Flank Pain: Side and Back Pain Below the Ribs and When to Be Seen

What it involves

The flank is the side of the body between the ribs and the hip. MedlinePlus describes the main symptom of a kidney stone as severe pain that starts and stops suddenly and may be felt in the belly area or the side of the back, which it calls the flank. A urinary tract infection can cause pain in the back or side below the ribs too.

Who this is for

• Adults with pain in the side or back below the ribs
• Patients with pain that comes in waves and may move toward the groin
• People with burning urination, blood in the urine or fever along with side pain
• Anyone who has had kidney stones before and thinks another may be moving

What to expect

• Questions about the pain: where it is, how it started, whether it comes and goes and whether it spreads to the groin
• A physical exam that includes the belly and back, plus a check of your temperature and blood pressure
• A urine test and blood work to look for infection, blood and kidney function
• Imaging such as an ultrasound or CT scan when needed, arranged as a referral

Kidney stones, the classic cause

MedlinePlus says a kidney stone is a solid mass of tiny crystals, that you may not have symptoms until a stone moves into the tube that drains the kidney, and that it can then block the flow of urine and cause pain. The pain starts and stops suddenly, may be felt in the side of the back, and can move to the groin or, in men, the testicles. Nausea, vomiting, chills, fever, blood in the urine or an abnormal urine color can come with it. The biggest risk factor it lists is not drinking enough fluid.

Urinary tract infections that reach the kidney

MedlinePlus lists pain in the back or side below the ribs among the signs of a urinary tract infection, along with pain or burning when you urinate, fever, an urge to urinate often and cloudy or reddish urine. Side pain with fever suggests the infection may have reached the kidney, which needs prompt treatment. The practice lists urinary tract infection care among its services, and the urinary tract infection guide explains what a visit covers.

Muscle, spine and other causes

Flank pain is not always from the kidney. A strained back muscle, a pinched nerve or arthritis of the spine can produce pain in the same area, and it tends to change with movement and position, which kidney stone pain usually does not. The low back pain guide describes the muscle and spine causes. Pain that comes with a rash on one side of the body can be shingles, covered in the shingles guide.

What testing may follow

MedlinePlus says that for a suspected kidney stone the provider does a physical exam, and tests may include blood tests to check calcium, phosphorus, uric acid and electrolytes, kidney function tests and a urinalysis to look for crystals and red blood cells. Stones or a blockage can be seen on an abdominal CT scan, abdominal x-ray or kidney ultrasound. The urinalysis guide explains what a urine test shows, and the blood in urine guide covers that finding in more depth.

What helps while a small stone passes

MedlinePlus says small stones most often pass on their own, that you should drink at least 6 to 8 glasses of water a day and that urine should be strained so the stone can be saved and tested. It notes pain can be very bad and that over-the-counter pain relievers can be effective, and that some people with severe pain need to be treated in the hospital. Ask your provider before taking anything if you have kidney, stomach or blood pressure problems, or take blood thinners.

When to go to the emergency room

Go to the emergency room for severe flank pain that does not ease, pain with fever and chills, repeated vomiting, inability to pass urine, or blood in the urine with heavy pain. Sudden severe belly or back pain with lightheadedness or fainting also needs 911. Milder, steady flank pain with urinary symptoms, or pain that comes and goes over several days, is a good reason to book a visit the same week.

Sources

• MedlinePlus: Kidney stones (medical encyclopedia)
• MedlinePlus: Urinary Tract Infections (health topic)