Merial interim template

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Equine Gastric Ulcers How do we diagnose and
treat?
Ellie Burfoot BSc (Hons)
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Agenda

• Introduction
• Prevalence How common is this disease?
• Anatomy/physiology
• Risk Factors
• Treatment
• Prevention

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Introduction

• Damage to the equine stomach lining due to
  excessive stomach acid or problems with the
  natural protection of the stomach lining
• Serious health problem in foals and horses
• Particularly prevalent in performance horses
• Many risk factors
• May or may not show clinical symptoms
• May result in foal mortality

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Prevalence How common is this disease?

• 93 racehorses in training (Murray et. al 1996,
  1989)
• 60 other performance horses (McClure et al.
  1999, Mitchell 2001)
• More than 50 of foals have been shown to have
  EGUS (Murray 1997)
• 37 in leisure/pleasure horses
• Donkeys 50?

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How did nature intend the horse to live?
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Compartments of the Equine Stomach
Cardia
Squamous mucosa
Duodenum
Pylorus
Margo plicatus
Glandular mucosa
Pagan, World Equine Vet Rev, 1997.
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Squamous Mucosa

• Non Glandular
• No sub mucosal glands.
• No secretary or absorptive function.
• No mucus and high susceptibility to peptic
  injury.
• Most common location for gastric ulcers

Squamous Mucosa
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Glandular Mucosa

• 2/3 of equine stomach.
• Contains many secreting cell types
• Gastric G cells ? Gastrin.
• Mast cells and ? Histamine.
• Chief cells ? Pepsinogen ? Pepsin at pH lt3.0.
• Mucus neck cells ? Bicarbonate and hydrophobic
  mucus barrier.
• Parietal cells ? Hydrochloric acid

Glandular mucosa
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Inhibit acid secretion
Stimulate acid secretion
H2
Acetylcholine
Gastrin
Prostaglandins
Parietal cell
Acid Pump
H
Bicarbonate barrier
H
H
Cl-
H
H
Cl-
HCl
Stomach lumen
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Ulcer Grading

• Range in severity size and depth
• Scoring techniques assess severity and
  improvement through treatment
• Severity and clinical signs dont always
  correlate

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Grade 0 Lesion

• Intact epithelium
• May have reddening

Freedom of Information (FOI) Summary for
GASTROGARD Oral Paste for Equine Ulcers. Photo
courtesy of MJ Murray.
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Grade 1 Lesion

• Small single or multiple lesions

Freedom of Information (FOI) Summary for
GASTROGARD Oral Paste for Equine Ulcers. Photo
courtesy of MJ Murray.
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Grade 2 Lesion

• Large single or multiple lesions

Freedom of Information (FOI) Summary for
GASTROGARD Oral Paste for Equine Ulcers. Photo
courtesy of MJ Murray.
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Grade 3 Lesion

• Extensive, often coalescing, ulcers with areas of
  deep ulceration.

Freedom of Information (FOI) Summary for
GASTROGARD Oral Paste for Equine Ulcers. Photo
courtesy of MJ Murray.
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Risk Factors

• Intermittent feeding
• Diet
• Intensive Exercise
• Physical Stress

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Intermittent Feeding

• Acidity in the equine stomach is greatest in
  absence of food
• Feeding decreases acidity
• Acid secretion stimulated by food
• Food neutralises most of the acid
• Bicarbonate in saliva neutralises some acid
• If denied food ulcers can develop within 24hrs
• Horses continuously grazing therefore unlikely
  to develop ulcers

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Physiology of the Equine StomachPatterns of
Acidity
Murray and Schusser, Equine Vet J, 1993.
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Physiology of the Equine StomachPatterns of
Acidity
Murray and Schusser, Equine Vet J, 1993.
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Exercise (walk)

• High speed treadmill exercise abdominal pressure
  increases (Lorenzo-Figueras and Merritt, AJVR
  2002)
• High speed treadmill exercise pH decreases
  (Lorenzo-Figueras and Merritt, AJVR 2002)
• Acidic contents forced into acid sensitive non
  glandular stomach region

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Exercise and Gastric pH
Lorenzo-Figueras and Merritt, AJVR 2002
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Physical Stress

• Stall Confinement
• Hospitalization,
• Transportation,
• Relocation

Murray, Vet Med, 1991.
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Equine Gastric Ulcer Syndrome Stall confinement

• Day 7 in stall

• Horses on pasture normal mucosa
• 7 days stall confinement, free choice hay
  squamous lesions

Day 7 in stall
Day 0 in stall
Murray et al, Equine Vet J, 1996 Murray
(personal communication), 1999.
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Clinical Signs in Adult Horses

• Poor appetite.
• Poor bodily condition.
• Attitude changes.
• Decrease in performance.
• Mild to moderate colic.

