Acute Renal Colic

What is Acute Renal Colic?

Acute renal colic is a type of severe, sudden pain in the side of the body, commonly referred to as flank pain. This pain usually starts near the back, near the ribcage, and moves down and forward toward the groin or testicle. Most often, acute renal colic happens because of an unexpected blockage in the urinary tract, usually because a kidney stone or calculus has become stuck. This obstruction is commonly accompanied by nausea and vomiting.

Kidney stones, also known as urolithiasis, affect approximately 1 in 11 people in the United States at some point in their lives. These stones are typically caused by tiny crystals or groups of crystals that start in the kidney and then travel through the urinary system. These stones can become stuck, most commonly in the ureter and cause a blockage. This blockage can cause the ureter and the part of the kidney connected to it (renal pelvis) to dilate or enlarge, a condition known as hydroureteronephrosis. This dilation is what directly causes the intense pain known as renal colic.

The amount of pain a person feels relates to the extent of the blockage, not the size of the stone itself. Although, the size of the stone can be a good indicator of whether it will pass on its own. While kidney stones are not the only cause of flank pain, their frequent occurrence and the severity of the pain they cause make them the most likely cause when sudden, severe flank pain is associated with blood in the urine.

For most people, renal colic pain reaches its peak about 1 to 2 hours after it begins. The pain’s nature, onset, location, and severity can all depend on the cause, but in most cases, it is related to the presence of kidney stones. Common causes of kidney stones include not drinking enough water, producing too much acid in the urine, chronic urinary infection, and having high levels of certain substances in the urine.

When a patient comes in presenting signs of acute renal colic, the first steps are usually laboratory tests, urinalysis, and imaging studies to determine the exact cause. Immediate treatment usually involves controlling the pain, hydrating the patient, prescribing medicine to control nausea, and possibly antibiotics. If the symptoms are challenging to control, the patient might need to be admitted to the hospital. In some cases, emergency surgery may be necessary, such as when an infection has caused the renal pelvis to fill with pus.

There are several treatment options for obstructions caused by ureteral stones, ranging from watchful waiting to several surgical options. These include inserting a tube to keep the ureter open (double J stenting), using shockwaves to break up the stone (extracorporeal shockwave lithotripsy), using a scope to remove the stone and laser therapy. Open surgery is rarely necessary.

It’s worth noting that people who experience multiple kidney stone attacks tend to report lower quality of life. This decrease in quality is especially true for those who have had five or more renal colic episodes. In these cases, preventive measures like 24-hour urine testing are highly recommended.

What Causes Acute Renal Colic?

Renal colic, a type of severe pain that occurs when there is a blockage in the urinary tract, is typically caused by an enlargement of the parts of the body that produce urine (the renal pelvis and ureter). Generally, this pain is triggered by the sudden blockage of these areas, often due to something like a kidney stone. However, other conditions such as muscle spasms in the ureters following specific medical procedures might also lead to this pain. It’s worth noting, though, that not all blockages cause this acute pain. For instance, long-term obstructions caused by certain health issues, like cancers or scars in the urinary tract, usually don’t lead to such severe pain.

There are various factors that increase the risk of forming kidney stones, including:

1. Having high levels of acid in your urine, in a condition known as aciduria, is a common reason for the formation of uric acid stones, which make up about 5% to 10% of all kidney stones. This could be a result of consuming a lot of animal meat protein or certain medical conditions. Usually, treatment involves medications that can reduce the acidity of your urine.

2. Cystinuria is a hereditary disorder that can cause high levels of a particular protein (cystine) in your urine, which can further form hard-to-treat stones. Drinking plenty of water and medication to reduce the acidity of your urine are common prevention strategies.

3. Hypercalciuria is the presence of an excessive amount of calcium in the urine, which is a key cause of kidney stones. Various factors, such as consuming too much Vitamin D or certain medical conditions, can cause hypercalciuria. Treatment often involves adjusting diet and taking specific medications.

4. If you excrete a high amount of oxalate (a chemical in your urine), known as hyperoxaluria, you’re at a higher risk of developing calcium oxalate stones. This can be managed by reducing intake of high oxalate foods and taking supplements that can bind with oxalate, limiting its absorption.

5. Hyperuricosuria, or high levels of uric acid in the urine, can contribute to different types of stone formation. Treatment usually involves dietary changes or medications aimed at reducing the uric acid in your urine.

6. Hypocitraturia, the condition of having a low amount of citrate in your urine, can also increase the risk of forming kidney stones. Treatment includes oral supplements to increase the citrate in your urine.

