equine respiratory tract disorders

neonatal pneumonia
prepartum EHV 1 infection
fractured ribs
meconium aspiration
prematurity/dysmaturity

60-80 and after 1 hour 30/min

because significant consolidation or interstitial disease can occur without abnormal sounds on auscultation

it is a common sequel to bacteraemia and septicaemia. treat with ABs (C&S ideally) but pen/gent, ceftiofur, and cefquinome good empirital choices
supplement IgG as ill be concurrent FPT
intense nursing, oxygen, fluids and turning of recumbent foals

PCR or histo of liver, lungs, thymus - can submit fresh foal carcase, placenta and mare blood

mind most stud mares vaccinated against EHV1 and 4 but protection is incomplete

ultrasonography and careful palpation

stabilise with adhesive bandage and confine foal to stable for a few weeks - surgery if flail chest

nursing and broad spectrum antibiotics - aspirate from airways can be attempted

inadequate lung maturation --> severe respiratory effort and lung dysfunction.

provide surfactant (expensive), respiratory support and antibiotics - prognosis poor if under 300 days gestation

rhodococcus equine
pneumonia
strep equi var zooepidemicus

probably infected as neonates (inhale/ingest) but do not develop clinical signs until 2-6 months old

ill thrift
debility
progressive dyspnoea
less commonly coughing and nasal discharge
can spread to mediastinal and mesenteric lymph nodes, joints, physes and GIT --> diarrhoea and immune mediated polysunovitis.

hyperfibrinogenaemia, neutrophilia and thrombocytopaenia

6-8 weeks of rifampin and erythromycinc, clarithromycin or azithromycine
- hyperimmune serum available

also screen other in contact foals - likely to be infected: serological test available but not 100% accurate

- improve management by reducing stock density, collect faeces from paddocks, rotate paddocks and move water and feed areas around to prevent dust build up
administer appropriate prophylactic antibiotics or hyperimmune serum to neonates

vaccine under development

nuisance rather than concern

cough, nasal discharge, slight SM LN enlargement, intermitent mild pyrexia but animals not sick

give penicillin and turn out or ignore - may ax and ane for eeks

influenza
EHV1 and 4
rhinovirus
EVA

strangles
M. felis and equirhinis
B. bronchiseptica
Strep pneumonia
pasteurella
actinobacillus

pyrexia
dullness
anorexia
coughing
mucoid to mucopurulent nasal discharge
bilateral SM LN enlargement

influenza likely if spreads very quickly

always test for strangles as method of control differs as does its treatment
- nasopharyngeal swab or guttural pouch wash

nasopharyngeal swab, tracheal aspirate, BALF, serum or heparinised blood

ELISA via secretions - takes 4 hours

because it takes several weeks - more useful for epidemiology

2-3 weeks

nasopharyngeal swab (strangles) or tracheal aspirate

takes 3-4 days

maintain horses in clean air environment that is ell ventilated with shaving bedding and haylage fed from ground (gravitational drainage)

antibiotics if horse remains febrils for more than 4-5 days or if respiratory secretions purulent or marked respiratory signs occur - particularly in young and very old horses

CLENBUTEROL may aid mucociliary clearance

EHV 4

abortion and encephalomyelopathy. can occasionally cause respiratory disease

early in life - and probably all become asymptomatic carriers of latent virus that may recrudesce with intercurrent disease or stress - immunity short lived and get repeatedly infected especially following mixing of horses at sales or rases

causes immunosuppression and vaccines not very effective but may afford some protection in younger race horses

largely affects URT - not that big of a deal - infection occurs in conjunction with other infectious agents

general signs of respiratory disease
severe conjunctivitis
profound depression
periorbital oedema

venerally spread. prevent via vaccine (effective)

weeks to months

cases that have no lymph node abscessation and may be misclassified as viral respiratory disease unless culture or PCR is done

culture or PCR of bacteria in nasal, nasopharyngeal or guttural pouch swabs/washes.

need to differential from strep zooepidmicus var zooepidemicus - common commensal

can treat with penicillin early in disease course to stop clinical progression, but unclear if develop immunity: so isolate

do NOT administer antibiotics with lymph node abscesses

bastard strangles: lymph nodes, physes -weight loss, malaise, etc

purpura haemorrhagica - type 3 immune mediated vasculitis 1-3 months after infection - oedema, petchiae, multiorgan failure

guttural pouch empyema

immunosupp dex, penicillin, supportive care

recurrent airway obstruction
summer pasture associated obstructive pulmonary disease
inflammatory airway disease
lungworm
idiopathic pulmonary eosinophilia
interstitial (restrictive) lung disease
pulmonary oedema
thoracic neoplasia
pulmonary abscesses and pleuropneumonia
pleural effusion
pneumothorax
diaphragmatic hernia
exercise induced pulmonary haemorrhage

inflammatory response to pro inflammatory agents inhaled in dust - moulds, endotoxin, particulates, ammonia, from poorly conserved hay and straw

--> bronchospasm, thickening of airway walls and oedema with leucocyte (neutrophil) infiltration, mucus plugging and epithelial deciliation

controlled exposure of hay or straw

over 5yo
poor stable hygiene
genetics
respiratory infection
exposure to hay/straw early life

coughing - 85%: exacerbated by exercise, poor exercise tolerance
bilateral mucopurulent nasal discharge in 55% - others sallo it
tachypnoea (>12/min)
heave line
if severe - wheeze/crackle

endoscopy: mucopus
tracheal aspirate: over 20% neutrophils
BALF over 5% neutrophils
(lavaged distal airways with 250-300ml saline via endoscope or BAL tube under heavy sedation

