Monitoring
Long-term management of granulomatosis with polyangiitis (GPA) (formerly known as Wegener granulomatosis) involves careful monitoring of disease activity in order to maximize early detection of relapse and to optimize treatment regimens. This strategy allows the use of less toxic therapies for remission induction, and earlier intervention can help minimize tissue damage related to active GPA. To reduce treatment-related toxicities, it is essential that immunosuppressive therapy is used judiciously.
Proper assessment of disease activity does not depend on a single factor, but requires integration of a thorough history and physical exam, along with laboratory and radiographic findings. For example, evidence of chronic damage due to prior disease activity (e.g., hearing loss or long-standing lung nodules) or persistently abnormal laboratory findings (e.g., positive antineutrophil cytoplasmic antibody [ANCA] or elevated erythrocyte sedimentation rate) should not necessarily be interpreted as active GPA in the absence of more compelling evidence of active disease. Indeed, while ANCA testing is helpful in supporting the diagnosis of GPA, evidence does not support the routine use of ANCA for monitoring of disease activity.[32] For all patients with suspected relapse of GPA, the possibility of infection, malignancy or disease- or treatment-related complications should always be considered.
Laboratory evaluation, including complete blood count, metabolic panel, inflammatory markers, and urinalysis every 1 to 3 months is recommended, even during a sustained disease remission.[38] If a patient is on cyclophosphamide, more frequent blood monitoring may be necessary. In addition to providing information regarding current disease status and toxicity of current therapies, these tests can help identify patients who develop myelodysplasia, leukemia, or bladder toxicity as a result of cyclophosphamide exposure.
The identification of nonglomerular hematuria (reddish or pink urine, blood clots, normal sized, biconcave erythrocytes, absence of cellular casts) should prompt a cystoscopic examination, because urine cytology does not have sufficient negative predictive value to rule out the presence of a bladder malignancy.
To reduce the risk of skin cancer, patients who have received or are receiving cyclophosphamide treatment should take measures to reduce ultraviolet light exposure. An annual dermatologic evaluation is also prudent. People with GPA should undergo appropriate malignancy screening.
All patients treated with long-term corticosteroids should receive screening and preventive measures against corticosteroid-induced osteoporosis.[44] See Osteoporosis.
Validated disease activity scores (e.g., Birmingham Vasculitis Activity Score modified for GPA [BVAS/GPA]) and damage scores (e.g., Vasculitis Damage Index [VDI]) can aid assessment of GPA disease activity, and are routinely used in clinical studies.[81][82]
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