Respiratory Flashcards
pathogens of foal pneumonia 1-10mnths
- Bacteria
- Strep equi subsp. zooepidemicus
- Rhodococcus equi
- Pasteurella sp, Bordetalla bronchiseptica, Actinobacillus
- Salmonella, Klebsiella, Pseudomonas
- Anaerobes - Viruses: EHV-4
- Mycoplasma
- Parasites/Fungi
Empirical ABs for foal pneumonia
- Penicillin
- TMS
- Doxycycline
age frame for rhodococcus equi bronchopneumonia
3wks - 6mo
non-resp form of Rhodococcus equi causes
- abdominal abscessation
- infectious synovitis (lame)
- immune-mediated non-septic polysynovitis (not lame)
- uveitis
- ulcerative lymphangitis
- placentitis
dx of rhodococcus
- CS
- Bloods
- Imaging; US, rads
tx rhodococcus
- Erythromycin + rifampin
US screening of rhodococcus is:
- decision to tx based on number and size of abscesses if absence of CS
strangles pathogen
Streptococcus equi subsp. equi
Strangles CS progression
- Initial
- depression, reduced appetite, fever
- mucopurulent nasal discharge
- pharyngitis and laryngitis
- cough - Later signs:
- suppurative lymphadenopathy: sumandib + retropharyngeal (and dysphagia secondary to massive LNs)
- purulent nasal discharge
- asphyxiation
why is it appropriate to quarantine horses for 14-21days re. strangles?
initial signs occur 3-14days after exposure
– also asymptomatic carriers
what are bastard strangles?
metastatic strangles to abdominal LNs/haematogenous spread
dx of strangles
- Culture
- PCR infectious diseases panel: EVA, equine influenza, EHV1/4, Strep equi subsp equi
- Serological tests: antibodies to M-protein portion of the bacteria
tx of strangles in animal w/ systemic signs but no LN enlargement
- Pen 22mg/kg IM BID
3. NSAIDs: bute/flunixin/meloxicam
tx of strangles in horse w/ retropharyngeal LN abscessation resulting in airway compromise
- Pen +/- Rifampin
- NSAIDs
- Tracheostomy
- US guided/endoscopic LN drainage
what kills strep equi subsp. equi
- Heat, Povidone iodine, Chlorhex, Bleach
2. Pasture rest 4wks
site of strep equi subsp equi carriage?
guttural pouches
—> swab and tx positive animals w/ Pen + reculture
Strangles vaccines available in AUS
- IM vaccines - minimise severity of disease, not protective assoc. w/ injection site xns –> 3 doses 2wks apart + annual
Define red, amber and green group when managing a strangles outbreak
- Red: CS
- Amber: exposed but no CS
- Green: not exposed to red group
protocol for horse entering a property re. strangles control
- ELISA blood test -> neg –> 2wks then rpt –> neg OKAY
- Any positives —> guttural pouch sampling + culture
- Guttural pouch positives –> tx
what is purpura haemorrhagica?
- acute necrotizing vasculitis occurs in 1-2% strangles 2-4wks after acute infection
- IgA combined w/ soluble protein (M-protein of Strep.equi subsp. equi)
- immune complexes bind to neutrophils and mast cells causing release of cytotoxic products –> vasculitis
tx of purpura haemorrhagica
- corticosteroids: dexamethasone
- local cold hosing/pressure wraps
- ABs to cover against persistent Antigen release
EIV incubation, shedding time
incubation 18hs to 7d
viral shedding 24hs after infection persists for 4-10days
CS 1-3days after exposure - resolve w/in 7-14days +/- cough 3wks
CS of EIV
- fever >40degrees, peaks 2-4d
- complete refusal of feed
- dry non-productive and painful cough
- lymphadenopathy
- nasal discharge serous to mucoid after 3-4days
- stiffness
dx of EIV
- Antigen detection
- Virus isolation: 1-2days after onset of signs only
- Immunoassays
- Reverse transcriptase PCR
NOTIFIABLE
tx of EIV
- Symptomatic: NSAIDs + secondary ABs if suspected
2. Rest 3-4wks min
vaccines types of EIV
- inactivated strains
- mod. live strains
EHV-1 is associated with
abortion, neuro, perinatal, resp disease
EHV-4 is assoc. w/
resp. disease
Dx of EHV-4/1
- virus isolation via nasopharyngeal swab
- antibody detection -serology
- PCR antigen detection (respiratory panel)
vaccines available against EHV-1 and EHV-4
- inactivated vax avail in AUS
- live virus vax internationally
compare equine rhinitis A and B CS?
