Renal biopsy correlation between indications and histopathology diagnosis

Introduction: Renal biopsy is a procedure in which a sample of renal tissue is obtained for microscopic examination. Renal biopsy has contributed greatly to the classifi cation of intrinsic renal diseases and, therefore, to a better knowledge of the pathogenesis involved. Although there are many studies regarding Renal Biopsy. There is little literature regarding correlation between indications and histopathology Diagnosis especially from India. Patients and Methods: Patients who presented with clinical and/or laboratory features of renal disease, whose diagnosis were uncertain with non invasive modalities and fulfi lled the requirement for renal biopsy were subjected to renal biopsy Aims and objectives: The aim of this study was to fi nd out the correlation between indications and histopathology of renal biopsy. Results: In this prospective study 115 renal biopsies were performed in 70 males and 45 females. The mean age of males were 36 ± 14.3 and in females mean age was 29.6 + 12.8. The most common age group biopsied was between 19-45yrs of age both among males (58.6%) and females (66.7) respectively. The number of patients below 18yrs of age was 21, 11 male and 10 female. Patients above the age of 45 were 23. 18 male and 5 females. The most common indication for renal biopsy was protinuria with hematuria and subnephrotic protinuria 26 patients each followed by nephrotic syndrome 25 patients. IgA nephropathy was the most common histopathology diagnosis (15.7%). The second most common histopathology diagnosis was Minimal change disease (10.4%) patients, however all these patients had nephrotic syndrome and normal renal biopsy on histology as no electron microscopy was done. Nephrosclerosis was third most common histopathology diagnosis seen (8.7%) patients. Focal segmental glomerulosclerosis was reported in (7.8%), Membranous glomerulonephritis in (7%), Lupus nephritis in (7%) Mesangiocapilary glomerulonehritis in (7%), chronic graft rejection in 3 (2.6%) all these three patients had presented with post, transplant azotemia. Acute tubular necrosis was reported in 5 (4.2%) patients, chronic interstitial nephritis in (5.2%) patients. In 6 patients (5.2%) biopsy were inconclusive which showed either blood clot, medullary tissue. Conclusion: Renal biopsy is one of the most important diagnostic modality with nephrologists. In our study most common indication for renal biopsy was Protinuria and Hematuria and most common histopathology diagnosis was IgA nephropathy. Thesis Renal biopsy correlation between indications and histopathology diagnosis Ashaq Parrey1*, Imtiyaz Ahmad2, Khurshid Banday3 and Shabir Rather4 1Department of Internal Medicine SKIMS Soura Srinagar jammu and kashmir India 2Department of Nephrology SKIMS Soura Srinagar jammu and kashmir India 3Department of Nephrology SKIMS Soura Srinagar jammu and kashmir India 4Department of Internal Medicine SKIMS Soura Srinagar jammu and kashmir India Received: 26 November, 2018 Accepted: 05 December, 2018 Published: 06 December, 2018 *Corresponding author: Ashaq Parrey, Department of Internal Medicine SKIMS Soura Srinagar jammu and kashmir India, Email:


