Achalasia

Background

Sir Thomas Willis described achalasia in 1672. In 1881, von Mikulicz described the disease as a cardiospasm to indicate that the symptoms were due to a functional problem rather than a mechanical one. In 1929, Hurt and Rake realized that the disease was caused by a failure of the lower esophageal sphincter (LES) to relax. They coined the term achalasia, meaning failure to relax.

Achalasia is a primary esophageal motility disorder characterized by failure of a hypertensive LES to relax and the absence of esophageal peristalsis. These abnormalities cause a functional obstruction at the gastroesophageal junction.

Pathophysiology

LES pressure and relaxation are regulated by excitatory (eg, acetylcholine, substance P) and inhibitory (eg, nitric oxide, vasoactive intestinal peptide) neurotransmitters. Persons with achalasia lack nonadrenergic, noncholinergic, inhibitory ganglion cells, causing an imbalance in excitatory and inhibitory neurotransmission. The result is a hypertensive nonrelaxed esophageal sphincter.

Frequency

United States

The incidence of achalasia is approximately 1 per 100,000 people per year.

International

Chagas disease may cause a similar disorder.

Sex

The male-to-female ratio of achalasia is 1:1.

Age

Achalasia typically occurs in adults aged 25-60 years. Fewer than 5% of cases occur in children.

Treatment

Medical Care

The goal of therapy for achalasia is to relieve symptoms by eliminating the outflow resistance caused by the hypertensive and nonrelaxing LES. Once the obstruction is relieved, the food bolus can travel through the aperistaltic body of the esophagus by gravity.

• Calcium channel blockers and nitrates are used to decrease LES pressure.
• • Approximately 10% of patients benefit from this treatment.

  • This treatment is used primarily in elderly patients who have contraindications to either pneumatic dilatation or surgery.

• Endoscopic treatment includes an intrasphincteric injection of botulinum toxin to block the release of acetylcholine at the level of the LES, thereby restoring the balance between excitatory and inhibitory neurotransmitters.
  • This treatment has limited value. Only 30% of patient's treated endoscopically still have relief of dysphagia 1 year after treatment.

  • This treatment can cause an inflammatory reaction at the level of the gastroesophageal junction, making a subsequent myotomy very difficult.

  • Use this treatment in elderly patients who are poor candidates for dilatation or surgery.

• Pneumatic dilatation performed by a qualified gastroenterologist is the recommended treatment in those sporadic cases in which surgery is not appropriate.
• • A balloon is inflated at the level of the gastroesophageal junction to blindly rupture the muscle fibers while leaving the mucosa intact.

  • The success rate is 70-80%, and the perforation rate is approximately 5%.

  • If a perforation occurs, emergency surgery is needed to close the perforation and perform a myotomy.

  • As many as 50% of patients may require more than 1 dilatation.

  • The incidence of abnormal gastroesophageal reflux after the procedure is approximately 25%.

• A laparoscopic Heller myotomy is considered by many to be the appropriate primary treatment of patients with achalasia (see Surgical Care). A Heller myotomy and a partial fundoplication performed from the chest (thoracoscopic) have a high incidence of gastroesophageal reflux.

Surgical Care

Because of excellent results, a short hospital stay, and a fast recovery time, the primary treatment is considered by many to be a laparoscopic Heller myotomy and partial fundoplication. In the author's experience and in the experience of many authors, this treatment provides a fine balance in relieving symptoms of dysphagia by performing the myotomy and in preventing gastroesophageal reflux by adding a partial wrap. A prospective randomized study from Vanderbilt University has recently shown that a Heller myotomy plus a partial fundoplication was superior to a Heller myotomy alone in regard to the incidence of postoperative reflux. The same authors of this study have also shown that in patients with achalasia, adding a partial fundoplication not only is more effective in preventing postoperative reflux but also is more cost-effective at a time horizon of 10 years.

However, the use of preoperative endoscopic therapy remains common but has resulted in intraoperative complications (eg, esophageal perforation) and postoperative complications and in a high failure rate

• Minimally invasive surgery for achalasia is carried out under general anesthesia with the use of 5 trocars. A controlled division of the muscle fibers (myotomy) of the lower esophagus (5 cm) and the proximal stomach (1.5 cm) is carried out , followed by a partial fundoplication to prevent reflux.
  

• Patients remain hospitalized for 24-48 hours and return to regular activities in about 2 weeks.
  

• The operation relieves symptoms in 85-95% of patients, and the incidence of postoperative reflux is 10-15%.
  

• For patients in whom surgery fails, they may be treated with an endoscopic dilatation first. If this fails, a second operation (extending the previous myotomy onto the anterior gastric wall) can be attempted once the cause of failure has been identified with imaging studies. The last resort is to surgically remove the esophagus (ie, esophagectomy).

Medication

Calcium channel blockers and nitrates both decrease LES pressure but do not improve LES relaxation. Approximately 10% of patients benefit from medical treatment, which should be used primarily in elderly patients who have contraindications to either pneumatic dilatation or surgery or as a temporary measure while other treatments are considered.

Drug Category: Calcium channel blockers

These agents interfere with calcium uptake by smooth muscle cells that are dependent on intracellular calcium for contraction. They have a relaxant effect on the LES muscle.

Drug Name	Nifedipine (Adalat)
Description	Inhibits transmembrane influx of calcium ions into smooth muscle, which, in turn, inhibits contraction of the muscle fibers.
Adult Dose	10-30 mg SL 30 min ac; hs prn if nocturnal regurgitation and cough are prominent
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; increased angina; acute myocardial infarction; congestive heart failure
Interactions	Cimetidine can increase blood levels; may decrease blood levels of quinidine; may increase beta-blocker withdrawal symptoms
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May cause lower extremity edema; allergic hepatitis has occurred but is rare

Drug Category: Nitrates

These agents relax vascular smooth muscle.

Drug Name	Isosorbide dinitrate (Isordil)
Description	Has a relaxant effect on smooth muscle fibers of LES. Relaxes vascular smooth muscle by stimulating intracellular cyclic GMP.
Adult Dose	5 mg SL or 10 mg PO 10-15 min ac
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; anuria; severe dehydration; frank or impending acute pulmonary edema; severe cardiac decompensation
Interactions	Coadministration with alcohol may cause severe hypotension and cardiovascular collapse; aspirin may increase serum concentrations and effects; coadministration with calcium channel blockers may increase symptomatic orthostatic hypotension (adjust dose of either agent); may decrease effects of heparin
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Tolerance to vascular and antianginal effects of nitrates may develop; minimize tolerance by using smallest effective dose, pulsing therapy (intermittent dosing), or alternating with other coronary vasodilators (take last daily dose of short-acting agent no later than 7 pm); caution when administering to patients with glaucoma