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It is generally believed that significant renal ablation leads to hyperfiltration and eventually progressively worsening chronic kidney disease. The data behind this belief have not been scrutinized intensively. More importantly, the above belief leads many physicians to manage patients differently than they otherwise would manage. Here, we examine the data behind whether hyperfiltration occurs when patients lose kidney mass (by excision or by disease) and whether the hyperfiltration is uniformly injurious.

Membranous glomerulonephritis is most often idiopathic, but it can be secondary to systemic lupus erythematosus, viral hepatitis, and drugs. A number of malignancies have also been associated with membranous glomerulonephritis, although a causal link has not been established yet. A young patient with lymphangioleiomyomatosis is described who developed massive proteinuria and was found to have membranous glomerulonephritis on renal biopsy. There were many pathological features and some clinical features that suggested the patient also suffered from systemic lupus erythematosus.

Membranous glomerulonephritis is typically classified as idiopathic or secondary to systemic lupus erythematosus (SLE), hepatitis B, drugs, toxins, other infections, or malignancy. Not infrequently in some patients without a definite diagnosis of SLE, pathologic features of secondary membranous nephropathy are seen e.g., mesangial and/or subendothelial deposits, tubuloreticular inclusions, and full house immunofluorescence. In these patients, there is uncertainty about the etiology, response to therapy, and prognosis of membranous GN. We retrospectively reviewed the charts of 98 patients with membranous GN at San Francisco General Hospital and John Stroger Hospital of Cook County over a 10-year period. Data were collected and analyzed using SPSS.18. Thirty-nine (40 %) had idiopathic membranous GN (Group 1), thirty-six (37 %) had lupus membranous GN (Group 2) and twenty-three (23 %) had some pathological features of secondary membranous GN, but no definite etiology of membranous GN (Group 3). At baseline (at time of renal biopsy) and after mean follow-up of 3.5 years, the average serum creatinine (in mg/dL) in Group 1 was (1.6 ± 1.0 versus 1.6 ± 1.7), Group 2 was (1.8 ± 2.5 versus 1.2 ± 0.9) and Group 3 was (1.1 ± 0.4 versus 1.27 ± 0.83), respectively. For the same time points, the average urine protein to creatinine ratio (g/g) in Group 1 was (9.8 ± 7.1 versus 5.7 ± 6.7), Group 2 was (4.2 ± 3.9 versus 1.7 ± 2.2), and Group 3 was (7.4 ± 5.7 versus 3.1 ± 3.8). In addition, during the follow-up period, eleven of 39 (28 %) in Group 1, two of 36 (6 %) in Group 2, and three of 23 (13 %) in Group 3 progressed to end-stage renal disease and were started on dialysis. It appears that patients with lupus membranous GN have better renal prognosis than patients with idiopathic membranous GN. The renal prognosis for patients with pathological features of lupus membranous but no diagnosis of systemic lupus (lupus-like membranous GN) falls in between. Further studies are needed to determine if Group 3 patients can (a) definitively be classified as true idiopathic membranous GN or lupus membranous GN or (b) they have a separate disease from either M-type phospholipase A2 receptor membranous nephropathy or systemic lupus-induced membranous nephropathy.

A high incidence of hypernatremia is often observed in patients recovering from acute kidney injury (AKI) in intensive care units.An unselected cohort of 20 adult patients recovering from AKI in the intensive care unit of a single institution during a 1-year period, were investigated. Serum and urine electrolytes, osmolality, urea nitrogen and creatinine were measured in an attempt to determine the cause of the hypernatremia.Eighty-eight percent of patients who could not drink fluids were found to have hypernatremia (serum Na145 mEq/L). Even though the hypernatremia was mild in most patients (146-160 mEq/L), the average rise in serum sodium concentration was 17.4 mEq/L. The average urine osmolality was 384 mmol/kg of which 47.6 and 32.8 mmol/kg were contributed by sodium and potassium, respectively. The patients had hypervolemia as evidenced by the presence of edema and an average weight gain of 21.5 kg at the onset of the hypernatremia. The rise in serum sodium level coincided with an increase in urine output.The hypernatremia is believed to be due to post-AKI diuresis in the face of inability to maximally concentrate the urine because of renal failure. The diuresis caused a disproportionate loss of water in excess of that of sodium in the absence of replenishment of the water loss. Additionally, the patients were hypervolemic due to the retention of large quantities of sodium and water as a result of infusion of substantial volumes of physiological saline prior to the development of hypernatremia.