AchalasiaProf. Dr. Faisal Ghani Siddiqui

PreambleIntroductionPathogenesisClinical findingsInvestigationsDifferential diagnosisComplications Treatment

Oesophageal Peristaltic WavesPrimarySecondaryTertiary

Oesophageal Motility Disorders PrimaryUnknown causes

SecondaryManifestations of systemic diseases

Oesophageal Motility DisordersPrimary

AchalasiaOesophageal spasmNutcracker oesophagusHypertensive LES

Secondary

Diabetes mellitusSclerodermaAlcoholPsychiatric illnesses

Pathogenesis

Achalasia -aetiology

Clinical FindingsDysphagiaRegurgitationHeartburnChest pain

Distal Oesophageal narrowing(birds beak)Dilated proximal Oesophagus

Oesophageal ManometryAbsence of oesophageal peristalsis

Partial or no relaxation of LES

Differential DiagnosisBenign stricturesOesophageal carcinoma

ComplicationsAspiration | pneumoniaChronic irritation | carcinoma oesophagus

TreatmentMedical treatmentEndoscopic treatmentSurgical treatment

Intersphincteric Injection of Botulinum Toxin

Pneumatic Dilatation

Heller Myotomy

in summaryPrimary motility disorderAbsence of primary peristaltic waves & hyperactive LESDysphagiaManometry diagnosticPneumatic dilatation | Heller myotomy

?

The tubular esophagus is a muscular organ, approximately 25cm in length, and has specialized sphincters at proximal and distal ends. The upper esophageal sphincter (UES) is composed of several striated muscles, mainly cricopharyngeus, creating a tonically closed valve and preventing air from entering into the gastrointestinal tract. The lower esophageal sphincter (LES) is composed entirely of smooth muscle and maintains a steady baseline tone to prevent gastric reflux into the esophagus.

The body of the esophagus is similarly composed of 2 muscle types. The proximal esophagus is predominantly striated muscle, while the distal esophagus and the remainder of the GI tract contain smooth muscle. The mid esophagus contains a graded transition of striated and smooth muscle types. The muscle is oriented in 2 perpendicular opposing layers: an inner circular layer and an outer longitudinal layer, known collectively as the muscularis propria. The longitudinal muscle is responsible for shortening the esophagus, while the circular muscle forms lumen-occluding ring contractions.

Esophageal peristalsisThe muscle layers contract simultaneously and produces peristalsis. Peristalsis is a sequential, coordinated contraction wave that travels the entire length of the esophagus, propelling intraluminal contents distally to the stomach. The LES relaxes during swallows and stays opened until the peristaltic wave travels through the LES, then contracts and redevelops resting basal tone.

Primary peristalsis is the peristaltic wave triggered by the swallowing center. The peristaltic contraction wave travels at a speed of 2cm/s and correlates with manometry-recorded contractions. The secondary peristaltic wave is induced by esophageal distension from the retained bolus, refluxed material, or swallowed air. The primary role is to clear the esophagus of retained food or any gastroesophageal refluxate. Tertiary contractions are simultaneous, isolated, dysfunctional contractions. These contractions are nonperistaltic, have no known physiologic role, and are observed with increased frequency in elderly people. Radiographic description of this phenomenon has been called presbyesophagus.*Esophageal motility disorders are not uncommon in gastroenterology. These disorders may be primary esophageal motility disorders, where the cause is unknown or may occur as manifestations of systemic diseases, referred to as secondary motility disorders.

*Primary esophageal motility disorders, include diffuse esophageal spasm (DES), nutcracker esophagus, and hypertensive LES Nonspecific esophageal motility disorder (inefficient esophageal motility disorder)

Secondary esophageal motility disorders related to scleroderma, diabetes mellitus, alcohol consumption and psychiatric disorders.

*The predominant neuropathologic process of achalasia involves the loss of ganglion cells of the myenteric plexus of Aurbachs from the wall of the esophagus, starting at the LES and developing proximally. These mediate the relaxation of the of LES. Because the postganglionic cholinergic neurons are spared, there is unopposed cholinergic stimulation, which increases the LES resting pressure and decreases the LES relaxation.

In the peristaltic esophageal body, achalasia is characterized by a loss of intrinsic acetylcholine-containing nerves. Extrinsic nerves may also be affected, characterized by Wallerian degeneration of the axoplasm and myelin sheaths within the vagus nerve and dorsal motor nucleus. The physiologic process of achalasia is correlated most directly to the loss of the inhibitory nerves at the sphincter, resulting in failure of the LES to completely relax and causing relative obstruction.

Two theories exist:A degenerative disease of the neurones, and Infections of the neurons by a virus (eg. Herpes zoster)

Idiopathic achalasia is an inflammatory disease of unknown etiology characterized by esophageal aperistalsis and failure of LES relaxation due to loss of inhibitory nitrinergic neurons in the esophageal myenteric plexus. Proposed causes of achalasia include gastroesophageal junction obstruction, neuronal degeneration, viral infection, genetic inheritance, and autoimmune disease. Current evidence suggests that the initial insult to the esophagus, perhaps a viral infection or some other environmental factor, results in myenteric plexus inflammation. The inflammation then leads to an autoimmune response in a susceptible population who may be genetically predisposed. Subsequently, chronic inflammation leads to destruction of the inhibitory myenteric ganglion cells resulting in the clinical syndrome of idiopathic achalasia. Further studies are needed to better understand the etiology and pathogenesis of achalasia-such an understanding will be important in developing safe, effective, and possibly curative therapy for achalasia.*The myotomy is carried cephalad for at about 6cm and through the longitudinal and circular muscle fibers down to the esophageal submucosa and extended 2cm in the caudal direction from the GEJ on the anterior stomach to ensure complete division of the sling fibers, making the total length of the myotomy about 8cm.

Fig: A completed 8-cm myotomy is shown. Arrow 1 points to the anterior vagus nerve. Arrow 2 points to the left edge of the myotomy. Arrow 3 points to the exposed esophageal submucosa.*