Definition

Causes

The primary cause of renal colic is urinary tract stone disease. Urinary tract stones can be located anywhere within the urinary system and come in various sizes. They may be found in the kidneys, ureters, or bladder. The most common constituents of urinary tract stones are calcium and uric acid. These substances or minerals accumulate in the urinary tract, adhere to each other, and form crystals. Over time, these crystals can increase in size.

The larger the size of the stone, the more severe the blockage it causes. When urine cannot flow smoothly through the urinary tract, symptoms of renal colic can occur. The pain that arises is a combination of:

• Tension in the muscles of the urinary tract
• Inflammation caused by the stone
• Swelling and irritation of the kidney because urine cannot exit the body and backs up into the kidney

Stone blockages most commonly occur in the ureter, the tube that connects the kidney to the bladder. A blocked stone causes inflammation and swelling in the ureter. Consequently, the ureter enlarges and expands, resulting in intense pain.

In addition to urinary tract stones, several other conditions can also cause renal colic. Some of these conditions include:

• Infections
• Narrowing of the urinary tract
• Stretching and inflammation of the muscles of the ureter or bladder

Risk factor

The risk factors for renal colic are closely related to the risk factors for forming urinary stones. Dietary and lifestyle changes can significantly affect the risk of urinary stone formation and renal colic pain. Here are some factors that can increase the risk of renal colic:

• Consumption of high-purine foods such as alcohol and red meat
• Previous history of urinary tract stones or a family history of stones
• Dehydration resulting from insufficient fluid intake or fluid loss due to vomiting and diarrhea
• Use of certain medications
• Obesity
• Inflammatory conditions in the digestive tract, such as Crohn's disease or ulcerative colitis
• Gastric bypass surgery, which can increase the accumulation of calcium and other substances that form urinary tract stones
• Metabolic disorders such as hyperparathyroidism (a condition where the parathyroid glands produce too much parathyroid hormone)
• Gout, a joint inflammation caused by the accumulation of uric acid crystals
• Urinary tract infection

Symptoms

The symptoms of renal colic include characteristic pain. Renal colic pain is intermittent and typically lasts for 20 to 60 minutes. The pain has other characteristics such as:

• Severe pain in the lower back or lower abdomen usually felt on only one side of the body.
• Pain radiating to the back, lower abdomen, or groin.
• Nausea and vomiting.

Other symptoms that may accompany the pain include:

• Pain during urination.
• Changes in urine, such as:
• Blood in the urine or a change in color to pink, red, or brown.
• Cloudy or foul-smelling urine.
• Presence of sand in the urine.
• Urgency to urinate.
• Nausea and vomiting.
• Increased frequency of urination.
• Fever and chills if an infection is present.

Diagnosis 

Renal colic is a symptom of an underlying condition, often caused by urinary stones. Doctors typically begin with a medical interview to inquire about symptoms, signs, and medical history. This is followed by a physical examination and diagnostic tests to establish a diagnosis. Some tests that may be performed for complaints of renal colic include:

• Blood tests
• Urine test or urinalysis to check for blood, white blood cells, signs of infection, or crystals in the urine
• Imaging tests such as ultrasound (USG), X-ray, or CT scan of the kidneys and urinary tract
• These tests help locate blockages in the urinary tract caused by stones and estimate their size. 
• The results of these tests are essential for determining the appropriate therapy. 

If no abnormalities are found from these examinations, the doctor may refer you to a urology specialist for further evaluation.

Management

Managing renal colic alleviates pain and addresses the underlying cause, often urinary tract stones. Initially, doctors provide pain relievers for temporary relief, adjusting the type and dosage according to the severity of the pain. NSAIDs like ibuprofen or muscle relaxants may be prescribed to reduce muscle tension in the ureter or bladder. Applying a warm compress to the lower back or abdomen can help alleviate discomfort.

Therapy primarily focuses on removing urinary stones. Large stones may require multiple procedures to be broken into smaller pieces. Small stones can pass naturally with urine flow, aided by adequate hydration. Procedures commonly used to break up large stones include:

• Extracorporeal Shock Wave Lithotripsy (ESWL): Shock waves are directed at the stone to break it into small fragments.
• Ureteroscopy: A small tube with a camera and light is inserted through the urethra and bladder to locate, remove, or break up the stone.
• Percutaneous Nephrolithotomy: Surgical intervention involving an incision in the back to remove the stone using specialized instruments performed under anesthesia.
• Ureteral Stent Placement: A small tube is inserted to widen the ureter and facilitate stone passage.

Complications

Complications of renal colic can arise if the underlying cause of the pain is not adequately addressed. For instance, if renal colic stems from urinary tract stones that are not effectively treated, urinary tract infections and kidney damage may occur. The accumulation of urine in the kidneys and urinary tract, obstructed by stones, also heightens the risk of infection.

Prevention

Preventing renal colic involves averting the formation of urinary tract stones. Here are some strategies to achieve this:

• Drink plenty of water according to your body's needs throughout the day.
• Avoid consuming soda and alcohol.
• Reduce intake of high-salt foods.
• Limit consumption of high-purine animal proteins found in foods such as red meat.

When to see a doctor?

If you experience severe pain in the lower abdomen or lower back, along with urination-related complaints, seek medical attention immediately. Renal colic is an emergency condition that requires prompt treatment. The underlying cause may persist without timely intervention, and complications can arise. Additionally, urinary tract stones can recur, so it's advisable to undergo an examination if you have a history of kidney stones.

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