Recurrent Chest Pain.

[quote="GI"]A 35-year-old woman presents to her local physician with a chief complaint of recurrent chest pain of 8 months? duration. The pain is sharp and substernal, radiates to her neck and under her left breast when severe, and on occasion awakens her from sleep. The pain does not appear to be associated with meals, position, or exertion, although at times it is worsened by emotional stress. At times, the patient also feels that she has a lump in her throat, although this does not interfere with breathing or swallowing. She denies shortness of breath, edema, syncope, dysphagia, heartburn, weight loss, cough, wheezing, or fever. Her current medications include birth control pills, multivitamins, and alprazolam (Xanax), the last taken for anxiety. There is no history of diabetes, hypertension, hypercholesterolemia, or smoking. Her father had a myocardial infarction at age 50 years, and her mother died from a ruptured berry aneurysm at age 40 years. Her physical examination is unremarkable. A chest radiograph, complete blood count, chemistry-18 panel, urinalysis, and electrocardiogram are normal. A cardiology evaluation ruled out ischemia. A week later, her physician ordered an upper endoscopy. The endoscopy showed a small, 3-cm sliding hiatal hernia, but no evidence of esophagitis, gastritis, peptic ulcer disease, or tumors. Esophageal manometry was normal. The 24-hour pH monitoring was reported as abnormal, with a total acid exposure time of 12% (normal for the laboratory is < 10%). The patient received a therapeutic trial of a high dose of the proton pump inhibitor omeprazole, 20 mg orally twice daily for 8 to 12 weeks. During this period, she was to keep a diary of the frequency and severity of her symptoms. Three months after beginning therapy with omeprazole, the patient reports no change in the frequency, severity, or pattern of symptoms. What is the appropriate diagnostic test at this juncture?
A) Ultrasonography of the gallbladder
(B) Upper gastrointestinal series
(C) Bernstein (acid perfusion) test
(D) 24-hour esophageal pH monitoring on omeprazole therapy[/quote] Educational Objective: Select the appropriate diagnostic test to rule out gastroesophageal reflux disease in a patient with unexplained chronic chest pain. The appropriate diagnostic test in this patient is to perform 24-hour esophageal pH monitoring on omeprazole therapy. The reason for this is to determine if the empiric trial of high-dose omeprazole accomplished the goal of normalizing or ablating the excessive esophageal acid exposure. If pH monitoring shows that it has been successful, as it should be in approximately 75% to 80% of patients taking 20 mg of omeprazole twice daily, reflux disease is excluded as the cause of recurrent chest pain. This conclusion is based on the facts that the major injurious agent within the refluxate is gastric acid and that control of esophageal acidity should be paralleled by amelioration of symptoms. If the omeprazole has not normalized esophageal acidity, as occurs in 20% to 25% of patients, the therapeutic trial is inconclusive and should be repeated at a higher dose of medication (for example, omeprazole, 30 to 40 mg orally twice daily) or, for nocturnal acid breakthrough, by the addition of a nighttime dose of a histamine-2 receptor antagonist (for example, ranitidine, 150 to 300 mg at bedtime). It is important to note that although an abnormal 24-hour esophageal pH monitoring study may suggest the possibility of reflux disease as the cause of the patient?s chest pain, it is far from being either sensitive or specific in the setting of atypical chest pain. It is for this reason that the therapeutic trial with a high-dose proton pump inhibitor ? as utilized in this patient ? is the preferred method of supporting the diagnosis of reflux-induced chest pain. The finding of an abnormality consistent with reflux on upper endoscopy, upper gastrointestinal series, or Bernstein test would still fail to establish reflux disease as the cause of the atypical symptoms. Proof, therefore, would still require a therapeutic trial to establish a causal relationship between acid reflux and the patient?s complaint. Ultrasonography is not indicated to resolve this issue. Even if the patient had an abnormality on ultrasonography, it would not affect the patient?s reflux. The key point in this case is to decide whether or not reflux is the cause of the patient?s symptoms.