In brief, the case revolved around a resident of the Cape Cod area who presented with evidence of acute Lyme disease including several weeks malaise, nausea/vomiting and myalgias. The patient was given a diagnosis of Lyme disease based on a positive IgM Lyme titer, and was treated with doxycycline. At a return visit, it was noted that the individual had developed an acutely elevated creatinine (went from a baseline of 1.1 mg/dL to 1.8 mg/dL) and had a urinalysis showing hematuria, about 1 gram of proteinuria, and dysmorphic RBCs. A renal biopsy was performed, demonstrating an immune-complex-mediated MPGN histologic pattern. Despite a thorough workup to exclude other causes of this type of injury (e.g., SLE, hepatitis, endocarditis, etc), nothing could be pinpointed, and based on the temporal association between the onset of Lyme infection and renal disease, a tentative diagnosis of "Lyme Nephritis" was considered the most likely.
There are other case reports in the literature of Lyme Nephritis (see 2004 AJKD article by Kirmizis et al), and furthermore it has been noted that dogs infected with Lyme disease frequently experience an often lethal glomerulonephritis. However, Lyme Disease is common around these parts (somebody quoted a 1 in 5 Lyme infection rate amongst residents of nearby Martha's Vineyard, with rates of about 1 in 20 around the Cape Cod area), and it is possible that in this instance the Lyme Disease and GN are separate processes which just happened to occur at the same time.