Kidney stones
Kidney stones are hard mineral deposits that form in the urinary tract. Small stones may pass with little difficulty, while a stone that enters and blocks a ureter can cause severe colicky pain, blood in the urine, nausea and—in the presence of infection—a urologic emergency.
At a glance
Quick facts
- Category
- Urinary stone disease
- Common type
- Calcium stone
- Classic symptom
- Severe flank pain
- Blood in urine
- Common
- Main concern
- Obstruction + infection
- Treatment
- Passage, removal or fragmentation
Dr. Francis Chibueze Nwokpoku
Medical Officer · 9th Division Hospital, Nigerian Army
Reviewed for clinical accuracy, important omissions and patient-facing safety wording.
Names & terminology
How this entity may be named or searched
- Kidney stone
- A solid mineral deposit formed in the kidney or urinary tract.
- Nephrolithiasis
- Medical term for stones in the kidney.
- Urolithiasis
- Broader term for stones anywhere in the urinary tract.
- Renal colic
- Severe, often wave-like pain caused by obstruction as a stone moves through the ureter.
Structured entity profile
Clinical profile
Overview
Kidney stones form when minerals or salts crystallize and aggregate in the urinary tract. Calcium oxalate stones are the most common, but uric acid, struvite and cystine stones have different causes and prevention strategies. [1]
A stone may remain in the kidney without symptoms. Pain typically begins when it moves into the ureter and obstructs urine flow. Obstruction combined with urinary infection can rapidly become dangerous and requires urgent drainage and antibiotic treatment. [1] [2]
Symptoms and warning signs
Typical symptoms include sharp pain in the back, side, lower abdomen or groin; blood in the urine; urinary urgency or pain with urination; nausea and vomiting. Pain may come and go in waves as the ureter contracts around the stone. [2]
SYMPTOM MATRIX
Stone symptoms depend on location, obstruction and infection
Fever or systemic illness with an obstructed urinary tract is an urgent pattern.
- Sharp flank or side pain
- Pain radiating toward the groin
- Blood in the urine
- Nausea or vomiting
- Pain that comes in waves
- Urinary urgency or frequency
- Pain during urination
- Cloudy or foul-smelling urine
- Small-volume urination
- No symptoms with a non-obstructing stone
- Fever or chills with stone symptoms
- Inability to urinate
- Severe persistent pain with vomiting
- Signs of sepsis or collapse
An infected obstructed urinary tract is a urologic emergency and needs urgent decompression and antibiotics.
Diagnosis
Diagnosis uses symptom history, examination, urine and blood tests plus imaging. Imaging identifies stone size and location and whether urine flow is obstructed. CT is highly sensitive; ultrasound is frequently used when avoiding radiation is important, including many pregnancy pathways. [3]
Urinalysis can show blood, infection or crystals, while blood tests assess kidney function and metabolic contributors. When a stone is passed or removed, analysis of its composition helps guide recurrence prevention. Recurrent stone formers may undergo 24-hour urine and other metabolic testing. [1] [3]
Diagnostic pathway
Locate the stone, assess obstruction and check for infection
Stone size and location matter, but infection and kidney function determine urgency.
Imaging choice varies with age, pregnancy, recurrence history and clinical urgency; radiation exposure is considered when CT is selected. Source [3]
Stone type changes prevention
Calcium oxalate, uric acid, struvite and cystine stones arise from different risk patterns. Stone analysis and metabolic evaluation are especially useful in recurrent disease because prevention should address the specific urinary chemistry rather than rely on a universal diet. [1]
Treatment and management
Small uncomplicated stones may pass spontaneously with pain control, hydration appropriate to the clinical situation and follow-up. Treatment is escalated when pain is uncontrolled, the stone is unlikely to pass, obstruction threatens kidney function or infection is present. [1]
Procedures include ureteroscopy, shock-wave lithotripsy and percutaneous stone removal, selected according to stone size and location. Prevention after an episode may include higher fluid intake, dietary changes and medicine targeted to the stone type or 24-hour urine findings. [1]
Treatment & care hub
Relieve obstruction, control pain and prevent recurrence
Treatment is based on stone size, location, infection, kidney function and likelihood of spontaneous passage.
Allow spontaneous passage when safe
Pain control and follow-up are used when the stone is likely to pass and there is no dangerous obstruction or infection.
Decompress the urinary tract
Obstruction with infection requires urgent drainage and antibiotics rather than waiting for passage.
Remove or fragment the stone
Ureteroscopy, shock-wave lithotripsy or percutaneous approaches are selected according to anatomy and stone burden.
Reduce recurrence risk
Hydration, diet and medicines are tailored to stone composition and metabolic findings.
Preventing future stones
NIDDK advises adequate fluid intake for most stone formers unless a clinician has given a different fluid plan. Sodium, animal protein, calcium and oxalate advice should be individualized because inappropriate restriction—especially of normal dietary calcium—can be counterproductive for some calcium oxalate stone formers. [1]
In follow-up I emphasize adequate fluid intake because concentrated urine promotes stone formation. The exact fluid target should be individualized to the person and clinical circumstances.
United States lifetime estimate
Kidney stones affect a substantial minority of adults
NIDDK estimates about 11% of men and 6% of women in the United States have a kidney stone at least once during their lifetime.
Common questions
Frequently asked questions
It is often sharp or severe pain in the side or back that may radiate to the lower abdomen or groin and come in waves.
No. Many small uncomplicated stones pass on their own, while larger, obstructing or complicated stones may need a procedure.
Fever can indicate infection behind an obstructing stone, a urologic emergency that may require urgent drainage and antibiotics.
Calcium stones, especially calcium oxalate stones, are the most common.
Yes. Recurrence is common, so stone analysis and prevention based on hydration, diet and metabolic risk can be important.
Sources
- NIDDK, NIH — Kidney Stones — Definition & Facts
- NIDDK, NIH — Kidney Stones — Symptoms & Causes
- NIDDK, NIH — Diagnosis of Kidney Stones
This article is based on trusted medical sources and has undergone clinician review. It is not a substitute for personalized medical advice.
Small stones can often pass without a procedure. Pain control, the ability to maintain hydration, obstruction, infection and the course of symptoms help determine whether outpatient care remains appropriate or escalation is needed.