Treat the Syndrome, Not the Lab Test

Jonathan Kay, MD


October 15, 2014

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Hello. I am Dr Jonathan Kay, professor of medicine and director of clinical research in the Division of Rheumatology at the University of Massachusetts Medical School and the University of Massachusetts Memorial Medical Center, in Worcester, Massachusetts.

In my August 2014 blog, I described the sad case of an elderly woman with dermatomyositis that was very poorly responsive to corticosteroid therapy. She underwent a malignancy workup, which uncovered an abdominal mass. Sadly, this mass turned out to be pancreatic cancer, and several weeks later she passed away. Thus, the importance of screening for malignancy in dermatomyositis is underscored by this case. This was a wonderful woman, a great person, someone who was full of life and much loved by her family and many others. She will be missed.

I want to share with you another very interesting case, of a woman in her mid-20s who was experiencing failure to thrive. Her case is interesting in that she had hypothyroidism occasioned by an episode of thyroiditis when she was a teenager. For this, she was treated with thyroid replacement therapy.

She also had been diagnosed earlier with Castleman disease because of lymphadenopathy and had been treated with rituximab with regression of the lymphadenopathy. Around that time, before treatment with rituximab, she also had experienced autoimmune pancreatitis; that, too, improved with rituximab. When rituximab therapy was discontinued, however, the autoimmune pancreatitis recurred, and she developed nausea, generalized pain, and failure to thrive.

She was referred to me for a clarification of her diagnosis; this constellation of thyroiditis, lymphadenopathy, and autoimmune pancreatitis raised the possibility of immunoglobulin G4 (IgG4)-related disease. I examined her IgG subsets, and she had no elevation or reduction in any of the subsets. A review of the histopathology from a pancreatic biopsy showed no characteristic features of IgG4-related disease, and she had no other serologic markers.

In spite of this and because of her previous response to rituximab, we treated her with a course of intravenous rituximab 375 mg/m2 weekly for 4 weeks according to the standard non-Hodgkin lymphoma regimen. Remarkably, she felt much, much better after two weekly doses of rituximab. I ran into her on the day of her infusion just outside my clinic area, and I did not recognize her at first because she was much more vivacious, had gained a little bit of weight, and felt much better. Thus, whatever her underlying diagnosis, her clinical response to rituximab therapy suggested that what she had was a rituximab-responsive syndrome.

This syndrome of IgG4-related disease is not as discreet as might be indicated by the literature in that one cannot always find elevation of IgG4 or characteristic histologic features. However, the clinical syndrome should suggest consideration of rituximab therapy, as in this patient.

Thank you for your attention. I look forward to seeing you again on Medscape.


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