KIDNEY STONE | CAUSES | TREATMENT | DIAGNOSIS

Kidneys are a pair of organs that are located at both sides of the spine, back of the ribcage and they play a major role in the process of filtration of waste materials out of the blood and regulate blood pressure and electrolyte levels. Kidney Stones also referred to as Nephrolithiasis or urolithiasis or renal calculi are hard deposits of minerals and salts which can form at any part of the urinary tract. In this article, we will know about the kidney stone symptoms, kidney stone treatment, kidney stone causes and other factors.

When there’s an excessive amount of waste present and the body doesn’t make enough urine, crystals begin to accumulate within the kidney. Kidney stones vary in size and shape. They can vary from being as small as a grain of sand or as large as a pea.

Kidney Stone Causes

kidney stones causes are multifactorial :

Low urine volume | Kidney stone causes

• A major threat for kidney stone causes is continual low urine output which may be due to dehydration from strenuous exercise, staying in a very warm place and not drinking plenty of fluids.
• Low urine volume means that urine is dark and concentrated as there’s less fluid to keep salts dissolved .
• This can be improved by more fluid intake thus salts get diluted in urine thereby reduces the risk of stone formation .

Bowel Conditions | Kidney stone causes

• Bowel conditions like Crohn’s disease or inflammatory bowel disease or gastric bypass surgery that cause diarrhea , can increase the risk of forming kidney stones.
• Diarrhea leads to loss of large quantities of fluid which lowers urine volume and also the body takes lots of salts from the bowel , inflicting additional oxalate in urine.
• Low urine volume and high levels of urine oxalate can cause calcium oxalate kidney stones to form. Bowel conditions is one the kidney stone causes .

Obesity | Kidney stone causes

• It is a common risk factor contributing to kidney stones related to resistance to the hormone insulin ,which results in raised blood glucose levels and metabolic derangements that results in  calcium kidney stone formation.

Diet | Kidney stone causes

• Common causes of calcium kidney stones are high levels of calcium in the urine which may be due to increased intake of animal protein such as beef, fish, chicken, and pork.
• Decreasing the salt within the diet lowers urine calcium levels because more salt in urine keeps calcium from getting reabsorbed into blood.

Medical conditions | Kidney stone causes

• Parathyroid glands (which control calcium metabolism) with abnormal growth can cause more calcium levels in blood and urine.
• Another condition called distal renal tubular acidosis (acid build up in the body ) can cause formation of calcium phosphate kidney stone.

Types of Kidney Stone| Kidney Stone

Depending on the components in the stone these are categorized into 4 main types of kidney stones :

Calcium stones

• These are the foremost common and account for about 75% of all urinary stones.
• It might be pure stones of calcium salt (50%) or calcium phosphate (5%) or a mix of calcium oxalate and calcium phosphate (45%).

Struvite stones

• Around 15 % of kidney stones are composed of magnesium, ammonium, calcium phosphate , generally said as struvite (mixed) ,so they’re collectively known as struvite stones or triple phosphate stones.
• These usually occur because of infections like urinary tract infection.

Uric acid stones

About 6% of urinary calculi are products of uric acid. Uric acid calculi are radiolucent in contrast to radiopaque calcium stones.

Cystine stones

Cystine stones include less than 2% of kidney stones.

Risk factors of Kidney Stones

• Gout (uric acid stones).
• Hyperparathyroidism.
• Kidney disease such as renal tubular acidosis.
• Chronic diseases such as diabetes and hypertension.

• Inflammatory bowel disease.
• Individuals who have undergone intestinal bypass or ostomy surgery.
• Genetic predisposition -cystinuria (a condition characterized by the buildup of amino acid cystine in kidneys and bladder), idiopathic hypercalciuria.
• Chronic urinary tract infection (struvite stone).
• Some medications- certain diuretics, calcium containing antacids, Protease inhibitors like indinavir sulfate, steroids.

Kidney Stone Symptoms

The most common symptom is severe pain, mainly in the side of the abdomen, that’s commonly associated with nausea.

