Definition of kidney pain
Kidney pain — also called renal pain — refers to pain arising from infection, injury or inflammation of a kidney. You may feel kidney pain as a dull, one-sided ache in your upper back, often accompanied by fever and urinary symptoms.
Some people are surprised to learn exactly where the kidneys are located. Your kidneys are located relatively high in your body, under your lower ribs. It’s not unusual to attribute back pain or side (flank) pain to your kidneys. But more often than not, your kidneys probably aren’t the cause of your back or flank pain.
Causes of kidney pain
Possible causes of kidney pain include:
- Bleeding in your kidney (hemorrhage)
- Blood clots in kidney veins (renal vein thrombosis)
- Urinary tract infection
- Arteriosclerosis / atherosclerosis (hardening of the arteries leading to the kidneys)
- Horseshoe kidney, a condition present at birth in which the two kidneys are fused together
- Kidney cancer or kidney tumor
- Kidney infection (pyelonephritis)
- Kidney swelling due to a backup of urine (hydronephrosis)
- Polycystic kidney disease
However, it’s possible to have one of these conditions and experience few symptoms, including kidney pain.
Kidney stones cause pain, but it’s not referred to as kidney pain. Kidney stones generally are painless — or relatively painless — as long as they remain in the kidneys. It’s when the stones move out of the kidneys that pain typically occurs — waves of sharp, intense pain, which doctors call renal colic or ureteral colic.
When to see a doctor
Call your doctor for a same-day appointment if:
- You have constant, dull, one-sided pain in your back or flank
- You experience fever, body aches and fatigue
- You’ve recently had a urinary tract infection
Seek emergency care if you develop sudden, severe kidney pain, with or without blood in your urine. This could mean you have a problem with the blood circulation in your kidneys, such as a blood clot or hemorrhage, and it’s important to have it evaluated right away.