Kidneys are bean shaped organs situated in the upper abdomen, posteriorly. There are 2 kidneys, one on each side.
Their main function is to excrete toxic metabolites through urine. The other functions include production of hormones to aid in red blood cell production, and maintaining electrolyte and water balance in the body, and they control blood pressure by controlling certain hormones.
Kidneys can have numerous diseases. In younger age group, they can have developmental anomalies in the form of dysplasia or obstruction or reflux, which can adversely damage their function. Occasionally, children may have kidney stones with infection.
In adolescents and adults, they can develop infection, stones or obstruction. In many, the kidneys are indirectly affected due to obstruction or diseases which are beyond the kidneys.
In elderly patients, the kidneys may get affected by stones, obstruction and indirectly due to diabetes mellitus and hypertension. The kidneys may develop malignancy (cancer) in elderly group.