• Sharp pain in back, in between the ribs, hips and lower abdomen : This severe pain is termed renal colic and it lasts for 20-60 minutes. Pain is often mild, moderate and severe or intense depending on the size of the stone.
• Pain while urination as it blocks the passage of urine.

• Hydronephrosis : It’s a condition in which abundant fluid is present in the kidney because of retention of urine. Hydronephrosis occurs due to a block in the tube connecting the kidney to the bladder (ureter).
• Hematuria (Blood in urine).
• Nausea and vomiting.
• Fever with chills.
• Cloudy and smelly urine.
• Perspiration .
• Fatigue.
• Elevated BP and respiration.
• Infection.
• Incontinence.

Diagnosis of Kidney Stones

Diagnosis of a kidney stone is done to visualize the exact shape and size of kidney stones which begins with a patient’s medical history, physical examination, and imaging tests.

Blood tests are performed

• Blood tests may suggest that an excessive amount of calcium or uric acid is present in the body.
• Blood test results can help monitor kidney health and may prompt him or her to look for other medical issues.
• Diagnosis of kidney stones requires a complete health history assessment and a physical exam. Other tests include:

• Blood tests for calcium, phosphorus, uric acid, and electrolytes.
• To estimate kidney functioning blood urea nitrogen (BUN) and creatinine is taken.
• Urinalysis to check for crystals, bacteria, blood, and white cells.
• Examination of passed stones to determine their type.

Urine analysis

• The 24-hour urine collection test may reveal that the patient is excreting either too many or too few stone-forming minerals.
• Collect two samples of urine over the course of two days for this test.

Imaging

• Urinary tract imaging test may reveal kidney stones.
• Even small stones can be detected using high-speed or dual-energy computerized tomography (CT).
• Abdominal X-rays are less commonly employed because this type of imaging examination can miss tiny stones

A high-resolution CT scan

• The kidneys all the way down to the bladder or an x-ray referred to as a “KUB x-ray” (kidney-ureter-bladder x-ray) which can show the dimensions of the stone and its position.
• The KUB x-ray is principally for verifying if the stone is appropriate for wave treatment.
• The KUB check could also be used to monitor your stone before and when treatment is done, however the CT scan is most popular for diagnosis.

How common are kidney stones?

• Renal calculi or kidney stones are worldwide in distribution, but are significantly common in geographic areas such as parts of the United States, in South Africa, India, and Southeast Asia.
• It is estimated that around 2% of the population suffers from kidney stones at some point in their life with a male to female ratio of  3: 1.
• It is commonly seen at the age of 20 to 40 years.

Kidney Stones formed by

The process of stone formation includes the following steps:

• Saturation
• Supersaturation
• Nucleation
• Crystal growth and aggregation
• Crystal retention
• Stone formation

Calculi occur when urine elements that are highly concentrated crystallize and become hard. The urine includes more crystal-forming chemicals, such as calcium, which causes kidney stones to form uric acid, calcium, and oxalate. The urine, on the other hand, maybe devoid of chemicals that stop crystals from sticking together, making the best environment for kidney stones to grow.

Saturation

• When the active product of solutes is poor to change the formation or dissolution of crystals created of the solutes, the solution is said to be saturated.
• Once the active product is larger than this value, however, spontaneous crystallization is less likely to occur.

Supersaturation

• Supersaturated or metastable refers to a solution that is supersaturated or metastable in phrases of the moieties .
• The ratio of urinary calcium oxalate or calcium phosphate concentration to solubility, which is the driving factor in stone formation, known as supersaturation.
• Patients with ordinary kidney stones have higher urine supersaturation than the ones without, and the form of stone generated corresponds with urinary supersaturation.
• Crystals can nucleate and broaden supersaturation levels over 1, increasing stone formation, while they deteriorate at values below 1.
• Supersaturation of calcium oxalate is unaffected by urine pH; conversely, supersaturation of calcium phosphate increases fast as urine pH rises from 6 to 7.

Nucleation

• The process of nucleation is the development of tiny particles from free ions in solution.
• Crystallization can occur in solution microenvironments, such as those found in some parts of the nephron , as well as on cell and extracellular matrix surfaces.

