Acute Interstitial Nephritis and Membranous Nephropathy in the Context of IgG4-Related Disease.

We present the case of a patient with IgG4-related disease, which manifested in an asynchronous manner as vitiligo, cholecystitis, sialadenitis, lymphadenopathy, facial palsy and kidney dysfunction. The patient underwent a renal biopsy, and a presumptive diagnosis of lupus nephritis was made due to compatible clinical and immunological findings. The biopsy revealed IgG4-related kidney disease with severe interstitial nephritis and membranous nephropathy. Corticosteroids treatment restored all disease manifestations. We bring this case to the attention of the nephrologists because of the protean, asynchronous, multisystemic nature of the disease that necessitates a multidisciplinary approach, a low threshold for kidney biopsy and a high index of suspicion for making the correct diagnosis and treatment.