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Updated: 03/12/08 02:37 PM |
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Author: C.E. Pope ♦
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F. Methods of Investigation
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1. Esophagram
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X-ray diagnosis depends upon evaluation of the esophageal silhouette filled with barium or other contrast agent and the evaluation of the mucosal lining seen with double contrast (a thin layer of barium with the esophageal lumen distended with air). The diagnosis of esophagitis in its severe stages can be made by changes such as stricture or large ulcer. Smaller ulcers and mucosal-fold thickening can be established by double-contrast techniques. Esophagram is less sensitive for establishing the presence or absence of gastroesophageal reflux, since many people are shown to have reflux by other methods despite the absence of reflux during fluoroscopy. There is much wasted effort in trying to decide whether or not a hiatal hernia is present. Although it is true that reflux and hiatal hernia may be associated, it is the reflux which is the important cause of symptoms and this is best determined by other methods.
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2. Esophagoscopy
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Another method of evaluating the lining is esophagoscopy. Certain changes in the surface can be observed and are obvious, with little disagreement between observers, such as hemorrhage, ulceration and the presence of a gross tumor. The method is also helpful in determining the extent and severity of a thermal or chemical injury. This is a subjective evaluation at best, and much depends upon the endoscopist's training and experience. Lesions seen can be photographed and provide a basis for discussion between several experienced observers. A more objective method is to obtain biopsies under visual control during endoscopy. The histologic diagnosis of esophagitis is made by the observation of erosions, ulcerations, and acute inflammation. A biopsy from the lower esophagus of a patient with reflux is shown in Figure 7. It represents a reparative response rather than esophagitis. Note the hyperplasia (increased cell numbers) of the basal cell layer and that the dermal pegs almost reach the lumen.
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3. pH Studies
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In order to document the presence or absence of reflux, or to attempt to correlate symptoms with episodes of reflux, a thin wire with one or more pH electrodes can be placed in the esophagus and connected to a portable data recorder, allowing an ambulatory test to be done. Alternatively, a small capsule containing a pH sensor can be placed in the distal esophagus endoscopically. The capsule broadcasts a telemetry signal to a recorder - the monitoring period can be as long as 48 hours. The capsule eventually detaches itself and passes out of the body. Impedance tests of non-acid reflux can also be performed, although the interpretation of these results can be controversial.
When intraesophageal pH is monitored for 24 hours, normal controls are shown to have brief periods of reflux, usually after meals and, while in the upright position, but refluxed material usually does not reach the proximal esophagus and is not found in the pharyngeal area. Symptomatic GERD patients will have a greater percent of the 24-hour period with a pH of less than 4, and a good (but not perfect) correlation between episodes of heartburn and episodes of reflux. Prolonged episodes of nocturnal reflux are much less common and are usually found in patients with complicated reflux (strictures, Barrett’s epithelium). |
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4. Manometry
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The presence of muscle disease or neuromuscular incoordination can be best documented by intraluminal manometry although X-ray examination can also be of benefit. Manometry in such diseases shows some defect in the normal, elegantly coordinated sequence of deglutition. In achalasia the lower sphincter does not relax appropriately and normal progressive peristalsis is lacking. Usually, a low-amplitude prolonged contraction is seen simultaneously in three recording tips spread 5 cm apart. In diffuse spasm, the lower esophageal sphincter closes early and repetitive contractions of the whole lower two-thirds of the esophagus may be seen, especially in response to a water swallow.
Manometry can also be used to localize the position of the lower esophageal sphincter. Measurement of the exact pressure of the lower esophageal sphincter is not usually helpful, as the overlap between patients with reflux and control subjects is substantial. A normal resting pressure does not rule out reflux; transient relaxations can still lead to a large amount of reflux. An extremely low sphincter pressure (below 4 mm Hg)is usually associated with reflux. |
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Next Section (G): Approaches to Therapy » |
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