Everything you need to know about renal pain
Labs and Tests
A urinalysis is central to the diagnosis of any renal disorder. A complete urinalysis is performed by a lab to assess the chemical composition of your urine and to find any evidence of kidney dysfunction, including excessive protein, albumin, or red blood cells. Abnormal findings will suggest a kidney problem. Normal findings, by contrast, can usually rule out the kidneys as the cause.Blood tests will also be used to evaluate your kidney function. These include:
- Serum creatinine (SCr), which measures the level of a substance called creatininethat the body produces and excretes in urine at a regular rate
- Glomerular filtration rate (GFR), which uses the SCr to calculate how much blood is being filtered by the kidneys
- Blood urea nitrogen (BUN), which measures the level of a compound called urea that is also produced and excreted in urine at a constant rate
Any abnormalities in the excretion would indicate that the kidneys are not working as they should.If an infection is suspected, a blood test known as erythrocyte sedimentation rate (ESR)may be used to check for inflammation, while a urine culture can help isolate and identify specific bacterial or fungal infections.Finally, a complete blood count (CBC) and liver function test (LFT) can offer further insights as to whether the dysfunction is caused by an associated disease (such as high blood pressure, diabetes, or cirrhosis) or if changes in the blood chemistry are consistent with cancer. (There are no blood or urine tests that detect renal cancer).
Imaging tests are used as a means to indirectly visualize the kidneys and adjacent structures. They can identify irregularities in the shape or structure of the kidneys, identify cysts and solid tumors, or pinpoint the location of a bleed or obstruction.
Among the three tools commonly used for this:
- Ultrasounds use sound waves to create high-contrast images of internal organs. It is often the first test used as it is fast, portable, and does not expose you to ionizing radiation. Ultrasounds are particularly useful in differentiating cysts from solid tumors.
- Computed tomography (CT) uses a series of X-rays to create a cross-sectional image of your kidneys. The test is ideal for identifying lesions, abscesses, stones, tumors, and other abnormalities that an ultrasound or X-ray might miss. While radiation is kept to a minimum, it may still be 200 times that of standard chest X-ray.
- Magnetic resonance imaging (MRI) uses a magnetic field and radio waves to visualize the kidneys, providing finer details than a CT or ultrasound. While an MRI doesn’t expose you to ionizing radiation, a radioactive contrast agent may be needed to visualize certain tissues.
If imaging tests are unable to provide a clear image of an obstruction or disorder of the lower urinary tract, the doctor may recommend a procedure known as cystoscopy. This involves the insertion of flexible fiberoptic scope into the urethra to view the bladder and is commonly used to help diagnose bladder stones, cystitis, strictures, and cancer.Cystoscopy is performed under local anesthesia and may cause pain and mild bleeding. Infection is also possible.If cancer is suspected, a biopsy may be performed to obtain a sample of cells from suspicious growth. It can be performed with a fine needle aspiration (FNA), in which a narrow needle is inserted into a tumor with the aid of an ultrasound, or a core needle biopsy (CNB), which utilizes a thicker, hollow-core needle. Both are nearly equal in their ability to correctly diagnose renal cancer.
People will often be surprised at how high up the kidneys are in the back. In many cases, a persistent pain will be incorrectly attributed to the kidneys when it is, in fact, muscle or skeletal problem. To this end, doctors will often need to explore other causes of “kidney pain” if urinalysis and other tests do not suggest a renal disorder.
- A fracture of the 11th or 12th rib, which can mimic a renal injury
- An upper thoracic or lumbar spine injury, in which spinal nerve pain can radiate to the flank (known as referred pain)
- Neuropathic flank pain caused by shingles (herpes zoster)
- Pleuritis, inflammation of the pleura (lining of the lungs)
- A retroperitoneal abscess, a serious pus-filled infection situated between the anterior abdominal wall and the peritoneum (lining of the abdominal cavity)
While some people assume that kidney pain is a sign of kidney failure, it rarely is. Whether you have chronic kidney disease (CKD) or acute renal failure (ARF), you are more likely to feel pain in the joints and muscles (due to the build-up of toxins and depletion of electrolytes) than in the kidneys.
