horse diseases Flashcards
1
Q
what pathogen causes strangles?
A
streptococcus equi subsp equi
G+ve
2
Q
how is strangles spread?
A
direct contact
fomites
environment
shedding carriers (56m ) from guttural pouthc
3
Q
what is the incubation time of strangles?
A
2-6 d
4
Q
what are the clinical signs of classic acute strangles?
A
fever depression cough mucoid to purulent nasal discharge abscessation of LN (rupture in 7-10d) (suppurative lymphadenitis) dyspnoea dysphagia
5
Q
how can you treat very early strangles?
A
can give penicillin but have to weight up as may inhibit immunity
nursing
soft food
6
Q
how do you manage abscesses from strangles?
A
poultice and drain
abx controversial
nursing
soft food
7
Q
what determines if strangles presents classically of atypically?
A
strain
own immunity
8
Q
what are the signs of atypical strangles?
A
mild infl of URT slight nasal discharge cough fever self limiting lymphadenopathy NO abscess
9
Q
how can you diagnose strangles?
A
- leucocytosis
- hyperfibrinogenaemia
- 1 x GP lavage or 3x nasophargyngeal swabs then culture or pcr
- US / rectal for abd abscess
- endoscopy or rads for GP empyema and chondroids
- blood test for AG
10
Q
how can you manage an outbreak of strangles?
A
- isolate horse and premises
- phenolics disinfectant for equipment
- iodophores and chlorhexidine for staff
- blood test for asymptomatic carriers
- remove chondroids and put penicillin in GP
11
Q
how can you prevent strangles?
A
- intramucosal vax not very effective
- test new horses for carrier status
12
Q
what are some possible complications of strangles?
A
- internal abdominal abscessation
- purpura haemorrhagica
- generalised vasculitis
- death
- GP empyema and chondroids(solid pus)
- retropharyngeal abscess
13
Q
what can be the consequence of internal abscesses from strangles and how can you treat it?
A
- colic, pyrexia, anorexia, depression, wt loss
- 6w penicillin/trimethoprim sulfa / rifampin
14
Q
how can you treat purpura haemorrhagica?
A
penicillin immune suppression NSAIDs fluids pallative care guarded prognosis
15
Q
why do you get generalised vasculitis with strangles?
A
- caused by type 3 hypersensitivity and get thrombosis of small arteries
- necrosis, petechial haemorrhages on mm
16
Q
what is rhodococcus equi?
A
G+ve intracellular obligate aerobe lives in soil +manure late spring and summer foals 1-6mo more in US, australia and ireland
17
Q
what is the pathogenicity of the respiratory form of rhodococcus equi?
A
- foals infected in first few days after birth but dont get signs till later
- bacteria destroy macrophages giving a pyogranulomatous response
18
Q
what are the clinical signs of respiratory rhodococcus?
A
bronchopneumonia abscess formation (caseous necrosis in lungs + LN) anorexia depression fever dyspnoea and tachypnoea cough
19
Q
how do you diagnose respiratory rhodococcus?
A
fibrinogen high neutrophilia tracheal wash - PCR for VapA gene of bacteria rad for abscess US for surface abscess PM
20
Q
how can you treat rhodococcus?
A
- erythromycin and rifampin
- clarithromycin or azithromycin with rifampin
- treat until resoluved on rad and CBC / fibrinogen normal
- 4-12 w
21
Q
what are some complications of giving erythromycin and rifampin to foals?
A
- some resistance
- hyperthermia
- tachycardia
- increased liver enzmes
- fatal colitis in dam if she licks foal
22
Q
how can you prevent rhodococcus?
A
- difficult as shed in faeces
- increase ventilation
- decrease dust
- rotate pastures
- collect manure
- isolate infected
- try prophylaxis with hyperimmune plasma
- check TPR, monthly CBC and fibrinogen
- Screen rads / US
23
Q
what is the intestinal form of rhodococcus?
A
- ulcerative entercolitis with mesenteric lymphadenitis and abscess formation
- from swallowing infected sputum
24
Q
what are the signs of intestinal rhodococcus?
A
depression fever diarrhoea colic wt loss
25
what can equine rhinovirus cause?
subclinical / mild URT signs in young horses
26
what is the pathogenesis of equine viral arteritis?
