I recently developed a new focus or, at least a major distraction: Nonspecific Interstitial Pneumonitis, or NSIP.
NSIP is an Interstitial Lung Disease, or ILD, a group of disorders I learned of in May during my initial appointment with a pulmonologist. He said I didn’t have an ILD and that was good because these were nasty. At the meeting, it was clear the pulmonologist had been briefed by my primary care physician who had told me for more than a year that my concern about shortness of breath was unwarranted. Still, the pulmonologist said I should go ahead and get an X-ray.
The X-ray led to a high resolution CT scan, followed by a call about “abnormalities.” The pulmonologist said he was surprised. Me, too. I sought the referral thinking I needed an antibiotic, not a surgical lung biopsy involving a robot and video: ouch. Before the surgery, a Pulmonary Function Test had bad numbers; another surprise to the doctors and a vindication I could have lived better without. The NSIP diagnosis was delivered June 30.
The pulmonologist was right, ILDs are nasty.
NSIP turns out to be one of the better ILDs. Nevertheless, it has changed my life and is likely to shorten it. “More favorable prognosis than …” often appears in descriptions of NSIP, followed by a reference to something evil. In NSIP’s favor is that treatments are available. Some ILDs have no effective therapy other than a lung transplant. Prognoses can be as dire as for lung cancer.
NSIP is rare. To search for it on the Internet, spell it out or at least type “NSIP lung.” The National Sheep Improvement Program in Australia was at the top of my first Google search for NSIP. [Update 6/4/2012: The sheep site is now on Google's malware list and I removed the link.] Wikipedia gives Non-specific Interstitial Pneumonia 20 words in two sentences (not counting footnotes): one sentence merely says it has a better prognosis than Usual Interstitial Pneumonia, where you can click to read a scary outcome.
NSIP is new. It was identified in 1994, which enabled all the doctors I’ve talked to about it to have told me it didn’t exist when they were in medical school. The American Thoracic Society and the European Respiratory Society in 2002 elevated NSIP to a provisional diagnosis of an Idiopathic Interstitial Pneumonia, which is a group of ILDs that includes Idiopathic Pulmonary Fibrosis and Usual Interstitial Pneumonia, a deadly pair often cited together as IPF/UIP. NSIP was cited to explain why some patients originally diagnosed with IPF/UIP responded better to treatment and lived longer.
The 1994 finding inspired research. A new diagnosis calls into question every previous study where a subject thought to have one disease might suffer, in fact, from something else. The 2002 decision by the two groups of pulmonologists came with a recommendation for increased research to better define NSIP, including distinguishing features, prevalence, its relationship to other types of ILDs and whether further subclassification should be made. In 2008, the American Thoracic Society Project concluded that idiopathic NSIP is a distinct form of Idiopathic Interstitial Pneumonia but called for more study of both idiopathic NSIP and NSIP linked to known associations.
Academic journals of the last 10 years provide a volume of studies about NSIP that belies its rarity. Readers with a personal interest in answers, like me, can be disconcerted to find controversy in the continued debate to define NSIP and mystery in metrics being crunched in a quest to best predict survival.
NSIP is diagnosed by eliminating other possibilities. It is easier to say what it isn’t than what it is: not surprising for a disorder with “nonspecific” in its name. In addition to disagreement over a hyphen in nonspecific, it is sometimes called pneumonia and sometimes, my preference, pneumonitis (noo-moe-NIE-tis). The 2002 document that made it a provisional diagnosis acknowledges the name’s indecisive nature, noting: “Although there are several reasons to be critical of the term NSIP, one advantage is that the name implies the uncertainty that prevails.”
“Broad” and “heterogeneous” are often used to describe the family of Interstitial Lung Diseases. It’s a big group and information can be, well, nonspecific: ILDs number more than 100, more than 130, about 180 or more than 200. That makes for a lot of names, many using the same words. Diseases can have different names in different countries. Some ILDs are from a known cause or association, with — thanks to lawyers with advertising budgets — the best-known example being asbestosis. Others have an unknown origin and a name that may include “idiopathic.” Even NSIP’s subgroup of Idiopathic Interstitial Pneumonia is described as heterogeneous.
What’s common among ILDs is inflammation deep inside lungs of the interstitium, the tissue around the tiny air sacs, or alveoli, where oxygen enters the blood stream and carbon dioxide exits. In people with interstitial lung disease, this tissue becomes stiff or scarred, and the air sacs lose the ability to expand. The inflammation can lead to scarring, or fibrosis. Inflammation can be stopped and reversed; scarring cannot. If inflammation or scarring prevent the air sacs from expanding or make the tissue too thick for the gas transfer, less oxygen is available to the body and its organs. Lungs become smaller and less flexible. You don’t see it in the academic journals, but “slowly petrifies” gets the point across in news reports.
NSIP has its own subgroups. By structure, it is divided into cellular, fibrotic or mixed fibrotic and cellular. Survival statistics worsen as fibrosis increases. Another grouping looks at associations: autoimmune diseases including lupus, arthritis or AIDS; environmental exposures; prior acute lung injury; and unknown.
The structural and associational subsets, along with diseases that were underlying or that develop, combine in different ways to challenge physicians who attempt to treat an ILD that is actually treatable. A favorite sentence from my reading appears in “Fibrotic Idiopathic Interstitial Pneumonia: The Prognostic Value of Longitudinal Functional Trends” by Panagiota I. Latsi et al: “Thus, it has been argued that when a histopathologic diagnosis of NSIP has been made, the work of the clinician has only just begun.”
Also, the focus of the patient begins.