Presentation on theme: "Diseases of the Stomach"— Presentation transcript:
1 Diseases of the Stomach Frank M. Andrews, DVM, MS, DACVIMProfessor of LA MedicineThe University of Tennessee, CVM
2 Equine Gastric Ulcer Syndrome Photo courtesy of MJ Murray.
3 Prevalence of Equine Gastric Ulcer Syndrome (EGUS) 60% to 93% in performance horses25% to 50% in foalsMurray et al, Equine Vet J, 1996; Murray, JAVMA, 1989; Murray, AAEP, 1997.
4 EGUS: Public Perceptions Telephone Survey conducted in 2003, of 300 performance horse owners
5 Impact of EGUS on Adult Horses Results in poor body conditionCan disrupt trainingCan impair performanceCan cause colicCan have severe complicationsduodenal stricturesMurray, AAEP, 1997; Murray, Vet Med, 1991.
6 Photos courtesy of MJ Murray. Impact of EGUS on FoalsGastric outflow obstructionEsophagitisChronic ulcerationPerforation (rupture) & peritonitisPhotos courtesy of MJ Murray.
7 The Stomach of the Horse Nonglandular region(squamous epithelium)EsophagusDuodenumMargo plicatusPylorusGlandular region(glandular epithelium)
8 Compartments of the Equine Stomach Squamous (nonglandular) tissue. Less resistant to acid injury. 80% of equine ulcersGlandular & mucus-secreting tissue. More resistant to acid injury. 20% of equine ulcersPagan, World Equine Vet Rev, 1997.
9 Cause of EGUS: Aggressive Factors Overpowering Defensive Factors Gastric lining damage occurs when:Aggressive (acid, pepsin, bile, organic acids) factors overpowerDefenses (bicarbonate, mucus) of gastric mucosaSquamous mucosa lining lacks these defensesSMMPGMMurray, Equine Vet J Suppl, 1992; Sweeney, In Practice, 1992; Pagan, World Equine Vet Rev, 1997; Murray and Schusser, Equine Vet J, 1993.
10 Risk Factors for EGUS: Training/Racing Intensive exerciseReduced blood flow to the stomach lining?Increased gastric acidity?Altered eating behavior?March 25June 3
11 Acids forced into the proximal stomach Increased intra-abdominal presssure during intense exercise causesgastric compression, pushing acid contents into proximal stomachHCl,VFAsBile acidsLorenzo-Figueras and Merritt, AJVR 2002;63:
12 Risk Factors for EGUS: Feeding Feeding managementLow prevalence of ulcers in horses at pastureMurray et al, Equine Vet J, 1996.
13 Risk Factors for EGUS: Feeding Decreased acid when roughage availableIncreased serum gastrin when fed concentrates (grains & sweet feeds)Intermittent feed deprivation = gastric ulcersStall confinement = gastric ulcersFeeding alfalfa hay may help!
14 Gastric Acidity Profile: No Feed 24-Hr Gastric pH: Feed Withheld7654pH3216121824Time (hours)Murray and Schusser, Equine Vet J, 1993.
15 Gastric Acidity Profile: Grass Hay 24-Hr Gastric pH: Free Choice Hay87654pH3216121824Time (hours)Murray and Schusser, Equine Vet J, 1993.
16 Hydrochloric Acid-Induced Ulcers Gastric acidity is high in empty stomachIntermittent feed deprivationLesions form in squamous mucosaNo lesions form in glandular mucosaLesions prevented by ranitidine (Zantac®)Day 048 hours96 hoursMurray and Schusser, Equine Vet J, 1993; Murray and Eichorn, Am J Vet Res, 1996.
17 Risk Factors for EGUS: Stress Physical stressIllnessPainful musculoskeletal disorderBehavioral stressStall confinementTransportUnfamiliar environment, social regrouping
18 Risk Factors for EGUS: Non-Steroidal Anti-Inflammatory Drugs Phenylbutazone & Flunixin Meglumine and other NSAIDsAssociated with ulcers throughout the intestinal tract (Cecum & Colon)Inhibit prostaglandins, interrupting mucosal blood flow and mucusLocal toxicityMurray, Vet Med, 1991.
