The short explanation
Pyelonephritis is the medical name for a kidney infection. It usually happens when a bladder infection travels up to one or both kidneys. Typical symptoms are fever, shivering, pain in the back or side below the ribs, nausea or vomiting, and often burning or frequent urination. It is more serious than a bladder infection. It needs prompt medical treatment, and some people need hospital care, especially if they are vomiting, pregnant, or very unwell. If not treated, it can lead to a serious blood infection or kidney damage.
What depends on your situation
The parts of this that change from woman to woman. Uncertainty is stated, not hidden.
- Doctors diagnose it from symptoms, an examination, a urine test and culture, and sometimes blood tests and an ultrasound. Treatment is chosen by a clinician based on how unwell you are and the urine culture result.
- Pregnancy, diabetes, kidney stones, and problems with the urinary tract increase the risk of complications.
What this answer cannot determine
The boundary of online education. These need a clinician who can see you.
- This answer cannot tell whether you have a kidney infection. That needs a clinician's examination and tests.
Questions for your clinician
Take these with you. You can add any of them to an appointment card.
- Do my symptoms suggest a kidney infection?
- Do I need hospital care?
- Will a urine culture be done?
- Do I need a scan?
When to seek help
Clinician-approved guidance for this topic. When in doubt, being seen is never the wrong choice.
Emergency — call 112 now
- Call 112 or go to the nearest emergency department if you have high fever with shivering, feel faint or confused, are breathing fast, cannot keep fluids down, or pass very little urine.
Get help the same day
- Get seen today for fever and back or side pain with urine symptoms.
Raise it at a routine appointment
- Book a follow-up after treatment to check the infection has cleared.
Sources
The evidence this explanation is built on.
- Kidney infection NHS
- Urinary tract infections (UTIs) NHS
- Urinary tract infection — adults MedlinePlus (NIH)
Who wrote and reviewed this
Every AskHer answer names its author. A clinically reviewed answer also names the clinician who signed it off — if no clinician is named below, it has not been clinically reviewed.
- Author
- AskHer Editorial (AI-assisted draft) AskHer's editorial team — not an individual clinician Works in English, தமிழ், हिन्दी
- Clinical reviewer
- Nobody yet No clinician has signed this answer off, and no person on the editorial team has read it yet. That is what the “Written with AI assistance” label means. It is queued for an editor to read, and then for a clinician who works in this area. The sources it was drafted against are listed above.
- Review status
- Written with AI assistance — not yet reviewed by a person
- Last reviewed
- Not yet reviewed by a person
- Version
- 1
Correction history
Substantive changes are listed, not quietly edited away.
No corrections have been made since this answer was first published.
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