Your kidneys filter waste and extra water from the blood, balance salts, help control blood pressure and keep bones and red blood cells healthy. Kidney disease is often silent until a large part of kidney function is lost, which is why simple blood and urine tests matter so much. This guide covers the warning signs, the difference between nephrotic and nephritic syndrome, acute and chronic kidney failure, kidney stones, and the tests that pick problems up early.
Quick answer: Early kidney disease usually has no symptoms. Later signs include swelling of the feet, ankles or around the eyes, foamy or bloody urine, passing much less urine, tiredness, poor appetite, itching and high blood pressure. Two tests check kidney health: a blood creatinine test to calculate eGFR, and a urine test for protein (albumin). People with diabetes or high blood pressure, the two most common causes, should have both at least once a year.
Key takeaways
- ✅ Diabetes and high blood pressure cause most chronic kidney disease in India.
- ✅ Nephrotic syndrome means heavy protein loss and swelling; nephritic syndrome means blood in the urine, high BP and less urine.
- ✅ Avoid regular use of painkillers such as ibuprofen and diclofenac, and unregulated herbal remedies.
- ✅ Severe flank pain with fever, or very little urine, needs urgent care.
Warning signs of kidney problems
- Swelling (edema) of the feet, ankles, legs or face, especially puffiness around the eyes in the morning
- Foamy or frothy urine, a sign of protein loss
- Red, brown or cola-coloured urine
- Passing much less urine, or needing to pass urine often at night
- High blood pressure that is new or hard to control
- Tiredness, poor appetite, nausea, itching and muscle cramps (in advanced disease)
- Breathlessness from fluid build-up
Nephrotic vs nephritic syndrome
Both are caused by damage to the glomeruli, the kidney's tiny filters, but they look different.
|
Nephrotic syndrome |
Nephritic syndrome |
| Main problem | Filters leak large amounts of protein | Inflammation of the filters, which leak blood and work less well |
| Urine | Very foamy; heavy protein (adults over 3.5 g per day) | Red or cola-coloured (blood), some protein, reduced volume |
| Swelling | Marked, often whole body (anasarca) | Mild, often around the eyes |
| Blood pressure | Usually normal at first | Raised |
| Blood tests | Low albumin, high cholesterol | Raised creatinine and urea |
| Common causes | Children: minimal change disease. Adults: diabetes, membranous nephropathy, FSGS | After a throat or skin infection (post-streptococcal), IgA nephropathy, lupus, vasculitis |
| Treatment | Steroids (most children respond well), BP medicines that reduce protein loss, low-salt diet, diuretics | Treat the cause, control BP and fluids; many post-infection cases in children recover fully |
A kidney biopsy is often needed in adults to find the exact cause, because treatment differs.
Acute kidney injury and chronic kidney disease
Acute kidney injury (AKI) is a sudden drop in kidney function over hours or days. Common causes are severe dehydration from diarrhoea or vomiting, serious infections, snake bite, certain medicines and painkillers, and blockage of urine flow. It is often reversible if treated quickly.
Chronic kidney disease (CKD) is kidney damage lasting more than three months. It is staged using the eGFR, calculated from a blood creatinine test:
| Stage |
eGFR (mL/min/1.73m²) |
What it means |
| G1 | 90 or above | Normal function, but other signs of kidney damage such as protein in urine |
| G2 | 60 to 89 | Mildly reduced |
| G3a / G3b | 45 to 59 / 30 to 44 | Moderately reduced; complications start to appear |
| G4 | 15 to 29 | Severely reduced; plan for dialysis or transplant |
| G5 | Below 15 | Kidney failure |
Protein in the urine (urine albumin-to-creatinine ratio, UACR) is graded separately: below 30 mg/g is normal, 30 to 300 is moderately raised, and above 300 is severely raised. More protein means a higher risk of progression. Main causes of CKD are diabetes, high blood pressure, chronic glomerulonephritis, kidney stones and blockages, polycystic kidney disease and long-term painkiller use. In some farming regions of India, CKD also occurs without these causes and is being studied.
Treatment focuses on slowing the damage: controlling blood sugar and blood pressure, medicines such as ACE inhibitors, ARBs and SGLT2 inhibitors that protect the kidneys, a lower-salt diet, and avoiding harmful medicines. Kidney failure is treated with dialysis or a transplant. Free dialysis is offered at district hospitals under the Pradhan Mantri National Dialysis Programme.
Kidney stones
Kidney stones are hard deposits, usually of calcium oxalate, that form when urine is concentrated. They are common in hot climates and with low water intake.
- Symptoms: sudden, severe pain in the side or back that spreads to the groin and comes in waves; blood in the urine; nausea and vomiting; burning or frequent urination
- Tests: urine test, ultrasound, and a CT scan (KUB) if needed
- Treatment: small stones (under about 5 mm) often pass with fluids and pain relief; larger stones may need medicines to relax the ureter, shock-wave lithotripsy, ureteroscopy or keyhole surgery
- Prevention: drink enough to pass 2 to 2.5 litres of pale urine a day, limit salt and animal protein, and do not cut calcium from your diet unless told to
Seek urgent care if you have:
- Stone pain with fever or chills, which can mean an infected, blocked kidney
- Very little or no urine for 12 hours or more
- Sudden swelling with breathlessness
- Confusion, severe vomiting or chest pain in someone with known kidney disease
Tests for kidney health
- Serum creatinine and eGFR: how well the kidneys filter
- Urine routine and microscopy: protein, blood, pus cells and casts
- Urine albumin-to-creatinine ratio (UACR): an early sign of damage, especially in diabetes
- Blood urea, electrolytes, hemoglobin, calcium and phosphate
- Ultrasound of the kidneys: size, stones, blockages or cysts
- Kidney biopsy in selected cases of nephrotic or nephritic syndrome
Protecting your kidneys
- Keep blood sugar and blood pressure in the target range
- Limit salt to under 5 g a day (about one teaspoon, including hidden salt)
- Drink enough water, especially in hot weather
- Avoid regular painkillers and unregulated herbal or "kidney cleanse" products
- Do not smoke, and stay active
- Have a yearly creatinine and urine test if you have diabetes, high blood pressure, or a family history of kidney disease
Frequently asked questions
Can kidney damage be reversed?
Acute kidney injury often recovers. Chronic kidney disease usually cannot be reversed, but good treatment can slow it down a great deal, often for many years.
Is nephrotic syndrome in children curable?
Most children with minimal change disease respond to steroids. Relapses are common, but many children outgrow the condition by adulthood.
What does foamy urine mean?
Occasional foam can happen with fast urination or concentrated urine. Persistent foam may mean protein in the urine, which should be checked with a urine test.
Does drinking a lot of water cure kidney disease?
No. Enough water helps prevent stones and dehydration, but in advanced kidney disease too much fluid can be harmful. Follow your doctor's advice on fluid intake.
Related reading: Diabetes symptoms and tests, the most common cause of kidney disease.
Last updated: September 2026. General health information only, not a diagnosis or a treatment plan. Please discuss your kidney test results and medicines with a qualified doctor.
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