Reviewing inflammatory markers involved in inflammatory bowel disease

When a patient presents with chronic and recurrent abdominal pain, it can be tough to nail down the cause. In this video, we’ll look at how to use inflammatory markers to differentiate between inflammatory and non-inflammatory causes of IBD, why it’s crucial that you figure out the difference, and what to do when the diagnosis is unclear.

Inflammation got you all flustered? With this course, you'll master the use of inflammatory markers to get to the right diagnosis.

Clinicians encounter inflammation daily and there are lots of inflammatory markers to consider. Which should you order for your patient? Here, you’ll learn the strengths and limitations of each marker, when they’re useful, and when they’re not. We’ll look at laboratory markers of inflammation as well as radiologic and clinical signs so you can take your diagnostic skills to the next level.

Chronic and recurrent abdominal pain, with or without bowel changes is a challenging presentation. The differential diagnosis is very broad, including a diverse set of disorders like pancreatitis, mesenteric ischemia, hepatitis, and appendicitis. We can't address all of these possibilities in this Medmastery chapter. Instead, we will focus on the use of inflammatory markers to help distinguish between inflammatory colitis, infections, and other non inflammatory causes of colitis. This can aid in the workup of patients with these complaints. The presence or absence of systemic inflammatory markers separates many diseases into two broad categories. disorders that have a major inflammatory component from those without a significant inflammatory component.

Some diseases that have a major inflammatory component are Crohn's disease and ulcerative colitis, collectively called inflammatory bowel diseases, or IBDs. IBDs are diseases driven by an out of control inflammatory response. They are both associated with an increase systemic inflammatory markers, and can include extra intestinal disease such as arthritis. Non inflammatory disorders are a diverse set of disorders whose only common factor is that they tend to be associated with low or no markers of systemic inflammation. Some of these conditions include Irritable Bowel Disease, small intestinal bacterial overgrowth, or SIBO and diverticulosis.

Another condition is FODMAP insensitivity, where patients will have difficulty digesting certain foods called FODMAPs, which stands for fermentable oligo, di, monosaccharides and polyols. This insensitivity leads to a variety of symptoms. Another group of non inflammatory disorders are functional gut syndromes. This group has undergone numerous nomenclature changes, but includes functional constipation, functional diarrhea, centrally mediated abdominal pain syndrome, or CAPS, narcotic bowel syndrome, and opioid induced GI hyperalgesia. Functional gut syndromes tend to have minimal elevations in inflammatory markers.

The pathophysiology is thought to be related to the interaction between central nervous system and GI function and motility. A third set of non inflammatory conditions are equally broad, such as malabsorption syndromes, like exocrine pancreatic insufficiency, GI lymphomas, and lactose intolerance. These also tend to have low or no elevation of major inflammatory markers. A special consideration includes celiac disease, and non celiac disease associated gluten sensitivity. Celiac disease is thought to be an autoimmune disease triggered by gluten or one of the components of gluten. Gluten is composed of two sets of peptides, gliadins and glutenins.

There is a genetic association with celiac disease, whereas no genetic association is known for non celiac gluten sensitivity. One thought is that in both conditions, inflammation that causes damage to the GI system is triggered by certain peptides in wheat, such as gluten or gliadins. The relationship between celiac disease and non celiac gluten sensitivity is still unclear. Celiac disease has been described as having elevated inflammatory markers, placing it squarely in the category of inflammatory bowel disease. Non celiac gluten sensitivity does not normally have these elevations in inflammatory markers and it is unclear how this related disorder fits into the broad categories of inflammatory versus non inflammatory disorders.

Another special consideration are infections like diverticulitis and C. difficile colitis. Both conditions are inflammatory conditions driven by infectious agents. Of note, there is a while spectrum of disease from localized inflammatory states like acute uncomplicated diverticulitis, to sepsis and septic shock. Importantly, C. Diff infections can correlate with IBD exacerbations and or new presentations of IBD. The primary advantage of distinguishing between inflammatory and non inflammatory disorders is the choice of management strategies and prognosis. In general, inflammatory bowel disease when left untreated, leads to significant increases in mortality, hospitalizations, and the need for life saving surgeries, as well as increased risk for colon cancer. The management choices for patients with IBD focus on suppressing inflammation and on early aggressive screening for colon cancer. On the other hand, well patients with non inflammatory bowel disorders clearly suffer greatly from pain and discomfort, they tend not to have a major impact on mortality or the need for life saving surgical interventions.