Causes Of Fd - Functional Dyspepsia: Digestive Disorders

Content provided by the Faculty of the Harvard Medical School

Causes of FD

Although there are several theories, no one really knows what causes FD. Many experts don't think that excess gastric acid is to blame. Studies have found no irregularities in acid secretion in dyspeptic patients and no correlation between symptoms and increased acid production. But the theory remains under consideration, as does the possibility that the abdominal pain associated with FD results from acid leaking through the gastric or duodenal mucosa, which has been altered in some way.

Some other ideas include the following:

Visceral hypersensitivity. Many experts believe that patients with FD are more sensitive to gastrointestinal stimuli than people without FD, and that they may have a lower threshold for pain than their healthy counterparts.

Abnormal motility or sensation. The symptoms of FD may reflect abnormal motility, that is, the spontaneous movement of the digestive tract. Some patients' stomachs empty more slowly than normal, so food is retained longer. The patient feels as though food is not leaving the stomach; he or she fills up quickly during a meal and may belch or burp. The problem may be a mechanical failure of gastric contractions to empty the stomach. In addition, some FD patients have relatively stiff stomach walls, so that little distention can occur after a meal.

Functional dyspepsia: What else could it be? At least some of the distress associated with FD is due to the nagging fear that a more serious condition may be going undetected. This is rarely the case, especially when symptoms persist for months or years without worsening. Fortunately, more serious ailments have characteristics that set them apart from FD (see Figure 9). Gallstones. Stones can dwell silently in the gallbladder or can produce painful attacks, typically after a large, high-fat meal, if the gallbladder contracts and a stone lodges in its neck. The pain is usually located just under the right rib cage and may radiate to the right shoulder or back. If a stone is stuck for several hours, inflammation can result, and the patient may experience extreme tenderness if a hand is pressed below the ribs on the right side. He or she may develop a fever and an elevated white blood cell count. Jaundice (a yellowing of the skin and the whites of the eyes), dark urine, and pale stools occur when a gallstone slips out of the gallbladder and obstructs the duct that drains bile from the liver into the duodenum. Symptomatic gallstones are usually treated by surgical removal of the gallbladder (usually by laparoscopy). Occasionally, gallstones may be dissolved by the use of oral bile salts or crushed through a procedure that uses shock waves. Stones in the bile duct can be removed by endoscopic techniques. Stomach cancer. Malignancies of the stomach generally occur later in life, after age 50. Tumors that burrow into the stomach wall often produce symptoms that resemble those associated with ulcers. Eating a full meal can become impossible if growths extrude into the hollow of the organ or spread through the stomach wall, making it too stiff to expand. Warning signs include bleeding, persistent vomiting, a constant sense of nausea or fullness that interferes with normal eating, and weight loss. Stomach cancer usually requires the surgical removal of all or part of the stomach. Figure 9: Causes of pain Other conditions that have symptoms similar to functional dyspepsia include gallstones, which can block the neck of the gallbladder causing pain, or cancer of the lining of the stomach, which can create a painful sensation of bloating.

H. pylori infection. While the role of H. pylori infection as a cause of ulcers and gastritis is established, its involvement in FD is unclear. H. pylori infection is only slightly more common in people with FD than in the general population. Although the organism may contribute to FD symptoms in some cases, there's currently no way to distinguish these people from those in whom H. pylori does not cause FD. In a majority of cases, eradicating H. pylori with antibiotics doesn't significantly improve FD symptoms.

Duodenitis. Another condition that might produce symptoms of FD is duodenitis, a long-term inflammation of the lining of the duodenum. However, less than 20% of people with FD have this condition.

Psychological factors. Although scientific data are scarce, psychological stress may be important in the development of some cases of dyspepsia.

Diet. Certain fatty foods and fatty acids are often blamed for dyspepsia. This connection makes sense because fat ingestion not only delays gastric emptying but also increases distention of the stomach. Substances like alcohol and coffee may also aggravate symptoms.

Drugs. Nonsteroidal anti-inflammatory drugs (NSAIDs), especially aspirin, can cause dyspepsia, ulcers, and gastritis. A number of other drugs, such as opiates, iron preparations, and digitalis, may also cause dyspepsia.

Last updated:	August 21, 2007