The advent of high-resolution manometry with esophageal pressure topography has revolutionized the categorization of achalasia by differentiating the contractile function of the esophageal body. All forms have an “integrated relaxation pressure” or mean esophagogastric junction pressure persisting for 4 sec after a swallow that is greater than 15 mmHg; however, classic achalasia requires absent peristalsis, while achalasia with esophageal compression includes at least 20% of swallows associated with panesophageal pressurization to >30 mmHg, while spastic achalasia has spastic contractions with >20% of swallows.
Source: Kahrilas PJ. Esophageal Motor Disorders in Terms of High-Resolution Esophageal Pressure Topography: What Has Changed? Am J Gastroenterol 2010;105:981–987.
Upper gastrointestinal endoscopy
Upper gastrointestinal endoscopy often misses achalasia but is necessary to exclude malignancy after the diagnosis is made. Typically, endoscopy reveals esophageal dilation, atony, and erythema, friability, and ulcerations from chronic stasis. The LES may be puckered but passage of the endoscope into the stomach should not be difficult in the absence of malignancy. Careful examination of the gastric cardia is mandatory to rule out secondary causes of achalasia.
- Absence of peristalsis in esophageal body
- Incomplete relaxation of lower esophageal sphincter (complete relaxation of short duration may be seen in early achalasia)
- Elevated resting pressure of lower esophageal sphincter (common, not required)
- Elevated intraesophageal pressure relative to gastric pressures (common, not required)
Management
Achalasia is not curable, and no treatment can restore normal esophageal body peristalsis or complete LES relaxation. Treatment therefore rests with measures to reduce LES pressure sufficiently to enhance gravity-assisted esophageal emptying.
Medication therapy
Nitrates and calcium channel antagonists are the most common medical therapies for achalasia. Sublingual isosorbide dinitrate reduces LES pressures by 66% for 90 min. Sublingual nifedipine 30–40 mg per day is significantly better than placebo in symptom relief and lowers LES pressure by 30–40% for an hour or more. Sildenafil transiently decreases LES pressure in achalasia. Any medication therapy has significant limitations, such as duration of action and tachyphylaxis. However, elderly patients, patients who refuse more invasive therapy, patients who cannot give consent, and patients with very mild symptoms may benefit from these relaxant drugs.
Injection therapy
Botulinum toxin, a potent inhibitor of neural acetylcholine release, reduces LES pressure and relieves symptoms for up to 6 months in patients with achalasia when directly injected into the LES during endoscopy (80 units total divided into four-quadrant injections). Because of incomplete symptom control and the requirements for costly repeat injections, botulinum toxin is best reserved for elderly or frail patients who are poor risks for more definitive therapy.
Pneumatic dilation
Bougienage with a standard dilator (up to 20 mm diameter) usually produces only transient symptomatic relief. In contrast, pneumatic dilation to >30 mm diameter that forcefully disrupts the LES circular muscle produces long-lasting reductions in LES pressure. Balloons are inflated for several seconds to 5 min at pressures ranging from 360 to 775 mmHg, which produce responses in 32–98% of cases. A postdilation LES pressure of less than 10 mmHg predicts sustained remission to 2 years. Approximately 20–40% of patients require further dilation several years later. The most common complication of pneumatic dilation is perforation (1–5% of cases). It is common to obtain a water-soluble radiographic swallow film followed by barium swallow radiography (if no perforation is detected).
Surgery
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