Glomerulonephritis associated with myasthenia gravis.

In a follow-up study of 128 myasthenic patients from a neurological center in Northern Italy, three were found to have developed glomerulonephritis at variable intervals after the onset of myasthenia gravis, thymoma (two patients), and thymectomy. By renal biopsy, two patients (cases 1 and 3) were found to have membranous nephropathy; and one (case 2), pauciimmune extracapillary glomerulonephritis. At follow-up, patient 1 was persistingly nephrotic and developed renal failure, and patient 3 only had urinary abnormalities. Patient 2 developed end-stage renal disease. The review of the literature showed 10 other cases of glomerulonephritis associated with myasthenia gravis with or without thymoma and thymectomy. Therefore, it is likely that these conditions are pathogenetically linked. The role of autoantibodies, thymoma, and thymectomy in favoring glomerulonephritis in myasthenic patients is discussed.