Severe pain that starts in the side or lower back and spreads to the groin, coming in waves, may be kidney stones. The UK National Health Service (NHS) says small stones may pass unnoticed, but stones causing symptoms need urgent help. Most are treated at home with medicine and pass over a few weeks; larger stones are broken up with shock waves or removed through a thin tube. To prevent more, adults should drink 2.5 to 3 litres a day and keep salt under 6g a day.
1. Pain from the side or lower back spreading to the groin, coming and going.
2. Symptoms mean urgent help — especially severe pain or fever and shivering.
3. Prevention: 2.5–3 litres of water a day (children 1–2), salt under 6g, enough calcium.
Symptoms — NHS
| Type | What the NHS says | Worth noting (ours) |
|---|---|---|
| Small stones | May pass in urine unnoticed | — |
| Pain | Usually starts in the side or lower back, spreading to the groin (testicles, area around the vaginal opening); may come and go | — |
| Other | Fever, hot, cold or shivery; feeling or being sick; peeing often; cloudy urine | — |
When to get help — NHS
Get urgent help if stones are causing symptoms, especially with severe pain or a fever or feeling hot, cold or shivery (urgent GP or NHS 111). Diagnosis is usually from symptoms, with urine or blood tests, and for severe pain a CT scan in adults or ultrasound in pregnancy and under 16s. In Korea, urology or an emergency department (ours).
Causes and treatment — NHS
| Type | What the NHS says | Worth noting (ours) |
|---|---|---|
| Causes | Chemicals in urine form hard lumps in the kidneys; not drinking enough, conditions like metabolic syndrome, medicines such as aspirin, antacids, diuretics, antibiotics | — |
| Recurrence risk | High-protein, low-fibre diet; inactivity or bed rest; frequent kidney or urine infections; a close relative with stones; a previous stone | — |
| At home | Most treated at home with medicine; can take a few weeks to pass; plenty of water; painkillers, anti-sickness and passing aids; you may collect the stone for testing | — |
| In hospital | Larger stones: shock waves to break them (awake), or a thin tube via the urethra or a small cut in the back (general anaesthetic) | No mm thresholds on the page |
Preventing stones — NHS
| Type | What the NHS says | Worth noting (ours) |
|---|---|---|
| Water | Adults 2.5–3 litres a day, children 1–2 litres; fresh lemon juice in water suggested | 10–12 cups of 250ml (ours) |
| Drinks | Not too many fizzy, caffeinated or alcoholic drinks | — |
| Calcium | Enough in your diet | Not cutting it |
| Urine colour | Dark urine means dehydration | — |
| Salt | Adults under 6g a day; less for under 11s by age | — |
| Diet changes | Don’t change your diet a lot without a doctor | — |
Urine infections are in cystitis and UTIs; back pain in back pain.
Checklist
- ☐ Side-to-groin waves of pain: get seen
- ☐ With fever or shivering: urgent
- ☐ 2.5–3 litres of water; watch urine colour
- ☐ Salt under 6g; enough calcium
- ☐ Had one before? Watch for recurrence
Questions that remain
What size passes on its own?
The page gives no size threshold; a doctor decides from imaging.
Shouldn’t I cut calcium?
The NHS says get enough calcium in your diet.
Sources
- NHS — Kidney stones — source (page shows: reviewed 17 September 2026, next review 17 September 2029; checked 20 October 2026). Symptoms, urgent criteria, diagnosis (CT, ultrasound), causes and recurrence risk, home and hospital treatment, prevention (2.5–3 litres, children 1–2, lemon juice, calcium, salt under 6g).
- Not read. Size-based treatment thresholds; Korean urology guidance.
- What we added. The “worth noting” column and the Korean care gloss.
Where to check further
- Urology or emergency department — severe pain or fever.
Written on 20 October 2026. The content is from the NHS; the glosses are ours.