A = fever (40degrees) 5d, nasal discharge, moist cough, mild regional lymphadenopathy B = slight pyrexia, mild resp signs
EVA causes what in horses?
abortion - not an important resp. disease in horses.
Virus shed in semen
EVA CS
- fever
- conjunctivitis, periorbital oedema
- cough/nasal discharge
- body/limb oedema
EVA diagnosis
- nasopharyngeal swab antigen detection
when are EVA vax indicated?
abortion storms only
- not avail in AUS/NZ
aerobic bacteria causing pneumonia adults
- Strep equi subsp. zooepidemicus, Strep penumonia
- Staph
- Pasteurella, Actinobacillus, B.bronchiseptica, Klebsiella, E.coli, Pseudomonas, Enterobacter
anaerobic bacterial causes of adult pneumonia
- Bacteroides spp
- Clostridium spp.
- Eubacterium spp.
- Peptostreptococcus spp.
when infectious aetiology suspected that has the potential to be life threatening - how should you get a sample (pneumonia)?
transtracheal aspirate (over transtrach wash via scope)
what does fibrin in fluid look like?
echoic, wavy
empirical ABs for adult pleuropneumonia
Pen, Gent, Metronidazole
benefits of pleural drainage
- improves ventilation
- removes bacteria, inflam mediators and cellular debris
- if not removed v. unlikely to resorb –> will result in increased fibrin deposition = poor prognosis
tx of chronic pleural abscesses
- rib resection
- intercostal incision
complications/sequelae of pleuropneumonia
- pulmonary abscessation
- cranial mediastinal abscessation
- bronchopleural fistulae/pneumothorax
- laminitis
cause of fungal pneumonia in WA
crypto gatii
tx of fungal pneumonia
- Amphotericin B **caution - nephrotoxic
2. Fluconazole: >3months
normal RR
8-20bpm
what causes the heaves line
hypertrophy of rectus abdominus muscles –> heave line (obstructive breathing pattern)
normal rebreathing bag exam
- Inc RR in 60 seconds
- Recover w/in 5 breaths
* no coughs
commonly used tests to invest. resp
- endoscopy
- resp. tract sampling: transtracheal, BAL, thoracocentesis
- US
- Rads (URT/foals)
direct transtracheal aspirate technique
- Mid trachea btwn tracheal rings: 12G 2 inch large bore IV cath + 22 inch 6Fr polyprolylene catheter
BAL good for
diffuse diseases/non-infectious eg. asthma
non-infectious LRT disease
- IAD
- Heaves
- EIPH
non-infectious URT disease
pharyngeal lymphoid hyperplasia
grades of PLH
G1 - small number of follicles over dorsal pharyngeal wall
G2 - many small white follicles, some larger, pink and oedematous
G3 - many large pink follicles, may extend to soft palate and dorsal pharyngeal recess
G4 - numerous pink and oedematous follicles packed in close alignment and covering the entire pharynx
Mild equine asthma CS
- no increased RE at rest
+/- poor performance/recovery/cough (exercise induced)/ serous nasal discharge
mild heaves CS
- -> moderate
- –> severe
Mild: exercise intolerance
Mod: cough, incRR/RE, marked exercise intolerance
Severe: weight loss, heave line, nostril flare, expiratory dyspnoea
BAL technique
- sedation: butorphanol + LA infusion
- lavage: 250-500ml
BALF cytology with severe asthma
> 35-50% neuts
BALF cytology with mild asthma (IAD)
5-10% = neutrophilic IAD
Mast cell associated = >2-5%
Eosinophilic associated IAD >1-5%
management aims of non-infectious resp. disease
- Primary = reduce exposure to the offending agent (trigger) that causes the inflammation
- Secondary = reduce the inflammatory response and hyper reactivity (bronchoconstriction) that occurs as a result of exposure
environmental causative agents in severe asthma often include:
- endotoxin
- moulds
- volatile gases
—> straw/hay
eg. systemic corticosteroids to tx heaves
- dexamethasone
- prednisolone
eg. inhaled corticosteroids to tx heaves
- fluticasone + salmetorol
- dexamethasone
EIPH dx
- exercised -induced epistaxis –> endoscopy post exercise + BAL
management of EIPH
- Tx underlying equine asthma if present
- Rest (4-12wks)
- Train on diuretics: frusemide 1-2hrs prior to fast work
- Race sparingly, in warm weather
tx of progressive ethmoid haematoma
- Sx excision via bone flap if large
- Laser ablation if accessible via endoscope
- Intralesional injection of 4% formaldehyde: if <5cm, q2-3wks until resolution
drainage from all major sinuses can be achieved by trephine and lavage of which two sinuses?
