Porth's Essentials of Pathophysiology, 4e

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Disorders of Gastrointestinal Function

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sphincter (e.g., alcohol, chocolate, fatty foods, and heavy smoking) also cause refluxate, as may central nervous sys- tem depressants, obesity, pregnancy, hiatal hernia, delayed gastric emptying, and increased gastric volume. Although acid damages the esophageal mucosa, the combination of acid and pepsin many be particularly injurious. Clinical Manifestations. The most frequent symptom of GERD is heartburn. It frequently is severe, occurring 30 to 60 minutes after eating. It often is made worse by bending at the waist or assumption of the recumbent posi- tion and usually is relieved by sitting upright. The sever- ity of heartburn is not indicative of the extent of mucosal injury; only a small percentage of people who complain of heartburn have mucosal injury. Often, the heart- burn occurs during the night. Antacids provide prompt, although transient, relief. Other symptoms include belching and chest pain. The pain usually is located in the epigastric or retrosternal area and often radiates to the throat, shoulder, or back. Because of its location, the pain may be confused with angina. The reflux of gastric contents also may produce respiratory symptoms such as wheezing, chronic cough, and hoarseness. 8 Diagnosis and Treatment. Diagnosis of GERDdepends on a history of reflux symptomatology and selective use of diagnostic methods, including radiographic studies using a contrast medium such as barium, esophagos- copy, and ambulatory esophageal pH monitoring. 8–10 The treatment of GERD usually focuses on conser- vative measures. These measures include avoidance of positions and conditions that increase gastric reflux. 8–10 It is recommended that large meals and foods that reduce lower esophageal sphincter tone (e.g., caffeine, fats, chocolate) be avoided, that meals be eaten sitting up, and the recumbent position be avoided for several hours after a meal. Bending for long periods should be avoided because it tends to increase intra-abdominal pressure and cause gastric reflux. Sleeping with the head elevated helps to prevent reflux during the night. Weight loss usually is recommended in overweight people. Pharmacologic treatment includes the use of antac- ids and inhibitors of gastric acid secretion. Antacids neutralize gastric acid and are used for rapid relief of occasional heartburn. Histamine-2 (H 2 )–receptor antag- onists inhibit gastric acid production. They are available as over-the-counter drugs and often are recommended when additional treatment is needed. The proton pump inhibitors act by inhibiting the gastric proton pump, which regulates the final pathway for acid secretion (see Chapter 28, Fig. 28-10). These agents may be used for persons who continue to have daytime symptoms, recur- rent strictures, or large esophageal ulcerations. Surgical treatment may be indicated in some people. Complications. Complications of GERD result from persistent reflux, which produces a cycle of hyper- emia, edema, and erosion of the mucosal surface of the esophagus. Esophageal mucosal damage is related to acidity of the refluxate. These complications include strictures of the esophagus and a condition called Barrett

esophagus. Strictures are caused by a combination of scar tissue, spasm, and edema. They produce narrowing of the esophagus and cause dysphagia when the lumen becomes sufficiently constricted. Barrett esophagus is characterized by a reparative pro- cess in which the squamous mucosa that normally lines the esophagus gradually is replaced by columnar epithe- lium resembling that in the intestines. 11 The diagnosis of Barrett esophagus is based on endoscopic evidence of abnormal mucosa above the level of the gastroesopha- geal junction and histologically documented intestinal metaplasia (called specialized intestinal metaplasia ) that predisposes to the development of adenocarcinoma.  Gastroesophageal Reflux in Children Gastroesophageal reflux is a common problem in infants and children. The small reservoir capacity of an infant’s stomach coupled with frequent spontaneous reductions in sphincter pressure contribute to reflux. At least one episode of regurgitation a day occurs in as many as half of infants ages 0 to 3 months. By 6 months of age it becomes less frequent and usually abates as the child assumes a more upright posture and eats solid foods. 12,13 Although many infants have minor degrees of reflux, complications such as esophageal damage and second- ary respiratory disease can occur in children with more frequent or persistent episodes. The condition occurs more frequently in children with cerebral palsy, Down syndrome, and other neurologic disorders. Clinical Manifestations. Clinical manifestations of reflux esophagitis include evidence of pain when swal- lowing, hematemesis, anemia due to esophageal bleed- ing, heartburn, irritability, and sudden or inconsolable crying. Parents often report feeding problems in their infants. 12,13 These infants often are irritable and demon- strate early satiety. Sometimes the problems progress to actual resistance to feeding and failure to thrive. Tilting of the head to one side and arching of the back may be noted in children with severe reflux. 12 This head posi- tioning is thought to represent an attempt to protect the airway or reduce the pain-associated reflux. Sometimes regurgitation is associated with recurrent otalgia. The ear pain is thought to occur through referral from the vagus nerve in the esophagus to the ear. In some chil- dren, chronic regurgitation may prompt dental caries. A variety of respiratory symptoms are caused by dam- age to the respiratory mucosa when gastric reflux enters the esophagus. Reflux may cause laryngospasm, apnea, and bradycardia. Asthma may co-occur with GERD in about 50% of asthmatic children. Asthmatic children who are particularly likely to have GERD as a provoca- tive factor are those with symptoms of reflux, those with refractory or steroid-dependent asthma, and those with nocturnal worsening of symptoms. 14 Diagnosis and Treatment. Diagnosis of gastroesoph- ageal reflux in infants and children often is based on parental and clinical observations. The diagnosis may