Kidney Stones

Overview

Kidney stones also referred to as renal calculi, nephrolithiasis, or urolithiasis, are solid masses or crystals composed of minerals and salts that form within the kidneys. These stones can vary in size, from tiny grains of sand to large spheres resembling golf balls. Kidney stones may affect any part of the urinary tract — from the kidneys to your bladder. Usually, the concentration of urine causes stones, allowing minerals to crystallize and stick together. Passing kidney stones is quite painful, but if they are detected timely, the stones usually cause no permanent damage.

Depending on your circumstances, you may only require pain medication and increased water intake to pass a kidney stone. In some cases – for example, surgery is required to remove large stones that get trapped in the urinary tract. They are associated with a urinary infection, may cause complications.

Your doctor might suggest preventive treatment to diminish your risk of recurrent kidney stones in case you’re at increased risk of developing them again.

Symptoms

Mostly, kidney stones do not show any symptoms until they move around within your kidney or pass into your ureters. If it becomes stuck in the ureters, it may block the flow of urine and, which can cause the kidney to swell and the ureter to spasm, and it might be very painful. At this point, you may experience these signs and symptoms: 

Pain in waves and of varying intensity
Radiating pain in lower abdomen and groin
Sharp or intense pain in the side and back, below the ribs
Pain or burning sensation while urinating

Other indication and symptoms may include:

Pink, red, or brown urine
Cloudy or foul-smelling urine
A persistent urge to urinate, urinating more frequently than usual, or passing urine in small amounts
Nausea and vomiting
Fever and chills indicates that an infection is present

Level of pain caused due to a kidney stone may change. For example, moving or if it shifts to a different location. The pain intensity may also increase as the stone moves through your urinary tract.

Causes & Stone types

There is no single cause of getting kidney stones. Several factors may increase your risk. Calcium, uric acid and oxalate are crystal forming substances. This creates an ideal environment for kidney stones to form. The stone-forming substances are:

Calcium
Oxalate
Uric acid
Phosphate
Cystine (rare)
Xanthine (rare)

The above-mentioned substances are also types of commonly found kidney stones.

Risk Factors

While white men in their 30s and 40s are more commonly affected by kidney stones. Factors that heighten the risk of kidney stone formation include:

Family or personal history.  A family history of kidney stones can add up to the chances for you to get them as well. If you have previously experienced one or more kidney stones, you are at an elevated risk of developing another.
Dehydration. Staying dehydrated and not drinking enough water everyday can increase your risk of kidney stones. People who live in warm and dry weather and sweat a lot may be at higher risk than others. 
Certain diets. Eating food that has high amounts of protein, high sodium(salt), and sugar can increase your risk of some types of kidney stones. Excessive salt intake in your diet can escalate the amount of calcium that your kidneys need to filter, substantially heightening your risk of developing kidney stones.
Obesity. Elevated body mass index (BMI), larger waist circumference, and weight gain have all been associated with a heightened risk of kidney stones.
Digestive diseases and surgery. Inflammatory bowel disease, gastric bypass surgery, , or chronic diarrhea can lead to alterations in the digestive process, impacting the absorption of calcium and water. Consequently, this can result in elevated levels of stone-forming substances in your urine.
Other medical conditions. Conditions like renal tubular acidosis, hyperparathyroidism, cystinuria and recurrent urinary tract infections can also elevate the likelihood of developing kidney stones.
Certain supplements and medications: Substances such as vitamin C, dietary supplements, excessive use of laxatives, calcium-based antacids, and certain medications commonly used for treating migraines or depression can heighten your risk of developing kidney stones.

Complications

Kidney stones can cause symptoms such as pain, vomiting blood in the urine, and other severe medical complications. These include: 

Severe infections, including septicemia (blood poisoning) can be life-threatening. 

Renal scarring and damage, resulting in permanent renal failure. 
Loss of function of a kidney results in the need for removal of the kidney (nephrectomy).
Bladder blockage can result when a large kidney stone has managed to pass into the bladder but gets stuck in the urethra, resulting in painful urinary retention.

Diagnosis and Tests

If your doctor suspects that you have a kidney stone, you may have diagnostic tests and procedures, such as:

Blood testing. Blood tests may reveal too much calcium or uric acid in your blood. Blood test results help monitor the health of your kidneys and may lead your doctor to check for other medical conditions.
Urine testing. The 24-hour urine collection test may show that you’re excreting too many stone-forming minerals or too few stone-preventing substances. For this test, your doctor may request that you perform two urine collections over two consecutive days.
Imaging. Imaging tests may show kidney stones in your urinary tract. High-speed or dual energy computerized tomography (CT) may reveal even tiny stones. Simple abdominal X-rays are used less frequently because this kind of imaging test can miss small kidney stones. Ultrasound, a noninvasive test that is quick and easy to perform, is another imaging option to diagnose kidney stones.
Analysis of passed stones. You may be asked to urinate through a strainer to catch stones that you pass. Lab analysis will reveal the makeup of your kidney stones. Your doctor uses this information to determine what’s causing your kidney stones and to form a plan to prevent more kidney stones.

