Flank pain: when it could be a kidney stone—and when it becomes urgent
Flank pain (pain in one or both sides of the back) is the kind of pain many patients remember vividly. It can come suddenly, feel severe, and make it difficult to sit still. If you're reading this during an episode, the first priority is safety: controlling pain, preventing dehydration, and making sure there isn't an infection or dangerous obstruction. Many cases are due to kidney stones. But the right response depends on your symptoms, your temperature, and what imaging shows. You do not need to panic. You do need a structured approach like what India's top urologists follow at MyDocsy.
Quick navigation
- How kidney stone pain typically feels
- The red flags: when to go to emergency immediately
- What could cause flank pain besides stones
- What tests doctors use (USG vs CT KUB) and why
- What you can do right now
- How treatment decisions are made (size + location + risk)
- Procedures you may hear about: URSL, RIRS, mini-PCNL
- Which page should you go to next
- FAQs
How kidney stone pain typically feels
Stone pain (renal colic) is often described as:
- Severe pain in the side/back (between ribs and hip)
- Pain that comes in waves
- Pain that may move towards the lower abdomen or groin
- Restlessness (many people can't find a comfortable position)
- Sometimes nausea or vomiting
Some people also notice: burning urination, blood in urine (pink/red/brown tinge), urgency/frequency (especially if stone is near the bladder). But pain alone does not tell us the whole story. The questions that decide urgency are: Is there fever (infection risk)? Is there vomiting/dehydration? Is the stone causing obstruction? Do you have one kidney or reduced kidney function?
The red flags: when to go to emergency immediately
Please do not wait at home if you have any of the following:
1) Flank pain + fever/chills
This can indicate infection with obstruction. In that situation, delaying care can become dangerous.
2) Persistent vomiting or inability to keep fluids down
Dehydration plus obstruction risk needs urgent management.
3) You have one kidney, known kidney disease, or pregnancy
The threshold for urgent evaluation is lower.
4) Severe weakness, fainting, confusion, very low urine output
Urgent evaluation is necessary.
5) Pain that is uncontrollable despite medication
You may need IV pain control and evaluation.
If any of the above apply, go to the nearest emergency department now. Once you're safe, you can message us and we'll help coordinate next best steps.
What could cause flank pain besides stones?
Kidney stones are common, but flank pain can also be due to: urinary infection (pyelonephritis), muscular strain, spine-related pain, less commonly other kidney issues that imaging will clarify. A urine test plus imaging helps separate these.
What tests doctors use (USG vs CT KUB) and why
Urine test (often first)
This checks for: infection signs, blood in urine, other abnormalities that change management.
Ultrasound (USG KUB)
Ultrasound is: radiation-free, quick, helpful for detecting kidney swelling (hydronephrosis), sometimes misses small ureteric stones or gives incomplete detail about size/location. Ultrasound is often the first imaging step, especially if symptoms are mild or if avoiding radiation is important.
CT KUB (Non-contrast CT scan)
CT KUB is often the most accurate way to see: exact stone size, exact stone location, degree of obstruction, multiple stones. CT is especially helpful when: pain is severe, ultrasound is inconclusive, symptoms are recurrent, procedural planning is needed. A good clinician uses the right test for the situation rather than ordering everything for everyone.
What you can do right now
Unless you have an emergency as mentioned above (in which case you should go to the hospital NOW), you can take some steps at home to safely improve and feel better.
1) Hydration—balanced, not forced
If you are not vomiting and you have no urgent red flags: sip water steadily, avoid "forcing" large volumes rapidly (this can worsen pain in some cases).
2) Pain control
Pain control should be safe and structured. Avoid mixing multiple medications without guidance, especially if you have kidney disease, gastritis, or are on blood thinners. If your pain is severe, you deserve medical evaluation rather than suffering at home.
3) Do not ignore fever
If fever/chills are present, do not self-manage. This is the most important safety point.
4) If you have a scan/report, keep it ready
Even a phone photo of the report can help guide next steps quickly.
How treatment decisions are made
Gold standard of kidney stone treatment done by India's best urologists like MyDocsy depends on first understanding the size, location and risk of kidney stone disease. The decision depends on: Is there infection or sepsis risk? Is there obstruction and how severe is it? Stone size and location, your kidney function and comorbidities, how long symptoms have been present, whether the stone is likely to pass naturally.
Stone size (general principle)
Smaller stones are more likely to pass naturally; larger stones are less likely. But size alone is not everything—location and symptoms matter.
Stone location
Kidney stones may be managed differently from ureteric stones (stuck in the ureter ie urinary passage from kidneys to bladder), which often cause more acute pain and obstruction.
Infection changes everything
A stone with infection is managed urgently and safely. The priority becomes relieving obstruction and controlling infection before elective stone removal planning.
Procedures and Surgeries you may hear about
You may hear different names. The right one depends on where the stone is and how big it is.
URSL (Ureteroscopy for ureteric stones)
Used when the stone is in the ureter and not passing safely.
RIRS (Flexible scope for kidney stones)
Used for suitable kidney stones where a flexible scope can reach and laser the stone.
Mini-PCNL
Used for larger or complex kidney stones that are less suitable for RIRS.
A responsible doctor will never "sell" one procedure - they will choose the least invasive effective option for your stone pattern and safety profile. At MyDocsy, every doctor is trained to offer this evidence-based, ethical care in order to treat patients with the best option for them - and only offering a surgery when they actually need it.
Which page should you go to next?
If you suspect stones or have a scan showing stones
If you've been told a procedure or surgery name
If you also have visible blood in urine
Talk to a doctor now
If you want quick guidance, message us: your symptoms (pain severity, vomiting, fever yes/no), any urine test result, any scan report (USG or CT KUB), whether you have one kidney or known kidney disease. A doctor-led team will callback soon and can tell you what is urgent and what can be planned.
