LETTER TO THE EDITOR
Year : 2012 | Volume
: 23 | Issue : 6 | Page : 1292--1293
Clinicopathological correlation of primary nephrotic syndrome in adults
Mary Grace, Vinu Thomas
Department of Medicine, Government Medical College, Thrissur, Kerala State, India
Department of Medicine, Government Medical College, Thrissur, Kerala State
|How to cite this article:|
Grace M, Thomas V. Clinicopathological correlation of primary nephrotic syndrome in adults.Saudi J Kidney Dis Transpl 2012;23:1292-1293
|How to cite this URL:|
Grace M, Thomas V. Clinicopathological correlation of primary nephrotic syndrome in adults. Saudi J Kidney Dis Transpl [serial online] 2012 [cited 2022 Sep 29 ];23:1292-1293
Available from: https://www.sjkdt.org/text.asp?2012/23/6/1292/103580
To the Editor,
There are salient features in the clinical data of the patient that can often guide the clinician to predict the histologic type of nephrotic syndrome without performing renal biopsy. These include epidemiologic, clinical and laboratory features, which, when judiciously applied to the individual scenario, can help in making an empirical histological prediction. We designed a prospective study to determine the potential of such design.
Adult patients aged above 12 years with nephrotic range proteinuria and disclosing no secondary causes for nephrotic syndrome were included in this study. Age, gender, duration and degree of proteinuria, hematuria, oliguria, hypertension, edema, pleural effusion, ascites, hemoglobin, total and differential count, urine albumin, urine sediment, 24-h urinary protein, renal function tests, serum cholesterol, serum albumin and ultrasound of the abdomen of these patients were studied. Prior to renal biopsy, each patient was analyzed in detail and the possible histopathological lesion was predicted. Renal biopsy was done with an automated tumor biopsy gun under ultrasonic guidance. The tissue specimens were analyzed by light and immunofluorescence microscopy. Correlation to the histopathological lesions and demographic, clinical and laboratory parameters was studied. The predictive value was determined for these clinical and laboratory parameters to predict the renal histology.
We studied 86 patients who underwent renal biopsy in the nephrology unit of our hospital. Among them, 65 were found to have nephrotic syndrome and 50 met the selection criteria for this study. The mean age of the patients was 34 ± 14.7 years, and 35 (70%) were males.
The histological subtypes found in our patients included minimal change disease (MCNS) [11 (22%) patients], focal segmental glomerulosclerosis (FSGS) (23 [46%] patients) and membranous glomerulonephritis (MN) [16 (46%) patients].
The observations on clinical presentation and the disease manifestations revealed several interesting data. Macrohematuria was revealed in five out of a total of 50 patients, and the majority of the patients (80%) gave a history of passing frothy urine. The pattern of distribution of hypertension among the histological subtypes did not show significant differences. Three of the 11 cases of MCNS, seven of the 23 cases of FSGS and four of the 16 cases of MN had hypertension. There were 23 (46%) patients who had ascites at the time of presentation; 15 of 23 (65%) cases of FSGS had ascites, four of 11 cases had MCNS and four of 16 cases had MN. Microhematuria was revealed in 13 out of 50 (26%) patients in this study; 11/13 of them had FSGS and 2/13 cases had MN. Of the 18 patients with proteinuria more than 5 g/day, 11 patients had serum cholesterol more than 400 mg%, and 11 of 18 patients with massive proteinuria (empirically defined as >10 g/day) had severe hypoalbuminemia. Six of 50 (12%) patients had renal impairment; all had FSGS and only one had massive proteinuria; another patient had hypertension. Severe hypoalbuminemia (serum albumin < 2.5 g/dL) was observed in 34 of 50 (68%) cases; seven of 11 cases of MCNS, 11 of 16 cases of MN and 16 of 23 cases of FSGS had severe hypoalbuminemia. Of the 23 patients with serum cholesterol more than 400 mg%, 18 had severe hypoalbuminemia. Tubulointerstitial (TI) changes in the renal biopsy were noted in 27 of 50 cases; two of 11 cases of MCNS had TI changes, eight of 16 (50%) cases of MN had TI changes and 17 of 23 (74%) cases of FSGS had TI cjanges. Only five of 27 cases with TI changes had renal failure.
The clinicopathological correlation rendered the prediction unviable. Of the 20 cases clinically predicted as FSGS, only 14 turned out to be true. Similarly, predictions held good only in 5/9 of MCNS and 11/21 of MN cases. The margin of error would be 30% in FSGS, 44% in MCNS and 48% in MN. These are unacceptable when we consider the ease with which a renal biopsy can be done and the hazards of inappropriate immunosuppressive therapy.
Several schemes have been proposed whereby the histology could be reasonably predicted so that steroids are started without a renal biopsy. ,,, These include various demographic, clinical and laboratory parameters of adult nephrotic syndrome (NS) patients, such as age, renal function, hypertension and urinary sediment with the histological type so that empirical steroid therapy can be offered to a selected group of adult NS patients before renal biopsy. There was a substantial clinicmorphological correlation (60%) in our study. Considering the ease of renal biopsy in adults, the unpredictability of steroid therapy in the designated patients and its toxicity, a model for histological prediction does not appear to be viable. We strongly recommend renal biopsy in all adult patients with NS prior to steroid treatment.
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