19 Clinical Signs of EGUS in Adult Horses Poor appetitePoor body conditionAttitude changesDecrease in performanceMild to moderate colicMurray, AAEP, 1997.
20 Clinical Signs of EGUS in Foals Poor appetite or intermittent nursingColicPoor body conditionFrequently lies on backBruxism (grinding of teeth)Excessive salivation (Ptylism)DiarrheaMurray, Vet Med, 1991.
22 How can you tell that a Horse has EGUS? (Diagnosis) Clinical signs are suggestive of, but not specific for, EGUSLab: Mild anemiaResponse to treatment can be usefulGastric endoscopy is only definitive diagnostic tool
23 Endoscopic Evaluation Endoscope quality & dimensions9 ft longSmall diameterPatient preparationExperienceMurray, Vet Med, 1991.
28 Treatment of EGUS Eliminate clinical signs Promote healing Prevent complicationsPrevent recurrencesMacAllister, Vet Med,
29 There Are Two Compatible Approaches to Treatment Management modificationsMedical therapy-approaches that have been usedControl gastric acidMucosal protectantsMurray, AAEP, 1997; MacAllister, Vet Med, 1995.
30 Traditional Management Modifications Reduce level of training
31 Traditional Management Modifications Diet modificationsLimit periods of fastingIncrease roughagepasture turnout (green grass)free choice hayAlfalfa hay-dietary antacidReduce grain/concentratesSeahorn, LSU Equine Vet Res Program Newsletter, 1998; Pagan, World Equine Vet Rev, 1997.
32 Dietary Management Fresh Rice Bran and Rice Bran Oil Contains surface active phospholipids and cytoprotective factors that maintain health of the stomach liningRancidity can be a problemProduces ketoaldehydes which are ulcerogenicSteam pasteurization can help decrease potential for rancidityStorage in refrigerator
34 Organic Acids (VFAs or SCFAs) High Concentrate Diets Acetic, Butyric, Propionic, and Valeric AcidsByproducts of carbohydrate fermentation in the stomachSynergistic with HClMay lead to non-glandular ulcersIncreased VFA’s with increased grain
35 Medical Management of EGUS Neutralizing agentsAntacidsAntisecretory agentsHistamine H2 receptor antagonistsProstaglandin analogAcid pump inhibitorsOthers (antibiotics, neutriceuticals)MacAllister, Vet Med, 1995.
36 Route of administration Commonly used Anti-Ulcer Medications, Routes, & DosesDrugDosage (mg/kg BWT)DosingintervalRoute of administrationRanitidine*6.6Q 6-8 hPORanitidine1.5Q 6 hi.v., i.m.Cimetidine20-25Omeprazole **(GastroGard)4Q 24 hOmeprazole0.5i.v.Sucralphate20-40Q 8 hAl/MgOH antacids0.5 to 1.0 ml/kgQ 4-6 h**GastroGard, Merial LTD, Atlanta, GA. Only Drug Approved for horses
37 GASTROGARD® (Omeprazole) New oral-paste formulation of omeprazole developed specifically for horsesWell-studied, effective, and safe therapy for EGUSApproved for use in horses, March 1999
38 Ulcer Treatments Act at Different Sites Site of ActionH2 antagonistsH2 (+)ACh (+)Gastrin (+)Prostaglandins (-)PARIETAL CELLGASTROGARD™ACID PUMPH+H+SucralfateMUCUS/BICARBONATE BARRIERH+H+H+CI-CI-CI-H+H+CI-STOMACH LUMENAntacids
39 GastroGard® Allows Healing/Improvement of Ulcers Sham Dosed (n = 25)69/75 (92%)100GASTROGARD (n = 75)58/75(77%)75Percent (%)508/25 (32%)251/25(4%)ImprovedHealedFreedom of Information (FOI) Summary for GASTROGARD Oral Paste for Equine Ulcers; Andrews et al, Equine Vet J Suppl, 1999.
40 GastroGard® Advantages Profound gastric acid suppressionProlonged duration of actionOnce-daily dosingWell studied in horsesNo reported treatment-relatedhealth problems in equine trialsPrevents ulcer recurrenceCan maintain training programApproved for use in horses (GASTROGARD®)Andrews et al, Comp Cont Educ Pract Bet, 1996.