- venereal or droplet spread
- stallions can be chronic shedders
- 3-14d incubation
- replicates in macrophages then travels to local LN - leucocyte associated viraemia - virus localising in endothelial cells - necrotising arteritis - oedema and haemorrhage
27
what are the signs of EVA?
```
abortion and stillbirth
fever
anorexia
oedema
lacrimation
conjuctivitis
nasal discharge
coughing
```
28
how can you diagnose EVA?
blood serology
nasal swabs / semen for viral isolation and PCR
*notifiable in stallions / mares inseminated in last 14 d
29
how can you prevent EVA?
vaccinate
30
what can cause profuse epistaxis
GP mycoses - aspergillus nidulans
30
how can you diagnose paranasal sinusitis?
- reduced resonance on percussion
- sinus and facial swelling
- reduced airflow
- rads
- CT
- sinuscopy
30
what can cause GP disease?
GP empyema from strangles
GP catarrah (infl - - excessive mucus)
mycosis - aspergillus nidulans
neoplasia
30
where would you see a swelling associated with GP disease?
viborgs triangle
30
how do you diagnose GP disease?
endoscopy
| rad
30
how can you treat GP disease?
- medical - pouch lavage and abx
- remove chondroids before lavage or else get mushy
- surgical drainage
- tacheostomy if dyspnoeic
30
What are common sites of URT obstruction?
Nostrils - alar collapse, incomplete dilation
Nasal passage - septal disease, small passage, eruption bumpbs, mass lesion
Sinuses - cysts, mass
Pharynx - DDSP, postural compression, cysts
Larynx - RLN , epiglottic entrapment, arytenoid chondroitis
30
what disease can cause abnormal resp noise / poor performance?
DDSP - dorsal displacement of the soft palate
pharyngeal cysts
RLN - recurrent laryngeal neuropathy
Epiglottic entrapment
arytenoid chondritis
dynamic obstruction
foal stridor
30
what is DDSP?
- dorsal displacement of the soft palate
- common in the young horse
- the palate is normally buttoned onto the larynx forming an airtight seal
- in DDSP the palate moves dorsally towards the epiglottis during exercise causing a functional obstruction and increased resistance to airflow
- most commonly due to neuromuscular dysfunction
30
what are common signs of DDSP?
- choking down (when airway blocked)
- expiratory stertor
- decreased performance
- mouth breathing
30
how can you diagnose DDSP?
dynamic endoscopy at exercise
| -assess GP
30
how do you treat DDSP?
- treat concurrent GP disease
- keep mouth closed during exercise to maintain negative pressure
- Tongue-tie
- cornell collar to mimic thyrohyoideus muscle
- llewelyn procedure
- thermal palatoplasty - stiffen soft palate
- laryngeal tie forward
30
what is RLN?
- recurrent laryngeal neuropathy
- degenerative axonopathy of the recurrent laryngeal nerve
- normally left side affectes
- impaires function of cricoarytenoideus dorsalis muscle and primary abductor of the arytenoid cartilage
- get airway collapse
30
what are the signs of RLN?
- ok at rest or low level exercise
- inspiratory stridor with exercise
- impaired athletic performance at high levels of exercise
30
how is RLN graded in resting, unsedated horses?
Grade 1 = synchronous full abduction of both arytenoid cartilages
Grade 2 = asynchronous movement of L arytenoid cartilage. Full abduction of the L arytenoid cartilage inducible by nasal occlusion
Grade 3= asynchronous movement of L arytenoid cartilage. Full abduction cannot by induced.
Grade 4 = marked asymmetry at rest. no substantial movement of the L arytenoid cartilage
30
how do you treat grade 3C and grade 4 RLN?
laryngoplasty (tie cartilage open) and ventriculocordectomy
30
what are complication after RLN surgery?
non-protected airway so can get cough and aspiration pneumonia etc
30
What is epiglottic entrapment?
envelopment of the epiglottis of the subepiglottic mucosa and aryepiglottic folds
30
what are the signs of epiglottic entrapment?
expiratory stridor
| reduced performance
30
how do you surgically treat epiglottic entrapment?
midline division of entrapping tissue
- can get re-entrapment
- the correction may predispose to DDSP
30
what is arytenoid chondritis?
chronic infection of the cartilage resulting in thickening and intraluminal granulation
30
what are the signs of arytenoid chondritis?
inspiratory stridor with exercise
30
how can you treat arytenoid chondritis?
excision of intraluminal protuberances
| -parital / complete removal of affected cartilage
30
what is choanal atresia?
membrane retained over nasopharynx in foals
30
what disease can present as epistaxis?
progressive ethmoidal haematoma (PEH)
GP mycosis
fungal sinusitis
30
what is progressive ethmoidal haematoma?
