A Woman with Proteinuria

Posted by • November 13th, 2015

72-Year-Old Woman with ProteinuriaIn a new Case Record of the Massachusetts General Hospital, a 72-year-old woman presented with flank pain, proteinuria, and a new kidney mass. Magnetic resonance imaging of the kidney revealed a complex, solid mass (3 cm x 2.9 cm x 2.9 cm) in the lower pole of the right kidney. Diagnostic tests were performed.

Membranous nephropathy, an immune-complex glomerular disease, is the most common cause of the nephrotic syndrome in white adults.

Clinical Pearls

• Describe some of the features of adult minimal change disease.

Adult minimal change disease is rare and seen in only 10 to 15% of biopsy specimens from patients with nephrotic-range proteinuria, although the prevalence is increased among white patients who are 80 years of age or older. Patients with adult minimal change disease may present with a rapid onset of features of the classic nephrotic syndrome, with abrupt development of hypoalbuminemia (within days to weeks) and edema and possibly even acute kidney injury due to intravascular volume depletion. Overt hematuria is uncommon.

• What is the association between membranous nephropathy and cancer?

It is not entirely clear whether there is an association between the development of membranous nephropathy and cancer, but evidence suggests that the incidence of malignant tumors among patients with histologically proven membranous nephropathy is in the range of 5 to 10%. This rate may be increased in elderly patients. The pathogenesis of membranous nephropathy in patients with cancer remains uncertain.

Morning Report Questions

Q: What cancers have most commonly been associated with membranous nephropathy?

A: Membranous nephropathy is the most common glomerular disease that is associated with solid cancers. Lung, gastrointestinal, prostate, and breast cancers are the cancers that have most commonly been associated with membranous nephropathy. There are only a few reported cases of membranous nephropathy with concurrent renal-cell carcinoma.

Q: What evidence suggests that idiopathic membranous nephropathy may be an autoimmune disease?

A: Approximately 75 to 80% of cases of membranous nephropathy are idiopathic, without a known, specific, identifiable inciting event, such as a medication, infection, or cancer. Membranous nephropathy is characterized by deposits that develop on the subepithelial surfaces of the glomerular capillary wall, mainly on the podocytes. An autoantibody targeting the M-type phospholipase A2 receptor (PLA2R), an antigen normally expressed on the surface of podocyte-cell membranes, has been discovered; it has been suggested that cases of idiopathic membranous nephropathy may actually be cases of an autoimmune disease targeting podocytes with autoantibodies to PLA2R. Approximately 75 to 80% of cases of primary membranous nephropathy are associated with a positive test for antibodies to PLA2R at the time of diagnosis.

Figure 3. Biopsy Specimens of the Uninvolved Kidney.

2 Responses to “A Woman with Proteinuria”

  1. Mhd Samer Aldardary says:

    What is the best treatment option if its a solitary kidney .and why you didn’t do a Ct scan  after preparation the patient with bicarbonate .?

  2. Daniel Toledo says:

    I am preparing my exam for the specialty I would like to send me more to go studying clinical cases.