Achalasia
From Wikipedia, the free encyclopedia
| ICD-10 | K22.0 | |
|---|---|---|
| ICD-9 | 530.0 | |
| OMIM | 200400 | |
| DiseasesDB | 72 | |
| MedlinePlus | 000267 | |
| eMedicine | radio/6 med/16 | |
| MeSH | C06.405.117.119.500.432 | |
Achalasia, or failure of a ring of muscle (sphincter) to relax adequately, refers most commonly to esophageal achalasia. This is a disorder of the smooth muscle cell layer of the esophagus (an esophageal motility disorder), characterized by (1) reduced muscular ability to move food down the esophagus (peristalsis), and (2) failure of the lower esophageal sphincter or "LES" to relax properly in response to swallowing. The cause is unknown in most cases. However, in South America, achalasia is sometimes caused by Chagas disease.
Synonyms are achalasia cardiae, cardiospasm (this archaic term refers to the symptoms of the disease), dyssynergia esophagus, and esophageal aperistalsis.
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[edit] Signs and symptoms
Signs and symptoms result from a functional obstruction of the esophagus:
- Dysphagia, or difficulty swallowing
- Regurgitation of undigested food
- Heartburn
- Difficulty belching
- Frequent hiccups
- Non-cardiac chest pains (NCCP) or spasms, which sometimes increase after eating and may radiate to the back, jaw, neck, and arms
- Weight loss
- Coughing, especially at night or when lying down
[edit] Diagnosis
Due to the similarity of symptoms, achalasia can be misdiagnosed as other disorders, such as gastroesophageal reflux disease (GERD), hiatal hernia, and even psychosomatic disorders. Unfortunately, it is not uncommon for achalasia to be misdiagnosed or not diagnosed at all, often for many years.
Investigations for achalasia include
- X-ray with a barium swallow, or esophagography. This shows narrowing at the level of the gastroesophageal junction ("bird beak" presentation of the lower esophagus) and various degrees of megaesophagus (esophageal dilation) as the esophagus is gradually stretched by retained food. A five-minute timed barium swallow is useful to measure the effectiveness of treatment.
- Manometry, the key test for establishing the diagnosis. A probe measures the pressure waves in different parts of the esophagus and stomach during the act of swallowing. A thin tube is inserted through the nose, and the patient is instructed to swallow several times (this is called a nasogastric intubation).
- Endoscopy, which provides a view inside the esophagus and stomach. A small camera is inserted through the mouth while the patient is under sedation.
- CT scan may be used to exclude pseudoachalasia, or achalasia symptoms resulting from a different cause, usually esophageal cancer.
Pathological examination reveals a defect in the nerves that control the motility of the esophagus (the myenteric plexus). The esophagus is dilatated and hypertrophied. In Chagas disease, the ganglion cells are destroyed by Trypanosoma cruzi, the causative parasite.<ref name=pathology> (2001) Rubin's Pathology - Clinicopathological Foundations of Medicine. Maryland: Lippincott Williams & Wilkins, p. 665. ISBN 0781747333.</ref>
[edit] Complications
- Gastroesophageal reflux disease (GERD) or heartburn.
- Barrett's esophagus or Barrett's mucosa: in 10% of patients.
- There are two kinds of esophageal cancer: squamous cell carcinoma and adenocarcinoma. Achalasia is a predisposing condition that may lead to esophageal adenocarcinoma if present for a long time. In up to 5% of cases, Barrett's esophagus leads to esophageal adenocarcinoma.
- Aspiration pneumonia: food, liquid, and saliva is retained in the esophagus, and patients may breathe it into the lungs, especially while sleeping in a horizontal position.
[edit] Treatment
- Medication:
- Intra-sphincteric injection of botulinum toxin (or botox), to paralyze the lower esophageal sphincter and prevent spasms. As in the case of botox injected for cosmetic reasons, the result is only temporary, and symptoms return quickly in most of patients. Botox injections cause scarring in the sphincter which may increase the difficulty of later Heller myotomy. This therapy is only recommended for elderly patients who cannot risk surgery.
- Drugs that reduce LES pressure may be useful, especially as a way to buy time while waiting for surgical treatment. These include calcium channel blockers such as nifedipine, and nitrates such as isosorbide dinitrate and nitroglycerin. Unfortunately, many patients experience unpleasant side effects such as headache and swollen feet, and these drugs often stop helping after several months.
- Balloon (pneumatic) dilation, also called dilatation. The muscle fibers are stretched and slightly torn by forceful inflation of a balloon placed inside the lower esophageal sphincter. Gastroenterologists who specialize in achalasia and have done many of these forceful balloon dilations have better results and fewer perforations than inexperienced ones. There's always a small risk of a perforation which would have to be fixed by surgery right away. Gastroesophageal reflux (GERD) occurs after pneumatic dilation in some patients. Pneumatic dilation causes some scarring which may increase the difficulty of Heller myotomy if this surgery is needed later. Pneumatic dilation is most effective on the long term in patients over the age of 40; the benefits tend to be shorter-lived in younger patients. This treatment may need to be repeated with larger balloons for maximum effectiveness.
- Surgery: Heller myotomy helps 90% of achalasia patients. It can usually be performed by a keyhole approach, or laparoscopically. The myotomy is a lengthwise cut along the esophagus, starting above the LES and extending down onto the stomach a little way. The esophagus is made of several layers, and the myotomy only cuts through the outside muscle layers which are squeezing it shut, leaving the inner muscosal layer intact. A partial fundoplication or "wrap" is added in order to prevent excessive reflux, which can cause serious damage to the esophagus over time. In a Dor (anterior) fundoplication, part of the stomach is laid over the esophagus and stitched in place so whenever the stomach contracts, it also closes off the esophagus instead of squeezing stomach acids into it. After surgery, patients should keep to a soft diet for several weeks to a month, avoiding foods that can aggravate reflux.
- Alternative treatments: Some patients have reported temporary improvement with acupuncture, traditional Chinese herbal medicine, or relaxation techniques.
- Lifestyle changes: Achalasia patients need to eat slowly, chew very well, drink plenty of water with meals, and avoid eating near bedtime. It is helpful to sleep with the head elevated by raising the head of the bed or using a wedge pillow. Proton pump inhibitors may help prevent reflux damage after surgery by inhibiting gastric acid secretion. Foods that can aggravate reflux, including ketchup and other tomato products, citrus fruits, chocolate, mint, alcohol, and caffeine, should also be avoided.
- Follow-up monitoring: Even after successful treatment of achalasia, swallowing may still deteriorate over time. It's important to check every year or two with a timed barium swallow because some may need pneumatic dilations, a repeat myotomy, or even esophagectomy after many years. Some doctors recommend pH testing and endoscopy to check for reflux damage, which may lead to a stricture or cancer of the esophagus if untreated.
[edit] References
<references/>
- Intelihealth: Achalasia - Retrieved November 6, 2006.
[edit] External links
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