Equine Gastrointestinal Health Quiz

Equine Upper Gastrointestinal Tract Conditions

• Learning Objectives:
  • Describe risk factors, clinical presentations, treatment options, and consequences of esophageal obstruction (choke) in horses.
  • Explain the pathophysiology of equine gastric ulcer syndrome (EGUS).
  • Differentiate between squamous and glandular ulceration.
  • Outline treatment options and appropriate management strategies for EGUS.

Esophageal Obstruction (Choke)

• Cause: Physical obstruction of the esophagus, typically by organic matter (e.g., food).
• Risk Factors:
  • Rapid ingestion of food.
  • Dry, coarse feedstuffs.
  • Poor mastication (chewing).
  • Dental disease.
  • Primary esophageal abnormalities.
• Location: Can occur at different levels within the esophagus: proximal esophagus, thoracic inlet, heart base, cardia.
• Clinical Signs:
  • Profuse salivary/food-stained nasal discharge.
  • Drooling.
  • Repeated neck muscle spasms.
  • Anxiety/agitation.
  • Coughing.
  • Possibly mild tachycardia.
  • Palpable mass in the left lateroventral aspect of the neck.

Esophageal Obstruction - Treatment

• Conservative treatment: Time for spontaneous resolution is often effective.
• Give time: Many cases resolve themselves, or with conservative treatment.
• Sedation:
  • Intravenous sedation with alpha-2 agonists (detomidine/romifidine).
  • Potentially with butorphanol (opioid).
• Intravenous sedation: Alpha-2 agonists relaxation of skeletal muscles/smooth muscle relaxation, and potentially butorphanol.
• Massage the esophagus: Encourage food/saliva drainage.
• Pass Nasogastric (NG) Tube: For simple obstructions, cautious use, to help clear material.
• Low volume lavage (with NG tube): To hydrate, lubricate obstructions.
• High volume lavage/endoscopic removal: For severe obstructions requiring removal under general anesthesia.

Esophageal Obstruction - Chronic Cases

• Treatment Failure: For cases not resolving within 24 hours.
• Further Investigation: Warrant further investigation.
• More Aggressive Therapy: May require more aggressive therapy and/or referral to a hospital.
• Fluid Therapy: In need of fluid therapy.
• Antimicrobials: Should receive systemic antimicrobials (e.g., potentiated sulfonamides, penicillin).
• Pain Management: NSAIDs (e.g., phenylbutazone/flunixin) are helpful for pain relief (use caution due to possible renal compromise in dehydrated horses).
• Important Complications:
• Dehydration
• Fatigue
• Aspiration
• Pneumonia

Esophageal Obstruction - Recurrent Cases

• Underlying Pathology: Secondary choke episodes associated with underlying conditions affecting the upper GI tract.
• Dental Disease: Incomplete mastication of food due to dental disease.
• Esophageal Abnormalities: Structural abnormalities or diverticulum.
• Diagnostics
• Closely assess eating and drinking habits
• Complete dental examination
• Endoscopy of larynx/pharynx and upper respiratory tract
• Endoscopy of esophagus, and
• Barium swallow study (fluoroscopy).

Esophageal Obstruction - Prevention

• Modify Feeding Regimen:
  • Dampen "high-risk" hard feeds (e.g. sugar beet pulp, coarse chaff);
  • Feed smaller volumes more regularly;
  • Do not feed immediately after exercise or sedation;
  • Reduce excitement prior to feeding;
  • Provide obstacles to limit access within the food bowl to prevent issues from fast eating;
  • Provide pre-chopped fine roughage for dental disease;
  • Soaking pelleted feed for esophageal disease.

Equine Gastric Ulcer Syndrome (EGUS)

• Gastric Anatomy and Physiology:
  • Squamous mucosa: Lines the cardia and fundus, not involved in digestion.
  • Glandular mucosa: Secrete hydrochloric acid (HCl) and mucus/bicarbonate to protect gastric tissues, with involvement of parietal cells and histamine.
• Glandular Mucosal Protection:
  • Mucus and bicarbonate secretion for buffering.
  • Prostaglandin synthesis to improve blood flow (healing).

Equine Squamous Gastric Disease (ESGD)

• Cause: Direct contact with gastric acid along the greater or lesser curvature dorsal to the margo plicatus.
• Risk Factors:
  • High carbohydrate, low forage diet.
  • Intermittent feeding, fasting periods.
  • Water restriction.
  • Stress.
  • Intense exercise.

Equine Glandular Gastric Disease (EGGD)

• Cause: Breakdown in mucosal defenses leads to inflammation
• Risk Factors: Similar to ESGD, plus NSAID administration (in theory).
• Location: High-grade lesions and lesions associated with the pyloric region are usually clinically significant.
• Specific complications: Inflammation, hyperemia,erosion, and ulceration.

EGUS - Clinical Signs

• Signs can be variable and vague.
• Performance issues.
• Altered or erratic appetite/feeding preferences.
• Weight loss/gain issues.
• Behavioral changes.
• Coat changes (ill thrift).
• "Girthing" or epigastric pain.
• Recurrent colic.

EGUS - Diagnosis

• Clinical signs are not reliable.
• Gastroscopy is required for definitive diagnosis

EGUS - Management/Prevention

• Ensure continual grazing behavior (18 hours per day or close to this) (to reduce periods of stomach fasting and stress).
• Regular access to pasture (reduce the likelihood of stress related issues).
• Feed smaller volumes more regularly (to prevent stomach stress).
• Provide good quality forage: Lucerne is a good option due to its high calcium content.
• Reduce or avoid high-starch/soluble carbohydrate diets, if possible.
• Utilize oil (e.g., corn oil) for weight gain as needed.
• Minimize stress (reduce stress and anxiety).
• Tailor exercise regimen: Reduce high-intensity exercise periods
• Supplements: No proven efficacy, potential benefits to pectin-lecithin compounds.

EGUS - Treatment

• Aim to keep stomach pH >4: To protect the lining of the stomach and reduce the likelihood of HCl damage.
• Treatment Options:
  • Antacids/buffers: CaCO3, Mg(OH)2, Al(OH)3 (given every 1-3 hours for effectiveness)
  • Mucosal protectants: Sucralfate (12-25mg/kg, BID or TID, to bind to damaged areas and increase prostaglandin synthesis)
  • Proton pump inhibitors (PPIs): Omeprazole (4mg/kg once daily, for 28 days or longer to manage ESGD).
• Follow-up gastroscopy is essential to monitor treatment responses to make management and treatment more planned and effective.
• Refractory Cases: Long-acting injectable omeprazole or esomeprazole can be considered, as well as misoprostol for resistant cases.

References

• ECEIM Consensus Statement on Equine Gastric Ulcer Syndrome (Sykes et al., 2015).
• UK Vet Equine information on EGUS.

Test your knowledge on equine gastrointestinal health, focusing specifically on esophageal complications and related pathology in horses. This quiz covers diagnostic methods, potential risks, and management strategies in preventing esophageal obstruction. Ideal for veterinary students and horse owners alike.