Flank pain refers to pain in one side of the trunk between the upper abdomen and the back.

Flank pain often means kidney trouble. If flank pain is accompanied by fever, chills, or urinary problems, then a kidney is the likely point of origin.

One in seven people in the US has kidney stones at some time. The pain from a kidney stone is agonizing, comes in sharp, stabbing waves or spasms, and usually radiates into the groin.

• Kidney problems
  • Acute pyelonephritis (kidney infection)
  • Kidney stone
  • Kidney abscess
• Shingles (flank pain with one-sided rash)
• Spinal arthritis
• Disk disease
• Muscle spasm

Treatment depends on the cause. Follow your provider's instructions.

Rest, physical therapy, and exercise may be recommended for flank pain caused by muscle spasm.

Anti-inflammatory drugs and physical therapy may be prescribed for flank pain caused by spinal arthritis. Continue physical therapy exercises at home.

Antibiotics are used to treat most cases of pyelonephritis. Plenty of fluids and pain medications are used to treat kidney stones. Hospitalization may be required for either condition.

• There is flank pain accompanied by high fever, chills, nausea, or vomiting.
• There is blood (red or brown color) in the urine.
• There is prolonged, unexplained flank pain.

If the pain is related to an injury, this condition will be stabilized. Then the provider will obtain your medical history and perform a physical examination.

Medical history questions documenting flank pain in detail may include the following:

• Is the pain on one side only (unilateral) or both sides?
• Which side?
• Is the pain mild?
• Is the pain periodic and changing intensity over minutes?
• Is the pain crampy or colicky?
• Is the pain severe enough to require narcotic pain relievers?
• Did the pain begin recently?
• Has the pain been gradually getting worse over months?
• Did the pain rapidly get worse?
• Does the pain go into your groin?
• Does the pain go into your back?
• Does the pain go up into your chest?
• Does the pain occur with nausea or vomiting?
• What other symptoms are also present?

Fluid intake and output may be monitored and recorded.

Diagnostic tests that may be performed include the following:

• Urinalysis and urine culture
• Renal or abdominal ultrasound
• Abdominal CT scan
• Cytoscopy
• Intravenous pyelography
• Retrograde ureteropyelography
• Serial urine and serum analysis
• Voiding cystourethrography
• Lumbosacral spine x-ray