Equine Upper GIT Conditions PDF

CONDITIONS OF THE EQUINE UPPER GASTROINTESTINAL TRACT HOLLY LENAGHAN BVETMED FHEA MRCVS With thanks to: Mike Cathcart LEARNING OBJECTIVES 1. Describe the risk factors and typical clinical presentation of oesophageal obstruction i...

CONDITIONS OF THE EQUINE UPPER GASTROINTESTINAL TRACT HOLLY LENAGHAN BVETMED FHEA MRCVS With thanks to: Mike Cathcart LEARNING OBJECTIVES 1. Describe the risk factors and typical clinical presentation of oesophageal obstruction in horses and understand the treatment options and potential consequences of choke. 2. Understand the pathophysiology of equine gastric ulceration syndrome (EGUS) 3. Differentiate between squamous and glandular ulceration 4. Outline the different treatment options and recommend appropriate management strategies in the treatment of EGUS OESOPHAGEAL OBSTRUCTION (CHOKE) Physical obstruction of the oesophagus, usually with organic matter Rapid ingestion of food Dry, coarse feed stuffs Poor mastication / Dental disease Primary oesophageal abnormalities Can occur at any level of the oesophagus. Common areas; 1. Proximal oesophagus 2. Thoracic inlet 3. Heart Base 4. Cardia OESOPHAGEAL OBSTRUCTION (CHOKE) Clinical Signs Profuse salivary/food stained nasal discharge Drooling Repeated spasm of neck muscles – stretching neck Anxiety/agitation Coughing Possibly mild tachycardia Palpable mass in left lateroventral aspect of neck https://youtu.be/qk47XCBvDNk?t=50s https://youtu.be/PzHfOdO_z6U?t=30s OESOPHAGEAL OBSTRUCTION (CHOKE) O E S O P H A G E A L O B S T R U C T I O N - T R E AT M E N T Many cases self-resolve, or with do so with GIVE TIME conservative treatment O E S O P H A G E A L O B S T R U C T I O N - T R E AT M E N T Many cases self-resolve, or with do so with GIVE TIME conservative treatment Lower head, encourage drainage of food/saliva SEDATION Relax oesophageal muscle Intravenous sedation Alpha-2 agonist (e.g. detomidine/romifidine) + / - Butorphanol (opioid) Oesophageal relaxation Skeletal muscle or smooth muscle relaxation??? Buscopan (butylscopalamine) Well tolerated and safe Oxytocin Can cause colic signs O E S O P H A G E A L O B S T R U C T I O N - T R E AT M E N T Many cases self-resolve, or with do so with GIVE TIME conservative treatment Lower head, encourage drainage of food/saliva SEDATION Relax oesophageal muscle Massage Oesophagus Encourage breakdown of obstruction Simple obstructions may clear with passage of tube Pass Nasogastric (NG) Tube MUST BE CAUTIOUS – can cause damage to oesophagus Only used to lubricate / hydrate obstruction Low Volume Lavage with NG Tube NOT USED TO ‘FLUSH’ obstruction High Volume Only appropriate when the AIRWAY IS PROTECTED Lavage/Endoscopic Removal Cuffed Nasogastric tube (Referral) Endotracheal intubation under GA OESOPHAGEAL OBSTRUCTION – CHRONIC CASES All cases of choke that haven’t resolved with 24 hours of conservative treatment; Warrant further investigation May require more aggressive therapy Referral to hospital Will be in need of fluid therapy Should receive systemic antimicrobials Potentiated sulphonamides Penicillin Pain relief NSAIDs e.g. Phenylbutazone/Flunixin (care: possible renal compromise if dehydrated) Aspiration Dehydration Fatigue Pneumonia OESOPHAGEAL OBSTRUCTION – CASE EXAMPLE OESOPHAGEAL OBSTRUCTION – CASE EXAMPLE O E S O P H A G E A L O B S T R U C T I O N – L O N G T E R M C O M P L I C AT I O N S Stricture formation Circular fibrous submucosal scarring Diverticulum formation Defects in muscular layers of oesophagus Oesophageal rupture Iatrogenic from NG tube OESOPHAGEAL OBSTRUCTION – RECURRENT CASES Some horses develop recurrent secondary choke episodes, associated with underlying pathology of the upper GI tract. Dental disease – incomplete mastication of food Oesophageal abnormalities – structure or diverticulum Further diagnostics Closely assess the horse eating & drinking Complete dental examination Endoscopy of larynx/pharynx & GP Diastemata Oesophagoscopy Barium swallow study (Fluoroscopy) OESOPHAGEAL OBSTRUCTION – RECURRENT CASES Some horses develop recurrent secondary choke episodes, associated with underlying pathology of the upper GI tract. Dental disease – incomplete mastication of food Oesophageal abnormalities – structure or diverticulum Further diagnostics Closely assess the horse eating & drinking Complete dental examination Wikivet Endoscopy of larynx/pharynx & GP Oesophagoscopy Barium swallow study (Fluoroscopy) Hillyer 1995, In Practice OESOPHAGEAL OBSTRUCTION – PREVENTION Modify feeding regimen Dampen ‘high risk’ hard-feeds; Sugar Beet pulp Coarse chaff Feed smaller volumes more regularly Do not feed immediately after exercise (or after sedation!) Reduce excitement prior to feeding Allow access to hay prior to feeding hard-feed Place obstacles in the food bowl Large stones or plastic balls Pre-chopped, fine roughage for horses with dental disease Pre-soaked pelleted ration for horses with oesophageal disease EQUINE GASTRIC ULCER SYNDROME ( EGUS) G A S T R I C A N AT O M Y A N D P H Y S I O LO G Y – R E V I S E ! Squamous mucosa Lines the cardia and fundus – no digestive function Glandular mucosa True gastric