Megaoesophagus in adult dogs secondary to Australian tiger snake envenomation

Abstract

Four cases of megaoesophagus secondary to tiger snake envenomation are reported. History in all cases suggested megaoesophagus was not present prior to snake envenomation. Diagnosis of megaoesophagus was confirmed by thoracic radiography in all cases. One dog died of respiratory failure. The remaining three dogs recovered, with gradual resolution of clinical signs associated with megaoesophagus.

Acquired megaoesophagus in a Suffolk ram

“…The most common forms of the disease are congenital idiopathic megaoesophagus and secondary acquired megaoesophagus (Washabau and Hall 1997). The acquired condition is most commonly associated with myasthenia gravis hypoadrenocorticism, hypothyroidism (Mears and Jenkins 1997) and snake bite (Hopper and others 2001). …”

Four cases of snake envenomation responsive to death adder antivenom

“…Megaoesophagus is a frequent finding in other lower motor neuron disease, including tiger snake envenomation, 19 so it is reasonable to assume that the death adder venom caused megaoesophagus in Case 2. Haematuria and proteinuria in Case 2 were not investigated and method of collection was not recorded.…”

Acquired Megaesophagus Associated with Accidental Overdose of Vincristine in a Dog

“…Megaesophagus is a generalized esophageal dilation resulting from an aperistaltic esophagus, secondary to a neuromuscular disorder (Charles, 2015). It results in regurgitation, vomiting, anorexia, halitosis and aspiration pneumonia (Hopper et al, 2001;Charles, 2015). Megaesophagus can occur as a congenital or acquired disorder, or as an adult onset idiopathic disease (Quintavalla et al, 2017).…”

“…Megaesophagus can occur as a congenital or acquired disorder, or as an adult onset idiopathic disease (Quintavalla et al, 2017). Acquired megaesophagus can be caused by any diseases that inhibits esophageal peristalsis by disrupting central, efferent or afferent pathways, or function of the esophageal muscles (Hopper et al, 2001;Masoud et al, 2009;Mosallanejad et al, 2010;Charles, 2015). These diseases include polymyositis, myasthenia gravis, peripheral neuropathies and central nervous system disease (Hopper et al, 2001).…”

“…Vincristine is the vinca alkaloid class anticancer agent that is used for canine lymphoma or other hematopoietic tumors (Tsukamoto et al, 2011). Vincristine administration is known to have several side effects in dogs, including hematologic, gastrointestinal, and neurologic toxicity (Hopper et al, 2001;Masoud et al, 2009;Tsukamoto et al, 2011). These neurologic side effects include polyneuropathy and polymyopathy and can appear immediately during or shortly after administration of the drug but sometimes after cessation of chemotherapy treatment (Masoud et al, 2009).…”