RESUMO
Chronic kidney disease of unknown etiology (CKDu) is a major healthcare issue in Sri Lanka. This study included 125 consecutive patients with a diagnosis of CKDu undergoing renal biopsy at one hospital from 2008 to 2012. Associations between renal outcome parameters, epidemiological data, and histopathological findings were examined and regression models constructed based on univariate associations with outcome variables as serum creatinine >1.2 and stage of CKD >3. The mean patient age was 46.21 years (standard deviation = 11.64). A marked male predominance was noted. A positive family history of CKD was seen in 35.8%. Prominent histopathological features were glomerular sclerosis (94.8%), interstitial infiltration (76%) with lymphocytic infiltration, interstitial fibrosis (71.2%), and tubular atrophy (70.4%). Importantly, significant histological changes were seen in patients with early CKDu. For CKD stage >3 independent associations were: interstitial fibrosis [P = 0.005; odds ratio (OR) =0.153] and interstitial infiltrate (P = 0.030; OR = 0.2440. For serum creatinine >1.2, independent predictors were >50% glomerular sclerosis (P = 0.041; OR = 0.92), tubular atrophy (P = 0.034; OR = 0.171, and more than 40 residential life years (P = 0.009; OR = 9.229). Chronic tubulointerstitial nephritis (TIN) appears to be the predominant histopathological finding in patients with CKDu, with significant renal pathology established early on in the course of the disease. Interstitial infiltration appears to be an independent association of advancing CKD, CKDu, histopathology, histology, and TIN.
RESUMO
Chronic kidney disease of unknown etiology (CKDU) is endemic among the rural farming communities in several localities in and around the North Central region of Sri Lanka. This is an interstitial type renal disease and typically has an insidious onset and slow progression. This study was conducted to identify the pathological features in the different clinical stages of CKDU. This is a retrospective study of 251 renal biopsies identified to have a primary interstitial disease from regions endemic for CKDU. Pathological features were assessed and graded in relation to the clinical stage. The mean age of those affected by endemic CKDU was 37.3 ± 12.5 years and the male to female ratio was 3.3:1. The predominant feature of stage I disease was mild and moderate interstitial fibrosis; most did not have interstitial inflammation. The typical stage II disease had moderate interstitial fibrosis with or without mild interstitial inflammation. Stage III disease had moderate and severe interstitial fibrosis, moderate interstitial inflammation, tubular atrophy and some glomerulosclerosis. Stage IV disease typically had severe interstitial fibrosis and inflammation, tubular atrophy and glomerulosclerosis. The mean age of patients with stage I disease (27 ± 10.8 years) was significantly lower than those of the other stages. About 79.2%, 55%, 49.1% and 50% in stage I, II, III and IV disease respectively were asymptomatic at the time of biopsy.
RESUMO
OBJECTIVES: To study the early pathological changes in renal lesions of asymptomatic patients with kidney diseases, with no definite aetiology living in regions endemic for chronic kidney disease of unknown etiology (CKDUe). Design Retrospective study. SETTING: Regions endemic for CKDUe in and around the North Central Province of Sri Lanka. STUDY POPULATION: Two hundred and eleven asymptomatic patients living in endemic regions detected with renal disease by screening for proteinuria using the dipstick method. Those with long standing hypertension, diabetes mellitus, histological diagnosis of primary glomerular diseases, immunocomplex mediated diseases or renal lesions secondary to systemic diseases were excluded. MEASUREMENTS: Renal lesions were divided into seven histological categories depending on the pathological changes: Category 0: no detectable changes. Category 1: Interstitial fibrosis ± mild interstitial inflammation ± tubular atrophy; no glomerulosclerosis. Category 2: Interstitial fibrosis ± mild interstitial inflammation ± tubular atrophy; glomerulosclerosis. Category 3: Moderate or severe interstitial fibrosis, interstitial inflammation and tubular atrophy ± glomerulosclerosis; Category 4: Interstitial inflammation ± tubular atrophy ± glomerulosclerosis; no interstitial fibrosis. Category 5: The prominent change is interstitial inflammation with tubulitis. Category 6: Severely scarred kidney. Histological categories were compared with calculated glomerular filtration rates and age of the patients. RESULTS: Number of cases in histological categories 0 to 6 were: 7 (3.3%), 71 (33.6%), 53 (25.1%), 63 (29.9%), 0, 2 (0.9%) and 15 (7.1%) respectively. The mean glomerular filtration rate was >90 ml/min in patients in category 0 and 1 and declined progressively in categories 2 and 3. Apart from category 0, all had interstitial fibrosis and in category 1, 62 (87.3%) had interstitial fibrosis without inflammation. Severity of interstitial inflammation increased from category 1 to 3. CONCLUSIONS: The early disease among asymptomatic patients is characterized by interstitial fibrosis without significant interstitial inflammation and glomerular sclerosis with preserved glomerular function. Although the role of interstitial inflammation in the initiation of the disease is not clear, it appears to have a role in the progression of the disease.