By Paramesh Ramadugu, MD / IPC Nephrology, St. Luke’s Hospital, Cedar Rapids, Linn County LIVING WELL Magazine

The kidneys are bean shaped organs that work to remove metabolic waste and excess water from the bloodstream. They are located near the center of your back a little below the rib cage.  Kidney pain is usually characterized as a sharp pain typically felt in the flank area, which is in the back, just at the lower edge of the ribs on either side of the spine. People sometimes equate back pain with kidney pain, but musculoskeletal back pain typically gets worse with movement, and is relieved by heat or massage.

Common Causes of Kidney Pain:

Kidney Stones

While kidney stones are usually painless as long as they remain in the kidney, it is their movement out of the kidney that really hurts. The pain caused by kidney stones occurs when a stone becomes lodged in the ureter, the slender tube that connects the kidney with the bladder. It is referred to as “colic,” meaning that it comes in waves as opposed to being a steady continuous pain. Although the pain starts in the right or left flank area, it may radiate down to the groin as the stone travels down the ureter. Calcium stones are the most common type (80%).

Hydronephrosisrefers to distension of the renal pelvis (funnel-like portion of the beginning of the ureter) caused by obstruction of the free flow of urine. Hydronephrosis that occurs with sudden onset (kidney stone) can cause intense pain in the flank area and scarring of the kidney if untreated.

Kidney Infection (Pyelonephritis)

Pain caused by kidney infection (pyelonephritis) is related to infection and inflammation within the kidney tissue. Infection causes the kidney to swell, and stretches the pain-sensitive capsule surrounding the kidney. It leads to sharp aching pain associated with high fever, nausea, and vomiting. Pyelonephritis needs to be treated promptly with intravenous antibiotics in order to prevent spread of infection to the bloodstream and to prevent the occurrence of renal abscess (pus).

Renal Cyst

Kidney pain can occur due to bleeding/rupture within preexisting kidney cysts (fluid filled cavity) leading to an sudden increase in cyst size causing distention of the renal capsule. A hereditary disease called polycystic kidney disease (PKD) is a condition where progressive cyst development replaces normal kidney tissue and leads to enlarged dysfunctional kidneys over years. In the U.S., about 600,000 people have PKD, and cystic disease is the fourth leading cause of kidney failure. Ruptured cysts also cause gross hematuria (blood in urine) as the cyst often communicates with the urine collecting system.

Kidney  Infarction

Infarction of the kidney occurs when the blood supply is suddenly cut off because of blockage of the artery to the kidney. The two major causes of renal infarction are thromboemboli, which usually originate from a thrombus (clot) in the heart or aorta, and in-situ thrombosis of a renal artery, which is less common.

Other Causes

Rarely a kidney tumor or cancer can grow and stretch the kidney capsule slowly, or involve nerves in the kidney area, causing pain. Renal vein thrombosis (occlusion) is most often due to trauma, severe dehydration or a generalized hypercoagulable state, protein leaking disorders of the kidney (nephrotic syndrome).

It is important to call your doctor if you notice a dull or sharp, one-sided pain in your back or flank especially with fever, blood in your urine and burning pain while passing urine. All these symptoms could be a warning for a more serious underlying kidney disorder that requires prompt medical attention.

Dr. Ramadugu is located at IPC 115 Eighth Street NE  |  Cedar Rapids, Iowa 52401-1097  |  Phone: 319-363-3565  |  Fax: 319-363-4001  |