Issue No. 1
For a Low-Profile Illness, an Elusive Treatment
Date: March 1, 2010
In terms of tricky diagnoses, sphincter of Oddi dysfunction (SOD) ranks among the most problematic. With symptoms that can easily be mistaken for irritable bowel syndrome or gallbladder dysfunction, the disease is easy to miss.
It’s also controversial: Many overseas physicians say SOD doesn’t even exist.
Given these issues, it’s no wonder that SOD can go undiagnosed for years while physicians struggle to figure out why a patient originally diagnosed with gallbladder disease continues to experience abdominal pain after the gallbladder is removed. And even when the diagnosis is made, standard treatment comes with its own risks, including chronic pancreatitis.
Now, though, gastroenterologists at The Johns Hopkins Hospital are part of a multicenter clinical trial that aims to wrangle the mysterious disease and pinpoint whether the current methods of diagnosing and treating it are also the most beneficial.
Before an SOD diagnosis is made, patients undergo a battery of tests, including blood tests, ultrasounds and CT scans, all with the purpose of ruling out other potential causes, such as bile duct stones or other causes of pancreatitis. Because the pain of SOD is often confused with that caused by gallbladder-related illnesses, most patients have usually had a cholecystectomy.
“We most frequently see patients who thought their issue was because of their gallbladder; they have it removed, but the pain comes back,” says gastroenterologist Anne Marie Lennon, one of the researchers for the Johns Hopkins arm of the trial. Those patients, she continues, are quickly suspected of having SOD.
Once that suspicion arises, traditional diagnosis and treatment involves endoscopic retrograde cholangiopancreatography, during which the physician performs a manometry study to measure the pressure in the sphincter.
“If the pressure is too high, that suggests SOD,” Lennon explains. “When that’s the case, we’ll do a sphincterotomy to relieve the pressure.”
Lennon and her colleagues believe sphincterotomy is the most effective way to alleviate the condition, but the procedure comes with an increased risk of pancreatitis, which, in its worst forms can cause serious illness or even death. But for many patients, the alternative—living with frequent episodes of extreme pain—is no alternative at all.
“They accept the risk,” Lennon explains. “These people are otherwise healthy, but they have serious pain.”
This is where researchers hope the clinical trial will prove valuable. Known as the EPISOD study—for “Evaluating the Predictors and Interventions of Sphincter of Oddi Dysfunction”—the trial aims to assess the benefits of sphincterotomy by comparing results in patients who receive the treatment and those who do not.
“This could prove that what we’re doing is worthwhile,” Lennon says, “which is so important, especially with a higher-risk procedure.”