Murray, AAEP, 1997.
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Clinical Signs in Foals

• Poor appetite or intermittent nursing.
• Colic.
• Poor body condition.
• Frequently lies on back.
• Bruxism (grinding of teeth).
• Ptyalism (excessive salivation).
• Diarrhea or history of diarrhea.

Murray, AAEP, 1997.
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Diagnosis

• Ulcers difficult to diagnose due to subtle,
  non-specific clinical signs
• Endoscopy
• Only definitive method of diagnosis
• Can be difficult due to length of digestive
  tract
• Not all veterinary practices may have 3m
  endoscope required

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Treatment of Gastric Ulcers

• Eliminate clinical signs
• Promote healing of ulcer
• Prevent recurrence
• Inhibit gastric acid secretion

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Treatment of Gastric Ulcers

• Main traditional drug therapies
• Antacids
• Histamine H2 Receptor Antagonists
• Ulcer-coating agents (sucralfate)
• Not approved for use in horses
• No large-scale assessment of safety or
  effectiveness
• No recommended dose or administration schedule
• Variable results
• Horses removed from training

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Omeprazole

• Proton pump inhibitor binds to HK - ATPase
  pump
• Blocking pump shuts down the acid secretion
  allowing ulcers to heal
• Only medication capable of blocking pump
• Identifying pump stimulator not necessary.
• First and only medication approved for use in and
  prevention of gastric ulcers in foals and horses
• Do not have to remove horse from training. Most
  widely prescribed anti-ulcer therapy in humans
  (Losec)
• Suppressor of gastric acid secretion
• GastroGard - Omeprazole paste - developed
  specifically for EGUS in horses

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The Acid Pump
Stimulate acid secretion
H2 Receptor Antagonists
H2
Gastrin
Acetylcholine
Prostaglandins
Parietal cell
Acid Pump
Acid pump Inhibitor GASTROGARD
H
Bicarbonate barrier
H
H
Cl-
H
H
Cl-
Stomach lumen
HCl
Antacids
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Ulceration does not just affect racehorses!
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Case study 1

• 8 yo Welsh section C
• Jumping pony
• At pasture for 4 hrs per day (overweight), good
  eater
• No history of ulcers but really naughty in stable
  and under saddle
• Better jumper in summer
• Bad cribber wind sucks
• Recently lethargic, and had bout of colic
• Scoping revealed squamous ulceration grade 2/3
  localised to fundus, appearing to be along fold

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Case Study 2

• 6 year old advanced eventer currently off work at
  pasture as season over 2 months previous I.e on
  holiday
• During season difficult to keep weight on and can
  be bucking bronco especially when show jumping
• Ulceration in squamous region grade ¾ in
  glandular grade 4

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Case Study 3 - 9yo Warm blood Dressage

• Kept lying down, especially before a competition
  although never developed colic
• Became lethargic and thin, poor coat
• Grade 2 ulcers
• 4 weeks GastroGard at 4mg/kg.
• Clear after 4 weeks.
• In an effort to cut costs switched to ranitidine.
  Signs reappeared almost immediately
• Now on low dose GastroGard throughout the season
• Increased frequency of feeds from 2 to 4 times
  daily and always has a full hay net

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Case Study 4 14yr old KWPN Paralympic Team
Dressage horse

• Team dressage horse always done well, recently
  seen inconsistent performances especially if
  travelled
• Pain on girthing up and bucking bronco for first
  few strides!
• Routine scoping of Team GB horses revealed grade
  3 squamous and glandular ulcers
• Successfully treated for 2 weeks, and performance
  is more consistent and no bucking!

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Prevention of Gastric Ulcers

• ENVIRONMENTAL
• Turn the horse out to pasture as much as possible

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Prevention of gastric Ulcers

• FEEDING PRACTICE
• Regular feeding - the less time a horse has an
  empty stomach the better
• Have hay available at all times while the horse
  is in the stall 2/3 hay nets?
• Alfalfa hay can help buffer stomach acid due to
  high calcium and protein content (Nadeau et al
  2000)
• Limit grain rations
• Scatter feeding and apple bobbing!

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Prevention of Gastric Ulcers

• EXERCISE
• Dont train on an empty stomach
• Consider exercise regime increased risk of
  ulcer formation in horses under intense training
  schedules

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The Take Home Message!

• Ulcers can affect any breed, age or discipline.
• As horse owners you can prevent ulcers through
  good management.
• Clinical signs are subtle and non specific.
• Ulcers can be successfully treated with no long
  term affects.

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Gastroscopy Clinic at Priors Farm

• Wednesday 6th June
• 6-8 horses can be scoped.
• If you feel your horse is a suitable candidate
  please speak to one of the Vets tonight or phone
  the practice.
• Gastroscopy will be free on the day for those
  horses selected.

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• Thank you!