What are the current management strategies for megaesophagus in dogs?

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Canine megaesophagus (ME) management is multimodal and primarily palliative, centered on elevated feeding, dietary modification, aspiration pneumonia prevention, and treatment of any identified underlying cause. Reported median survival times range from 1 to 3 months with an overall fatality rate of 74%, though individual outcomes vary substantially based on etiology and owner commitment.37 Elevated feeding is the cornerstone of management. Upright positioning during and after meals — using a Bailey chair or equivalent — reduces esophageal retention of ingesta and subsequent regurgitation.5 The optimal food consistency (liquid, soft, or solid) differs by individual dog, and determining the best regimen may require a period of trial and adjustment.5 Treatment success is defined as weight gain, reduced regurgitation frequency, and improved owner-perceived quality of life.1 Identifying and treating an underlying cause is the highest-yield intervention when one exists. Acquired ME is associated with myasthenia gravis, hypoadrenocorticism, systemic myopathies, dysautonomia, lead toxicity, severe esophagitis, and systemic lupus erythematosus.9 Myasthenia gravis carries a 50% response rate to treatment.11 Anti-acetylcholinesterase therapy is the relevant intervention for myasthenia gravis-associated ME; a positive serum anti-acetylcholine receptor antibody titer (reference limit < 0.6 mmol/L) confirms the diagnosis.8 Sildenafil, a phosphodiesterase-5 inhibitor, is used to relax the gastroesophageal sphincter (GES) and facilitate gastric emptying of esophageal contents. Liquid sildenafil at 1 mg/kg has been evaluated in dogs with ME and was well tolerated, with owner-reported reductions in regurgitation frequency and improvements in weight gain.312 Maximum GES relaxation occurs approximately 10 minutes after administration and lasts approximately 1 hour.3 Sildenafil has not demonstrated short-term benefit in ME secondary to demyelinating polyneuropathy, suggesting efficacy