Achalasia

Submitted by Susannah E. Berke, MS IV

 

 

Definition

·         Form of esophageal dysmotility characterized by loss of distal esophageal peristalsis and failure of lower esophageal sphincter relaxation

 

Etiology & Pathophysiology 

·         Usually idiopathic in origin

o       Degeneration of neurons within the myenteric plexus of the esophageal smooth muscle

·         Neuronal destruction is typically inflammatory in nature

o       Histologically: lymphocytic infiltrate surrounding the plexus

o       Predominantly involves the nitric-oxide producing inhibitory neurons

§         Cause smooth muscle relaxation by inhibiting the acetylcholine producing excitatory neurons

·         Loss of inhibitory input results in unopposed contractile stimulation and aperistalsis

o       Acetylcholine producing neurons (which stimulate smooth muscle contraction) are relatively spared in this degenerative process

 

Types

·         Primary achalasia (idiopathic)

o       Unknown cause of inflammatory neuronal degeneration

·         Secondary achalasia (pseudoachalasia)

o       Recognized pathologic causes of esophageal motility disorders often indistinguishable from primary achalasia

§         Malignancy (especially gastric cancer)

§         MEN, Type 2B

§         Chagas’ disease

§         Juvenile Sjogren’s

§         Amyloidosis

§         Chronic idiopathic intestinal

§         Sarcoidosis

§         Pseudo-obstruction

§         Neurofibromatosis

§         Eosinophilic gastroenteritis

§         Fabry’s disease

§         Scleroderma

 

Epidemiology

o       Annual incidence of 1 case per 100,000

o       Men and women affected equally

o       Occurs at any age

o       Typically between 25-60 years of age

§         Onset rare before adolescence

 

Clinical Findings

·         Dysphagia for solids and liquids predominate (85-95% of patients)

o       Dysphagia for liquids especially should prompt evaluation for achalasia

·         Difficulty belching

·         Hiccups

·         Weight loss

·         Chest pain

o       Usually secondary to failure of LES relaxation

o       More common in younger patients and tends to regress

·         Regurgitation of retained material in esophagus, especially upon lying down

o       May lead to recurrent aspiration

·         Heartburn in 40-60%

o       Tend to have lower LES pressures than those without GERD

·         Increased incidence of esophageal cancer

o       Usually squamous cell

o       Surveillance endoscopy not recommended (usually seen 15-20 years after development of achalasia)
 

Imaging Findings

·         Barium studies

o       95% diagnostic accuracy

o       Early/Stage I

§         Primary peristaltic waves absent with abnormal distal peristalsis

§         Only minimal narrowing of the GE junction

§         Occasionally may see nonpropulsive peristaltic waves in the esophageal body (“vigorous achalasia” secondary to tertiary waves)

o       Progressive disease

§         “Bird’s beak” appearance of GE junction

·         Distal esophagus makes right angle before entering stomach

o       Hurst phenomenon

§         With the patient upright, barium builds up to a point where the hydrostatic pressure of the barium overcomes the LES pressure

·         Occasional “spurt” of barium through the GE junction as it is intermittently  forced open

§         Dilated, aperistaltic esophageal body; may assume a sigmoid shape

o       Severe disease

§         Significant esophageal body dilation with large amounts of fluid/food retention

§         Entire esophagus atonic in late stages

 

·         Chest x-ray

o       With severe disease, may readily see the large, dilated esophagus with air fluid level at the aortic arch or above

o       Stomach bubble frequently absent 

·         CT Scan

o       Not typically used for diagnosis

o       Seen as dilated luminal structure with retained debris and narrowing at level where it enters the stomach 

 

 

CT scan of the chest demonstrates a markedly dilated esophagus

containing barium, debris and a fluid level

 

·         Manometry

o       Usually required for confirmation of diagnosis

§         Elevated resting LES pressure

§         Incomplete LES relaxation

§         Absence of peristalsis 

·         Endoscopy

o       Must rule out malignancy

o       Reveals dilated esophagus with normal mucosa

o       Retained fluid/food

o       Possible candidal infection secondary to esophageal stasis

o       Endoscope should pass easily through LES with gentle pressure applied

§         Unlike strictures caused by neoplasms, fibrosis etc

 

Differential Diagnosis

·         Reflux esophagitis with stricture

o       Narrowing is usually higher than the EG junction

o       Normal esophageal peristalsis

·         Carcinoma

o       Only minimal dilation with normal peristalsis

·         Scleroderma

o       Barium should empty when patient is upright

o       Other associated GI abnormalities

·         Chagas disease

o       Not distinguishable by x-ray; history needed

 

Treatment

·         Medical therapy

o       Nitrates, calcium channel blockers (nifedipine)

§         Cause smooth muscle relaxation but with limited success

·         Pneumatic dilation of the LES

o       Tears muscle fibers of LES, thus weakening it

o       Varying protocols regarding type and diameter of dilator, balloon inflation pressure and rate at which it is inflated, duration of inflation, and number of inflations per session

o       Good short-term results, but many patients require further intervention, with successive dilations adding little benefit

§         Potential complications of esophageal perforation (2-6%) and GERD

·         Surgical myotomy

o       LES muscle fibers cut

o       Laparoscopy becoming more popular

o       Good relief of symptoms in majority of patients with complication rate similar to that of dilation

o       Superior method for achieving better long term results

o       Debate as to whether fundoplication is necessary to prevent longstanding GERD

·         Botulinum toxin injection

o       Inhibits release of excitatory acetylcholine from nerve endings (thus causing lower LES pressures)

o       Good short­-term results, but long term efficacy unknown