Tubulointerstitial damage as the major pathological lesion in endemic chronic kidney disease among farmers in North Central Province of Sri Lanka

Abstract

Chronic kidney disease of uncertain etiology (CKDu) in North Central Province of Sri Lanka has become a key public health concern in the agricultural sector due to the dramatic rise in its prevalence and mortality among young farmers. Although cadmium has been suspected as a causative pathogen, there have been controversies. To date, the pathological characteristics of the disease have not been reported. Histopathological observations of 64 renal biopsies obtained at Anuradhapura General Hospital from October 2008 to July 2009 were scored according to Banff 97 Working Classification of Renal Allograft pathology. The correlations between the histological observations and clinical parameters were statistically analyzed. Interstitial fibrosis and tubular atrophy with or without nonspecific interstitial mononuclear cell infiltration was the dominant histopathological observation. Glomerular sclerosis, glomerular collapse, and features of vascular pathology such as fibrous intimal thickening and arteriolar hyalinosis were also common. Although hypertension was identified as one of the common clinical features among the cases, it did not influence the histopathological lesions in all the cases. This study concludes that tubulointerstitial damage is the major pathological lesion in CKDu. Exposure(s) to an environmental pathogen(s) should be systematically investigated to elucidate such tubulointerstitial damage in CKDu.

Fig. 1

Glomerular pathology. a Ischemic glomerular obsolescence. The glomerular capillary tufts are wrinkled and collapsed (arrow). Bowman’s space is filled with collagen (arrow head) (PASM ×200). b Perihilar focal segmental glomerulosclerosis. The perihilar segment is obliterated by increased matrix and hyalinosis (arrow) (PAS ×200)

Fig. 2

Tubulointerstitial pathology. a Interstitial inflammation. Obsolescent glomeruli, tubular atrophy, and interstitial mononuclear cell infiltration are seen on the right side. A hypertrophic nephron is seen on the left side (arrow) (PAS ×40). b Interstitial fibrosis. Tubular atrophy and interstitial fibrosis can be seen (Masson’s trichrome ×100)

Fig. 3

Vascular pathology and subcapsular cortical atrophy. a Arteriosclerosis (intimal fibrosis). An interlobular artery showing fibrous thickening of the intima and elastosis is seen (Masson’s trichrome ×200). b Subcapsular cortical atrophy. Subcapsular fibrotic area contains obsolete glomeruli, atrophic tubules, and chronic inflammation (PAS ×40)