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“[…] When he was an adult, it necessitated surgery that almost killed him. He feared choking so much that he nibbled at his food, slicing it into minuscule pieces. Sometimes he stood and literally hopped up and down, struggling to make the food go down his throat. He once confessed to his friend Timothy Fenris that being able to finally swallow a mouthful of food gave him an absurd sensation of pleasure and relief. […]”

From Carl Sagan: A Life by Keay Davidson.

Food. A necessity, a luxury, a pleasure in life. It silences the rumble of bellies and keeps us going, and it caresses the palate of the discerning gourmet. So if, as George Bernard Shaw once said, there is no love sincerer than the love of food, what greater misery could there be for a gourmet than a medical condition that forces him out of love with his cuisine?

The oesophagus

The oesophagus consists of three functional parts: the upper oesophageal sphincter (UES), a specialised ring of muscle forming the upper end of the oesophagus and separating the tube from the throat. Another specialised ring of muscle at the other end, the lower oesophageal sphincter (LES or cardia), controls the entrance of food into the stomach. Both sphincters are closed for most of the time to avoid food backing up into the throat (UES) or into the oesophageal tube (LES). Between the two is the long, flexible body of the oesophagus, a long, muscular tube about 8 inches in length, which ferries food from the mouth to the gastric vat of acid.

When you swallow your food, the upper sphincter relaxes to allow the food to enter the oesophageal body. Muscles in the oesophagus then contract coordinately, propelling solids and liquid and saliva downward to the stomach in what is known as a peristaltic wave. By the time the wave reaches the lower sphincter, it is open, allowing passage into the stomach for further processing.

What is achalasia?

Achalasia refers to the failure of a ring of muscle (a sphincter) to relax completely. It is usually synonymous with oesophageal achalasia, the most recognized of neuromuscular disorders of the oesophagus whereby the lower oesophageal sphincter is unable to open and admit food into the stomach.

The reduced ability of food movement down the oesophagus and failure of the LES to function properly manifests as the following symptoms:

1. Consistent dysphagia (difficulty swallowing), with a sensation of ‘food sticking in the chest’;
2. Regurgitation of undigested food;
3. Heartburn;
4. Spasm-type pains (relatively uncommon; most patients describe only a heavy sensation in their chest after eating that causes them to stop; however, sharp pain radiating to the back, jaw, neck and arms has been reported);
5. Weight loss, due to difficulty in swallowing food.

Achalasia was first described by Sir Thomas Willis in 1672*, who cured a patient of the condition by dilating the oesophagus with a sponge attached to a whalebone. (However, official credit for the first mesophageal dilatation goes to Purton in 1821). The condition was apparently only verifiable in post mortem until 1877, when Zicker and Ziemissan devised means for detecting achalasia in living persons. In 1881** and 1888 von Mikulicz and Einhorn both hypothesized that the condition was due to the absence of opening of the cardia (‘cardiospasm’), thereby indicating that the symptom was due to functional failure rather than a mechanical one. It wasn’t until 1929 that Hurst and Rake pinpointed the cause of achalasia as failure of the LES to relax.

*Some sources say 1674.
**Or 1882, again depending on the source

What causes achalasia?

The reasons for the failure of the oesophageal muscles are unknown. Hurst and Rake hypothesized that it was due to interference with the normal neuromuscular mechanism controlling the relaxation of the sphincter.

The question is currently unresolved, however. While heredity has been named a possible aetiology, nevertheless childhood and familial cases of achalasia are very uncommon and do not support the hypothesis for primary achalasia; in fact, fewer than 10 suspected cases of vertically-transmitted achalasia have been reported worldwide.

Given the uniform age distribution of the condition, infection would seem to be a plausible explanation, especially in light of the fact that Chagas’ disease (caused by the parasite Trypanosoma cruzi) causes achalasia-like symptoms. Several studies have detected a rise in antibody titers against the measles and Varicella Zoster viruses in people with achalasia compared with controls. These findings are unsubstantiated, however, and more recent studies using more advanced techniques have failed to verify these results. Nevertheless, these negative studies do not exclude the possibility of untested viral species or disappearance of the responsible pathogen from the host as being the cause of achalasia – as supported by a recent study demonstrating the presence of immune response cells in patients with achalasia that reacted to herpes simplex type 1 (HSV-1) virus antigens even though there was no trace of the virus itself inside the patients, thereby suggesting that the HSV-1-reactive lymphocytes might contribute to neuron damage in the myenteric plexus (or Auerbach’s plexus*, a part of the nervous system in the gut) and subsequently lead to motor dysfunction.

*Regarded by many as the body’s second brain.

Speculation about the host’s own immune system’s involvement in achalasia arose from early descriptions of inflammatory infiltration of areas of the oesophagus in achalasia. A study by detected inflammatory infiltration of the myenteric plexus in 100% of specimens from patients with achalasia; Storch et all demonstrated antibodies against the plexus in 37 of 58 patients with achalasia. However, because primary achalasia is quite specific for the oesophagus, it is to be wondered what significance there is to a circulating antibody that targets the neurons of not just the oesophagus but also the intestines.

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