Introduction
Renal biopsy an invasive procedure in which a sample of renal tissue is obtained [1]. Microscopic examination of the biopsied tissue can provide information needed to diagnose, monitor and/or treat renal disorder. The introduction of renal biopsy in clinical practice has represented one of the most important advances in the fi eld of clinical nephrology.
Renal biopsy has contributed greatly to the classifi cation of intrinsic renal diseases and, therefore, to a better knowledge of the pathogenesis involved. In spite of the fl ood of new and less invasive tests, renal biopsy is still an irreplaceable tool in assessing diagnosis and prognosis and guiding, the treatment of many renal diseases. It is being more frequently used, especially with the advancement of new biopsy guns and real-time ultrasound guidance .The fi rst open renal biopsy was carried out in 1899 [2]. Percutaneous renal biopsy was fi rst performed by Alwall in 1944 [3]. Iversen and Brun [4] stated that percutaneous renal biopsy is the most useful tool for diagnosing renal diseases causing acute renal failure DOI: http://dx.doi.org/10.17352/acn.000032 (ÁRF). After the publication of the Iversen and Brun study, percutaneous renal biopsy became a diagnostic procedure used increasingly all over the world, making possible the knowledge of diseases previously known only on the basis of autoptic renal sample. The procedure allowed the understanding of the natural history of all renal diseases. In the following years the technique increased its diagnostic potential with the development of immunofl uorescence microscopy and electron microscopy. Thus, renal biopsy became a crucial means for establishing the most important knowledge of histopathology, pathogenesis and classifi cation of renal disease [5]. At present with the use of real time ultrasound and automated needles >99% biopsies are diagnostic [6].
There is no doubt that percutaneous renal biopsy is extremely useful in clinical nephrology to establish an accurate diagnosis, to obtain data of prognostic value and to chose the most appropriate treatment for most patients affected by renal disease [7]. Nevertheless, the morbidity and occasional mortality associated with this procedure require a careful evaluation of the risk to benefi t ratio for each patient. This evaluation, however, is quite subjective [8,9]. Thus, it is not surprising that the indications for kidney biopsy vary considerably among nephrologists [10,11].
Indications for renal biopsy 1. Rapidly progressive glomerulonephritis failure (RPGN):-In patients with rapid fall of kidney function when an acute infl ammation involving small vessels, glomeruli, or interstitium is suspected, renal biopsy should be done. In these circumstances, the clinical diagnosis may be diffi cult and incomplete. In such a condition, renal biopsy is indicated despite a high risk of complication is the determining factor in identifying potentially treatable diseases.

Haematuria:-
There is no rule of renal biopsy in patients with isolated haematuria with or without asymptomatic proteinuria. The presence of 75 to 80 per cent of dysmorphic erythrocytes and/or more than 4 to 5 per cent of acanthocytes strongly suggests an underlying glomerular disease. Only renal biopsy can allow a fi rm diagnosis in these cases 3. Chronic renal failure:-Chronic renal failure represents a contraindication to renal biopsy. However, for patients with moderate renal insuffi ciency and a normal sized kidney, a kidney biopsy may be indicated to recognize the type of renal disease and the potential reversibility of histological lesions.

Non-nephrotic proteinuria:-
The indications for renal biopsy in patients with proteinuria less than I to 2 g per day, normal renal function, and mild urine sediment abnormalities. Some of them may have orthostatic proteinuria" others have an underlying nephrosclerosis or a refl ux nephropathy causing a secondary focal glomerulosclerosis. However, biopsy is considered if the clinical setting is compatible with a primary glomerular disease.

5.
Diabetic nephropathy:-Proteinuric non-insulindependent diabetic patients without retinopathy may require renal biopsy. However, non-diabetic renal disease may develop in diabetic patients. Moreover, a multitude of glornerulopathies may be associated with diabetic nephropathy, including membranous nephropathy [11], minimal change nephropathy [12] , acute glomerulonephritis [13] , anti-GBM nephritis [14], and IgA nephropathy [15]. These events are particularly frequent in type 1 diabetes mellitus [16]. The indications of renal biopsy in patients with diabetes are. a) The absence of retinopathy or neuropathy in patients with evidence of nephropathy may imply that the underlying pathology is unrelated to diabetes [17]. b) Rapid fall of renal function, and microscopic or macroscopic hematuria [18].  biopsy in native single kidney. Good results have been obtained in selected cases both in adults [19] and in children [20]. Open biopsy is an alternative option in patients with a single kidney.

Objectives
The objective of this study was to fi nd out the correlation between indications and histopathology of renal biopsy.

Ethical issues
The research followed the tenets of the Declaration, informed consent was obtained; and the research was approved by the ethical committee of Shere-kashmir institute of medical scinces (SKIMS) soura Srinagar India.

