Equine respiratory Flashcards
What does increased exudate when head is lowered indicate
Guttural pouch infection
What does unilateral nasal discharge during exercise with no other respiratory disease signs suggest?
Sinusitis
Normal RR (adult/young) horse
8-24 / 25-40
Normal RR (adult/young) cow
12-36 / 30-60
Normal RR (adult/young) sheep/goat
12-40 / 30-70
What lymph nodes should be evaluated in horses for respiratory exam
Submandibular and retropharyngeal
What should palpation of larynx and trachea evaluate (3)
Symmetry/collapse; sensitivity; induction of cough for airway irritation
Where should be checked for edema
Ventral abdomen, muzzle, legs
Where should percussion be evaluated in resp exam
Paranasal sinuses
How long should it take for a patient to recover from raised CO2 in rebreathing bag
les than 10 breaths
What breaths should be evaluated after rebreathing bag
The first deep breaths - would reveal abnormal lung sounds
What are the normal resp sounds
Bronchovesicular - coarser over mainstem bronchi and decrease in intensity peripherally- uniform bilaterally
What do normal tracheal sounds sound like
Coarse I and E, equal pitch and duration, short silent interval
What causes breath sounds
Turbulent flow in central airways greater than 2mm
Why dont peripheral airways make sounds
Velocity too low to generate sound
Inflated lung vs consolidated
Inflated attenuates, consol good conducting medium
Non-musical, short, sharp, explosive sounds
Crackles
What causes crackles
Equaliztion of pressure when a collapsed region is reinflated or movement of secretions in trachea/bronchi
When do crackles occur
I and E, randomly
Musical, high pitched sounds of variable duration
Wheezes
What causes wheezes
vibration of airway walls before complete closing (expiratory) or opening (inspiratory)
Wheezing- mostly I or E?
Either, but one predominantly
What conditions cause wheezing?
airway compression, stenosis, masses, bronchoconstriction
When are wheezes more common in horses
Expiratory
What is primary cause of wheezes in horses
recurrent airway obstruction/heaves (expiratory)
What would indicate severe consolidation, lung abscess or pleural fluid
Abscence of audible sounds
What would absence of sounds indicate
severe consolidation, lung abscess or pleural fluid
No sounds ventral, heart sounds loud =
Pleural effusion
What structures are evaluated by endoscopy
Nasal passages, ethmoid turbinates, nasal openings of paranasal sinuses, nasopharynx, guttural pouch opening, larynx, trachea
What size scope can enter eustachian tube?
1.2 cm or less
Ultrasound- what cannot be penetrated
Normal lung parenchyma
Ultrasound- what can be studied
Pleura and lung surface
Evaluate pleural surface and space- which method
Ultrasound > xray bc can see small amounts radiographs cant detect
Diagnose viral infection, strep eq. eq.,
Nasal/nasoph swab or nasal wash
Why are Nasal/nasoph swab or nasal wash not very effective
Normal flora will culture
Dx bacterial or fungal infection suspected
TBA- tracheobronchial aspiration prior to Abx
TBA methods (2)
TTW or guarded catheter through scope
Describe normal pulmonary alveolar cytology from TBA
macrophages, columnar ciliated epithelial cells, less than 40% neutrophils
Describe pneumonia cytology from TBA
Primarily neutrophil (degenerate with karyolysis, pyk, hyperseg), intra/extracell bacteria
Describe heaves cytology from TBA
non-degen neutrophils and mucus
Non-infectious disease dx method
BAL bronchoalveolar lavage
Why is BAL > TBA in diffuse non-infectious lower airway dz
BAL fluid more consistent among normal
TBA or BAL in bacteriologic culture sample
TBA > BAL
Dx diffuse non-infectious lower airway dz
BAL
Dx pleural effusion
Thoracocentesis
When should you use lung biopsy
Diffuse dz processes where TTW/BAL give inconclusive results
Main complication of lung biopsy
Hemorrhage (uncommon- pneumothorax)
What vessels for blood gas
Carotid, facial, or great mesentary arteries
How quickly should a blood gas sample be used
10 min, then on ice, 1.5 hours
What does PaO2 reflect in blood gas
Pulmonary gas exchange and oxygen available to tissues
What does PaCO2 reflect in blood gas
Pulmonary ventilation
Normal PaO2
> 85 mmHg
Normal PaCO2
40-45 mmHg
Low O2 with normal CO2 =
Decreased inspired O2, R-L shunting, difusion impairment, ventilation/perfusion mismatching
