Megaesophagus in Dogs (Canis) | Vetlexicon (2024)

• Generalized and diffuse dilation of esophagus and loss of peristalsis preventing normal forward propulsion of ingesta.
• Cause: primary congenital, secondary acquired.
• Signs: regurgitation, repeated swallowing attempts, poor body condition + coughing/nasal discharge with secondary aspiration pneumonia.
• Diagnosis: plain radiography.
• Treatment: dependent on cause.
• Prognosis: guarded.

Print off the owner factsheet MegaoesophagusMegaoesophagus to give to your client.

Presenting signs

• Persistent regurgitationRegurgitation.

• Repeated swallowing attempts.
• Dysphagia.
• Weight loss or poor growth.

• Coughing.
• Nasal discharge.
• Ptyalism.
• Halitosis.
• Other signs depend upon underlying etiology.

Age predisposition

• <1-2 years old, usually at weaning from liquid diets to more solid foods(congenital).

• Any age depending on the etiology (acquired).

Breed/Species predisposition

Congenital

• Wire Haired Fox TerrierFox Terrier - Wire(autosomal recessive).
• Miniature SchnauzerSchnauzer: miniature(autosomal dominant or 60% penetrance autosomal recessive).
• Irish SetterIrish Setter.
• Great Dane Great Dane.
• Shar Pei Chinese Shar Pei.
• NewfoundlandNewfoundland.
• German Shepherd dogGerman Shepherd Dog.

Special risks

• Contrast radiography: force-feeding barium risks barium aspiration → bronchopneumonia.

Etiology

• Failure of sensory perception of a food bolus in esophagus, so no peristaltic contraction.
• Primary:
  • Congenital.
• Acquired:
  • Idiopathic.
  • Esophageal foreign bodyEsophagus: foreign body.
  • Esophageal strictureEsophagus: stricture.
  • Esophageal or periesophageal neoplasia Esophagus: neoplasia (lymphoma, leiomyoma...).
  • Right aortic archVascular ring anomalies.
• Acquired systemic:
  • Myasthenia gravisMyasthenia gravis.
  • Myositis/myopathic disease Myopathies.
  • Suspected hereditary generalized neuropathy in a number of breeds.
  • BotulismClostridium botulinum.
  • Addison's diseaseHypoadrenocorticism.
  • Lead poisoningLead toxicity.
  • Organophosphate toxicity Organophosphorus poisoning.
  • HypothyroidismHypothyroidism.

Specific

• Neuromuscular disease, eg myasthenia gravis Myasthenia gravis, Addison's disease Hypoadrenocorticism, myositis or other myopathy Masticatory myopathies.
• Secondary esophageal obstruction.

Pathophysiology

• For both congenital and acquired idiopathic forms a selective vagal afferent dysfunction seems to play a major role.
• Failure of sensory perception of food bolus in esophagus, therefore no peristaltic contraction.
• Ingesta pools in esophagus.
• Regurgitation of food follows.
• Aspiration pneumonia common.

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.
• Bell S M, Evans J M, Evans K M, Tsai K L, Noorai R E, Famula T Ret al(2022) Congenital idiopathic megaesophagus in the German shepherd dog is a sex-differentiated trait and is associated with an intronic variable number tandem repeat in Melanin-Concentrating Hormone Receptor 2. PLoS Genet 18(3), e1010044doi.org/10.1371/journal.pgen.1010044.
• Mace S, Shelton G D, Eddlestone S (2012) Megaoesophagus. Compend Contin Educ Vet 34 (2), E1 PubMed.
• Fracassi F, Tamborini A (2011) Reversible megaoesphagus associated with primary hypothyroidism. Vet Rec 168 (12), 329b PubMed.
• McBrearty A R, Ramsey I K, Courcier E A, Mellor D J, Bell R (2011) Clinical factors associated with death before discharge and overall survival time in dogs with generalized megaoesophagus. JAVMA 238 (12), 1622-1628 PubMed.
• Wray J D, Sparkes A H (2006) Use of radiographic measurements in distinguishing myasthenia gravis from other causes of canine megaoesphagus. JSAP 47 (5), 256-263 PubMed.
• Gaynor A R, Shofer F S & Washabau R J (1997)Risk factors for acquired megaesophagus in dogs.JAVMA211 (11), 1406-1412 PubMed.
• Mears E A & Jenkins C C (1997)Canine and feline megaesophagus.Comp Cont Ed Prac Vet19 (3), 313-326 VetMedResource.
• YamP S, Shelton G D and Simpson J W (1996)Megaesophagus secondary to acquired myasthesia gravis.JSAP37 (4), 179-183 PubMed.
• Simpson J W (1994 )Management of megaesophagus in the dog.In Practice16, 14-16 InPractice.

Other sources of information

• Willard M D (1992)Dysphagia and swallowing disorders.In: Current Veterinary Therapy X. W B Saunders, Philadelphia. 572-580.
• Guilford W G (1990)Megaesophagus in the dog and cat.Seminars in Vet Med and Surg5, 37-45.

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