Wegener’s granulomatosis is a systemic vasculitis that primarily affects small- to medium-size vessels. The antineutrophil cytoplasmic antibody–associated disease typically involves the upper and lower respiratory tracts and the kidneys. But the disease can potentially involve any organ, including the central and peripheral nervous systems, according to Dr. Philip Seo. "When most general rheumatologists ask me about Wegener’s, they generally stick to the canonical manifestations [sinus, lungs, kidneys], but nervous system involvement is certainly relevant to the management of these patients, and probably underappreciated," he said.
Nervous system manifestations present in approximately 22%-54% of Wegener’s patients, according to a recent report. The report’s authors noted that the majority of the complications reflected in this estimate are cases involving the peripheral nervous system – specifically, polyneuropathy or mononeuritis multiplex (Curr. Opin. Rheumatol. 2011;23:7-11).
Central nervous system involvement is relatively uncommon in Wegener’s, affecting an estimated 7%-11% of patients, according to an investigation into mechanisms of CNS complications in which the authors identified three separate pathogenic patterns: contiguous invasion of granuloma from extracranial sites, remote intracranial granuloma, and CNS vasculitis (Medicine. 2006;85: 54-65).
In this month’s column, Dr. Seo discusses the diagnosis and management of neurologic complications associated with Wegener’s disease that are most likely to present in clinical practice.
Question: What are the potential neurologic complications that clinicians must have on their radar?
Dr. Seo: The most common complication is a sensory peripheral neuropathy. Although this can be associated with pain, many patients will complain about a lack of sensation, which they will describe as a cold feeling in their feet, or the feeling that their feet are wrapped in plastic wrap or covered in wax. Some patients might also describe this as a feeling akin to rubber bands being stretched over their feet. A more serious form of peripheral neuropathy is a mononeuritis multiplex, which can lead to a "wrist drop" or a "foot drop."
Question: What are the important diagnostic considerations? What signs and symptoms should clinicians look for?
Dr. Seo: Many patients learn to accommodate these symptoms subconsciously, or they won’t have the vocabulary to describe these problems clearly to you. Thus, it is important to test both strength and sensation explicitly, especially when you are meeting a patient for the first time. Often, the patient will be surprised to learn that they have had a neuropathy and just never realized it was a problem.
Question: How does the occurrence of neurologic manifestations affect patient management?
Dr. Seo: Sensory neuropathy in particular is difficult to manage, because immunosuppression halts the progression of symptoms but does not actually repair the damaged nerves. Most medications that are advertised for sensory neuropathy address only the pain associated with this phenomenon. Some patients do not complain that their feet and lower legs continue to feel numb, even after many years of being in remission.
Question: Is the damage caused by nervous system involvement reversible?
Dr. Seo: Unfortunately, the role of treatment is to arrest progression of the disease. So, although we hope that immunosuppression will prevent the neuropathy from becoming worse, it does not actually help repair the damaged nerves. I think that recovery does occur in these cases, but it can be excruciatingly slow. Recovery of motor function in a patient with mononeuritis multiplex is considerably faster, and patients can often regain normal function of the affected limbs with time. Currently, the early diagnosis and treatment of Wegener’s are the best ways to prevent or reduce potential damage associated with neurologic involvement.
Dr. Seo is in the division of rheumatology and is codirector of the vasculitis center at Johns Hopkins University in Baltimore. He reported having no relevant financial disclosures.