Additionally, being dehydrated and not producing sufficient urine volume is a prime cause of kidney stone formation. Maintaining hydration and ensuring your daily urine output is about 2.5 liters can help prevent stones.

Urinary tract infections caused by specific bacteria can cause an increase in urine pH and create ideal conditions for the formation of a type of stone known as struvite. Treatment typically involves managing the infection and removing the infection-related stones.

Risk Factors and Frequency for Acute Renal Colic

Kidney stones, also known as urolithiasis, affect about 0.5% of people in North America and Europe each year. About half of these people will get another kidney stone within ten years unless they take steps to prevent it. In the US, about 6% of women and 11% of men will have a kidney stone at some point in their lives, leading to over 1.2 million emergency room visits per year. Kidney stones are becoming more common worldwide and are most likely to happen to people aged 20 to 50. They are twice as common in men as in women. However, the number of women getting kidney stones is rising faster.

People who are overweight, have high blood pressure, have a family history of kidney stones, have irritable bowel syndrome, or have diabetes are more likely to get kidney stones. While the risk is lowest for Hispanic and Black people, the risk is highest for White people. This could be due to differences in diet, geography, or finances rather than genetics. Those who’ve had a kidney stone before have a 26% chance of having another painful kidney stone attack within five years. In their lifetime, the risk of having another stone is between 60% to 80%.

• People who’ve had weight loss surgery (especially a type called Roux-en-Y gastric bypass)
• People with heart disease
• People with chronic kidney disease
• People with diabetes
• People with a condition called enteric hyperoxaluria
• People who had their first kidney stone at a young age
• People who had cystine or uric acid stones before
• People with high blood pressure
• People with a condition called malabsorption
• People with a condition called metabolic syndrome
• People who are overweight
• People with a family history of kidney stones
• People who’ve had kidney stone attacks or surgery before
• People with a condition called primary hyperoxaluria
• People with untreated hyperparathyroidism
• People who are White (Not Black, Hispanic, or Asian)

These are the factors that can increase the risk of additional kidney stone attacks.

Signs and Symptoms of Acute Renal Colic

Renal colic is a condition that usually starts with a sudden, severe pain in the side or back, below the ribs, that can spread to the lower abdomen and groin. It is often a continuous pain that comes and goes, resulting in episodes of severe pain. This fluctuation of pain occurs because the kidney expands due to blockage, while wave-like motion of the ureter (a tube connecting kidney and bladder) muscles leads to severe pain.

Many people may also have nausea or vomiting, and up to 85% will have blood in their urine, seen visibly or under a microscope. As the blockage (usually a kidney stone) moves towards the bladder, they may also start to experience frequent and painful urination, urgency to urinate, or difficulty in urinating.

The pain from renal colic can be extremely severe. Patients are often restless and unable to find a comfortable position, unlike patients with severe abdominal pain, who typically stay still to avoid any movement. The physical examination will often show side or back pain and may even find tenderness in the abdomen. The patient may also appear sweaty or cool to the touch.

People with renal colic often have a personal or family history of kidney stones. Sometimes, the pain may come on after certain medical procedures such as ureteroscopy (a procedure examining the inner sides of the ureters) or after a small tube called a double J stent is removed from the urinary tract. These procedures can cause the ureter to spasm or contract involuntarily, leading to obstruction and subsequent pain, even in the absence of a stone. However, these symptoms will generally resolve with time. But in some cases, patients might need intervention to facilitate drainage or placement of a double J stent.

Patients who take certain medications like topiramate, acetazolamide, protease inhibitors (such as atazanavir and indinavir), sulphadiazine, ephedrine, and guaifenesin, are at a higher risk of developing kidney stones.

Testing for Acute Renal Colic

When diagnosing patients with kidney stones, doctors use a combination of patient history and physical exams, lab tests, and imaging studies. In about 85% of patients with kidney stones, a urine test will show the presence of microscopic or obvious blood in the urine. Urine can be further tested for crystals, pH level, and potential signs of infection such as white blood cells or bacteria. If infection is suspected, urine culture should be considered.

The presence of blood in the urine hints at kidney stones, but it’s not enough to confirm the diagnosis. Blood tests that check serum calcium and creatinine levels are also necessary to assess kidney function, hydration status, acid-base balance, and electrolyte levels. If an infection is suspected, a complete blood count can be checked as well.

Specific imaging techniques can help diagnose kidney stones. Renal ultrasound can measure kidney swelling and track larger kidney stones, particularly uric acid ones. However, it might not detect smaller stones or always see ureteral calculi. Still, it’s a good choice for patients who are pregnant or for whom radiation exposure should be avoided. To monitor the progress of the treatment or for follow-ups, a plain abdominal x-ray is often recommended.