Statistical analysis
Analysis was performed in SPSS version 16 software and P value less than 0.05 was considered as statistically signifi cant

Results
In this prospective study 115 renal biopsies were performed 70 males (60.9%) and 45 females (39.1%). The mean age of males were 36 ± 14.3 and in females mean age was 29.6 + 12.8 the most common age group biopsied was between 19-45yrs of age both among males (58.6%) and females (66.7). The number of patients below 18yrs of age were 21 (18.3%), 11 male and 10 female. Patients above the age of 45 were 23 (20%) 18 male and 5 females (Table 1).
 Inconclusive was reported in 6 (5.2%) patients among them 2 (33.3%) patients had subnephrotic protinuria, 2 (33.3%) patients had nephrotic syndrome,1(16.7%) patients had vasculitis with active urinary sedment and 1(16.7%) post renal transplant azotemia. Showing histopathology diagnosis and there incidence in our study. The most common diagnosis is IgA nephropathy the second most common diagnosis was MCD, however the diagnosis of MCD was considered in patients with nephritic syndrome and normal histopathology in renal biopsy.   glomerulonephritis disease, minimal change disease and membranous glomerulonephritis were the commonest fi ndings in children below the age of 16 years. Minimal change disease ranked fi rst in adults whole membranous glomerular disease and focal segmental glomerulosclerosis were more common in the elderly. In all patients lupus glomerular disease was the commonest secondary glomerular disease.
Maya et al.
[31], conducted a retrospective study outcomes of renal biopsy on patients undergoing a percutaneous native kidney biopsy during a 2-year period (January 1, 2004 to December 31, 2005). Of 129 renal biopsies, 65 were ultrasoundguided and 64 were performed by the blind technique. All biopsies were performed by nephrology fellows under direct faculty supervision. The two patient groups were comparable in terms of age, sex, race, diabetes, hypertension, serum creatinine, and hematocrit. The mean number of glomeruli per biopsy was higher in the ultrasound-guided group than in the patients with a blind biopsy (18 +/ 9 versus 11 +/-9, p = 0.0001). An inadequate tissue sample requiring repeat biopsy occurred in 0% of the ultrasound-guided biopsies and 16% of the blind biopsies (p = 0.0006). Large hematomas requiring vascular intervention or transfusion were less frequent in the ultrasound-guided biopsies (0% versus 11%, p = 0.006). The hematocrit 24 hours post biopsy was higher in the ultrasoundguided biopsies when compared with the blind biopsies (32 +/-5% versus 30 +/-4%, p = 0.04). When compared with blind renal biopsy, real-time ultrasoundguided percutaneous renal biopsy provides a superior yield of kidney tissue and results in fewer hemorrhagic complications. They concluded that Realtime ultrasound-guided renal b iopsy is the preferred technique.
The limitations of study were short duration of study and its prospective nature which resulted in small sample size of only 114 patients. There were no ethical errors made during the study as only those patients were subjected to renal biopsy who fulfi lled the criteria strictly for renal biopsy and were benefi ts outweighed the risk.

Conclusion
Renal biopsy is one of the most important diagnostic modality with nephrologists. In our study of 115 patients the indication for renal biopsy was Protinuria and Hematuria (22%) isolated subnephrotic protinuria (22.6%) Nephrotic syndrome (21.7) ARP (5; 2%) systemic disease (3.5%) Subnephrotic Protinuria wih azotemia (20%) and post renal transplant azoteamia (3.5%). The most common histopathology diagnosis was IgA nephropathy (15.7%) followed by MCD (10.4%) FSGS (7.8%) MGN (7%) Lupus nephritis and RPGN was (5.2%) and (4.3%) respectively.In5.2% of patients either no tissue was obtained or it was insignifi cant. I-ISP was reported in 2.6 % of patients, and nephrosclerosis in 7% of patients. The study reveals that there is no alternative to renal biopsy, as is evident from this study that same disease present with different urinary and renal abnormalities.

Limitations of the study
Non availability of electron microscopy and number of patients is a limitation of our study. However the project was to be completed in two and half years which limited the number of patients.