Mimics of Inflammatory Bowel Disease

This article is based on a  presentation during the Clinical Track Scientific Agenda of Advances in IBD 2013
Presenter: Sunanda Kane, MD, MSPH, FACG, AGAF, Mayo Clinic Rochester
 

Sunanda Kane, MD, used case studies to demonstrate how easy it is to mistake other serious gastrointestinal problems for inflammatory bowel disease (IBD). These are stories that make all of us cringe, because they show how easy it is to become lulled into simple pattern recognition-a habit that can cause us to miss important treatable conditions. And keep in mind that these were qualified gastroenterologists missing the diagnoses, not primary care doctors. All of these cases were probably seen by primary care before referral, so Dr Kane’s clinical pearls for recognizing IBD mimics are relevant for all of us:

1. If high-dose prednisone isn’t effective in presumed IBD, it’s probably not IBD. Non-response to corticosteroids is a red flag for misdiagnosis. Worse still, corticosteroids will accelerate progression of infection or neoplasm if either of those are the real problem.
2. Always think about infection, ischemia, or neoplasm. Even if there’s underlying IBD, the current complication or symptom picture may be caused by another process. And these are patients at increased risk for gastrointestinal infection, ischemia, or neoplasm-because of their underlying disease, and because of the medications they use.
3. Conditions can overlap. A patient can have more than one non-IBD problem, or they could have IBD plus another serious condition.

So why do gastroenterologists get fooled? Because other processes can affect our patients in the same anatomic locations as IBD, cause the same symptoms, or have similar endoscopic and radiographic appearance. And so-called SGI testing (serology, genetics, and inflammatory markers) only label the patient’s profile as “consistent with” IBD or not. Dr Kane doesn’t consider them to be specific for Crohn disease or ulcerative colitis (UC).

Esophageal infection, ulceration, or inflammation can mimic Crohn disease in terms of symptoms and endoscopic appearance. Or the patient may have esophageal HSV or HIV infection. What’s the most mundane esophageal mimic? Pill esophagitis. Obtain a careful history; Dr Kane recounted the case of persistent esophagitis being misidentified as Crohn disease: the patient finally recalled that the problems began after a course of doxycycline (tell your patients to drink lots of water with their pills).

Another common mimic is ischemic bowel, which can cause colonic ulceration and inflammation. A patient presented after using high-dose estrogen hormone treatment that she hadn’t mentioned, thinking that her gastroenterologists (who’d started high-dose prednisone with no effect), wouldn’t be interested. They should be-high-dose estrogen can cause ischemic bowel. Ulceration resolved when the estrogen was stopped. If high-dose prednisone fails, question the diagnosis of IBD.

More IBD mimics, here for the small bowel (these can look like Crohn disease):
•    Inflamed Meckel diverticulum
•    Neoplasm
•    Celiac disease
•    Autoimmune enteritis
•    Drugs: NSAIDs, SARBs
•    Endometriosis
 Large-bowel mimics a UC picture:
•    Prep effect
•    Normal colon: Dr Kane points out that the colon is in a constant state of inflammation, because it is in contact with the outside world’s antigens continuously
•    Histoplasmosis and CMV and Clostridium difficile infections
•    Neoplasm: Kaposi sarcoma, leukemia
•    Solitary rectal ulceration syndrome (SRUS), which Dr Kane humorously points out is not always solitary, not always rectal, and not always ulcerative. Its variable endoscopic presentation makes it easy to confuse with UC.
•    Drugs, such as ipilimumab
•    Segmental colitis associated with diverticulosis (SCAD)

And small or large bowel, radiation, neoplasm, irritable bowel syndrome, Behçet syndrome, or ischemia can mislead the clinician, whether primary care or specialist. If you don’t think of it, you won’t make the correct diagnosis. Don’t anchor too early to an IBD diagnosis, or you’ll miss its most common mimics.