Most common cause of Low O2 with normal CO2 =
ventilation/perfusion mismatching
Blood gas results from ventilation/perfusion mismatching
Low PaO2, normal PaCO2
Low PaO2 with increased PaCO2
hypoventilation/respiratory failure
hypoventilation/respiratory failure blood gas results
Low PaO2 with increased PaCO2
Strangles- species
Strep equi equi
Purulent lympadenitis of URT - dz
Strangles
LN involved in strangles
Retropharyngeal or submandibular
Strangles- epidemiology
direct nose/mouth or aerosol; contaminated water/food/walls
Strangles- signalment
Most severe and common in horses
Strangles- morbidity or mortality
up to 100% morbidity
Strangles- organism persistence explained by
Hyaluronic capsule, anti-phagocytic M protein, leukocidal toxin release
Strangles- shedding time
stop after 4-6 weeks post CS (10% become carriers)
Strangles- incubation
Moderate- 3-14 days
Dx- Acute fever 102-104, depression, bilateral serous nasal d/c changing to mucopurulent, enlarged LN 2-4 days post-fever
Strangles
Strangles- CS
Acute onset fever 102-104, depression, bilateral serous nasal d/c changing to mucopurulent, enlarged LN 2-4 days post-fever
Strangles- hematology
neutrophilic leukocytosis, increased fibrinogen, increased SAA
Strangles- how long before LN rupture
7-14 days
Dx- strangles
PCR > guttural pouch flush culture > nasal wash/swab culture
Strangles- tx
Early (w/o LN abscess) - penicillin; With LN abscess- help relieve drainage- (hot packs, lancing, etc), no Abx
When are Abx indicated in strangles
Early before LN involvement or if upper airway obstruction. bastard strangles (penicillin)
Strangles- complications
Empyema/chondroids from LN rupture into GP; pneumonia, bastard strangles in lung, mesentary, liver, spleen, kidney, brain; Rare- myocarditis, glomerulonephritis, purpura hemorrhagica
What is purpura hemorrhagica and what causes it
Immune mediated vasculitis causing edema in face, muzzle, limbs and ventral abdomen. Warm and painful to touch. Petechial hemorrhage possible. Occurs 2-4 weeks post-strangles
Dx purpura hemorrhagica
2-4 weeks post strangles, skin biopsy showing leukocytoclastic vasculitis
Tx purpura hemorrhagica
penicillin removes Ag’ic stimulus, corticosteroids or NSAIDS
Strangles vax and effectiveness
SeM protein (IM) or modified live (IN); 50% reduction; modified live may cause strangles symptoms
Accumulation of exudate within guttural pouch
Empyema
Empyema
Accumulation of exudate within guttural pouch
Most common organism for guttural pouch empyema
Strep. equi. zoo post-URT infection
Guttural pouch empyema- CS
mucopurulent d/c, more profuse when head lowers; rare: dysphagia, formation of chondroid mass
Guttural pouch empyema- dx
Endoscopy
Guttural pouch empyema- tx
Lavage GP with saline, antimicrobials,
Guttural pouch mycosis- describe
fungal infection involving internal carotid artery at roof of medial compartment
Guttural pouch mycosis -most common spp
Emericella (aspergillus) nidulans
Guttural pouch mycosis - CS
Epistaxis from erosion of mycotic plaque in internal carotid (occasionally maxillary, ext. carotid); horners, paralysis, laryngeal hemiplasia
Guttural pouch mycosis - cause of dysphagia
Vagus or glossopharyngeal
Guttural pouch mycosis - dx
endoscopy to examine mycotic plaque
Guttural pouch mycosis - tx
Surgical obstruction of affected artery proximal and distal to the lesion via transarterial coil or plug embolization; then resolves on own.
Guttural pouch tympany - describe
Distention of one or both GP with air causing parotid swelling behind vertical ramus
Guttural pouch tympany - origin
Congenital or acquired one way valve defect of pharyngeal opening to pouch
Guttural pouch tympany - signalment
less than 1 year
Guttural pouch tympany - CS
external swelling, dysphagia, respiratory distress
Guttural pouch tympany - tx
Surgical ablation of median septum; if bilateral - resection of internal opening cover; or fistula into GP through pharyngeal recess
Distention of one or both GP with air causing parotid swelling behind vertical ramus
Guttural pouch tympany
Sinusitis- CS
Unilateral mucopurulent nasal d/c +/- facial deformity
Unilateral mucopurulent nasal d/c +/- facial deformity
Sinusitis
Sinusitis- cause
primary or secondary to tooth root abscess, diastema
Sinusitis- spp
Strep. equi. zoo
Sinusitis- dx
Radiographs show fluid line in sinus