CT scans without contrast have become the gold standard for initial diagnosis, due to their ability to quickly identify and provide information about the size, location, and other characteristics of the stone. However, CT scans do expose patients to some amount of radiation. Pregnant patients and those with a previous history of kidney stones and showing similar obstructive symptoms may manage with an ultrasound examination. The use of other imaging techniques like ultrasound or MRI instead of CT scans is highly encouraged.

The stage of kidney stone disease can also be evaluated in pregnancy and treated via the surgical route with various safe methods. A degree of kidney dilation due to the urine not being able to pass the stone does not always correlate with the severity of pain felt by the patient or the likelihood of the stone passing spontaneously. However, severe kidney dilation could suggest less likelihood of spontaneous stone passage and, hence, early surgical intervention may be warranted.

Patients with symptoms of infection should be considered to be at higher risk of developing urosepsis or obstructive pyelonephritis and should be treated promptly. A high resolution CT scan or renal ultrasound should be done to investigate acute pyelonephritis, especially in patients with diabetes or those at increased risk of surgical complications. Tests for new potential biomarkers for urosepsis in the blood are also being considered to help identify septic patients faster.

Treatment Options for Acute Renal Colic

When it comes to managing acute renal colic, which is severe pain caused by kidney stones, the first steps are to manage pain, prevent nausea (with antiemetics), and keep the person appropriately hydrated through an IV drip. If there are signs of infection, antibiotics should also be given.

Non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are typically the first choices for pain relief. NSAIDs are often the initial choice as they avoid the many side effects of opioids. They work by reducing the substances that cause pain and they also block the production of certain chemicals that increase pain and cause ureter contractions. NSAIDs can reduce kidney functions temporarily to further decrease pain. Medications such as ketorolac and diclofenac are most commonly used.

Because opioids can cause breathing problems, slowed digestion, increased nausea, sleepiness, and even create dependence, they are generally used only if NSAIDs aren’t effective.

If more pain relief is needed, medications such as dexamethasone or morphine can be added to the treatment regimen.

Another strategy is to have the patient on ketorolac while also giving them IV acetaminophen, although this is typically not done for more than a few days, as the combined effectiveness of the two isn’t strongly validated by research.

Lidocaine, a local anesthetic, can also be used for pain relief. It is typically administered intravenously and has shown to be effective, especially for kidney stone pain that has been unresponsive to other treatments.

A surprising treatment that has had success is the injection of sterile water directly into the painful area. While it’s unclear exactly why this works, it might involve a pain inhibition reaction, a release of natural painkillers, or simply distraction from the intense pain. Since it’s safe, cheap, has virtually no major side effects, and can be repeated as necessary, it could become a worthwhile strategy for pain relief.

Anti-nausea medications (antiemetics) should be used as needed for relief of nausea and vomiting. Despite the lack of strong conclusions, it’s suggested that ondansetron might be the best antiemetic choice.

Hydration through an IV is highly recommended to assist in the initial treatment of acute renal colic, even though there’s no evidence suggesting it will help “flush out” a stone.

In more complicated situations, procedures like nerve blocks can be helpful, especially for chronic flank pain.

Kidney stone prevention, including a 24-hour urine test, should be discussed especially with high-risk and repeat stone formers.

When it comes to high-risk patients, even first-time stone formers, they should be informed about 24-hour urine testing and preventative therapy.

Dietary suggestions for kidney stone patients include:
– increasing fluid intake,
– reducing sodium and meat protein intake,
– increasing intake of fruits and vegetables,
– reducing oxalate intake (found in foods such as spinach, nuts, and chocolate).

Patients with specific types of kidney stones may need additional treatment strategies, like specific medications.

If kidney stones (also known as ureterolithiasis) are found, medical expulsive therapy is generally recommended, especially for smaller stones that are closer to the bladder. This involves medications that help the stone to pass by relaxing and widening the ureter, the tube that connects the kidneys and bladder.

The use of antibiotics should be limited to patients with clear evidence of a urinary tract infection. In patients with stones, the risk of serious kidney infection due to blockage by the stone is high and can become life-threatening within hours.

When surgical removal of a kidney stone is needed, various procedures are possible, including one which uses high energy shock waves to fragment the stones (extracorporeal shock wave lithotripsy) and another which uses a small scope to locate and remove the stone (ureteroscopy). Other types of surgery include laparoscopic and robotic-assisted surgery.

Patients at high risk for developing severe kidney infections due to kidney stones include older individuals, those with diabetes, those with a single kidney, a history of urinary tract infections, or an impaired immune system. In more critical situations, a double J stent or percutaneous nephrostomy (a tube that drains urine from the kidney) may be needed.