The treatment of kidney pain is as varied as the causes themselves. Severe disorders typically require the care of a kidney specialist known as a nephrologist or a urinary tract specialist known as a urologist.
Most kidney infections are bacterial and readily treated with broad-spectrum antibiotics. Fungal and viral infections are most commonly seen in people with compromised immune systems, including organ transplant recipients and people with advanced HIV.A urine culture can help isolate the bacterial strain so that the most appropriate antibiotic is chosen. The most commonly prescribed antibiotics include ampicillin, cotrimoxazole, ciprofloxacin, and levofloxacin. Severe cases may require intravenous rather than oral antibiotics. Resistant bacterial strains may require combination antibiotic therapy or more potent antibiotics like carbapenem.During treatment, you’ll need to drink plenty of water to promote urination and help flush the upper and lower urinary tract.
Treatment of a renal trauma is directed by the grading of the injury as follows:
- Grade 1 for a renal contusion (bruised kidney) or a non-expanding hematoma (blood clot)
- Grade 2 for a laceration of less than 1 centimeter
- Grade 3 for a laceration greater than 1 centimeter
- Grade 4 for a laceration greater than 1 centimeter that causes internal bleeding
- Grade 5 for a detached or shattered kidney or one in which the renal artery is blocked
Low-grade injuries can often be treated with extended bed rest. More severe events may require surgical repair, including the placement of renal stents to open obstructed vessels. Selective embolism, in which a chemical agent or metallic coil is used to block a blood vessel, may help control bleeding.In the worst-case scenario, a surgical procedure known as nephrectomy may be needed to remove one or, less commonly, both kidneys. While you can function normally with just one kidney, the removal of both would require you to be placed on dialysis until an organ donor can be found.
Treatment is primarily focused on relieving the source of the obstruction. This may involve antibiotics to resolve an infection, nephrostomy (the drainage of urine with a urethral catheter), or surgery if a stone cannot be passed on its own.Severe hydronephrosis may require percutaneous nephrostomy, a procedure in which a tube is inserted through your back to directly drain the kidneys. A ureter stent may also be placed during cystoscopy to open a blocked ureter.
Additional treatments may be needed to address the underlying cause.
Renal Tumors or Cysts
Depending on the findings, treatment may involve selective embolism to reduce the size of a tumor (essential “starving” the tumor of the blood needed for growth) or nephrectomy to remove part or all of the affected kidney. Benign tumors are often treated in the same way as cancerous ones if they obstruct vessels or tubules inside of the kidney.Cancer therapy is directed by the stage of the malignancy which is based on the size of the tumor, the number of nearby lymph nodes affected, and whether the tumor has metastasized (spread). Treatment options include chemotherapy, radiation therapy, immunotherapy, and newer-generation targeted therapy.
There are no treatments for PKD. Treatment would instead be focused on the avoidance of complications (including high blood pressure, renal infection, kidney failure, and brain aneurysm) in tandem with routine disease monitoring.
A Word From Verywell
The development of kidney pain isn’t something you should ignore. While over-the-counter painkillers like Advil (ibuprofen) or Tylenol (acetaminophen) may provide short-term relief, they are unable to treat the underlying cause, which in some cases may be serious and otherwise asymptomatic.
The same applies to hydration. While drinking plenty of water or cranberry juice may help ease a mild urinary tract infection, it is not considered curative. If in doubt as to whether you need a doctor, simply call your doctor’s office or check if your health insurance company offers free telemedicine consultations.On the other hand, if you experience sudden, severe kidney pain—whether or not there is blood, fever, nausea, or any other symptom—you need to seek emergency care without exception.