Renal colic is frequently described by patients as the worst pain they have experienced, and it is often compared with childbirth. Kidney stones are also common in India, particularly in the hotter regions, where dehydration concentrates urine.
Most stones pass without intervention, and most recurrence is preventable.
How Stones Form
Urine contains dissolved minerals. When it becomes too concentrated, or when the balance of stone forming and stone inhibiting substances shifts, crystals form and grow.
- Calcium oxalate: the most common type by a considerable margin
- Calcium phosphate
- Uric acid: associated with gout, high protein diets and acidic urine
- Struvite: related to urinary infection, and can grow large
- Cystine: from an inherited condition, uncommon
Knowing the type matters because prevention differs. If you pass a stone, collect it and take it for analysis. This is frequently not done, and it discards useful information.
The Pain and What It Indicates
Renal colic has a recognisable pattern that reflects where the stone is sitting.
- Sudden severe pain in the flank or side, coming in waves
- Radiating around to the groin and, in men, to the testicle as the stone descends
- Patients cannot find a comfortable position and move restlessly, which distinguishes it from peritonitis where people lie still
- Nausea and vomiting
- Blood in the urine, visible or detected on testing
- Frequency and urgency when the stone reaches the lower ureter
The restlessness is a useful clinical clue. Someone writhing with abdominal pain is more likely to have colic than an inflamed abdomen.
When It Is an Emergency
Most stones can be managed with pain relief and observation. These features change that entirely.
- Fever with the pain, which suggests infection above an obstructing stone. This is a urological emergency requiring urgent drainage
- Inability to pass urine at all
- Uncontrollable vomiting preventing fluid intake
- Pain not controlled by adequate painkillers
- A single functioning kidney, or a transplanted kidney
- Signs of kidney failure on blood tests
An infected obstructed kidney can progress to sepsis within hours. Fever with renal colic should never be managed at home. Our emergency department assesses this urgently.
Which Stones Pass on Their Own
Size is the main determinant, and it guides whether to wait or intervene.
- Under 5 mm: the majority pass spontaneously, often within a few weeks
- 5 to 10 mm: around half pass, often with medical assistance
- Over 10 mm: unlikely to pass, and usually needs intervention
Position matters too. Stones in the lower ureter pass more readily than those higher up.
Medical expulsive therapy with an alpha blocker relaxes the ureter and improves passage rates for stones in the lower ureter. Drinking large volumes of fluid and staying active help, though the old advice to drink excessive amounts during an acute episode is not supported.
The Procedures
Where a stone will not pass or is causing obstruction, several options exist.
- Shock wave lithotripsy: external shock waves fragment the stone. Non invasive, done as a day case, best for smaller stones in favourable positions
- Ureteroscopy: a thin scope passed up the urinary tract, with laser fragmentation. Highly effective, often with a temporary stent afterwards
- Percutaneous nephrolithotomy: a small tract made through the back into the kidney, for large or complex stones
- Emergency drainage: a stent or nephrostomy tube to relieve obstruction, particularly with infection, with definitive treatment later
Ureteric stents cause discomfort, urgency, frequency and blood in the urine. This is expected rather than a complication, and it resolves once the stent is removed. Ensure you know the removal date, since retained stents cause serious problems.
Preventing Recurrence: Fluid First
Around half of people who form one stone form another within five to ten years. Prevention is genuinely effective and starts with fluid.
- Drink enough to produce at least two to two and a half litres of urine daily
- Judge by urine colour, aiming for pale straw throughout the day
- Drink extra during hot weather, exercise and manual outdoor work
- Include a glass of water at night if you form stones frequently, since overnight urine is most concentrated
- Lemon juice in water increases urinary citrate, which inhibits stone formation
Fluid intake is the single most effective preventive measure and the most frequently neglected. In Chennai's climate, outdoor workers are at particular risk.
Dietary Changes That Actually Help
Some dietary advice around stones is wrong, and following it makes things worse.
- Do not restrict calcium. This is the most common error. Low dietary calcium increases oxalate absorption and raises stone risk. Maintain normal dietary calcium, and take supplements only with meals if needed
- Reduce salt, which increases calcium excretion in urine
- Reduce animal protein, which increases uric acid and reduces citrate
- Moderate high oxalate foods for calcium oxalate formers: spinach, beetroot, nuts, chocolate and excessive tea. Pair them with a calcium source in the same meal, which binds oxalate in the gut
- Increase citrus fruit for its citrate content
- Reduce sugary drinks, particularly cola
- For uric acid stones, reduce red meat, organ meat and seafood, and alkalinise the urine
Our dietetics team tailors this to the stone type, which is why stone analysis is worth doing.
Investigation for Recurrent Stone Formers
Anyone forming stones repeatedly, or forming them young, deserves a metabolic evaluation rather than repeated treatment of individual stones.
- Stone analysis where a stone is available
- Blood tests for calcium, uric acid, phosphate and kidney function
- Parathyroid hormone if calcium is raised, since hyperparathyroidism is a treatable cause
- Twenty four hour urine collection measuring volume, calcium, oxalate, citrate, uric acid and sodium
- Imaging to check for residual stones and anatomical abnormalities
Where specific abnormalities are found, targeted treatment substantially reduces recurrence. Our urology and nephrology departments provide this assessment.
Most kidney stones pass with pain relief and fluids. Fever with renal colic is an emergency. For prevention, drink enough to keep urine pale, reduce salt, do not restrict calcium, and get the stone analysed if you can catch one.
Our urology department at T. Nagar manages stone disease and prevention.
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