- Frontal
2. Rostral maxillary
common pathogen of primary sinusitis
Strep. equi subsp zooepidemicus
causes of secondary sinusitis
- sinus cyst
- trauma/facial fx
- progressive ethmoid haematoma w/in sinus
- neoplasia
- dental: apical tooth root infection, alveolar periostitis, patent infundibulum, tooth fracture
tx of sinusitis
- indwelling foley cath for lavage (1-2L saline SID or BID 5days)
- systemic ABs based on C&S
- feed off ground + light exercise
- NSAIDs
intermittent DDSP results when?
- muscles of nasopharynx have abnormal contraction or weakness
- air turbulence and neg pressures cause loss of palate control
- during maximal exercise
causes of persistent DDSP
- CN damage; IX, X (pharyngeal branch(
- head trauma
CS of DDSP
- gurgling/choking down/tongue swallowing when riding
- poor performance
conservative tx of intermittent DDSP
- medical tx of URT inflam: dex + glycerin + DMSO + bute + AB (if indicated)
- spell 2-3months
- tack: tongue-tied, dropped noseband
- change disciple/head position ie. dressage = band
sx tx of intermittent DDSP
- palatoplasty (stiffen soft palate)
- epiglottis augmentation (stiffen position)
- staphylectomy (soft palate caudal margin extension)
- laryngeal advancement procedure (tie forward)
compare simple and complicated epiglottic entrapment?
simple = thin fold of mucosa overlying epiglottis w/ no inflammation complicated = thickened, inflamed, ulcerated or adhered fold of mucosa
roarer presentation
- TBS, WBs, Clydesdales
- M, >15hh, 3-7yo
- left sided: recurrent laryngeal nerve –> atrophy of CAD and CAL –> paresis/paralysis of arytenoid cartilage and vocal cord
- dynamic axial collapse –> exercise intolerance/poor performance + roaring sound/whistling
Grades 1 RLN
normal symmetrical and synchronous movement, full abduction obtained and maintained
Grade 2 RLN
- asynchronous movement/flutter +/- intermittent resting asymm (2.1)
- asym and async movement at rest, but full abduction obtained and maintained on swallow (2.2)
grade 3 RLN
- full abduction achieved but not maintained (3.1)
- obvious asym, full abduction never achieved (3.2)
- marked asym, minimal movement + full abduction never achieved (3.3)
Grade 4 RLN
total paralysis of arytenoid cartilage (hanging in the airway)
sx tx of RLN
- Ventriculectomy/cordectomy
- Prosthetic laryngoplasty “Tie-back”
- Partial arytenoidectomy
- Nerve-muscle pedicle graft for C1/C2 nerve transplantation
which procedure achieves permanent abduction/stabilisation of the left arytenoid cartilage?
Prosthetic laryngoplasty (prosthesis replaces function of CAD muscle)
list of dynamic upper respiratory tract obstructions diagnosed on exercising endoscopy
- Intermittent DDSP
- Axial deviation of the aryepiglottic folds
- Vocal cord collapse
- Laryngeal hemiplegia
- Nasopharyngeal collapse
- Palatal instability
- Ventromedial luxation of the apex of the corniculate process of arytenoid cartilage
- Epiglottic retroversion/flaccidity
important structures in the guttural pouches
- internal and external carotid arteries
- CN IX, X, XII
- cranial laryngeal nerve
medical management of guttural pouch empyema
- ABs: systemic and local after lavage
- Lavage w/ saline daily
- Feed from ground - draining
guttural pouch mycosis common pathogen
aspergillus
sequelae of guttural pouch mycosis
- Fungal plaque over vessels –> epistaxis, exsanguination, death (1st bleed to fatal w/in 3wks)
- Fungal plaque over nerves –> dysphagia, horner’s, laryngeal hemiplegia, DDSP
guttural pouch mycosis medical tx (indications)
ONLY if no bleeding
- daily antifungal lavages via indwelling catheter
- systemic antifungals