Lecture 13 10/21/24

Question 1

What are the predisposing factors for bacterial pneumonia?

Answer 1

-viral resp. diseases
-athletic events
-recent long trailer rides
-immunologic compromise
-anesthesia
-pharyngeal/laryngeal dysfunction
-esophageal obstruction
-EIPH

Question 2

When does bacterial pneumonia occur?

Answer 2

-when bacteria are aspirated
-when bacterial infection is secondary to viral disease

Question 3

Which gram-pos. species are associated with bacterial pneumonia?

Answer 3

-Strep. zooepidemicus
-Strep. pneumoniae
-Staph. aureus

Question 4

Which gram-neg. species are associated with bacterial pneumonia?

Answer 4

E. coli
-Klebsiella pneumoniae
-Pasteurella spp.
-Actinobacillus spp.

Question 5

Which anaerobes are associated with bacterial pneumonia?

Answer 5

-Clostridium
-Fusobacterium
-Bacteroides fragilis

Question 6

What are the clinical signs of bacterial pneumonia?

Answer 6

-fever
-depression
-anorexia
-exercise intolerance
-tracheal sounds
-coughing
-nasal discharge
-resp distress
-weight loss

Question 7

What sounds can be heard on auscultation in bacterial pneumonia patients?

Answer 7

-crackles/alveoli snapping open
-wheezes/air passing over fluid
-absence of breath sounds

Question 8

What clinical pathology data is associated with bacterial pneumonia?

Answer 8

-hyperfibrinogenemia
-neutrophilia +/- left shift
-neutropenia in gram-neg infections
-hyperglobulinemia

Question 9

What changes on blood gas are seen with bacterial pneumonia?

Answer 9

-low pH/acidosis
-low pO2/hypoxia
-increased pCO2/resp. acidosis
-potentially increased pHCO3/metabolic alkalosis (compensatory)

Question 10

Which procedures are used to diagnose bacterial pneumonia?

Answer 10

-endoscopic examination
-transtracheal wash/bronchoalveolar lavage
-cytology and culture

Question 11

What changes can be seen on radiographs with bacterial pneumonia?

Answer 11

-increased bronchial and/or interstitial patterns
-air bronchograms

Question 12

What findings on ultrasound can be indicative of bacterial pneumonia?

Answer 12

-comet tails
-abscesses
-consolidation
-hepatisation
-pleural fluid

Question 13

What are the types of treatment for bacterial pneumonia?

Answer 13

-primary: directed at causative agent
-secondary: directed at response to causative agent
-supportive: directed at total patient

Question 14

What is the primary treatment for bacterial pneumonia?

Answer 14

-antimicrobial therapy
-based on culture/sensitivity, knowledge of common organisms, or trial and error

Question 15

What must be considered when using antibiotics for bacterial pneumonia treatment?

Answer 15

-dose, duration, interval, and route
-continue treatment until symptoms attenuate for 7-10 days
-understand common microbial agents
-broad vs narrow spectrum
-adverse side effects of the drugs
-frequently monitoring clinical signs

Question 16

Which antibiotics are first choice for bacterial pneumonia and used in a hospital setting?

Answer 16

-aminoglycosides
-beta-lactams
-cephalosporins

Question 17

Which antibiotics are second choice for bacterial pneumonia and used for at home therapy?

Answer 17

-tetracyclines
-potentiated sulfonamides

Question 18

Which antibiotics are the “big guns” for bacterial pneumonia treatment?

Answer 18

-fluoroquinolones
-macrolides
-chloramphenicol

Question 19

Which antibiotic is used for anaerobic bacterial pneumonia?

Answer 19

metronidazole

Question 20

When should antibiotic therapy be changed?

Answer 20

-temp. spikes after 24-48 hours
-no improvement in clinical signs
-adverse side effects occur
-lab support indicates resistance

Question 21

What are the goals of secondary treatment for bacterial pneumonia?

