosis
-chronic pulmonary disease
-upper resp tract neoplasia
-thrombocytopenia
-pulmonary hemorrhage

Question 15

What are the differentials for pulmonary hemorrhage?

Answer 15

-EIPH
-pulmonary abscess
-fungal granuloma
-trauma
-pneumonia
-foreign body
-neoplasia

Question 16

What is the epidemiology of exercise induced pulmonary hemorrhage?

Answer 16

-overall incidence of around 47%
-epistaxis in only 4% of cases
-risk increases with years spent racing
-females at greater risk than males
-steeplechasers at greater risk than flat racers
-seen with shorter races of higher intensity

Question 17

What is pathogenesis mechanism #1 for EIPH?

Answer 17

-mild infectious resp disease, chronic pulmonary disease, or inflammatory airway disease occurs
-intrathoracic airway obstruction leads to negative alveolar pressure
-hemorrhage occurs
**low evidence for this theory

Question 18

What is pathogenesis mechanism #2 for EIPH?

Answer 18

-visceral constraint of diaphragm
-increased mechanical forces develop in dorsal thorax
-parenchymal tearing
-rupture of capillaries during inspiration
-hemorrhage occurs

Question 19

What is pathogenesis mechanism #3 for EIPH?

Answer 19

-pulmonary hypertension leads to high CO, lack of pulmonary vasodilation, and increased blood viscosity during exercise
-stress failure of the pulmonary capillaries
-hemorrhage occurs

Question 20

What can lead to rupture of the alveolar capillaries?

Answer 20

-ventilation abnormalities caused by small airway disease
-mechanical constraints of abdominal viscera placed on dorsocaudal lung field
-stress failure of the pulmonary capillaries

Question 21

What are the clinical signs of exercise induced pulmonary hemorrhage?

Answer 21

-epistaxis following exercise
-exercise intolerance (may be minor)
-repeated swallowing during exercise
-labored breathing
-post exercise coughing
-may present with no clinical signs

Question 22

How is EIPH diagnosed?

Answer 22

-history and clinical signs
-endoscopic examination within 90 minutes of racing
-bronchoalveolar lavage
-transtracheal wash
-radiography

Question 23

What findings on bronchoalveolar lavage are consistent with EIPH?

Answer 23

-hemosiderophages***
-erythrocytes
-intact/degranulating neutrophils
-intracellular bacteria

Question 24

What is the treatment for EIPH?

Answer 24

-antibiotics following severe hemorrhage to prevent secondary infection
-rest
-potentially hyperbaric oxygen

Question 25

How is EIPH prevented?

Answer 25

-prevention, management, and treatment of small airway disease
-appropriate rest following episodes
-nasal strips
-lasix

Question 26

What are the characteristics of lasix use in EIPH?

Answer 26

-furosemide given to racehorses approx. 4 hours prior to race
-must be given by licensed vet
-does not prevent EIPH, but does reduce the incidence and severity

Question 27

What is the mechanism of lasix?

Answer 27

-diuretic
-reduces body weight
-reduces intravascular fluid vol. and pulmonary arterial pressure
-attenuates exercise-induced increases in pulmonary arterial pressure
-decreases incidence of alveolar capillary rupture
-decreases hemmorhage

Question 28

What is the severity of EIPH associated with?

Answer 28

-reduced probability of winning
-slower horse speed
-greater length behind winner
-less career earnings

Question 29

How does EIPH grade effect performance?

Answer 29

-grades 1-3 had moderate evidence that they do not shorten a career
-grade 4 has evidence that it does shorten a career