Role of botulinum toxin injection in treatment of achalasia

Achalasia is an uncommon disorder that can be found in children and adults of any age which typically presents with dysphagia, chest pain, and/or regurgitation of food. With the evolution of treatment options, decisions about optimal treatment have become more complex. This review aims to address the role for botulinum injection in the management of achalasia. After a period of enthusiasm for this treatment in the 1990s, most current guidelines suggest that its role is primarily restricted to adult patients who are unfit for more definitive therapies, such as balloon dilatation, Heller's myotomy with partial fundoplication (usually performed laparoscopically), or peroral endoscopy myotomy (POEM). Idiopathic achalasia occurs due to a loss of the nitric oxide-releasing inhibitory nerves in the lower esophageal sphincter, which creates an imbalance between excitatory input added to intrinsic myotonic tone and inhibitory input. The concept behind botulinum toxin injection for achalasia is that it addresses this imbalance by blocking acetylcholine release from excitatory neurones acting on the lower esophageal sphincter. This results in a decrease in lower esophageal sphincter tone that can allow improved esophageal emptying. This review is based on a Medline search of relevant guidelines and literature, with the aim of identifying when botulinum toxin is an appropriate treatment option for achalasia. We also examine what is known about patient selection, technique, efficacy, duration of efficacy, and best practice in terms of botulinum toxin injection for achalasia.