出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/13 20:33:32」(JST)
| Gastroesophageal reflux disease | |
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X-ray showing radiocontrast agent injected into the stomach entering the esophagus due to severe reflux
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| Classification and external resources | |
| ICD-10 | K21 |
| ICD-9 | 530.81 |
| OMIM | 109350 |
| DiseasesDB | 23596 |
| MedlinePlus | 000265 |
| eMedicine | med/857 ped/1177 radio/300 |
| MeSH | D005764 |
Gastroesophageal reflux disease (GERD), gastro-oesophageal reflux disease (GORD), gastric reflux disease, acid reflux disease, or reflux (in babies and young children) is a chronic symptom of mucosal damage caused by stomach acid coming up from the stomach into the esophagus.[1]
GERD is usually caused by changes in the barrier between the stomach and the esophagus, including abnormal relaxation of the lower esophageal sphincter, which normally holds the top of the stomach closed, impaired expulsion of gastric reflux from the esophagus, or a hiatal hernia. These changes may be permanent or temporary.
Treatment is typically via lifestyle changes and medications such as proton pump inhibitors, H2 receptor blockers or antacids with or without alginic acid.[2] Surgery may be an option in those who do not improve. In the Western world between 10 and 20% of the population is affected.[2]
The most-common symptoms of GERD in adults are heartburn[3] and regurgitation. Less-common symptoms include pain with swallowing/sore throat, increased salivation (also known as water brash), nausea,[4] chest pain, and coughing.
GERD sometimes causes injury of the esophagus. These injuries may include one or more of the following:
Some people[who?] have proposed that symptoms such as sinusitis, recurrent ear infections, and idiopathic pulmonary fibrosis are due to GERD; however, a causative role has not been established.[4][not in citation given]
GERD may be difficult to detect in infants and children, since they cannot describe what they are feeling and indicators must be observed. Symptoms may vary from typical adult symptoms. GERD in children may cause repeated vomiting, effortless spitting up, coughing, and other respiratory problems, such as wheezing. Inconsolable crying, refusing food, crying for food and then pulling off the bottle or breast only to cry for it again, failure to gain adequate weight, bad breath, and belching or burping are also common. Children may have one symptom or many; no single symptom is universal in all children with GERD.
Of the estimated 4 million babies born in the US each year, up to 35% of them may have difficulties with reflux in the first few months of their lives, known as 'spitting up'.[6] One theory for this is the "fourth trimester theory" which notes most animals are born with significant mobility, but humans are relatively helpless at birth, and suggests there may have once been a fourth trimester, but children began to be born earlier, evolutionarily, to accommodate the development of larger heads and brains and allow them to pass through the birth canal and this leaves them with partially undeveloped digestive systems.
Most children will outgrow their reflux by their first birthday. However, a small but significant number of them will not outgrow the condition. This is particularly true when a family history of GERD is present.
GERD may lead to Barrett's esophagus, a type of intestinal metaplasia,[5] which is in turn a precursor condition for esophageal cancer. The risk of progression from Barrett's to dysplasia is uncertain, but is estimated at about 20% of cases.[7] Due to the risk of chronic heartburn progressing to Barrett's, EGD every five years is recommended for people with chronic heartburn, or who take drugs for chronic GERD.[8]
GERD is caused by a failure of the lower esophageal sphincter. In healthy patients, the "Angle of His"—the angle at which the esophagus enters the stomach—creates a valve that prevents duodenal bile, enzymes, and stomach acid from traveling back into the esophagus where they can cause burning and inflammation of sensitive esophageal tissue.
Factors that can contribute to GERD:
GERD has been linked to a variety of respiratory and laryngeal complaints such as laryngitis, chronic cough, pulmonary fibrosis, earache, and asthma, even when not clinically apparent. These atypical manifestations of GERD are commonly referred to as laryngopharyngeal reflux (LPR) or as extraesophageal reflux disease (EERD).
