**5. Treatments of GI autoimmune diseases**

### **5.1 Achalasia**

Esophagectomy is only necessary for 5% of patients with end-stage achalasia. Among the options for treating achalasia are botulinum toxin injection, pneumatic dilation, laparoscopic Heller myotomy, and peroral endoscopic myotomy (POEM). Botulinum toxin injections are one of the first-line treatment options in achalasia. The injection reduces the lower esophageal sphincter (LES) pressure by inhibiting the release of acetylcholine from nerve endings [136]. The injection is extremely safe and rarely causes any adverse reactions. The injection is, however, limited in its durability, which lasts only for a few months [137–143]. Another common treatment option is the pneumatic dilation. Under fluoroscopic guidance, the balloon dilates the LES fibers through intraluminal dilation and can be either 30, 35, or 40 mm in diameter. If no success is achieved, the clinician will go for a bigger balloon size. The success rate as per Eckardt score is achieved in 84% of the patients [144]. Another common treatment is the laparoscopic Heller myotomy. This treatment was based on surgical myotomy to disrupt the LES fibers through an incision but now it has been minimally

invasive laparoscopic myotomy with a partial fundoplication. Clinical success is not purely determined by Eckardt's scores. The primary outcome measure was improvement of dysphagia, which was treated as a dichotomous variable. Overall, 87.7% of studies reported improvement in dysphagia through this treatment [144]. POEM is the last common treatment in achalasia, and this treatment was only established 12 years ago [145]. The clinical success in POEM was 98% [144].