Treatment and Medication

Upon diagnosis, your healthcare provider will initially assess whether treatment is necessary. In some cases, smaller kidney stones may pass naturally during urination, which can be accompanied by considerable pain. If your provider determines that treatment is warranted, options may include medications or surgical interventions.

Medications. Medications may be prescribed to:

Decrease pain. Your healthcare provider might suggest taking an over-the-counter medication such as ibuprofen, or if you’re in the emergency room, you may receive an intravenous narcotic.
Manage nausea/vomiting.
Relax your ureter so that the stones pass. Commonly prescribed medicines include tamsulosin (Flomax®) and nifedipine (Adamant® or Procardia®).

Before taking ibuprofen, it’s essential to consult your healthcare provider. This medication can heighten the risk of kidney failure, particularly during an acute kidney stone attack. This risk is amplified in individuals with a history of kidney disease, as well as related conditions such as diabetes, hypertension, and obesity.

Surgery. There are four types of surgeries utilized for treating kidney stones. The initial three are minimally invasive, indicating that the surgeon accesses your body through a natural opening, such as the urethra, or by making a small incision.

Ureteroscopy: To conduct this procedure, a small device known as a ureteroscope is inserted through your urethra, traversing your bladder and reaching into a ureter. This instrument enables visualization of the kidney stones, which are then either retrieved using a surgical “basket” or fragmented using a laser. The resulting smaller fragments of kidney stones can then be easily eliminated from your body through your urinary tract.
Shockwave lithotripsy: During this procedure, you are positioned on a specialized surgical table or tub. High-energy shockwaves are directed through water to the targeted stone(s). These shockwaves effectively fragment the stones, facilitating their passage out of your body more easily.

Percutaneous nephrolithotomy: 

When kidney stones cannot be effectively treated using other procedures, such as when there are numerous stones, they are too large or heavy, or they are located in challenging areas, percutaneous nephrolithotomy is considered. During this procedure, a tube is directly inserted into your kidney through a small incision made in your back. The stones are then disintegrated using an ultrasound probe and suctioned out, eliminating the need for you to pass any stone fragments. Following the procedure, a urethral stent is placed temporarily (an internal tube extending from the kidney to the bladder), which is typically removed one week later. Patients are usually kept overnight for observation.

Open stone surgery: A longer cut is used during this surgery. Compared to minimally invasive procedures, it’s rarely performed (0.3% to 0.7% of cases)

Prevention

There are several ways to decrease your risk of kidney stones, including:

Eat fewer oxalate-rich foods. If you’re prone to forming calcium oxalate stones, your doctor may advise restricting foods that are high in oxalates. Examples include rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, and nuts.
Increase water intake. For people suffering with a history of kidney stones, it is recommended to drink enough fluids to pass about 2.1 quarts (2 liters) of urine a day. You may be advised by your doctor to measure your urine output to ensure that you’re drinking enough water.
If you live in a hot, dry climate and you exercise regularly, you may need to drink even more water to produce enough urine. Light and clear urine indicates that your water intake is enough.
Prefer a low salt diet and animal protein. Try to eat low sodium food and choose non-animal protein sources, such as legumes. Consider using a salt substitute, such as Mrs. Dash.
Calcium rich foods over calcium supplements. High calcium diet doesnt impact your kidneys. Continue with them unless your doctor advise otherwise.
Consult your doctor prior to starting calcium supplements, as they have been associated with a higher risk of kidney stones. Taking supplements with meals may help lower this risk. For individuals with diets low in calcium, there might be an increased likelihood of developing kidney stones. 
It’s advisable to seek a referral from your doctor to a dietitian who can assist in creating a meal plan aimed at reducing your risk of kidney stones.

Prognosis

The prognosis for kidney stones is generally favorable, although there is a chance of recurrence, meaning the stones may reappear. Many kidney stones can naturally pass over time without requiring intervention. Medications and surgical procedures to remove larger stones are typically highly effective and require minimal recovery periods.

Recurring kidney stones are possible throughout one’s lifetime. If you experience repeated occurrences, your healthcare provider may collaborate with you to investigate the underlying reasons for their formation. Upon identifying the cause, dietary adjustments may be recommended to mitigate the risk of future stone formation.

Resources

References

https://my.clevelandclinic.org/health/diseases/15604-kidney-stones

https://www.mayoclinic.org/diseases-conditions/bladder-stones/symptoms-causes/syc-20354339

https://www.kidney.org/content/understanding-kidney-stones