Factors that have been linked with GERD, but not conclusively:
In 1999, a review of existing studies found that, on average, 40% of GERD patients also had H. pylori infection.[15] The eradication of H. pylori can lead to an increase in acid secretion,[16] leading to the question of whether H. pylori-infected GERD patients are any different than non-infected GERD patients. A double-blind study, reported in 2004, found no clinically significant difference between these two types of patients with regard to the subjective or objective measures of disease severity.[17]
The diagnosis of GERD is usually made when typical symptoms are present.[18] Reflux can be present in people without symptoms and the diagnosis requires both symptoms or complications and reflux of stomach content.[19]
Other investigations may include esophagogastroduodenoscopy (EGD). Barium swallow X-rays should not be used for diagnosis.[18] Esophageal manometry is not recommended for use in diagnosis being recommended only prior to surgery.[18] Ambulatory esophageal pH monitoring may be useful in those who do not improve after PPIs and is not needed in those in whom Barrett's esophagus is seen.[18] Investigations for H. pylori is not usually needed.[18]
The current gold standard for diagnosis of GERD is esophageal pH monitoring. It is the most objective test to diagnose the reflux disease and allows monitoring GERD patients in their response to medical or surgical treatment. One practice for diagnosis of GERD is a short-term treatment with proton-pump inhibitors, with improvement in symptoms suggesting a positive diagnosis. Short-term treatment with proton-pump inhibitors may help predict abnormal 24-hr pH monitoring results among patients with symptoms suggestive of GERD.[20]
Endoscopy, the looking down into the stomach with a fibre-optic scope, is not routinely needed if the case is typical and responds to treatment.[18] It is recommended when people either do not respond well to treatment or have alarm symptoms, including dysphagia, anemia, blood in the stool (detected chemically), wheezing, weight loss, or voice changes.[18] Some physicians advocate either once-in-a-lifetime or 5- to 10-yearly endoscopy for people with longstanding GERD, to evaluate the possible presence of dysplasia or Barrett's esophagus.[21]
Biopsies performed during gastroscopy may show:
Reflux changes may not be erosive in nature, leading to "nonerosive reflux disease".
Other causes of chest pain such as heart disease should be ruled out before making the diagnosis.[18] Another kind of acid reflux, which causes respiratory and laryngeal signs and symptoms, is called laryngopharyngeal reflux (LPR) or "extraesophageal reflux disease" (EERD). Unlike GERD, LPR rarely produces heartburn, and is sometimes called silent reflux.
The treatments for GERD include lifestyle modifications, medications, and possibly surgery. Initial treatment is frequently with a proton-pump inhibitor such as omeprazole.[18]
Certain foods and lifestyle are considered to promote gastroesophageal reflux, but most dietary interventions have little supporting evidence.[23] Weight loss and elevating the head of the bed are generally useful.[24] Moderate exercise improves symptoms, however in those with GERD vigorous exercise may worsen them.[23] Stopping smoking and not drinking alcohol do not appear to result in significant improvement in symptoms.[24] Avoidance of specific foods and of eating before lying down should only be recommended to those in which they are associated with the symptoms.[19] Foods that have been implicated include coffee, alcohol, chocolate, fatty foods, acidic foods, and spicy foods.[19]
The primary medications used for GERD are proton-pump inhibitors, H2 receptor blockers and antacids with or without alginic acid.[2]
Proton-pump inhibitors (PPIs), such as omeprazole, are the most effective, followed by H2 receptor blockers, such as ranitidine.[19] If a once daily PPI is only partially effective they may be used twice a day.[19] They should be taken one half to one hour before a meal.[18] There is no significant difference between agents in this class.[18] When these medications are used long term, the lowest effective dose should be taken.[19] They may also be taken only when symptoms occur in those with frequent problems.[18] H2 receptor blockers lead to roughly a 40% improvement.[25]
The evidence for antacids is weaker with a benefit of about 10% (NNT=13) while a combination of an antacid and alginic acid (such as Gaviscon) may improve symptoms 60% (NNT=4).[25] Metoclopramide (a prokinetic) is not recommended either alone or in combination with other treatments due to concerns around adverse effects.[2][19] The benefit of the prokinetic mosapride is modest.[2]
Sucralfate has a similar effectiveness to H2 receptor blockers; however, sucralfate needs to be taken multiple times a day, thus limiting its use.[2] Baclofen, an agonist of the GABAB receptor, while effective, has similar issues of needing frequent dosing in addition to greater adverse effects compared to other medications.[2]
