Foamy urine, weight gain due to water retention, swelling and poor appetite are some symptoms of a leaking kidney, also known as nephrotic syndrome, according MedlinePlus. High blood pressure in adults, low blood pressure in children, abdominal pain and shortness of breath are other symptoms, states Merck Manuals.
Swelling is the most common symptom of leaking kidneys and is especially seen in the feet and ankles, explains MedlinePlus. Facial and abdominal swelling are also common. Fluid retention in body tissues moves around, leading to swelling in different parts of the body depending on posture, state Merck Manuals. Simultaneous muscle wastage is often hidden by swelling. Secretion of nutrients into the urine leads to nutritional deficiencies and osteoporosis. In severe cases, infections, blood clotting and eventual kidney failure result from untreated leaking kidneys.