-progressively enlarging, non-neoplastic mass lesion originating in ethmoid turbinate
30
how can you diagnose PEH?
histology - resp mucosa capsule, stroma of blood, fibrous tissue, macrophages and haemosiderocyts
endoscopy - smooth green-black to red-brown mass
Rad / CT
30
how can you treat PEH?
radical excision
will recurr
laser to thermally destroy
intralesional formalin causing mass to slough -careful if through cribiform plate as will get into brain
30
why do you get epistaxis with GP mycoses?
injury of internal carotid a
external carotid a
maxillary a
30
how can you classify nasal discharge?
- character - serous/ purulent etc
- laterality
- odour
30
what does a unilateral nasal discharge tell you about its origin?
likely to be more rostral to the nasal septum
30
what nasal discharge is likely to have no odour?
LRT disease
sinusitis
pharyngitis
pouch empyema
30
what nasal discharge is likely to have a foul odour?
dental disease
neoplasia
necrotic disease
30
how can you classify an URT obstruction/noise?
- constancy - fixed/ dynamic
- quality - stridor / stertor
- phase - insp/exp/both
30
what are fixed lesions?
mass lesion
chondritis
strictures
30
what are dynamic lesions?
RLN
DDSP
AEE
30
what is stridor and what causes it?
narrowed airway
RLN
chondritis
mass lesion
stricture
30
what is stertor and what causes it?
tissue vibration
DDSP
nostril problem
30
what causes inspiratory noise?
RLN
30
what causes expiratory noise?
DDSP
| AEE
30
What causes inspiratory and expiratory noise?
mass lesions
| chondritis
30
how can epistaxis be classified?
- laterality
- association with work
- quantity
30
what can cause exercise induced epistaxis?
EIPH
30
what can cause epistaxis at rest?
GP mycosis
ethmoid haematoma
fungal sinusitis
30
what can cause modest epistaxis?
EIPH
ethmoid haematoma
fungal sinusitis
30
what disease can present as nasal discharge?
nasal passage disease - neoplasia / FB
paranasal sinusitis
guttural pouch disease
pharynx/larynx issues
30
what can cause nasal passage disease?
bacterial / fungal infection of septum/turbinates
neoplasia
FB
30
what are treatment options for nasal passage disease?
- laser to resect
- nasal septal resection
- rhinotomy
30
what can cause paranasal sinusitis?
```
dental disease
bacteria
fungi
neoplasia
inadequate drainage
```
30
what are some treatment options for paranasal sinusitis?
- medical - sinus centesis and lavage and abx
- surgical - sinoscopy and fenestration of ventral conchal bulla to encourage drainage
- flap sinusotomy if more sever
- treat dental disease
30
how is RLN graded at exercise?
Grade A = full abduction
Grade B = not fully abducted from resting position
Grade C = dynamic collapse
30
how do you treat grade 1 and 2 and 3A RLN?
no treatment
30
how do you treat grade 3B RLN?
ventriculocordectomy (stops noise) +/- laryngoplasty
30
how do you diagnose GP mycoses?
endoscopy and see blood exiting pharyngeal opening
rad - fluid line in pouch
30
how do you treat GP mycoses?
ligation of vessels
systemic antifungals
supportive care
30
what are signs of GP mycoses?
- dysphagia (CN IX, X)
- nasal dishcarge
- Horner's syndrome - symp trunk
30
what are some diseases that can present at URT swelling?
atheroma
sinus cysts
sinus neoplasia
GP tympany
30
what is an atheroma?
sebaceous cyst in nasal diverticulum
30
how do you treat an atheroma?
- normally just cosmetic
- surgical excision en toto via nostril / over atheroma
- drainage and chemical ablation of secretory lining
30
what are signs of a sinus cyst?
sinus swelling
reduced airflow
nasal discharge
epiphora (excess tears)
30
how do you treat a sinus cyst?
breakdown of cyst wall via sinusotomy
30
what diseases causing URT swelling occur in 1-2 yo?
atheroma
| sinus cysts
30
what are signs of sinus neoplasia?