The standard surgical treatment for severe GERD is the Nissen fundoplication. In this procedure, the upper part of the stomach is wrapped around the lower esophageal sphincter to strengthen the sphincter and prevent acid reflux and to repair a hiatal hernia.[26] It is only recommended in those who do not improve with PPIs.[18] Benefits are equal to medical treatment in those with chronic symptoms.[18] In addition, in the short and medium term, laparoscopic fundoplication improves quality of life compared to medical management.[27] When comparing different fundoplication techniques, partial posterior fundoplication surgery is more effective than partial anterior fundoplication surgery.[28]
In 2012 the FDA approved a device called the LINX, which consists of a series of metal beads with magnetic cores that are placed surgically around the lower esophageal sphincter, for those with severe symptoms that do not respond to other treatments. Improvement of GERD symptoms are similar to those of the Nissen fundoplication, although there is no data regarding long-term effects. Compared to Nissen fundoplication procedures, the procedure has shown a reduction in complications such as gas bloat syndrome that commonly occur.[29] Adverse responses include difficulty swallowing, chest pain, vomiting, and nausea. Contraindications that would advise against use of the device are patients who are or may be allergic to titanium, stainless steel, nickel, or ferrous iron materials. A warning advises that the device should not be used by patients who could be exposed to, or undergo, magnetic resonance imaging (MRI) because of serious injury to the patient and damage to the device.[30]
In pregnancy, dietary modifications and lifestyle changes may be attempted, but often have little effect. Calcium-based antacids are recommended if these changes are not effective. Aluminum- and magnesium-based antacids are also safe, as is ranitidine[31] and PPIs.[18]
Infants may see relief with changes in feeding techniques, such as smaller, more frequent feedings, changes in position during feedings, or more frequent burping during feedings.[32] They may also be treated with medicines such as ranitidine or proton pump inhibitors.[33] Proton pump inhibitors however have not been found to be effective in this population and there is a lack of evidence for safety.[34]
The use of acid suppression therapy is a common response to GERD symptoms and many patients get more of this kind of treatment than their individual case merits.[35] The overuse of this treatment is a problem because of the side effects and costs which the patient will have from undergoing unnecessary therapy, and patients should not take more treatment than they need.[35]
In some cases, a person with GERD symptoms can manage them by taking over-the-counter drugs and making lifestyle changes.[36] This is often safer and less expensive than taking prescription drugs.[36] Some guidelines recommend trying to treat symptoms with an H2 antagonist before using a proton-pump inhibitor because of cost and safety concerns.[36]
In Western populations GERD affects approximately 10% to 20% of the population and 0.4% newly develop the condition.[2] For instance, an estimated 3.4 million to 6.8 million Canadians are GERD sufferers. The prevalence rate of GERD in developed nations is also tightly linked with age, with adults aged 60 to 70 being the most commonly affected.[37] In the United States 20% of people have symptoms in a given week and 7% every day.[2] No data support sex predominance with regard to GERD.
An obsolete treatment is vagotomy ("highly selective vagotomy"), the surgical removal of vagus nerve branches that innervate the stomach lining. This treatment has been largely replaced by medication.
A number of endoscopic devices have been tested to treat chronic heartburn. One system, Endocinch, puts stitches in the lower esophogeal sphincter (LES) to create small pleats to help strengthen the muscle. However, long-term results were disappointing, and the device is no longer sold by Bard.[38] Another, the Stretta procedure, uses electrodes to apply radio-frequency energy to the LES. The long-term outcomes of both procedures compared to a Nissen fundoplication are still being determined.
The NDO Surgical Plicator creates a plication, or fold, of tissue near the gastroesophageal junction, and fixates the plication with a suture-based implant. The company ceased operations in mid-2008, and the device is no longer on the market.
Another treatment, transoral incisionless fundoplication, which uses a device called Esophyx, may be effective.[39]
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| リンク元 | 「胃食道逆流」「gastric regurgitation」「gastro-esophageal reflux」「gastro-oesophageal reflux」「GER」 |
| 関連記事 | 「reflux」「refluxed」 |
[★] 胃食道逆流 gastroesophageal reflux