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What to do if…
you develop sudden, wave-like flank pain that makes it hard to get comfortable

Produced and maintained by PanicStation.org Published: Last reviewed: Editorial policy USA guide

Short answer

Seek prompt medical assessment today. Go to the ER now, or call 911 if you need emergency transport, if the pain is severe and does not ease, is getting worse, or comes with fever, chills, inability to urinate, or repeated vomiting that stops you keeping fluids down.

Do not do these things

  • Do not delay emergency care if the pain is severe and does not ease, is getting worse, or comes with fever, chills, inability to urinate, or repeated vomiting.
  • Do not take more pain medicine than the label allows. Do not combine similar medicines, such as two NSAIDs. Ask a pharmacist or clinician before taking over-the-counter pain relief if you are pregnant, have kidney disease, or are unsure what is safe for you.
  • Do not drive yourself if the pain is distracting, you feel faint, or you have taken anything that makes you sleepy. Get a ride or call 911 if you need emergency transport.
  • Do not dismiss blood in your urine, burning when you urinate, cloudy or bad-smelling urine, or passing only a small amount of urine. Tell the clinician or triage service about these symptoms.

What to do now

  1. Go to the ER now if the pain is severe and does not ease, is getting worse, or comes with fever, chills, inability to urinate, or repeated vomiting that stops you keeping fluids down. Call 911 if you need emergency transport.
  2. If none of those warning signs apply, arrange prompt medical assessment today. An urgent care clinic may be reasonable if it can assess you promptly. Ask whether it can evaluate sudden flank pain and direct you to the ER if needed.
  3. When arranging assessment, mention if you are pregnant, have one functioning kidney, have significant kidney disease, have had a kidney transplant, or take medicines that suppress your immune system.
  4. Note the details that may help the clinician assess urgency:
    • when the pain started and whether it comes in waves
    • your temperature, if you can check it
    • when you last urinated and whether there was blood, burning, cloudiness, or an unusual smell
    • whether you are vomiting or able to keep fluids down
    • any medicines you have taken, including the name and time taken
  5. Take your medication list and allergy information with you. Be prepared to provide a urine sample if asked.

What can wait

  • You do not need to work out the exact cause yourself.
  • You do not need to force large amounts of fluid while arranging assessment, especially if you are vomiting. Sip fluids only as tolerated.
  • You do not need to make decisions now about prevention, diet changes, or long-term treatment.

Important reassurance

Seeking prompt assessment is reasonable. You do not need to decide whether this is a kidney stone or something else before asking for medical help.

Scope note

These are first steps for the next few hours. Clinicians may use your symptoms, a physical examination, urine tests, blood tests, imaging, and symptom treatment to decide what care you need.

Important note

This is general information, not medical advice or a diagnosis. It is not a substitute for assessment by a qualified healthcare professional.

Additional Resources

Closely connected guides that may be useful during the same situation or its immediate aftermath.

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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