Aggregation

• It is a cycle by which there is agglomeration of gems that structure in free arrangement into bigger multicomponent particles.
• It might likewise envelop the marvel of optional nucleation of new gems on the outer layer of those generally framed.
• The crystals develop and are deposited on the nucleus.
• These can cling to the renal papillae in rare cases.

Kidney Stone Treatment

Kidney stone treatment depends on the nature of the stone present; no matter how dangerous it is and how long you’ve had the symptoms. There are many different treatment options to choose from. It’s vital to speak to your doctor regarding what’s appropriate for you.

Check for the stone to pass itself | Kidney Stone Treatment

• Typically, you’ll merely watch for the stone to pass. Smaller stones are possible to pass away on their own than larger stones.
• Waiting for a period of 4 to 6 weeks for the stone to pass is safe as long as the pain is tolerable, when there aren’t any signs of infection, the kidney is not completely blocked and if the stone is small enough that it’s likely to pass.
• During the phase of watching for the stone to pass you must drink an adequate amount of water and should take pain medication once there is discomfort.

Medications| Kidney stone Treatment

• Some medications have shown to boost the possibility for a stone to pass. The foremost common medication prescribed for this is Tamsulosin.
• Tamsulosin in the brand name Flomax relaxes the ureter, creating an easier way for the stone to pass.
• With this the doctor may prescribe any antiemetic medications such as ondansetron and pain reliever like non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil) or naproxen (Naprosyn) in case of any nausea and pain.
• In case of large kidney stones that obstruct the urinary tract and flow, causing infection within the urine may require surgery to remove the stone.

Kidney stone removal

A urologist will remove the kidney stone or break it into little sections with subsequent treatments:

Cystoscopy and Ureteroscopy| Kidney Stone Treatment

• In cystoscopy the doctor uses a cystoscope to look within the duct and bladder to seek out a stone in the urethra or bladder.
• During ureteroscopy, the doctor uses a ureteroscope, which is longer and thinner than a cystoscope, to look at the complicated image of the lining of the ureters and kidneys.
• The doctor inserts the cystoscopy or ureteroscopy through the canal to examine the remaining part of the urinary tract; once the stone is found, the doctor will remove it or break it into smaller pieces.

Percutaneous Nephrolithotomy (PCNL) | Kidney Stone Treatment

• This is the main treatment used for removal of large stones, during this the doctor uses a slim viewing tool, named as a nephroscope , to search out and remove the kidney stone.
• The doctor inserts the tool directly into the hollow center of a part of the kidney wherever the stone is existing through a tiny low cut created in the back.
• For large kidney stones, the doctor in addition might use a device to break the kidney stones into smaller pieces.
• The doctor performs this procedure with general anesthesia. Once the procedure is completed , several days’ hospital stay might be required.

Shock Wave Lithotripsy (SWL) | Kidney Stone Treatment

• Shock wave lithotripsy is sometimes used to treat the stones existing in the kidney and ureter.
• The shock waves are primarily targeted to the stone, using X-rays or Ultrasound to determine the stone.
• The continual firing of shock waves causes the stone to fragment into small pieces.
• These small lumps of stones disappear in the urine for a few weeks due to the potential discomfort caused by the shock waves and also the need to manage respiration throughout the procedure.
• At the time of procedure anaesthesia is usually administered. SWL doesn’t work well on hard stones, similar to cystine, certain varieties of calcium oxalate and calcium phosphate stones, or very large stones.
• Once the shock wave is done , hospital stay might not be needed and you can head home the same day.

After these procedures, the urologist may leave a thin flexible tube usually called as the ureteral stent in the urinary tract to facilitate the urine flow or to allow a stone to pass. Once the stone is removed it is sent to the laboratory to find out the type of stone.

