Renal parenchymal disease is not a single disease but a pathological state. It is caused by glomerular diseases, chronic interstitial nephritis, adult polycystic kidney disease, etc.
No matter what the original cause is, renal parenchymal diseases are characterized by scarring of the kidneys and renal fibrosis. There are many factors that can cause renal parenchymal damages such as infections, toxins (including some renal toxicity medicines), abuse or improper intake of drugs, etc. The doctor needs to tackle the renal damage due to renal fibrosis.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
i needed to inform early my brother is on dialysis for about an year.Now he is facing 20% heart efficiency can you please tell me the way how to improve it. or i send you reports.