Few pains are as intense as renal colic. Patients often describe the pain of a kidney stone as the worst they have ever felt, with some women saying it was worse than labour. Kidney stones are common worldwide, and they are particularly frequent in hot climates such as the Middle East, parts of Africa and South Asia, where dehydration is common. Nurses in emergency departments, urology wards and primary care see these patients regularly.
What are kidney stones?
Kidney stones (renal calculi) are hard deposits that form when minerals in urine crystallise. Most are made of calcium oxalate; others include uric acid, struvite (linked to infection) and cystine stones. Small stones may pass unnoticed, but when a stone moves into the ureter it can cause obstruction and severe pain: renal colic.
Risk factors
- Low fluid intake and dehydration, especially in hot climates or with long shifts without drinking
- High-salt or high-animal-protein diets
- Obesity and diabetes
- A family or personal history of stones
- Gout (uric acid stones)
- Recurrent urinary infections (struvite stones)
- Some medicines and bowel conditions such as inflammatory bowel disease
Nurses themselves are at risk: busy shifts with little time to drink or use the toilet are a recipe for dehydration.
Recognising renal colic
- Sudden, severe, colicky pain in the loin (flank), often radiating to the groin, testicle or labia
- The patient is restless, unable to get comfortable, and may pace or writhe (unlike peritonitis, where patients lie still)
- Nausea and vomiting
- Blood in the urine (visible or on dipstick)
- Urinary frequency or urgency if the stone is near the bladder
Red flags: think beyond the stone
Not every loin pain is a kidney stone. Some conditions are emergencies:
- Infected obstructed kidney: fever, rigors, or signs of sepsis with renal colic. This is a urological emergency. The kidney may need urgent drainage, as antibiotics alone can’t clear infection behind a blockage.
- Abdominal aortic aneurysm: especially in men over 60 with apparent “first episode” renal colic, low blood pressure, or a pulsatile abdominal mass. This can be fatal if missed.
- Single kidney or kidney transplant with obstruction, or bilateral obstruction: risk of acute kidney injury.
- Pregnancy: consider ectopic pregnancy in women of reproductive age. Always do a pregnancy test.
- Uncontrolled pain despite adequate analgesia.
Nursing assessment
- Full set of observations including temperature and an early warning score. Fever with loin pain must be escalated urgently.
- Pain assessment with a validated score, reassessed after each intervention.
- Urinalysis: blood, infection markers. Send a urine sample for culture if infection is suspected.
- Pregnancy test in women of childbearing age.
- Bloods as requested: kidney function, full blood count, CRP, calcium and urate; blood cultures if febrile.
- Imaging: low-dose non-contrast CT is commonly used to confirm stones; ultrasound is preferred in pregnancy and children. Prepare the patient and arrange transfer.
Pain relief
Fast, effective analgesia is a priority. NICE guidance on renal and ureteric stones recommends:
- NSAIDs (such as diclofenac or ibuprofen) as first-line analgesia, by any route, unless contraindicated (for example kidney impairment, GI bleeding risk, pregnancy).
- IV paracetamol if NSAIDs are contraindicated or not effective.
- Opioids if both are contraindicated or not enough.
- Antispasmodics such as hyoscine butylbromide are not recommended for renal colic in NICE guidance.
Antiemetics may be needed for nausea and vomiting. Reassess pain regularly and escalate if it isn’t controlled.
Further management
- Watchful waiting: many stones under about 5 mm pass on their own within a few weeks.
- Medical expulsive therapy: alpha-blockers (such as tamsulosin) may be offered for distal ureteric stones under 10 mm to help them pass.
- Procedures: shockwave lithotripsy, ureteroscopy with laser fragmentation, or percutaneous nephrolithotomy for larger stones. A ureteric stent or nephrostomy may be needed to relieve obstruction.
- Stone sieving: patients may be asked to strain urine to catch the stone for analysis.
Fluids: helpful, but don’t overdo it
Encourage normal oral hydration. Forcing large amounts of IV or oral fluids to “flush” a stone out hasn’t been shown to help and may increase pain from obstruction. IV fluids are used if the patient is dehydrated or vomiting.
Discharge advice
- Take analgesia as prescribed.
- Return urgently if they develop fever, rigors, uncontrolled pain, vomiting preventing fluids, or reduced urine output.
- Attend follow-up imaging and urology appointments.
Preventing recurrence
About half of people who have a stone will have another within some years. Teach patients to:
- Drink enough water to produce around 2 to 2.5 litres of urine a day (pale yellow urine is a good guide), more in hot climates or with heavy sweating.
- Reduce salt and limit processed foods.
- Maintain normal calcium intake from food. Cutting calcium can actually increase oxalate stone risk.
- Limit high-oxalate foods if advised, such as large amounts of spinach, nuts and strong tea.
- Moderate animal protein and avoid excessive sugary drinks.
- Maintain a healthy weight.
Stone analysis and blood and urine tests may guide specific advice.
A reminder for nurses
Keep a water bottle at the nurses’ station, drink regularly and use the toilet when you need to. Looking after your own kidneys is part of looking after your patients.