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

Flank pain often means kidney trouble. If flank pain is accompanied by fever, chills, blood in the urine, or frequent or urgent urination, then a kidney problem is the likely cause.

See also: Kidney stones

• 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 kidney infections. Plenty of fluids and pain medications are used to treat kidney stones. Hospitalization may be required for either condition.

Call your health care provider if you have:

• Flank pain along with a high fever, chills, nausea, or vomiting
• Blood (red or brown color) in the urine
• Prolonged, unexplained flank pain

If the pain is related to an injury, your condition will be stabilized. Then, the health care provider will perform a physical examination and ask questions about your medical history and symptoms, including:

• Is the pain on one side only or both sides?
• Which side?
• Is the pain mild or severe?
• Does the pain occur from time to time and get worse over seconds to minutes?
• Is the pain crampy or colicky?
• Is the pain severe enough to require strong pain relievers?
• Did the pain begin recently?
• Has the pain been gradually getting worse over time?
• 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 do you have?

The health care team may also monitor and record your fluid intake and output.

The following tests may be done:

• Abdominal CT scan
• Cytoscopy
• Intravenous pyelography (IVP)
• Kidney or abdominal ultrasound
• Lumbosacral spine x-ray
• Retrograde ureteropyelography
• Urinalysis and urine culture
• Voiding cystourethrography

Proctor DD. Approach to the patient with gastrointestinal disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders; 2007:chap 134.