Lastly, a delay in timely treatment of kidney infections can significantly increase the likelihood of death, even with treatment. The use of third-generation cephalosporin antibiotics is suggested in such situations, although the primary treatment should be surgical. After infection control, stone removal surgery can typically be safely performed within a week to two weeks.

What else can Acute Renal Colic be?

Flank pain, or pain in the side of the body between the ribs and hips, might feel like kidney stones, but there can actually be a range of causes, such as:

• A tear in the large blood vessel of the body (abdominal aortic aneurysm dissection)
• A lack of blood supply to the intestines (acute mesenteric ischemia)
• A rare lung condition (angiomyolipomas)
• Inflamed appendix (appendicitis)
• Gallbladder pain (biliary colic)
• A blockage in the gut (bowel obstruction)
• Inflamed gallbladder (cholecystitis)
• Pain in the rib cartilage (costochondritis)
• Certain kidney conditions
• Conditions related to the large intestine (diverticulitis)
• Medical procedures involving the ureters (tubes that carry urine from the kidneys)
• Pregnancy that occurs outside the womb (ectopic pregnancy)
• A condition where tissue similar to the lining of the womb grows outside it (endometriosis)
• Nerve pain (neuropathic pain)
• Bowel complaints like irritable bowel syndrome
• Certain lung conditions (lobar pneumonia)
• Tumors or growths
• Internal organ conditions
• Conditions affecting muscles or skeletons
• Twisted ovarian cyst
• Inflamed pancreas (pancreatitis)
• Kidney infection (pyelonephritis)
• Pain in other parts of the body that feels like it’s in the flank (referred pain)
• Abnormalities in the blood vessels of the kidneys
• Infection in the area around the kidney (renal abscess)
• A tumour or fracture in the spine

These are just examples of potential causes, and it’s important to get an accurate diagnosis from a healthcare professional.

What to expect with Acute Renal Colic

The chances of recovery depend on several factors such as the patient’s medical history, their current health conditions, the size and location of the stone and the patient’s anatomy.

Small stones, less than 5 mm in size found in the lower part of the ureter, are very likely to exit the body on their own. But, larger stones or those located further up in the ureter, might need medical help to be removed.

If the kidney gets infected, quick surgery to drain off fluids from the kidney might be needed to prevent severe consequences such as sepsis (a severe infection), blood clot-induced tissue death, limb removals, and in extreme cases, death.

All people with urinary stones should be informed about the importance of a 24-hour urine test to prevent future stone formation. This test is especially recommended for children, patients with kidney failure or a single kidney, those who had stones before or individuals at a higher risk during surgery due to pre-existing conditions.

Possible Complications When Diagnosed with Acute Renal Colic

There are several potential complications that could occur, such as:

• Embolic ischemia, a blockage in the blood supply
• Failure of the stone to pass naturally
• Forniceal (calyceal) rupture with leakage
• Blood in urine
• Unmanageable pain, nausea, or vomiting
• Obstructive pyelonephritis (infection in the kidneys)
• Pyelolymphatic backflow
• Kidney failure or damage
• Sepsis, a dangerous infection spread throughout the body
• Scarring or narrowing in the ureter
• Infection in the urinary tract

Preventing Acute Renal Colic

It’s important for patients to understand that we can now pinpoint certain chemical factors that increase the risk of developing kidney stones in the future. This involves a test that examines a full day’s worth of urine. The results of this test can indicate specific changes a patient might need to make in their diet, lifestyle, or medication to lower their chance of getting more stones. However, keep in mind that these measures don’t guarantee that stones won’t develop in the future.

This test is especially recommended for people with a higher risk of developing stones, including those with specific medical conditions, only one kidney, a unique kidney shape (like a horseshoe), a history of recurrent stones, children, and those who are at heightened risk from anesthesia or surgery.

How successful the preventive treatment will be largely depends on the patient’s commitment and discipline. Those who are determined to lower their risk of future stones and comply with the treatment plan in the long term will benefit most.

Even without a specific test, a few general tips would include drinking enough fluids to produce at least 2,000 mL (and ideally 2,500 mL) of urine daily, moderate consumption of calcium (both low and high intakes are not suggested), and reducing consumption of sodium, animal meat protein, and foods high in oxalate.

Patients with cystine stones need specialized treatment because their risk of developing stones is especially high. Keeping these patients stone-free demands aggressive medical treatment, including drinking enough to produce between 3,000 to 3,500 mL of urine daily and maintaining urine pH levels at 7.5.