```
sinus swelling
facial swelling
reduced airflow
nasal dishcarge
epiphora
pain
difficulty eating
```
30
how can you treat a sinus neoplasia?
excise via flap sinusotomy and chemo
| lateral obliteraion
30
what is a common sinus neoplasia?
sq cell carcinoma
| very aggressive
30
what is GP tympany?
excessive accumulation of air in GP
30
how can you get GP tympany?
congenital - abnormal formation of pharyngeal opening of pouch
acquired - swelling involving pharyngeal opening of pouch
30
what are some signs of GP tympany?
tympanitic swelling
dysphagia
resp distress
30
how can you treat GP tympany?
- if unilateral fenestrate the median septum via viborgs triangle / transendoscopic laser / electro scalpel
- if bilateral fenestrate median septum and restrict lateral lamina of auditory tube so air goes into nasopharynx and out
30
what anthelmintics work against dictycaulus arnfieldi?
ivermectin every 8 weeks
| moxidectin every 12 weeks
100
what is normal jugular pulse and filling?
should fill not more than 1/3 up neck
when occluded should take 4-5 secs for veing to fill up
-if prolonged suggests reduced venous return
101
common foal and weanling URT pathogens?
EHV 1+4
Equine influenza
step equi equi
102
common foal and weanling LRT pathogens?
```
EHV 1+4
Equine influenza
Bacterial pneumonia
strep. zooepidemicus
r.equi
strep equi equi
parascaris equorum
```
103
common horse URT pathogens?
```
Equine influenza
EVA
EHV1+4
strep equi equi
equine rhinovirus
```
104
common horse LRT pathogens?
```
Equine influenza
EHV 1+4
EVA
strep.zooepidemicus
strep.pneumonia
pasturella
actinobacillus
strep equi equi
```
105
What are some common ddx for horse coughing?
```
aspiration pneumonia
pleuropneumonia
pulmonary abscess
LSHF
epiglottic entrapment
URT FB
```
106
what are the clinical signs of RAO?
```
intermittent
neutrophilia
bronchospasm
dyspnoea
poor performance
heave lines
```
107
what is the pathogenesis of RAO?
lifelong condition
| -hypersensitivity reaction to an allergen in the stable
108
How can you diagnose RAO?
- endoscopy to asses mucus amount and inflammation
| - get tracheal sample and cytology - non-degenerate neutrophils, lots of mucus, curshmann's spirals
109
how can you control RAO?
bronchodilators
reduce mucus production
control environment
out in field
110
what is the difference between RAO and SPAPD
RAO is allergen in stable
| summer pasture associated disease is for allergen at pasture
111
What are the signs of inflammatory airway disease and who is it common in?
cough
reduced performance
-young performance horses
112
what causes and how can you treat inflammatory airway disease?
unknown definitive cause
- decrease dust
- Abx
- interferon
- corticosteroids
113
What pathogens are common in bacterial pneumonia?
Strep. zooepidemicus and rhodococcus equi
114
what are the signs of bacterial pneumonia?
pyrexia
cough
change on auscultation
115
how can you diagnose bacterial pneumonia?
- mucopurulent exudate in trachea
- bronchointerstitial pattern on rads
- degenerative neutrophils with intracellular bacteria
116
Where is EHV often latent and what activates it?
- bronchial Ln
- submandibular LN
- trigeminal ganglia
-stress eg lactating mares
117
what are some signs of EHV?
- abortion in last trimester
- neuro signs
- vasculitis
- viraemia
118
can you vaccinate against EHV?
- not really as natural immunity is short lived
| - also different Ag for different strains
119
who is equine influenza common in?
2/3 Yo rachehorses
| -highly infectious
120
what does influenza virus attack?
ep cells of RT - loss of ciliated ep so get secondary bacterial inf (starts upper and may spread to lower)
121
how long does influenza vax last and why is it needed?
- 2-3m
| - needed of jockey club and FEI
122
What is clenbutarol and what is it used to treat?
for RAO
- bronchodilator
- increases mucociliary clearance
- stabilises mast cells
- improves airways secretions
123
What are some anthelminitcs effective against dictycaulus arnfieldi in the horse?
oral ivermectin
oral moxidectin
oral fenbendazole
124
what are some secondary bacteria in horses?
strep zooepidemicus
strep pneumoniae
actinobacillus sp
mycoplasma
125
signs of EIV?
cough
pyrexia
depression
