Complications and Risks of Kidney Stones

Most small kidney stones pass without lasting harm, but larger or untreated stones can cause serious problems.

Blocked urine flow

A stone stuck in the ureter can swell the kidney (hydronephrosis). Long blockage can cause permanent kidney damage.

Infection

• Urinary infection above a blocked stone can spread to the kidney and blood
• Fever, chills and flank pain with a stone are an emergency (infected, obstructed kidney)
• Without urgent drainage this can cause sepsis

Kidney damage

• Repeated stones and infection can cause scarring and long-term kidney disease
• Risk is higher with a single kidney, existing kidney disease, diabetes and some inherited stone diseases

Recurrence

About half of people have another stone within 5 to 10 years without prevention.

Pain and daily life

Severe colic can cause time off work and repeated hospital visits.

Procedure-related risks

• Bleeding, infection and injury to the ureter
• Stone fragments that need another procedure
• Stent discomfort, with urgency and blood in the urine

In pregnancy

Stones can cause pain, infection and preterm labour risk. They need a doctor's care.

Warning signs needing urgent care

Fever with pain, very little or no urine, uncontrolled vomiting, severe unrelenting pain, confusion or fainting. Call 112.

Reducing risk

Drink plenty of water, follow the prevention advice, attend follow-up scans and treat infections early.

Key point

Prompt treatment of blockage and infection protects the kidney, and prevention reduces repeat stones.

Before your appointment

Note when the pain began, where it is, and whether you have noticed blood, fever, nausea or burning in your urine. Record how much you drink and pass urine in a day. List medicines and supplements, especially vitamin C, vitamin D, calcium and herbal products. Mention previous stones, gout, bowel surgery, urinary infections and family history. Bring earlier scans and reports. If you pass a stone, save it for analysis. Ask about tests, the stone type and a prevention plan. Call 112 for fever with pain or if you pass no urine.