equine dysautonomia

Question 1

Equine dysautonomia is described in the US?

Answer 1

yes, one case in a mule in the US

Question 2

Supportive factors for involvement of Clostridium Botulinum in ED (5)

Answer 2

• reported sucessful historic botulinium vaccine trial
• greater prevalence of intestinal C botulinium and/or toxin in patients with ED vs control
• risk factor supportive of involvement of a soil-borne agent
• inverse association between disease risk and systemic concentration of antibodies against C Bot bacteria and toxin
• higher mucosal IgA against BoNT/C and D in patient with acute ED vs control

Question 3

refutative factor for involvement of Clostridium Botulinium in equine dysautonomia (2)

Answer 3

• disease phenotipic difference between ED and neuroparalytic botulism
• greather prevalence of other (non C-botulinium) clostridial specied in intestinal tract of patient with ed vs controls
• neuropathology apparent inconsistent with action of C bootulinium neurotoxin
• lack of evidence of temporal and geographic clustering of ED and neuroparalytic botulism cases

Question 4

Supportive factors for involvement of mycotoxin in ED

Answer 4

association with grazing, seasonality, geographic and temporal clustering of cases

Question 5

factor associated with increased occurence of ED : horse level

Answer 5

• age (2-7 y)
• low serum antibodies to C Botulinium and BoNT/C
• good body condition
• contact with prevoious patient with ED

Question 6

factor associated with increased risk of ED:
premises level

Answer 6

previous ED occurence on premises (occ)
high soil nitrogen content (occ)
pasture/soil disturbance (occ)
high number of horses (occ)
presence of younger animal (occ/rec)
stud farms/ livery and riding establishment (rec)
loam and sandy soil (rec)
rearing of domestic birds (rec)
high herbage iron, lead, arsenic, chromium (ass)
abundance of ranunculus spp (buttercups) (ass)
high soil titanium (occ)
low soil zinc and chromium (occ)
chalk soil (decrase rec)

Question 7

factor associated with increased risk of ED
management level

Answer 7

grazing (occ)
recent movement (especially within preceding 2 weeks) (occ)
change in feed type/quantity within preceding 2 weeks (occ)
ultimate and penultimate use of an ivermectine-based antihelminthic (occ)
mechanical removing of feces from pasture (rec)
manual removing of feces from pasture (decrease rec)
grass cutting (decrease rec)
cograzing with ruminant (dec rec)
feeding of supplementary hay/haylage (dec occ)

Question 8

factor associated with increased risk of ED
climate level

Answer 8

recent (within 10-14d) cool, dry weather and irregular ground frosts (occ)
increase sun hours and frost days (occ)
higher averge max temperature ( dec occ)

Question 9

clinical signs present in acute/subacute and chronic ED (7)

Answer 9

dull mentation
reduced appetite
bilateral ptosis (almost invariably present)
rhinnitis sicca
dysphagia
sweating
muscle tremors (triceps, flanc, quadriceps)
elevated temperature

Question 10

clinical signs only present in acute ED (5)

Answer 10

marked tachycardia (60-120 bpm), hypersalivation (maj acute, intermittent), abdominal pain, absence of intestinal sound, intestinal distention

Question 11

prognostic indicator in chronic ED

Answer 11

degree of dysphagia

Question 12

clinical signs only present in chronic ED (6)

Answer 12

Base-narrow stance
tucked-up abdominal silhouette
stertor resulting from rhinnitis sicca,
paraphimosis,
esophageal choke,
pneumonial aspiration

Question 13

blood test abnomalities in ED

Answer 13

increase hematocrit, elevated serum urea concentration, elevated serum acute phase protein concentration, elevated urine specific gravity, protein and creatinine concentration, fecal C perfringens detection (ELISA), elevated peritoneal fluid specific gravity and prot concentration

Question 14

diagnostic test for ANS/ ENS dysfonction in ED

Answer 14

• temporary reversal of ptosis following topical application of 0.5% phenylephrine
• barium swallow study (retrograde flow)
• esophagoscopy (retrograde flow)
  -nasogastric intubation (voluminous foul smeling gastric fluid reflux)
• abdominal US (distended small intestine loops)
• transrectal palapation (generalised intestinal ileus, dessication of fibrous ingesta)

Question 15

histopathological examination of ileal biopsy in ED

Answer 15

1/ HE: neuronal loss and chromatolysis within myenteric and submucous plexuses
formalin fixed: 100% sensitive and specific
cryostat section: suboptimal (73%) specificity (processing artifact)
2/ synaptophysin immunostaining: combined assessement of neuronal density and intensity of synapto, 100% sensitivity and specificity

Question 16

histopathological examination of rectal biopsy in ED

Answer 16

HE: sensitivity 21% when applied to partial thickness
BAPP immunostaining: 100% spec/sens

Question 17

histopathological examination of gustatory papillae in ED

Answer 17

100% specificity, 98% specificity

Question 18

histological features of equine dysautonomia

Answer 18

chromatolysis with:
- loss of Nissl substance,
- eccentricity or pyknosis of the nuclei,
- neuronal sweling and vacuolation,

accumulation of intracytoplasmic eosinophilic spheroids and axonal dystrophy

Question 19

criteria used for selection of appropriate patients for treatment in chronic equine dysautonomia

Answer 19

• ability to swallow
• remaining appetite
• absence of continous moderate/severe abdominal pain

Question 20

prognostic indicator of equine dysautomia

Answer 20

persisatnce of complete anorexia
magnitude/ rate of weight loss
severity of rhinitis sicca
inhalation pneumonia

Question 21

long term complication of equine dysautonomia

Answer 21

poor exercice tolerence, persistent low garde dysphagia, reccurent esophageal obstruction, occasional mild colic episode, coat change
compensatory mechanism with interstitial cells of Cajal