Answer 21

-reduce/eliminate airway obstruction
-reduce/eliminate undesirable inflammatory reaction
-improve alveolar-vascular oxygen exchange
-provide immune enhancement

Question 22

What are the components of secondary treatment for bacterial pneumonia?

Answer 22

-mucolysis and expectoration
-bronchodilation
-copage/breaking up mucus
-anti-inflammatory therapy
-immunologic enhancement
-oxygen therapy via insufflation

Question 23

What are the supportive therapies for bacterial pneumonia?

Answer 23

-rest
-stress reduction
-nutrition
-adequate ventilation
-hydration

Question 24

Which viruses are involved in viral pneumonia?

Answer 24

-EHV1
-EHV4
-EHV5
-equine influenza virus
-equine viral arteritis

Question 25

What are the primary pathogens for fungal pneumonia?

Answer 25

-Blastomyces dermatitidis
-Coccidioides immitis
-Cryptococcus neoformans
-Histoplasma capsulatum
-Aspergillus spp.
-Pneumocystis carinii

Question 26

What is important about Pneumocystis carinii?

Answer 26

it is an opportunist; if it is causing infection, it indicates that there is immune deficiency

Question 27

What are the contributing factors to fungal pneumonia?

Answer 27

-exposure to large numbers of mycotic organisms in environment
-stabling of horses in moist environment
-prolonged administration of antibiotics
-immunosuppression
-neoplasia

Question 28

What are the clinical signs of fungal pneumonia?

Answer 28

-chronic cough
-anorexia and weight loss
-exercise intolerance
-nasal discharge
-non-responsive to antibiotics
-pleural effusion
-tachypnea/resp distress

Question 29

What are the findings on transtracheal wash that indicate fungal pneumonia?

Answer 29

-degenerate neutrophils
-yeast
-bacteria

Question 30

Why must TTW and BAL be interpreted carefully when evaluating for fungal pneumonia?

Answer 30

fungi can be picked up incidentally from the nose and skew results

Question 31

What findings on radiographs can indicate fungal pneumonia?

Answer 31

-circular masses
-accentuated interstitial pattern
-pleural effusion

Question 32

How is fungal pneumonia treated?

Answer 32

months of antifungal medication

Question 33

Which antifungals are used to treat fungal pneumonia?

Answer 33

-amphotericin B
-natamycin
-azoles, but not well absorbed in horses

Question 34

Which parasite is able to cause pneumonia in horses?

Answer 34

Dictyocaulus arnfieldi

Question 35

What are the characteristics of Dictyocaulus arnfieldi?

Answer 35

-donkeys and mules are asymptomatic carriers
-occurs in foals more than adults
-should always ask if horses are housed with donkeys/mules

Question 36

What is the pathogenesis of Dictyocaulus arnfieldi?

Answer 36

-prepatent period of 2-4 months
-can have donkey-horse or horse-horse transmission
-adults live in airways and cause inflammation

Question 37

What must occur in order for horses to acquire Dictyocaulus arnfieldi?

Answer 37

they must be on pasture, since the parasite has environmental requirements

Question 38

How do earthworms contribute to Dictyocaulus arnfieldi spread?

Answer 38

earthworms can ingest the larvae and move across the pasture without harming the larvae

Question 39

How does the fungus Pilobolus contribute to Dictyocaulus arnfieldi spread?

Answer 39

fungus develops on manure piles and disperses the larvae with its spores

Question 40

What are the clinical signs of Dictyocaulus arnfieldi?

Answer 40

-possibly asymptomatic
-chronic cough
-bilateral nasal discharge
-increased resp rate and effort
-crackles and wheezes
-similar signs to asthma

Question 41

How is Dictyocaulus arnfieldi diagnosed?

Answer 41

-TTW/BAL to look for eosinophils
-ID of parasite in sediment of centrifuged mucus
-Baermann fecal exam

Question 42

How is Dictyocaulus arnfieldi treated and prevented?

Answer 42

-ivermectin or moxidectin
-separate horses from donkeys and other known carriers