Lecture 19: Large Animal Cardiopulmonary Disorders (MacKay)

Question 1

importance of resp. diseases in LA

Answer 1

• 2nd only to MS system in limiting athletic performance of horses
• sig. cause of morbidity and mortality in cattle

Question 2

where is sterdor generated?

Answer 2

nose

Question 3

where is stridor generated?

Answer 3

larynx

Question 4

What should be included in a history of animal with resp distress?

Answer 4

• signalment
• intended use
• nature, duration, and progression of CS
• only 1 animal affected?
• previous tx and response to therapy
• vax history

Question 5

unilateral nasal d/c typical of:

Answer 5

sinus infection

Question 6

bilateral nasal d/c typical of:

Answer 6

pneumonia or guttural pouch issue

Question 7

malodorous nasal discharge assoc. with

Answer 7

gram = bacteria

Question 8

steps of resp. system exam

Answer 8

• observe from distance
• presence of nasal d/c?
• evaluate airflow at nose
• MM and CRT
• palpate larynx/trachea/regional lymph nodes
• percussion of paranasal sinuses
• observe ventral abd, muzzle, and limbs for edema

Question 9

char. of normal bronchovesicular lung sounds

Answer 9

• produced by turbulent air flow in the central airways
• louder ventrally than dorsocaudally
• attenuated by aerated lung parenchyma

Question 10

char. of abnormal (adventitious) lung sounds

Answer 10

• crackles (short, non-musical)
• wheezes (musical, high-pitched)
• friction rubs

Question 11

rebreathing CO2

Answer 11

helps to hear lung sounds

• make horse breathe in bag, and they will breathe deeper
• if takes longer than 6-8 breaths to recover, implies resp. insufficiency

Question 12

percussion use

Answer 12

• delineation of lung boundaries

- identify consolidation, abscesses and pleural effusion

Question 13

structures evaluated in endoscopy

Answer 13

nasal cavities
ethmoid
pharynx
larynx and epiglottis
trachea and bronchi
guttural pouches

Question 14

what do you hit with tube if you accidentally go up middle meatus?

Answer 14

ethmoturbinate

Question 15

rima glottidis

Answer 15

opening to lower airways

Question 16

tube usually goes into which bronchus?

Answer 16

R

Question 17

upper airway rad can visualize what structures?

Answer 17

Head: nasal cavities, sinuses, ethmoid, teeth
Pharynx: epiglottis, soft palate, guttural pouches

Question 18

lower airway rad can visualize what structures?

Answer 18

Lungs: normal/alveolar/interstitial/bronchial/mixed pattern

Heart

Question 19

can you visualize whole lung field on rad in adult horse?

Answer 19

No. Requires about 4 rads on each side!

Question 20

branching of pulmonary vessels over aorta and caudal heart in horses is a sign of cardiac health

Answer 20

:)

Question 21

ad/disad. of ultrasonography

Answer 21

ad:
-technique of choice for evaluating pleural space and peripheral lung
-penetrates water filled structures very well
-widely available
disad:
-doesn’t penetrate normal lung parenchyma
-can’t detect deep lung lesions w/ overlaying normal lung

Question 22

nasal washes useful for:

Answer 22

detection of microbes that don’t normally colonize the upper airways such as viruses and strep. equi equi

Question 23

Tracheobronchial aspirate (TBA)

Answer 23

technique of choice to obtain a culture of the lower airways when pneumonia is suspected. Collects from horizontal portion of trachea which collects secretions from the whole lung.

• Normal cytology has mainly macs and ciliated epithelial cells
• think video of cutting into trachea!
• not a sterile procedure

Question 24

Bronchoalveolar lavage (BAL)

Answer 24

cytology correlates well with histopath. of the lungs when a DIFFUSE dz is present, but not useful when a FOCAL dz is suspected, such as pneumonia. Culture not sterile

Question 25

when to perform thoracocentesis?

Answer 25

when pleural effusion suspected. Includes cytology and culture.

