Lecture 12 10/21/24 Flashcards
Which resp. viruses are of concern in equine?
-influenza
-EHV
-EVA (equine viral arteritis)
-rhinovirus
What are the clinical signs of viral resp. disease in equine?
-high fever (most common)
-dry cough
-submandibular lymphadenopathy
-serous nasal discharge
-rapid spread among susceptible animals
-anorexia and depression
-secondary pneumonia
How are resp. viruses diagnosed in equine?
-history/clinical signs
-CBC with leukopenia, lymphopenia, and anemia
-PCR
-virus isolation
-antibody detection
How are resp. viruses treated?
-clean, well ventilated, stress-free environments
-monitor for secondary bact. infections
-NSAIDs
-antiviral drugs
-rest
Which complications can arise from resp. viruses?
-bact. infections
-pneumonia
-predispose horse to asthma/EIPH
-pleuritis/bronchitis/sinusitis/pharyngitis
-laryngeal hemiplegia
-pharyngeal collapse
-soft palate paresis
How is influenza virus prevented?
-intranasal or IM vx every six months
-vx booster 1-2 weeks before potential exposure
How is equine herpesvirus prevented?
IM vaccine every six months against the 1 and 4 strains
How is equine viral arteritis prevented?
-identification of carrier stallions
-vx of females prior to breeding
How is rhinovirus prevented?
IM vx annually
What are the steps to physical exam when wanting to evaluate the lower resp tract?
-observation from a distance
-close up examination
-auscultation of lung fields at rest
-rebreathing exam
-percussion
What is epistaxis?
blood at the external nares
What is exercise induced pulmonary hemorrhage?
strenuous exercise associated with exudation of red blood cells from the pulmonary vasculature into the alveoli and airways of the caudodorsal lung segments
Where can epistaxis originate?
-nasal cavity
-paranasal sinuses
-guttural pouch
-pharynx
-larynx
-oral cavity
-lungs
What are the differentials for epistaxis?
-nasal trauma
-ethmoid hematoma
-guttural pouch mycosis
-chronic pulmonary disease
-upper resp tract neoplasia
-thrombocytopenia
-pulmonary hemorrhage
What are the differentials for pulmonary hemorrhage?
-EIPH
-pulmonary abscess
-fungal granuloma
-trauma
-pneumonia
-foreign body
-neoplasia
What is the epidemiology of exercise induced pulmonary hemorrhage?
-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
What is pathogenesis mechanism #1 for EIPH?
-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
What is pathogenesis mechanism #2 for EIPH?
-visceral constraint of diaphragm
-increased mechanical forces develop in dorsal thorax
-parenchymal tearing
-rupture of capillaries during inspiration
-hemorrhage occurs
What is pathogenesis mechanism #3 for EIPH?
-pulmonary hypertension leads to high CO, lack of pulmonary vasodilation, and increased blood viscosity during exercise
-stress failure of the pulmonary capillaries
-hemorrhage occurs
What can lead to rupture of the alveolar capillaries?
-ventilation abnormalities caused by small airway disease
-mechanical constraints of abdominal viscera placed on dorsocaudal lung field
-stress failure of the pulmonary capillaries
What are the clinical signs of exercise induced pulmonary hemorrhage?
-epistaxis following exercise
-exercise intolerance (may be minor)
-repeated swallowing during exercise
-labored breathing
-post exercise coughing
-may present with no clinical signs
How is EIPH diagnosed?
-history and clinical signs
-endoscopic examination within 90 minutes of racing
-bronchoalveolar lavage
-transtracheal wash
-radiography
What findings on bronchoalveolar lavage are consistent with EIPH?
-hemosiderophages***
-erythrocytes
-intact/degranulating neutrophils
-intracellular bacteria
What is the treatment for EIPH?
-antibiotics following severe hemorrhage to prevent secondary infection
-rest
-potentially hyperbaric oxygen
How is EIPH prevented?
-prevention, management, and treatment of small airway disease
-appropriate rest following episodes
-nasal strips
-lasix
What are the characteristics of lasix use in EIPH?
-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
What is the mechanism of lasix?
-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
What is the severity of EIPH associated with?
-reduced probability of winning
-slower horse speed
-greater length behind winner
-less career earnings
How does EIPH grade effect performance?
-grades 1-3 had moderate evidence that they do not shorten a career
-grade 4 has evidence that it does shorten a career