- eliminate organic dust: keep at pasture
- shallow shavings or paper bedding: remove all wet bedding daily
- complete cubed diet with alfalfa or silage (soaking hay does not work)
- adequate ventilation
- turn out in dust free environment
bronchodilator - clenbuterol or salbutamol or atropine as rescue drug
- inhaled beclomethasone or oral pred
- maintain hydration to avoid tenacious secretions

dyspnoea
crackles and wheezes heard on auscultation

coughing, exercise intolerance, increased volumes of neutrophilic mucopus in lower airways and occasionally nasal discharge - not depressed or pyrexic and do not have overt airway obstruction that characerises RAO

any horse- commonly identified at start of training (2yo flat horses, 4-8yo national hunt= with syndrome self resolving in a few wks or persisting for months to years

think multifactorial: S. zooepidemicus, pasteurella, actinobacillus, S. pneumoniae, B. bronchiseptica, mycoplasma, dust/endotoxin

provide dust free environment and reset
antibiotics C&S - oxytet, ceftiofur, cefquinome, enroflox, TMPS
inhaled glucocorticoids if chronic

summer or autumn

eosinophila in tracheal mucus or BALF confirms diagnosis, or via positive response anthelmintics. infection non patent to can't use Baermann flotation

treat in contact horses and donkeys with avermectin or benzimidazole and move to clean pasture

acute alveolitis, chronic small airway disease, chronic interstitial disease - respond to corticosteroids

- acute/chronic inflammatory alveolitis --> injury to type I epithelial and endothelial cells
- serum protein leak into alvoeli --> pulmonary oedema acutely
- inflammatory cells infiltrate alveoli and interstitium

if survive: get interstitial fibrosis and granuloma devlopment over weeks to years

--> decreased compliance, predominantly inspiratory dyspnoea

wheezes and crackles, especially end inspiratory

immunosuppressive glucocorticoids and frusemide

acute URT obstruction
cardiac failure
alveolitis/interstitial lung disease
smoke inhalation
neoplasia
plant and drug toxicity
immune mediated
volume overload

frothy nasal discharge 8often blood tinged), increased inspiratory effort with reduced compliance, widespread fine crackles (some may have quite chest despite obvious dyspnoea)

endoscopy - see frothy fluid in airways

treat underlying cause (e.g. tracheostomy if URT obstruction), frusemide, intranasal oxygen, antibiotis and steroids where appropriate

lymphosarc. signs nonspecific includeing plerual effusion, ventral oedema, jugular distension

prolonged transport: pulmonary defences compromised/sequel to aspiration of saliva and food: usually mixed infection

- bac colonise lung --> pneumonia or absces: extends to pleura: get sterile effusion - ABs may be effective in this stage
- bac infection extends to pleura --> purulent effusion: need to drain - fibrin formed which lines pleural space
- get significant fibrin deposition --> pleural peel which limits thoracic expansion

sterile inflammatory effusion seen in first phase of pulmonary abscesses/pleuropneumonia development - responds to ABs alone

sick - lethargy, anorexia, pyrexia
ventral oedema
respiratory distress
pleurodynia: reluctance to move, base narrow stance, elbow abduction
soft muffled coughin
fast shallow ventilation
malodorous breath: suggests anaerobic infection or lung necrosis = poor prognosis

can be mistaken for colic, laminitis, hypocalcaemia

diagnose with ultrasonogrphay : essential to assess nature and extent and to select site for thoracocentis s which confirms diagnosis, C&S and is part of treatment with antibiotic therapy

thoracic neoplasia (most common cause)
bacterial pleuropneumonia
penetrating chest wall ound
concurrent peritonitis
CHF
hypoproteinaemia
chylothorax
diaphragmatic hernia

perform cytology, aerobic and anaerobic culture and gram smear for bac

usually asymptomatic
- GI signs due to strangulaton or incarceratino of bowl or respiratory signs due to lung compression

very fast exercise horses bleed from DORSOCAUDAL LUNG becuae of very high pulmonary capillary pressures, sub atmospheric inspiratory pressures and presence of other disease: Urt (RLN), IAD, cardiac, etc

coughing is not a feature

can cause epistaxis, poor exercise performance, pulling up and rarely death

via bronchoscopy 30 minutes post exercise:

fresh blood in trachea and bronchi for dayws following bleed
haemosidering secretions visible for a wek
haemosiderophages identified in tracheal aspirate and BALF for months following bleed

rest, treat underlying disease, NSAID to reduce interstitial lung fibrosis, nasal dilator strips, dust free environment and train at slower speeds, train on softer track to reduce concussion

pre race admin of frusemide permitted in some countries but not UK and efficacy questionable

RETIRE NON RESPONSIVE HORSES TO LESS DEMANDING DISCIPLINES

RAO
SPAOPD
IAD
bacterial bronchopneumonia
lung abscess
pleuropneumonia
acute (under 10 days) viral airway disease

lungworm
parascaris equorum migration
idiopathic pulmonary eosinophilia
eosinophilic sub type of IAD

EIPH
trauma during collection (just erythrocyte)
neoplasia, abscess, coagulopathy (rare)

just above lateral thoracic vein

RHS: 6-8th intercostal space US guided

LHS 7-9th intercostal space US guided

1) decreased colloid pressure and increased hydrostatic pressure

2) increased capillary and lymphatic hydrostatic pressure

3) increased capillary permeability and decreased lymphatic drainage

when 3 nasopharyngeal swabs collected at weekly intervals negative for S equi var equi

low glucose (under 2mM)
low pH (under 7)
PF lactate > plasma lactate

absence of aerated lung dorsally