Achalasia is a disorder of both the lower esophageal sphincter (LES) and the smooth muscle fibers of the esophagus. In patients with achalasia, the primary problems are the failure of the LES to fully relax on swallowing and the failure of the esophageal smooth muscle to produce adequate peristalsis.
Achalasia is most commonly idiopathic and presents clinically with symptoms of chest pain and dysphagia. Unlike other motor disorders, achalasia can progressively become severe. Achalasia is often associated with more serious complications, such as weight loss, undigested food reflux, and episodes of suction pneumonia - all due to the failure to swallow solids and fluids in the stomach.
Food remains in the esophagus for varying lengths until it passes into the stomach. Patients' reports of waking up with indigestible food on the pillow should raise suspicions of severe esophageal motility.
Manometry contributes significantly to the demarcation of the diagnosis. The classic manometric finding in achalasia is the lack of primary peristalsis (peristalsis). Other relevant findings include increased LES resting pressure. Some patients may have recurrent large-scale contractions in manometry and are classified as having vigorous achalasia.
Achalasia is most often assessed using a barium ingestion test. Typical findings include a dilated esophagus with fluid level and narrowing of the distal esophagus in a "bird beak" configuration. Τ
The dilation of the esophagus in achalasia can be impressive and the course of the esophagus through the chest can be helical.
Gastroscopy in patients suspected of having achalasia will often confirm findings such as food retention and esophageal dilatation. In such patients, endoscopy is often helpful in detecting the presence or absence of malignancy. Suspicious lesions can sometimes be detected and patients who appear to have exogenous esophageal compression should be referred for more definitive imaging by endoscopic ultrasound (EUS) or computed tomography.
Drugs have a limited role in the treatment of achalasia. Nitrates and calcium channel blockers may reduce LES pressure and relieve relief in some patients.
Sausage toxin (Botox), which is injected directly into LES under endoscopic guidance, has been shown to significantly reduce LES pressure in humans and animals. The duration of the effect of the sausage toxin varies and many patients undergo repeated injections as needed.
Esophageal dilatation has been a key approach in the treatment of achalasia for literally hundreds of years. LES dilation for achalasia can be performed under endoscopic and / or fluoroscopic guidance with solid or pneumatic dilators that are significantly larger than standard esophageal dilators. Expanders or balloons of increasing size can be used during the same session, but caution should be exercised due to the risk of perforation and bleeding. The reported clinical response to dilation therapy varies widely, but approximately 60% to 80% of patients will improve after 1 session. The duration of the response is also highly variable and many patients need intermittent dilation indefinitely.
Endoscopic Myotomy (POEM)
Oral endoscopic myotomy, or POEM, is a modern minimally invasive method in which a tunnel is created under the mucosa of the lower esophagus separating it from the underlying muscle. This results in excellent access to the smooth muscle of the esophagus as well as to the lower esophageal sphincter which are the main problem of achalasia. The endoscope then performs the myotomy using a flexible endoscope, which means that the whole procedure can be done without external incisions.
Originally described by Heller, LES surgical myotomy has been modified in recent decades and can now be performed laparoscopically. During this operation, one or more incisions are made in the gastroesophageal junction to cut the muscle fibers that cause esophageal obstruction. Modern myotomies are sometimes performed at the same time as a fundoplication to prevent long-term complications.