What causes kidney pain?

Kidney pain, commonly referring to pain in the flank or lower back region, can have various causes. Common ones include: 1. **Kidney stones**: Small crystals or stones form within the kidneys and can cause severe pain when they move through the urinary tract. 2. **Pyelonephritis**: A kidney infection, often caused by bacteria, which may lead to flank pain accompanied by symptoms such as frequent urination, urgency, and painful urination. 3. **Renal cysts**: Fluid-filled sacs that form in the kidneys. Most are asymptomatic, but if the cysts grow large, they may cause pain. 4. **Kidney failure**: When the kidneys are unable to properly filter the blood, it may result in flank pain along with symptoms such as fatigue, edema, and decreased urine output. 5. **Renal vascular disease**: Such as renal artery stenosis, which may cause flank pain, especially in patients with hypertension. If kidney pain occurs, especially if it is persistent or accompanied by other symptoms such as fever or changes in urine, prompt medical attention should be sought.