title: Retrospective analysis of renal histology in asymptomatic patients with probable chronic kidney disease of unknown aetiology in Sri Lanka.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Regions endemic for CKDUe in and around the North Central Province of Sri Lanka.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
authors.affiliation: Department of Pathology, Faculty of Medicine, University of Peradeniya, Sri Lanka. suwijetunge@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Wijetunge
authors.forename: N V I
authors.initials: NV
authors.lastname: Ratnatunga
authors.forename: D T D J
authors.initials: DT
authors.lastname: Abeysekera
authors.forename: A W M
authors.initials: AW
authors.lastname: Wazil
authors.forename: M
authors.initials: M
authors.lastname: Selvarajah
authors.forename: C N
authors.initials: CN
authors.lastname: Ratnatunga
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases; D001284:Atrophy / Q000473:pathology; D002648:Child; D005260:Female; D005355:Fibrosis; D005919:Glomerular Filtration Rate; D006801:Humans; D007249:Inflammation / Q000473:pathology; D007668:Kidney / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000209:etiology / Q000473:pathology*; D012189:Retrospective Studies; D013188:Sri Lanka; D055815:Young Adult