What is Flank Pain?
Most people experience a bout of flank pain at least once. But, what is it exactly? Flank pain tends to be localized on one side, beneath the ribs but above the pelvis, and sometimes in the small of the back.
Keep in mind that flank pain is a symptom, not a condition. Depending on the trigger, flank pain will present itself in different forms along with other accompanying signs showing kidney problems and different health issues.
Cases of flank pain are usually short-lived. However, if the pain persists, it can be a sign of a serious infection in urinary tract or kidneys or dehydration. If the flank pain is severe, it could be from kidney stones. A large number of different conditions and triggers can be responsible for flank pain. Effectively recognizing the nuances that differ between causes is best left to your doctor, but that doesn’t mean patients need to be in the dark.
Learning about the conditions that cause flank pain means you’ll be able to better understand whether the pain is cause for alarm or something that can be managed on your own.
Causes of Flank Pain
1. Kidney Stones or Bladder Stones
Kidney/bladder stones are two of the most common causes of flank pain. They are the result of calcium deposits (calculi) building up in the relevant organ and becoming large enough that they cannot easily be excreted through urination. The classic sign of calculi is sudden, excruciating pain that radiates from the pelvis to the groin—often described as one of the most painful experiences humans can have.
If a stone becomes lodged in the urinary tract (which usually happens if pain is present) the irritation can provoke increased urination frequency and blood in the urine (red or brown coloration). Nausea and vomiting are also not uncommon. Kidney and bladder stones do not present themselves with a fever.
2. Obstructive Uropathy
This is a medical way of saying that a blockage is preventing urine from leaving the kidneys. Specifically, the blockage occurs in the ureter—the tube that links the kidneys to the bladder. Either one or both of the kidneys can experience a blockage and symptoms are less severe with only one affected. The most common cause of an obstruction is a kidney or bladder stone, but there are other ways it can happen.
Scar tissue, cancer, injuries, or an enlarged prostate are all capable of blocking off or compressing the ureter and leading to an obstruction. Flank pain in the lower back on the side of the affected kidney(s) commonly occurs with obstructive uropathy, along with an increase in urination frequency.
The actual volume of urine passed per day is not normally changed if only one of the kidneys is blocked, but frequency will go up. Bloody, tan, brown-colored, or foul-smelling urine is also common. Depending on the cause and duration, nausea, vomiting, raised blood pressure, and fever can also be present.
The appendix hangs at the end of the colon, in the lower-right area of the abdomen. Although no one knows what it does, what is known is that bacteria and feces can sometimes collect inside the appendix. As bacteria and pus build up, the appendix swells and puts pressure on nearby blood vessels. If the appendix ruptures, all of that bacteria and fecal matter suddenly spills into the abdomen, resulting in a medical emergency.
If it leaks instead, the infected appendix can still cause abscesses to form. Appendicitis causes pain along the lower right side of the abdomen, loss of appetite, nausea, vomiting, abdominal bloating, a low fever, and can result in both diarrhea and constipation. The pain can start off as a mild cramping sensation but will grow over time.
4. Bladder Infection or Urinary Tract Infection (UTI)
A Urinary tract infection is a catch-all term for when yeast, bacteria, or viruses infect the urinary tract. Normally, such infectious incidences are eliminated through urination, but sometimes they can cling to the walls of the urinary tract and multiply. A UTI does not necessarily cause flank pain, but people will feel a cramping or pressure in the lower abdomen or back depending on where the infection is located.
A burning sensation when urinating, cloudy or bloody urine, a frequent sense of having to urinate even with an empty bladder, and foul-smelling urine are all symptoms of a UTI. In rare cases, a low-grade fever may be present as well. UTIs occur when the infectious material enters through the urethra and travels upwards through the urinary tract. Women are more likely to experience UTIs than men, because their tracts are shorter and thus easier to traverse.
Renal cancer, bladder cancer, or certain forms of lymphoma can present themselves with persistent flank pain around the site of the tumor. The growth tends to result in fatigue, an abdominal lump, unexplained weight loss, bloody urine, and sometimes vision problems or urinary incontinence (uncontrollable urination).
The name refers to a specific form of sudden kidney infection. It results in swelling and can lead to permanent damage or death if left unaddressed. The steady, aching flank pain in pyelonephritis is usually accompanied by a high fever, a burning sensation when urinating, cloudy urine, urine containing blood or pus, a frequent need to urinate, and urine that smells reminiscent of fish.
Fatigue, shaking, mental confusion, chills, vomiting, and moist skin can sometimes occur as well, but are not as consistent. In rare cases, pyelonephritis can be a persistent (chronic) condition that comes and goes periodically. For people with chronic pyelonephritis, symptoms are generally milder and harder to notice.
Diagnosing Flank Pain
As you can see, there are a variety of causes for flank pain and this is not anywhere close to an exhaustive list. The causes of flank pain are diagnosed using a combination of techniques.
A urinalysis is commonly performed to check for infection or blood in the urine (blood is not always visible) and a renal scan can check kidney function. Other diagnosing methods include the use of an abdominal CT or ultrasound, or a bladder test.
How to Treat Flank Pain?
Treating flank pain always requires resolving the underlying cause. As a result, the available options will differ wildly from one case of flank pain to the other. Kidney stones, for instance, are treated either by passing the stones (with or without medication to help or the use of sound waves to break them up) or surgery. In cases of a blockage, short-term relief can be given by using a stent to hold the ureter open, surgery to reduce scarring, medication to reduce prostate swelling, or antibiotics to treat an infection.
UTIs are also managed with antibiotics, and pyelonephritis. Of course, the specific antibiotic needed is not always the same across all causes. With appendicitis, surgery is almost always required to remove the swollen or burst organ (appendectomy), along with the draining of any abscesses that have formed.
Almost all causes of flank pain have some urinary symptoms as well. Even if you discount the pain as the result of exertion or joint pain (which are also valid causes), it’s hard to miss if your pee smells like fish. Paying attention to the signs your body gives off and speaking with a doctor are the best ways to catch any conditions early and resolve them quickly.
Sources for Today’s Article:
“Appendicitis,” Mayo Clinic web site, August 20, 2014; http://www.mayoclinic.org/diseases-conditions/appendicitis/basics/definition/con-20023582.
“Bladder Stones,” Mayo Clinic web site, August 14, 2013; http://www.mayoclinic.org/diseases-conditions/bladder-stones/basics/symptoms/con-20030296.
“What causes flank pain? 21 possible conditions,” Healthline web site, http://www.healthline.com/symptom/flank-pain, last accessed August 26, 2015.