Chronic kidney disease of unknown etiology: Is time for prevention

Sir,

The article by Wijetunge et al.[1] is indeed interesting. Increasing number of chronic kidney disease of unknown etiology (CKDu) has been reported from Sri Lanka[1] and few parts of India.[2] We would like to share our experience of CKDu observed among 25 Sri Lankan immigrants along with probable etiology and prevention aspects. It was more among males (male:female = 4:1) belonging to the age group of 28–56 years engaged in agriculture works in whom the exact cause could not be identified. All were anemic and free from hypertension and edema at the time of presentation/diagnosis. Most of the cases (18/25) had moderate tubular proteinuria that did not exceed l g/day, with increased elimination of beta 2 microglobulin. Ultrasound revealed bilateral, shrunken kidneys with Grade 3–4 renal parenchymal changes. The histopathological appearance was tubulointerstitial pattern consisting of tubular atrophies with mild inflammatory interstitial infiltrate.

As we have noticed CKDu among several family members of patients in the same village and no manifestations in those who left the family from childhood, we believe that environmental factors and/or susceptibility of individual might have contributed for the occurrence of CKDu. Moreover, previous studies have shown that groundwater available in endemic regions is not of desirable quality. In our series, the source of drinking water was either from shallow wells or from water reservoirs. Dissanayake[3] has proposed the theory of cyanobacterial toxins as a causative factor for the pathogenesis of CKDu in Sri Lanka. He further stated that environmental factors including global warming and chemical fertilizers with runoff water provide a favorable ecological background for the production of toxins by cyanobacteria. Bioaccumulation of pesticide residues, heavy metals, and possibly toxins released from plants and/or aquatic animals were postulated as other causes for the development of CKDu. Though several theories were hypothesized, the exact cause for CKDu has not yet been identified.

The management is expensive and requires a lot of infrastructure and human power which are lacking at present in South Asia. Hence, it is ideal to implement preventive strategies such as provision of protected water, enforce regulations for the use of chemical fertilizers, and control of global warming, apart from early detection and management. The goal of no deaths due to acute kidney injury[4] by 2025 will be achievable only through training health science students as well as practitioners and nurses involved in the delivery of health care at villages. Moreover, the trainees have to inculcate the art of eliciting family history of renal disease and assess other family members for occult renal diseases and/or susceptibility.