Hiatal hernia and GERD

A hiatal hernia is the protrusion (or herniation) of the upper part of the stomach into the thorax through a tear or weakness in the diaphragm. The most common (95%) is the sliding hiatal hernia, where the gastroesophageal junction moves above the diaphragm together with some of the stomach.

Hiatal hernias affect anywhere from 1 to 20% of the population. Of these, 9% are symptomatic, depending on the competence of the lower esophageal sphincter (LES). 95% of these are "sliding" hiatal hernias, in which the LES protrudes above the diaphragm along with the stomach, and only 5% are the "rolling" type (paraesophageal), in which the LES remains stationary but the stomach protrudes above the diaphragm. People of all ages can get this condition, but it is more common in older people.

There are three anatomical factors that contribute to the prevention of reflux: (i) the acute angle at which the esophagus enters the stomach with its associated valve (called the angle of His); (ii) the phrenoesophageal ligament that seems to hold the gastroesophageal junction in place; and (iii) the diaphragmatic crura (which act to prevent reflux due to the position of the stomach below the diaphragm) and the intra-abdominal segment of lower esophageal sphincter. It has been reported that the angle of His is larger in the symptomatic group of endoscopically diagnosed acid reflux than in the asymptomatic group, indicating the importance of this angle with regard to gastroesophageal reflux.
Following any disturbance at any of these mechanisms, a sliding hernia would occur and cause gastroesophageal reflux. It is presumed that the tissues around the diaphragmatic hiatal that prevent GER maintain the form of cardia whenever abdominal pressure is increased.

The following are possible causes or contributing factors for having a hiatal hernia.
* Increased pressure within the abdomen caused by:
o Heavy lifting or frequent bending over
o Frequent or hard coughing
o Hard sneezing
o Violent vomiting
o Straining with constipation
o Obesity (extra weight pushes down on the abdomen increasing the pressure)
o Use of the sitting position for defecation.
* Heredity
* Smoking
* Drug use, such as cocaine.
* Stress

If mechanical forces set in play by stomach distention are important in pulling on the terminal esophagus and shortening the length of the high-pressure zone or sphincter, then the geometry of the cardia, that is, the presence of a normal acute angle of His or the abnormal dome architecture of a sliding hiatal hernia, should influence the ease with which the sphincter is pulled open. A close relationship exists between the degree of stomach distention necessary to overcome the high-pressure zone and the morphology of the cardia. Greater stomach dilatation, as reflected by a higher pressure inside stomach, is necessary to open the sphincter in patients with an intact angle of His compared to those with a hiatal hernia. This is what would be expected if the high-pressure zone were shortened by mechanical forces and accounts for why a hiatal hernia is often associated with the presence of GERD.

The symptoms include acid reflux, and pain, similar to heartburn, in the chest and upper stomach.
In most patients, hiatal hernias cause no symptoms. Sometimes patients experience heartburn and regurgitation, when stomach acid refluxes back into the esophagus.
A hiatal hernia per se may not cause any symptoms. The condition promotes reflux of stomach contents (via its direct and indirect actions on the anti-reflux mechanism) and thus is associated with gastroesophageal reflux disease (GERD). In this way a hiatal hernia is associated with all the potential consequences of GERD - heartburn, esophagitis, Barrett's esophagus and esophageal cancer. However the risk attributable to the hiatal hernia is difficult to quantify, and at most is low.

Besides discomfort from GERD and dysphagia, hiatal hernias can have severe consequences for patients if not treated. While sliding hernias are primarily associated with gastroesophageal acid reflux, rolling hernias can strangulate a portion of the stomach above the diaphragm. This strangulation can result in esophageal or GI tract obstruction and the tissue even become ischemic and necrose.
Another severe complication, although very rare, is a large herniation that can restrict the inflation of a lung, causing pain and breathing problems.

The diagnosis of a hiatal hernia is typically made through an upper GI series or endoscopy.
Gastroesophageal scintigraphy is a sensitive and non-invasive method for evaluation of GER. Most patients with typical GER symptoms exhibit scintigraphic evidence of reflux, and the severity of their reflux symptoms is correlated with the scintigraphic reflux index. The reflux index also increases as endoscopic esophagitis become more severe. The severity of reflux symptoms could be correlated with the reflux index, and the index increased significantly as endoscopic esophagitis became more severe. Therefore, the reflux index appeared to be a reliable measure of GER.
The severity of sliding hernia could be classified by esophagogastroscopy. Using the diameter of the fiberscope (9–10 mm) to estimate hernia size; also on the basis of severity. Evaluation of the relationship between the reflux index and the endoscopic grade of hiatal hernia demonstrated that the index was significantly higher in the mild hernia group compared with the severe group. Endoscopic esophagitis was found to be more prevalent in the severe group than in the mild group.
The relationship between reflux esophagitis and the size of the sliding hernia was also studied, concluding that hernia was significantly larger in patients with erosive esophagitis than in those without esophagitis and that hiatal hernia size was a reliable indicator of the severity of esophagitis.

In most cases, sufferers experience no discomfort and no treatment is required. However, when the hiatal hernia is large, or is of the paraesophageal type, it is likely to cause esophageal stricture and discomfort. Symptomatic patients should elevate the head of their beds and avoid lying down directly after meals until treatment is rendered. If the condition has been brought on by stress, stress reduction techniques may be prescribed, or if overweight, weight loss may be indicated. Medications that lower the lower esophageal sphincter (or LES) pressure should be avoided. Antisecretory drugs like proton pump inhibitors and H2 receptor blockers can be used to reduce acid secretion.
Where hernia symptoms are severe and chronic acid reflux is involved, surgery is sometimes recommended, as chronic reflux can severely injure the esophagus and even lead to esophageal cancer.
The surgical procedure used is called Nissen fundoplication. In fundoplication, the stomach fundus (upper part) of the stomach is wrapped, or plicated, around the inferior part of the esophagus, preventing herniation of the stomach through the hiatus of the diaphragm and the reflux of stomach acid. The procedure is now commonly performed laparoscopically. With proper patient selection, laparoscopic fundoplication has low complication rates and a quick recovery.
Complications include gas bloat syndrome, dysphagia (difficult swallowing), dumping syndrome, excessive scarring, and rarely, achalasia. The procedure sometimes fails over time, requiring a second surgery to make repairs.