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School of Medicine
Inside Tract - Center for a gut on the move or not
Inside Tract Winter 2011
Center for a gut on the move or not
Date: January 3, 2011
A new generation of GI probes, says specialist John Clarke, can tell more about gastrointestinal motility than ever before.
photo by Keith Weller
Esophageal reflux. Chronic constipation. Irritable bowel. Dyspepsia. Functional gastrointestinal disorders aren’t immediately life-threatening, but they’re a real drain on quality of life. Given how common they are, the price tag nationally for medical care makes the disorders even more significant. One in five Americans experiences reflux on a weekly basis; 30 percent describe themselves as typically constipated.
And just because the disorders aren’t rare doesn’t mean that diagnosis is a snap. That can take both persistence and sophisticated technology to do well.
The need, then, is genuine for Hopkins’ new Gastrointestinal Motility Center, with its array of tests and consultations for the underlying cause of functional GI illness.
Consider an otherwise very healthy patient who recently visited gastrointestinal motility specialist John Clarke, the center’s director. For two years, the 46-year-old man had suffered recurring, right-of-midline chest pain. This particular problem had been ruled out as cardiac-related by his home clinician and thought to be acid reflux. Then came a succession of five different acid-suppressing drugs. Still the pain. An upper GI endoscopy and esophageal pH test revealed nothing remarkable. A CT and ultrasound led him to gallbladder surgery, but the pain remained. An orthopedist nixed rib inflammation, and visits to a psychiatrist didn’t help.
Clarke, however, had the newest testing at his disposal. It was only after a pH plus impedance test (see bullet, right) that the situation came clear. “To my surprise,” says the clinician, “he had roughly twice the typical esophageal reflux.” This patient had significant non-acid reflux which, recent studies suggest, can account for chest pain in people sensitive to its added pressure. Rather than surgery, a course of an antidepressant with desensitizing properties caused the pain to fade.
“In the last decade, we’ve seen greater interest in what are typically disorders of motility,” says Clarke, and our testing reflects that. More recent techniques offer alternatives to traditional, less-revealing methods such as pH testing via a 24-hour nasal catheter to the esophagus. Tests at the new center include:
• High-resolution manometry with impedance. This technique uses a very thin catheter with 36 pressure sensors for upper GI readings. The improved sensing makes it especially helpful in diagnosing patients with achalasia or esophageal spasms. Added impedance rings allow direct measure of flow, an aid in defining bolus transit in patients with dysphagia.
• Combined pH/impedance testing. Having both pH and impedance sensors gives the benefits of standard pH testing with the ability to separate acid from nonacid reflux.
• Wireless pH testing. A temporary pH sensing chip—implanted by endoscope—transmits from the esophagus to a receiver every six seconds for 48 hours. No wires. No catheters.
• SmartPill. After swallowing an FDA-approved “capsule,” patients transmit information on temperature, pH and pressure—good for explaining chronic constipation or gastroparesis. “You can record throughout the GI tract and distinguish one organ’s motility from another,” says Clarke.
• Breath testing. Gastroenterologist Gerard Mullin tests breath for the excess hydrogen or methane that can signal malabsorbed lactose or fructose or small intestine bacterial overgrowth syndrome.
• Anorectal manometry. This high-resolution system relates anal sphincter function to muscle strength as a way to explain chronic constipation, fecal incontinence or rectal pain. It can reveal focal weakness or poorly coordinated contraction.
“Our aim,” says Clarke, “is to offer high-quality motility testing for any referring clinician whose patients need it.”