The new condition occurs after an acute bout of diverticulitis, scientists at the University of California, Los Angeles have found.
As they age, most people develop diverticulosis, or pouches in the lining of the colon. The pouches usually don't cause any problems but occasionally, they become inflamed, leading to diverticulitis, which causes pain and infection in the abdomen.
The condition, called Post-Diverticulitis Irritable Bowel Syndrome (PDV-IBS), validates the irritable bowel symptoms that many patients report long after suffering a bout of diverticulitis, but that many physicians wave off as being part of the original condition.
"We've known for a long time that after some people develop diverticulitis, they're a different person. They experience recurrent abdominal pains, cramping and diarrhea that they didn't have before," said study senior author Dr Brennan Spiegel, an associate professor of medicine at the David Geffen School of Medicine at UCLA.
"The prevailing wisdom has been that once diverticulitis is treated, it's gone. But we've shown that IBS symptoms occur after the diverticulitis, and it may result from an inflammatory process like a bomb going off in the body and leaving residual damage," he said.
"A major surprise in our study was that diverticulitis patients not only developed IBS at a higher rate than the controls, but they also developed mood disorders like depression and anxiety at a higher rate," Spiegel said.
"Because IBS and mood disorders often go hand in hand, this suggests that acute diverticulitis might even set off a process leading to long-standing changes in the brain-gut axis," he said.
The discovery of PDV-IBS could mean better attention to patients complaining of symptoms after diverticulitis, symptoms that up until now may have been dismissed by physicians.
Spiegel said the PDV-IBS patients often report ongoing IBS symptoms after the diverticulitis has long passed, and this study supports their beliefs and introduces a new diagnosis.
More than 1,000 patient records from the West Los Angeles Veteran's Affairs Medical Centre were examined for the two-year study, including patients that had suffered acute diverticulitis and another group of patients that did not have it.