mucosa, with acid secreting glands Parietal cells – Proton pumps secrete hydrochloric acid in response to histamine Glandular Mucosal Protection ✓ Mucus and bicarbonate secretion ✓ Prostaglandin synthesis Improves mucosal blood flow and promotes healing ✓ Buffering effect of food and saliva – should be continuous A NORMAL STOMACH Squamous mucosa Margo Plicatus Glandular mucosa EQUINE SQUAMOUS GASTRIC DISEASE (ESGD) Due to direct contact with gastric acid Common along greater or lesser curvature dorsal to the margo plicatus High prevalence in performance horses 90-100% prevalence in TB racehorses Risk Factors High carbohydrate - Low forage Diet Intermittent feeding / periods of fasting Water restriction Stress Intense exercise EQUINE SQUAMOUS GASTRIC DISEASE (ESGD) Due to direct contact with gastric acid Common along greater or lesser curvature dorsal to the margo plicatus High prevalence in performance horses 90-100% prevalence in TB racehorses Risk Factors High carbohydrate - Low forage Diet Intermittent feeding / periods of fasting Water restriction Stress Intense exercise EQUINE GLANDULAR GASTRIC DISEASE (EGGD) Due to breakdown in mucosal defenses Inflammation - hyperaemia - erosion - ulceration In conjunction with squamous or as sole lesions High grade lesions and lesions associated with the pyloric region are usually clinically significant Pyloric region more common Risk Factors Similar risk factors as for squamous ulceration Decrease prostaglandin synthesis Stress NSAID administration (in theory) EQUINE GASTRIC ULCER SYNDROME( EGUS) Other aetiologies Secondary gastric disease Reduced gastric emptying Gastric impaction Gastric neoplasia / granulomatous disease Bacterial involvement?? No primary pathogens have been definitively identified in equine EGUS H.pylori in humans Secondary bacterial infection of ulcer bed has been documented and may interfere with ulcer healing EGUS – CLINICAL SIGNS DIAGNOSIS Clinical signs can be variable/vague Clinical signs Not reliable or consistent Poor performance Altered or variable appetite Gastroscopy Definitive diagnosis Preference for certain feeds Weight loss or poor weight gain Changes in behavior Coat changes – ill thrift “Girthing”/epigastric pain Recurrent colic Response to treatment Expensive way to find out it’s not EGUS  Equine Squamous Gastric Disease (ESGD)  Equine Glandular Gastric Disease (EGGD) E G U S – T R E AT M E N T Aim to keep pH > 4 HCl → pH E G U S – T R E AT M E N T Proton Pump Inhibitors Antacids/Buffers OMEPRAZOLE CaCO3 - Mg(OH)2 - Al(OH)3 Only licensed treatment available Need to be given every 1-3 hours to be Very effective, high safety margin effective Irreversibly impair the H+K+ATPase pump No clinical evidence to support use Acid-labile – requires enteric coating or buffering to increase bioavailability Aim to keep pH > 4 Prostaglandin analogue HCl → pH Misoprostol 5 ug/kg PO BID or TID Increased gastric mucosal blood flow, supresses gastric acid Mucosal Protectants Not for ESGD / Not with Omeprazole Sucralfate 12-25mg/kg per os BID or TID Binds to ulcer bed and stimulates H2-Antagonists prostaglandin secretion Ranitidine Benefit in early ulcer treatment 6.6mg/kg per os TID for 4-6 weeks Inferior response cf Omperazole May have more benefit in foals Has been discontinued E G U S – T R E AT M E N T 4mg/kg per os once daily for 28 days = 70-77% healing rate (ESGD) Consider: Degree of acid suppression achieved (Dose) Very good responses often seen at 1 or 2mg/kg Persistence of effective suppression after one dose (Frequency) Is it worth giving twice daily in severe cases or those not responding Follow-up gastroscopy is important to assess response and plan further therapy E G U S – T R E AT M E N T O P T I O N S Equine Squamous Gastric Disease Equine Glandular Gastric Disease (ESGD) (EGGD) Proton Pump Inhibitors OMEPRAZOLE Proton Pump Inhibitors OMEPRAZOLE 3 weeks Mucosal Protectants Sucralfate 4-8 weeks E G U S – T R E AT M E N T O P T I O N S – R E F R A C T O R Y C A S E S Equine Squamous Gastric Disease Equine Glandular Gastric Disease (ESGD) (EGGD) Proton Pump Inhibitors Proton Pump Inhibitors Long-acting Injectable OMEPRAZOLE Long-acting Injectable OMEPRAZOLE Off License Or Esomeprazole 3 weeks Off License Or Prostaglandin analogue?? Misoprostol ?? 5 ug/kg PO BID or TID Increased gastric mucosal blood flow, supresses gastric acid Not for ESGD / Not with Omeprazole Off Licence EGUS – MANAGEMENT / PREVENTION Ensure continual grazing behaviour (18hrs per day!) Avoid prolonged fasting Provide regular access to pasture Feed smaller volumes more regularly Provide good quality forage Lucerne (legume roughage) high in Ca++ - natural buffering effect Avoid diets high in starch / soluble carbohydrates Utilise oil for weight gain if needed – corn oil shown to be beneficial Minimise stress Tailor exercise regimen – reduce periods of high intensity exercise Supplements – no evidence of efficacy, possible pectin-lecithin compounds REFERENCES ECEIM Consensus Statement - Equine Gastric Ulcer Syndrome in Adult Horses. B.W. Sykes., et al, J Vet Med 2015; 29:1288–1299 UK Vet Equine - Equine gastric ulcer syndrome in horses and foals 37