What You Must Know About Kidney Pain.

What are the kidneys?

The kidneys are two organs whose major functions are to remove waste products and excess fluid from the body and produce hormones that regulate blood pressure, red blood cell production, acid regulation and influence calcium, and electrolyte metabolism.

Where are the kidneys located?

The kidneys are bean-shaped organs (about 11 cm x 7cm x 3cm) that are located against the back muscles in the upper abdominal area. They sit opposite each other on both the left and right side of the body; the right kidney, however, sits a little lower than the left to accommodate the size of the liver.

     

What is the function of the kidneys?

The excess waste products and excess fluid are removed when the kidneys produce urine that is excreted from the body. In addition the kidneys play an important role in regulation of the body salt, potassium, and acid content. The kidneys also produce hormones that stimulate red blood cells to be produced, that help regulate blood pressure and help control calcium and electrolyte metabolism in the body

What are the symptoms of kidney pain?

The symptom of kidney pain (also termed renal or flank pain) are discomfort (acute or chronic) or aches or sharp pain that occurs in the back between approximately the lowest rib and the buttock. Depending on the cause of the pain, it may radiate down the flank to the groin or toward the abdominal area. Some individuals may develop these symptoms:

• fever,
• painful urination (dysuria),
• blood in the urine, 
• nausea,
• and vomiting.

Kidney pain itself is a symptom that may happen due to problems or diseases of the kidney or its associated renal structures like the ureters or bladder. However, other diseases may mimic kidney pain but are not due to the kidneys. For example, muscle strains in the back, spinal problems (fractures, abscesses), shingles, aortic abdominal aneurysm, and gynecological problems may mimic kidney or flank pain.
Although kidney pain often occurs on one side of the back, it can occur on both sides at the same time and may radiate toward the abdomen or groin.
Pain that occurs suddenly is sharp, severe and may increase and decrease in waves is often due to problems in the renal ureters (kidney stones). Pain caused by kidney stones is termed renal colic.

What are some of the kidney conditions and diseases that cause kidney pain?

Many of the causes of kidney disease that leads to kidney pain (also termed flank pain) are due to acquired underlying diseases that may acutely or chronically affect kidney function. Other diseases are congenital; individuals may be born with an abnormality that is genetically determined that affects the kidneys. Kidney pain or flank pain can be acute, relatively constant and sharp. This is termed "renal colic" by many clinicians. This kind of pain is usually seen when an acute process like kidney stones or other underlying causes stop or almost stop urine flow. However, other processes can cause chronic dull aching with occasionally sharp flank pain. This type of flank pain can be due to polycystic kidney disease, high blood pressure or diabetes due to cumulative damage to kidney tissue over time by these problems. Some of the major underlying causes of kidney pain or flank pain are as follows:

• Urinary tract infections
• Kidney infections
• Kidney stones
• Diabetes
• Gomerulonephritis
• High blood pressure
• Polycystic kidney disease (congenital)
• Congenital malformations in the renal system resulting in complete or partial blockage of urine flow
• Drugs or toxins that harm kidney tissue (for example, pesticide exposure or chronic use of medications such as ibuprofen [Advil, Motrin, and others])
• Drinking alcohol may cause acute or chronic flank pain; the pain source, depending on the individual, may be from the kidneys or the liver.

When should I see my doctor about kidney pain?

Individuals should not postpone seeing a doctor about kidney pain or flank pain. Although flank pain is often seen in underlying problems with the kidney, there are many other diseases that can mimic kidney pain and the physician can help with an accurate diagnosis of underlying problems that result in kidney or flank pain. Any acute onset of intense kidney or flank pain should be evaluated immediately.
Warning signs that kidney disease is present and may result in kidney pain or flank pain are the following:

• Blood or protein in the urine
• More frequent urination, especially at night and/or difficult or painful urination
• High blood pressure
• Swelling of the hands and feet and/or puffiness around the eyes
• Testing that shows an abnormal creatinine, blood urea nitrogen (BUN) or glomerular filtration rate (GFR) less than 60

In addition, if an individual has diabetes or any of the congenital problems that lead to kidney dysfunction, the individual should be routinely checked for the onset of kidney dysfunction or kidney failure by their physician.

What are common tests are available to diagnose kidney diseases?

The doctor usually will do a history and physical examination. Initial tests usually consist of a complete blood count (CBC), kidney function (creatinine and BUN), and urine test and when appropriate, a pregnancy test.
If kidney stones are suspected, a CT exam (renal protocol or non-contrast spiral CT) or renal ultrasound is done; an abdominal X-ray (KUB) may be ordered, but has been replaced in general by ultrasound and CT. As patients with kidney stones often need repeat X-ray studies or have repeat episodes of kidney stones, ultrasound with its lack of radiation is a good study to consider. Abdominal/pelvic CT's with contrast or magnetic resonance imaging (MRI) may be ordered to further define or differentiate underlying kidney (renal) and non-renal causes of flank pain.

How is kidney pain treated?

Kidney pain (flank pain) treatment depends on the underlying cause of the pain. Infections and kidney stones that cause pain are often treated with ibuprofen, ketorolac (Toradol), acetaminophen (Tylenol and others) or occasionally with small amounts of morphine (kidney stones). However, these agents treat pain and not the underlying cause(s) of pain.
Infections like urinary tract infections (UTI's) and pyelonephritis usually require antibiotic treatments in addition to pain medications. If kidney stones completely block a ureter or are about 6mm in diameter, they may require urologic surgery.
Other underlying causes of flank pain may need similar pain management and concurrent treatments. However, patients with known kidney problems (kidney disease) and/or renal function compromise should not be treated with pain medications that are either filtered (removed) through the kidneys and/or may cause further renal damage.

REFERENCES:

Medscape. Causes of Flank Pain.

National Kidney Foundation. How Your Kidneys Work.