Hydronephrosis in Children

Our kidneys make urine. Urine flows from the kidney, through a tube called the ureter, to the bladder, and out of the body. Hydronephrosis means swelling of the kidney because urine is not draining properly — it backs up and collects in the kidney. It can affect one or both kidneys.

Common causes in children:

• UPJ obstruction: blockage where the kidney meets the ureter — the most common cause
• VUR / reflux: urine flows back from the bladder to the kidney; also a stone or narrowing in the ureter
• Posterior urethral valves: in boys, a valve blocks urine flow
• Detected on a pregnancy scan: many babies are born with mild hydronephrosis

Many children have no symptoms and it is found during an ultrasound for other reasons. When symptoms come:

• Pain in the side or back, especially after drinking a lot of fluid
• Fever with chills — due to kidney infection
• Frequent urinary infections (UTIs)
• Blood in the urine
• Poor weight gain in infants

• Ultrasound of the abdomen: the first test — shows the swelling and its grade
• VCUG: checks for urine reflux, done with a catheter
• DTPA / MAG3 renogram: a nuclear scan to check how well the kidney is working and draining
• Blood tests: to check kidney function

• Grade 1–2: mild — often improves on its own
• Grade 3–5: moderate to severe — needs close follow-up and sometimes surgery

Treatment depends on the cause, grade, and kidney function.

• Observation: for mild cases, especially in babies — repeat the scan every 3–6 months; many improve
• Medicines: antibiotics to prevent UTIs if reflux is present, and pain medicine if needed
• Surgery: needed if kidney function is decreasing, there is severe pain or repeated infection, or grade 3–4 with poor drainage
• Common surgeries: pyeloplasty (removes the UPJ blockage, keyhole possible), ureteric reimplantation (for reflux), and valve ablation (for boys with posterior urethral valves)

Success rate is over 95%, and kidney function can improve after surgery.

• Drink enough water: 6–8 glasses per day
• Complete the full course of antibiotics if given
• Do not miss regular follow-up scans
• Watch for fever, pain, or burning while passing urine
• Healthy diet; low salt if advised