Chronic renal disease is the progressive loss of kidney function over time that eventually leads to kidney failure. It is caused by conditions like diabetes and hypertension that damage the kidneys. Symptoms include nausea, fatigue, swelling, and high blood pressure. Diagnosis involves tests like renal ultrasound. Treatment depends on the stage of disease, ranging from controlling risk factors to dialysis and transplantation. Diet and lifestyle changes can help manage the condition and prevent further kidney damage.