A healthcare appointment guide for patients and providers

What caregivers and healthcare providers need to know about IgG4-RD

I have been diagnosed with IgG4-related disease, also called IgG4-RD. IgG4-RD is a systemic immune-mediated disease that can cause inflammation, organ enlargement, and fibrosis in one or more parts of the body. It may present with mass-like lesions that mimic cancer or dysfunction of the affected organs leading to much diagnostic confusion until the full diagnostic picture is reviewed.

IgG4-RD is considered a rare disease and can involve nearly any organ system. Common sites include:

• the pancreatobiliary system (“autoimmune pancreatitis” and “IgG4-related sclerosing pancreatitis,” which resembles primary sclerosing cholangitis);

• the major salivary glands (parotid, submandibular) and the lacrimal glands;

• the orbits (extra-ocular muscles);

• the retroperitoneum (retroperitoneal fibrosis);

• as well as the lungs, kidneys, aorta and medium-to-large vessels, lymph nodes, and other tissues.

Care often involves coordination across rheumatology, gastroenterology, and other specialists, including nephrology and urology, depending on the specific organs involved.

There is no single test that confirms the diagnosis of IgG4-RD in every patient. Diagnosis usually depends on the pattern of symptoms, imaging, blood tests, biopsy findings when available, and careful exclusion of diseases that can mimic it. A normal or mildly elevated serum IgG4 level does not necessarily rule IgG4-RD in or out.

Please consider my known IgG4-RD history when evaluating new symptoms, but also please evaluate urgent symptoms on their own merits. People with IgG4-RD can still have infections, blood clots, heart problems, acute kidney injury, medication side effects, cancer, or other emergencies. They also often have glucose intolerance because of pancreatic involvement by the disease.

Please also be sure to consult my IgG4-RD treating physician before making changes to my IgG4-RD treatment, initiating corticosteroids for another condition, or attributing symptoms to medication side effects.