Renal colic (an attack of kidney stone pain) is one of the most severe pains a person can experience, and it usually comes on suddenly. The most common cause is a stone stuck in the ureter – the thin tube that runs from the kidney to the bladder. Urine cannot drain, the kidney stretches and the muscle of the ureter contracts in waves: hence the pain in the lower back that comes in waves and moves down towards the groin and genitals, often with nausea, vomiting and a frequent urge to urinate.
Most small stones come out on their own, but when infection is added to the blockage, the attack becomes dangerous for the kidney and even for your life. That is why it is important to know both what to do at home and when to stop waiting. More about the condition itself is in the article on renal colic.
What to do straight away
- Take a painkiller. For renal colic the most effective are non-steroidal anti-inflammatory drugs (NSAIDs) – for example ibuprofen or diclofenac at the usual dose given in the patient leaflet. They relieve the pain and reduce swelling in the ureter. Do not take them if you have a stomach ulcer, kidney disease, heart failure, an allergy, are taking blood thinners or are pregnant – in that case the alternative is paracetamol. Antispasmodics on their own are rarely enough.
- Apply heat. A hot-water bottle or a warm bath on the painful side relaxes the muscles and eases the spasm.
- Find a comfortable position. There is no right position – some people prefer to lie down, others to walk slowly; moving around does no harm.
- Drink in moderation. Small sips of water, just enough to avoid becoming dehydrated. Large amounts of fluid during the attack do not push the stone out; they raise the pressure in the blocked kidney and make the pain worse.
- Keep an eye on your temperature and urine. Take your temperature every few hours and pass urine through a sieve or gauze to catch the stone – analysing it shows how to prevent the next one.
- Write down when the pain started and what you have taken – this information is valuable for the doctor.
What not to do
- Do not drink litres of water, beer or “diuretic” teas to “flush out” the stone. Alcohol dehydrates you and dulls your judgement, and extra fluid with a blocked ureter only makes the pain worse.
- Do not start antibiotics on your own – they do not treat the stone, and with a real infection they mask the symptoms and make treatment more difficult.
- Do not exceed the dose of painkillers, do not combine products from the same group and do not drive while you are in pain or after a strong painkiller.
- Do not rely on herbs and “stone-dissolving” remedies instead of an examination – no remedy has a proven effect in dissolving a calcium stone that has already formed.
- Do not wait for weeks because “the pain has gone” – that does not mean the stone has come out.
When to go straight to the emergency department
Call 112 (the European emergency number) or go to the nearest emergency department, without waiting for a booked appointment, if:
- you have a temperature above 38 °C or shivering – a blocked and infected kidney can lead to sepsis within hours and must be unblocked urgently;
- the pain does not respond to a painkiller within about an hour or keeps coming back stronger;
- you vomit repeatedly and cannot keep fluids and medicines down;
- you pass no urine, or very little, for several hours;
- you have only one kidney or a transplanted kidney, or stones on both sides;
- you are pregnant – most painkillers are unsuitable and infection is particularly dangerous;
- your urine is heavily bloodstained or contains clots;
- you feel weak, confused, have palpitations or feel dizzy when you stand up.
Older people, people with diabetes, people with weakened immunity and children need a doctor’s assessment sooner.
What comes next, once the pain has eased
An attack of renal colic is a warning sign, not a diagnosis. See a urologist within a few days even if you feel completely well – sometimes the stone stays where it is and the kidney quietly loses function because of the prolonged blockage. A kidney stone consultation includes an ultrasound scan, which shows whether the kidney is swollen, urine and blood tests, and often a low-dose CT scan – the most accurate method for determining the size and position of the stone.
Treatment depends on these two factors. Stones up to roughly 5–6 mm often come out on their own within a few weeks with pain relief, enough fluids and, if needed, a medicine that relaxes the ureter. For larger stones, a lasting blockage, infection or no progress, a procedure is discussed: shock wave lithotripsy from outside the body (ESWL), endoscopic laser fragmentation through the ureter (URS), and for large stones in the kidney – percutaneous removal through a small opening in the back (PCNL). Dr Penev specialises in the endoscopic and laparoscopic treatment of kidney stones and performs these operations at Kaspela University Hospital (UMBAL Kaspela) in Plovdiv; follow-up consultations take place at his practices in Plovdiv and Karlovo.
Keep the stone if you catch it. Its composition, together with your test results, determines your personal rules on diet and fluids for kidney stones – without prevention, stones often come back.
The right painkiller, heat, moderate fluids and a clear line for when to seek emergency help – that is what to remember during an attack. Book an appointment with Dr Penev after your first attack to find the cause and prevent the next one.
Frequently asked questions
How long does an attack of renal colic last?
A single attack usually lasts from about twenty minutes to several hours, with the pain building up and easing off in waves. Attacks can recur over several days while the stone moves down the ureter.
Can I have renal colic without a stone?
Yes, although less often. A blood clot, a narrowing of the ureter or pressure from outside cause the same pain, which is why the diagnosis is made with an ultrasound or CT scan and not on symptoms alone.
Can I use painkillers left over from a previous attack?
Only if they were prescribed for you for the same condition and are still in date. Never take someone else's medicines – if you are pregnant, have a new illness or take new medicines, the contraindications may have changed.
Will I be operated on in the emergency department?
Rarely. In an emergency the pain is brought under control, and if there is infection or complete blockage, the kidney is unblocked with a thin internal stent or a drain. Removing the stone itself is usually planned once your condition has stabilised.
How long can a stone stay in the ureter before it becomes dangerous?
Under medical supervision – generally up to four to six weeks, with follow-up ultrasound scans. A longer blockage damages the kidney, so if the stone has not come out within this time, a procedure is usually performed.
The information on this website is for general education and does not replace an examination and consultation with a doctor. If you have urgent symptoms, seek medical help immediately or call 112.