Cytomegalovirus-Associated Nephrotic Syndrome in a Patient with Myasthenia Gravis Treated with Azathioprine: A Case Report

Objective: Rare coexistence of disease or pathology Background: Patients taking azathioprine (AZA) are very susceptible to development of cytomegalovirus (CMV) infection. The symptoms of CMV infection are varied. In some rare cases, CMV infection can even result in nephrotic syndrome. Case Report: Here, we present a rare case of nephrotic syndrome associated with CMV infection, induced by azathioprine intake. The patient, diagnosed with myasthenia gravis, was initially treated with azathioprine for 2 years. Then, the patient was admitted to the hospital due to nephrotic syndrome and acute kidney injury. Minimal change disease with acute tubular necrosis were diagnosed through biopsy. After an initial good response to hemodialysis and steroids, the patient developed severe pneumonia and oral ulcers. Further anti-CMV IHC staining of kidney tissues showed positive cells in tubules, indicating nephrotic syndrome secondary to CMV infection. Conclusions: This case reminded us that CMV may be an under-recognized cause of nephrotic syndrome. Patients treated with azathioprine are very susceptible to developing CMV infection. During the diagnosis of nephrotic syndrome, we should always take CMV infection into consideration, especially in patients with on azathioprine.