Kidney Stones can be Prevented

CHANGE IN DIET

Drinking plenty of fluids Everyday

• To produce adequate urine, drinking a minimum of three liters of liquid daily is advised. This equals the concerning 3 quarts that is about 10-ounce glasses .This will be helpful to lower the risk of forming new stones and will help keep the urine diluted.
• Remember to drink the extra amount of liquid to replace fluids lost after sweating due to exercise or in hot weather.
• Although water is preferable, alternative fluids such as citrus drinks can also help prevent kidney stones.
• Studies have shown that citrus drinks such as lemonade and orange juice protect against kidney stones because they contain citrate which prevents the crystals from turning into stones.
• Doctors suggest that people who form cystine stones should drink more fluids than others who form cystine stones. Generally, 4 liters of fluid is recommended to reduce cystine levels in urine.

Lower the amount of salt in diet

• The advice is for the people with high sodium intake as well as high content of calcium in the urine or cystine.
• Since sodium can increase both urine calcium and cystine levels. Doctors recommend avoiding foods that contain more salt.
• The Centers for disease control (CDC) and several health teams recommend that not to eat more than 2,300 mg of salt per day. The following foods are high in salt and should be eaten within limit :
• Cheese
• Pickles
• Canned and bottled sauces
• Table salt and some spice blends
• Salty snacks like chips.
• Breads , baked ,fried foods.
• Most frozen foods and meats include chicken, fish.
• Intake of recommended amount of calcium
• If taking calcium supplements make sure to take the required amount of calcium ,it should not be either too much or too little .
• Before taking it, you should ask your doctor if you need any supplements.
• Good sources of calcium to settle on are those that are low in salt. Consuming calcium-rich foods or drinks with meals on a daily basis could be a good habit.
• There are several non-dairy sources of calcium, non-dairy milk fortified with calcium.

Intake of fruits and vegetables

• It is recommended to eat at least 5 servings of fruits and vegetables per day for anyone suffering from kidney stones.
• Intake of fruits and vegetables provides potassium, fiber, magnesium, antioxidants, phytates, and citrates, which can help prevent stone formation.

Intake of foods with low oxalate levels

• This is recommended for patients with elevated urinary oxalate levels.
• Consumption of calcium rich foods like calcium fortified non-dairy milk products, juices, and buttermilk is advised as it often can control the oxalate level in urine.
• Avoid intake of some plant foods like spinach, rhubarb and almonds which contain oxalate.

Lower intake of meat

• In case of cysteine or calcium oxalate stones which form a lot due to intake of animal protein.
• It is advised to eat less meat, fish, seafood, pork, mutton, lamb than the usual intake or having in smaller portions.

MEDICATIONS

Diet changes and increased fluid intake in the body may not be enough to prevent stones formation. Your doctor may prescribe certain medications depending on the type of stone present and to help ease the conditions. Some of these medications are:-

Thiazide Diuretics

• These are prescribed in patients with calcium stones and high levels of calcium in urine .
• Thiazides decrease urine calcium by increasing the uptake of calcium out of urine by kidney and putting it back to the bloodstream.
• While taking thiazide , salt intake should be limited for better efficacy of the medication.

Potassium citrate

• It’s prescribed in patients with calcium stones and low levels of urinary citrate, and in those with uric acid and cystine stones.
• Potassium citrate works by optimizing the urine pH that prevents cysteine and uric acid stone formation and also increases urinary citrate levels, which helps prevent calcium stones.

Allopurinol

• It’s prescribed for patients with gout, which occurs due to high levels of uric acid in blood.
• Allopurinol works by lowering levels of uric acid levels in the blood and urine, which is why it is usually prescribed to prevent calcium and uric acid stones.

Acetohydroxamic acid (AHA)

• It’s used in patients who have struvite stones. These stones occur due to urinary tract infections .
• AHA is a strong antibiotic which doesn’t allow the formation of struvite stones in urine.
• To prevent formation of struvite stones is by stopping recurrence of UTIs by certain types of bacteria.

Cystine -binding thiol drugs

• It’s prescribed for patients with cystine stones.
• Medications like D-penicillamine or tiopronin bind to cysteine and build a component that’s less probable to crystallize in urine than cystine.

These medications are given once if alternative measures fail, like increasing fluid intake, reducing salt uptake or use of potassium citrate.