41 GastroGard®: Disadvantages No IV formulation available in USAndrews et al, Comp Cont Educ Pract Bet, 1996.
42 UlcerGard Prevention of ulcers Non-perscription strength of GastrogardSold through veterinarians
43 Histamine H2 Receptor Antagonists Zantac® (ranitidine), Tagamet® (cimetidine)Competitive inhibition of the interaction of histamine with parietal cellDose-dependent inhibition of gastric acid secretionMacAllister, Vet Med, 1995.
44 Histamine H2 Receptor Antagonists: Advantages & Disadvantages AvailabilityLow cost (generic)Zantac® has been shown to significantly inhibit gastric acid secretion in horsesMust be administered 3X dailyMurray, AAEP, 1997.
45 Antibiotic TreatmentAmoxicillin, metronidazole, clarithromycin, bismuth compounds, etc.Primarily used in humans with Helicobacter pyloriH. pylori has been associated with the stomach of horses, but not EGUSAntimicrobials may be used in horses with resistant EGUS
46 Recent Studies on Helicobacter spp. Helicobacter specific DNA isolated from horse stomachs2 horses with squamous erosions1 horse with glandular erosionsACVIM Forum-Dallas (May 2002)Scott DR, Marcus EA, Shirazi-Beechey SSP, et al. Evidence of Helicobacter infection in the horse. Proc Am Soc Microbiology 2001.
47 Feed Supplements (Neutriceuticals) NeighLox® (Kentucky Performance Products)Antacid and Coating Agents:Aluminum Phosphate, Calcium CarbonateDihydroxy-Aluminium Sodium CarbonateLabeled for prevention of heartburnNo studies in horses to prove or disproveProbably does not cause any harm
48 Feed Supplements (Neutriceuticals) G.U.T (Uckele Health & Nutrition)Gastric ulcer transnutrient for horses with ulcersIngredientsGelatinLactobacillus acidophilus, L. lactisFeed 15 grams (1 scoop) twice daily in horses with ulcersNo studies proving efficacy
49 Feed Supplements (Neutriceuticals) TractGard (Foxden Equine)Equine GI rehydrator, antacid, digestaid, and electrolyte saltIngredients (1 to 2 scoops daily)Calcium carbonate, Sodium sequiscarbonate, KCl, MgSO4, distiller’s grain, yeast, and linseed mealNo studies on efficacy
51 Conclusions- General EGUS is a major cause of illness 60-93% of performance horses have EGUSImpacts health, performance, economicsOccurs when aggressive factors overpower gastric defenses
52 Conclusions- General Diagnosis requires endoscopy Presumptive diagnosis made based on clinical signs following complete diagnostic evaluationTreatment: management and medical interventions
53 Conclusions- Treatment Zantac®-healing 3X daily treatmentDietary supplements-not testedGastroGard® (omeprazole)Only FDA approved treatmentProvides potent, long-lasting gastric acid suppression in horses (once daily administration)92% to 99% improvement in ulcer scores in trials and a wide safety marginUlcerGard Prevention of Ulcers
54 Duodenal Ulcers/Stricture Part of EGUS (more commonly in foals)Similar pathogenesisSimilar clinical signsUsually associated with bruxism, ptylism, and diarrhea (occurs most often in foals)Delayed gastric emptyingAssociated with esophagealulcers
57 Gastric Neoplasia Uncommon in older horses Squamous cell carcinoma, most commonOthers: lymphosarcoma, adenosarcomaArises from squamous mucosa and metastasizes to the abdominal cavity and viscera and/or extends up the esophagusClinical signs:Chronic weight lossAnemiaNaso-gastric refluxColic
59 Gastric Impaction Infrequent cause of Colic in horses Dry feed material and decreased water intakeMay occur during winter when dry hay is fed and water intake is lowerDiagnosed at surgery in horses with colicEndoscopic examinationTreatment with dioctyl sodium succinate (DSS)5% solution via NG tube in 4 to 6 L fluidLavage at surgery, resolve in 24 – 48 hours