What is Chronic Rhinosinusitis? Defining Chronic Rhinosinusitis (CRS)

Main Category: Allergy
Article Date: 27 Apr 2004 - 0:00 PDT

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Recently published guidelines describe causes and diagnostic criteria that could lead to better treatments for Chronic Rhinosinusitis CRS, a common and often debilitating form of sinusitis. The authors call for the creation of a standard definition.

CRS is now defined as a group of disorders characterized by inflammation of the mucosa of the nose and paranasal sinuses of at least 12 weeks duration. The group of CRS disorders annually accounts as many as 22 million office visits and more than 500,000 emergency department visits in the U.S., according to some estimates.

Annual CRS-related healthcare expenditures may reach as much as $3.5 billion.

New guidelines have recently been released by the Sinus and Allergy Health Partnership (SAHP) to help physicians make more accurate diagnoses and provide better clinical care. "These are not really guidelines, per se," according to lead author Michael S. Benninger, MD. "It is predominantly an effort to define disease and provide criteria for the diagnosis.

Past definitions have never really come to any conclusion about what it is, and specific authors would determine their own definition based upon what they were investigating. You would define it as a bacterial disease if you were looking at antibiotics; you would define it as a fungal disease if you were looking at antifungal medications; and you would define it as an allergic disease if you were looking at antiallergic medications.

We have come to realize it is really a spectrum of diseases; there are a number of disorders (fig. 1) that cause chronic inflammation of the nose and paranasal sinus. The critical thing is for physicians to take a good history about the potential causes, and then treat the most likely causes first. If you determine the cause to be allergic, for example, you are going to treat CRS very differently than if it were anatomical."

CRS is commonly diagnosed on the basis of symptoms alone, but many pathophysiological mechanisms play a role in the disease and determining the cause is central to developing an effective treatment plan.

"The diagnosis is typically more rigid in research," Benninger says. "In the clinical setting, some of the available diagnostic tools like CT scans may not be possible or cost-effective, particularly in primary care settings. The strategy therefore is to identify signs and list symptoms that can be seen by anterior rhinoscopy. If those aren't seen and you still suspect the disease, then move to nasal endoscopy or some type of radiograph."

The new SAHP guidelines provide both clinical criteria (fig. 2) and research criteria required to diagnose CRS.

"The most interesting thing now and into the future," he continues, "is the discussion of certain inflammatory mediators which may play a significant role and may suggest possible treatment. There is very good evidence that fungi and bacteria in chronic rhinosinusitis act very differently than they do in acute diseases. In acute illness they infect the tissue, but in chronic disease they colonize the sinus and by doing so

they cause a very aggressive inflammatory reaction. It is almost like an autoimmune reaction where the body releases all these inflammatory mediators to try and kill the fungus or bacteria but it actually injures the tissues. So the issue is whether CRS is truly an infection. Or, in other words, do antifungals or antibiotics work as well in CRS as they do in acute rhinosinusitis? The answer in my view is they probably do not."

Dr. Benninger notes that most CRS patients initially receive an antibiotic when they should instead be receiving an intranasal corticosteriod, which reduces inflammation regardless of the process. "It is important to think about inflammation rather than infection. If you give someone with sinus disease systemic steroids, they do better because you have reduced that inflammatory reaction no matter the cause of rhinosinusitis - allergy, environmental, fungus, bacteria, virus, you name it.

Systemic steroids are a valuable treatment for many patients with CRS. My favorite treatment is intranasal corticosteroids plus anti-allergy medication if they are allergic. I prefer a healthy blast of a short course of systemic steroids and stop without a taper, and I would prefer to do that once a year rather than give a continual low dose.

Most patients will respond to conservative treatment; allergy treatment if they are allergic, intranasal corticosteroids for most patients, and saline nasal irrigation in some cases. Conservative treatment is usually very effective."

Noting the role of the inflammatory process in CRS, the guidelines point out that rhinosinusitis is replacing the term "sinusitis" because it is often preceded by rhinitis and rarely occurs without concurrent nasal airway inflammation. Dr. Benninger believes, "�the future is trying to understand the inflammatory mediators, and what started the inflammatory process in the first place. The next thing for us is to determine the next steps, where we are in our effort, and the reasonable expectations for treatment. That should be out by mid-summer or shortly thereafter."

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