Chapter 039. Nausea, Vomiting, and Indigestion (Part 6)

Gastric Motor DysfunctionDisturbed gastric motility is purported to cause acid reflux in some cases of indigestion. Delayed gastric emptying is also found in 25–50% of functional dyspeptics. The relation of these defects to symptom induction is uncertain; many studies show poor correlation between symptom severity and the degree of motor dysfunction. Impaired gastric fundus relaxation after eating may underlie selected dyspeptic symptoms like bloating, nausea, and early satiety.Visceral Afferent HypersensitivityDisturbed gastric sensory function is proposed as a pathogenic factor in functional dyspepsia. Visceral afferent hypersensitivity was first demonstrated inpatients with irritable bowel syndrome who had heightened perception of rectal...
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Chapter 039. Nausea, Vomiting, and Indigestion (Part 6) Chapter 039. Nausea, Vomiting, and Indigestion (Part 6) Gastric Motor Dysfunction Disturbed gastric motility is purported to cause acid reflux in some cases ofindigestion. Delayed gastric emptying is also found in 25–50% of functionaldyspeptics. The relation of these defects to symptom induction is uncertain; manystudies show poor correlation between symptom severity and the degree of motordysfunction. Impaired gastric fundus relaxation after eating may underlie selecteddyspeptic symptoms like bloating, nausea, and early satiety. Visceral Afferent Hypersensitivity Disturbed gastric sensory function is proposed as a pathogenic factor infunctional dyspepsia. Visceral afferent hypersensitivity was first demonstrated inpatients with irritable bowel syndrome who had heightened perception of rectalballoon inflation without changes in rectal compliance. Similarly, dyspepticpatients experience discomfort with fundic distention to lower pressures thanhealthy controls. Some patients with heartburn exhibit normal esophageal acidexposure. These individuals with functional heartburn are believed to haveheightened perception of normal esophageal pH. Other Factors Helicobacter pylori has a clear etiologic role in peptic ulcer disease, butulcers cause a minority of cases of dyspepsia. Infection with H. pylori isconsidered to be a minor factor in the genesis of functional dyspepsia. In contrast,functional dyspepsia is associated with a reduced sense of physical and mentalwell-being and is exacerbated by stress, suggesting an important role forpsychological factors. Analgesics cause dyspepsia, while nitrates, calcium channelblockers, theophylline, and progesterone promote acid reflux. Other exogenousstimuli that induce acid reflux include ethanol, tobacco, and caffeine via LESrelaxation. Genetic factors may contribute to development of acid reflux. Differential Diagnosis Gastroesophageal Reflux Disease Gastroesophageal reflux disease (GERD) is prevalent in Western society.Heartburn is reported once monthly by 40% of Americans and daily by 7–10%.Most cases of heartburn occur because of excess acid reflux; however,approximately 10% of patients with functional heartburn exhibit normal degrees ofesophageal acid exposure. Functional Dyspepsia Nearly 25% of the populace has dyspeptic symptoms at least six timesyearly, but only 10–20% of these individuals present to physicians. Functionaldyspepsia, the cause of symptoms in 60% of dyspeptic patients, is defined as ≥3months of bothersome postprandial fullness, early satiety, epigastric pain, orepigastric burning with symptom onset at least 6 months before diagnosis in theabsence of organic cause. Most patients follow a benign course, but a smallnumber with H. pylori infection or on nonsteroidal anti-inflammatory drugs(NSAIDs) progress to ulcer formation. As with idiopathic gastroparesis, somecases of functional dyspepsia result from prior gastrointestinal infection. Ulcer Disease In most cases of GERD, there is no destruction of the esophagus. However,5% of patients develop esophageal ulcers, and some form strictures. Symptoms donot reliably distinguish nonerosive from erosive or ulcerative esophagitis. Some15–25% of cases of dyspepsia stem from ulcers of the stomach or duodenum. Themost common causes of ulcer disease are gastric infection with H. pylori and useof NSAIDs. Other rare causes of gastroduodenal ulcer include Crohns disease(Chap. 289) and Zollinger-Ellison syndrome (Chap. 287), a condition resultingfrom gastrin overproduction by an endocrine tumor. Malignancy Dyspeptic patients often seek care because of fear of cancer. However,