Acute Kidney Injury With Nephrotic Proteinuria: A Case Report

Introduction Nephrotic syndrome (NS) is caused by increased glomerular permeability to protein, which allows albumin to pass into the urine [1] . It can be primary, due to kidney lesions, or secondary, resulting from a systemic disease, such as diabetes or amyloidosis [2] . Most common cause of primary NS for adults is focal segmental glomerulosclerosis (FSGS), it affects more than 70% of patients [3] . Case Presentation 66 y.o. male presented with decreased urine output, waist pain and edema in the legs, genitals and face. Tests were conducted and showed nephrotic proteinuria of 25g/day. Biochemical blood tests revealed high serum creatinine, which was 167mmol/l and hypoalbuminemia at 18g/l. The patient was admitted to the Department of Internal Medicine and treated for acute renal failure and hyperkalemia. Since the origin of the acute kidney failure was unclear, the patient was transferred to the Department of Nephrology, where a renal biopsy was performed. It demonstrated segmental sclerosis and hyalinosis of the glomeruli. Laboratory test results and kidney biopsy confirmed the diagnosis of FSGS. Since there was no family history indicating genetic FSGS, further genetic testing was not performed. The patient was screened for HIV, hepatitis and other infections to determine whether FSGS was primary or secondary. All tests were negative confirming primary FSGS. The patient started treatment with angiotensin-converting enzyme inhibitors, diuretics and corticosteroids. After starting treatment, the edema decreased and kidney function gradually improved. Proteinuria dropped to below 3,5g/day and serum albumin levels began to increase. Discussion FSGS can be primary, secondary or genetic. It is important to differentiate between these types, because treatment may differ. Primary FSGS commonly has a sudden onset and is responsive to treatment [4] . It is unusual that FSGS is associated with acute kidney injury (AKI). AKI can be caused by prerenal, renal or postrenal factors [5]. In this case the postrenal component was ruled out. Therefore, AKI might be caused by severe hypoalbuminemia [6]. Conclusions This case illustrates an atypical case of NS with acute kidney injury, where primary FSGS was effectively treated with steroids. It demonstrates the importance of multidisciplinary approach in achieving successful treatment outcomes.