Definition

Kidney pain — also called renal pain — refers to pain from disease or injury to a kidney. You might feel kidney pain or discomfort as a dull, one-sided ache in your upper abdomen, side or back. But pain in these areas is often unrelated to your kidneys.

Your kidneys are situated in the back of your abdomen under your lower ribs, one on each side of your spine. People often are surprised at how high their kidneys are. Most conditions that cause kidney pain affect only one kidney. Fever and urinary symptoms often accompany kidney pain.

Causes

Possible causes of kidney pain include:

• Bleeding in the kidney (hemorrhage)
• Blood clots in kidney veins (renal vein thrombosis)
• Hydronephrosis
• Kidney cancer or a kidney tumor
• Kidney cysts
• Kidney infection (pyelonephritis)
• Kidney stones
• Polycystic kidney disease

Kidney stones are likely to cause pain only when they start to move out of the kidney. Also, it's possible to have one of these conditions, particularly most kidney cancers, and not have kidney pain.

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 side
• You have fever, body aches and fatigue
• You've had a recent urinary tract infection

Seek emergency care if you develop sudden, severe kidney pain, with or without blood in your urine.