Differential Diagnosis for Nephrotic Syndrome with Maltese Cross Fatty Casts

• Single most likely diagnosis:
  • FSGS (Focal Segmental Glomerulosclerosis): This is the most common cause of nephrotic syndrome in adults, especially in African Americans. The presence of heavy proteinuria (6 g) and Maltese cross fatty casts in the urine supports this diagnosis, as FSGS often presents with significant protein loss and lipiduria due to the damage to the glomeruli.
• Other Likely diagnoses:
  • Minimal Change Disease: Although less common in adults, minimal change disease can present with heavy proteinuria and is a consideration in the differential diagnosis of nephrotic syndrome. However, it is less likely than FSGS in an adult population, especially with the specific finding of Maltese cross fatty casts.
  • Membranous Nephropathy: This is an immune-mediated disease that can cause nephrotic syndrome. While it is a possibility, the presence of Maltese cross fatty casts and the demographic of the patient (black patient) might lean more towards FSGS.
• Do Not Miss diagnoses:
  • Amyloidosis: Although rare, amyloidosis can cause nephrotic syndrome and has a varied presentation. Missing this diagnosis could be critical due to its potential for systemic involvement and the need for specific treatment.
  • Diabetic Nephropathy: Given the high prevalence of diabetes and its potential to cause nephrotic-range proteinuria, it's crucial not to miss this diagnosis. The presence of diabetes would significantly alter the management approach.
• Rare diagnoses:
  • Lipid Nephrosis: Conditions that specifically affect lipid metabolism and lead to nephrotic syndrome are rare but could potentially explain the presence of Maltese cross fatty casts.
  • Other Glomerulopathies: Such as membranoproliferative glomerulonephritis or IgA nephropathy, which can occasionally present with nephrotic syndrome, although they are less likely given the specific findings in this case.