Question 26

complications of lung biopsy

Answer 26

hemorrhage, pneumonia

Question 27

arterial blood gas analysis measures:

Answer 27

gas exchange (PaO2) and ventilation (PaCO2)

Question 28

pulmonary function testing measures:

Answer 28

mechanical properties of lungs

Question 29

2 obstructive dzs of the upper RT

Answer 29

laryngeal hemiplasia | dorsal displacement of the soft palate

Question 30

4 infectious dzs of the URT

Answer 30

strangles guttural pouch diseases sinusitis viral resp. diseases

Question 31

5 dzs of the LRT

Answer 31

``` foal pneumonia rhodococcus equi pneumonia pneumonia/pleuropneumonia in adult horses exercise induced pulmonary hemorrhage heaves ```

Question 32

most infectious upper airway disease still in the U.S.

Answer 32

Strangles

Question 33

Strangles is caused by what bacteria

Answer 33

streptococcus equi subsp. equi

Question 34

Strangles transmission

Answer 34

direct contact, fomites

Question 35

morbidity and mortality of Strangles

Answer 35

high morbidity (30-100%), low mortality (<10%)

Question 36

pathogenesis of Strangles

Answer 36

1) ingest/inhalation 2) attach. to tonsils and translocation below the mucosa in the lymphatics 3) multiply and abscess in local lymph nodes 4) possible dissemination via lymph or blood

Question 37

CS of Strangles

Answer 37

- fever (1st) - depression - bilateral nasal d/c - retropharyngeal and submandibular lymphadenopathy - resp. distress - abscesses throughout body

Question 38

Which worse: retropharyngeal or submandibular abscesses from Strangles?

Answer 38

retrophar. Don't rupture to outside very easily and put pressure on larynx which can cause inspiratory dyspnea

Question 39

Explain Strangles and chronic carriers

Answer 39

Most horses stop shedding 3-6 wks after resolution of CS, however some will become chronic asymptomatic carriers. Carry bacteria primarily in guttural pouch and can shed for months-years

Question 40

Dx of Strangles

Answer 40

- presumptive based on CS and abscessed lymph nodes | - Culture or PCR (PCR 10x more sensitive!) amplification

Question 41

How do you dx/detect chronic carriers of Strangles?

Answer 41

-abscess aspirate -nasal or pharyngeal swab 3x -nasal flush 3x -guttural pouch flush submitted for culture or PCR**

Question 42

Tx of Strangles

Answer 42

- horses exposed or with early CS BEFORE abscess: penicillin | - horses with abscess: promote maturation/drainage, no Abx unless anorexic or in resp. distress, supportive therapy

Question 43

Complications of Strangles

Answer 43

- pneumonia - guttural pouch empyema and/or chondroids - bastard strangles - myocarditis, endocarditis - glomerulonephritis - purpura hemorrhagica

Question 44

purpura hemorrhagica

Answer 44

acute necrotizing immune-mediated vasculitis

Question 45

Path of purpura hemorrhagica in Strangles

Answer 45

immune complex formation --> deposition in blood vessels --> complement activation and mediator release --> vessel wall necrosis

Question 46

CS/Dx of purpura hemorrhagica

Answer 46

-warm/painful edema of limb, ventral abd, face -petechial hemorrhage -fever -stiffness Dx: history, CS, skin biopsy

Question 47

Tx of Purpura hemorrhagica

Answer 47

- systemic antimicrobials (penicillin +/- gram negs) - steroids - NSAIDs, hydrotherapy, bandages

Question 48

Strangles vaccination

Answer 48

-not very effective, but decreases severity/incidence 2 types: 1)IM: uses M protein extracts 2) Intranasal (Pinnacle IN): uses altered live virus, use in outbreaks, can cause CS in young horses, generates nasal immunity

Question 49

What can be visualized in medial compartment of guttural pouch?

Answer 49

internal carotid a. cn 9,10,11,12 cranial cervical ganglion

Question 50

What can be visualized in lateral compartment of guttural pouch?

Answer 50

external carotid a. maxillary a. cn 7

Question 51

guttural pouch empyema

Answer 51

accumulation of exudate in the guttural pouch(es). May solidify to form chondroids

Question 52

CS of guttural pouch empyema

Answer 52

-nasal d/c when head down | rarely dysphagia, not usually malodorous

Question 53

dx/tx of guttural pouch empyema

Answer 53

``` dx: -endoscopy -rads (fluid line, chondroids) -culture for Strep. equi Tx: -lavage with large volume of saline -systemic abx ```

Question 54

guttural pouch mycosis

Answer 54

fungal infection often over a major blood vessel (internal carotid most common)

Question 55

CS of guttural pouch mycosis

Answer 55

- epistaxis** - dysphagia - Horner's, laryngeal hemiplasia, facial paralysis,etc.