Kidney Stones – Causes, Symptoms, Prevention, Treatment

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Overview

Kidney stones (renal calculi or nephrolithiasis) are pieces of minerals that are localized at the level of the kidney. They can remain in the kidney or may be eliminated from the body via the urinary tract (the tubules that connect the kidneys with the urinary bladder and that which connects the urinary bladder with the outside – the urethra). The way calculi form may be asymptomatic or may cause an intense pain or other symptoms (the so-called renal colic). Typically, kidney stones do not cause (long term) chronic lesions of the urinary tract. About half of those with at least one renal calculus will develop new calculi in the next five years if no treatment is followed.
 
Article contents:
Overview
Causes
Symptoms
Physiopathogenic mechanism
Complications
Kidney stones in pregnant women
Kidney stones in children
Consulting a specialist
Watchful waiting
Recommended medical specialists
Investigation
Treatment – Overview
Initial treatment
Treatment of relapses
Prophylaxis
Home Treatment
Medications
Surgical treatment

Causes

Kidney Stones Causes & Prevention

Kidney stones are formed when the balance between water, salts, minerals and other substances in the urine change. The way in which this balance is altered determines the type of calculus that is formed. Most kidney stones are composed of calcium and occur when its level in the urine changes. The factors that cause the change of the urinary balance are:
-lack of adequate fluid intake (dehydration): in this case, salts, minerals and other substances in the urine precipitate and form the calculus, this is the most common cause of kidney stones
-medical diseases: there are many diseases that can affect the normal balance leading in this way to the formation of calculi; people who have an inflammatory bowel disease or who have had bowel surgery, do not absorb normally fats found at this level; these changes interfere with the way in which calcium and other minerals are metabolized causing kidney stones
-foods high in oxalates: people who eat foods high in oxalates, such as green vegetables and chocolate, are prone to calculi; this can be a bigger problem if the diet is also low in calcium.
Renal calculi can be an inherited disease that occurs over several generations of the same family. In rare cases, kidney stones may occur due to the increased production of hormones by the parathyroid glands, which results in the increase of calcium in the blood and the formation of kidney stones.

Symptoms

Kidney stones may remain in the kidney or may be eliminated from the body via the urinary tract (the tubules that connect the kidneys with the urinary bladder, called ureters and the tube that connects the bladder with the outside – the urethra).
Their mobilization in the kidney may cause:
-no symptoms, if the stone is small enough
- sudden onset of a constant pain; calculi can cause severe pain in the lumbar area (lower back portion), the sides of the trunk ( the the flanks), the abdomen, the pelvis or the genitals; people who have had such pains do usually describe them as the worst pain they have ever had
-Nausea and vomiting
-appearance of blood in the urine (hematuria), it may be associated with the kidney stones that remain or those who are mobilizing in the urinary tract
-frequent and painful urination,which frequently occurr when the stone is in the ureter or after it left the urinary bladder and is found in the urethra; frequent urination can occur in urinary tract infections
-fever
-loss of appetite
-diarrhea or constipation
-sweating (diaphoresis)
-fatigue.

The diseases that have similar symptoms are appendicitis, hernia, ectopic pregnancy (pregnancy that develops outside the uterus) and prostatitis.

Physiopathogenic mechanism

At first, the kidney stones look like small pieces of minerals found in the kidney. When the urine leaves the kidney, it may or may not connect these clusters of minerals. If these clusters remain in the kidneys more time, they join together and form a larger stone. Most stones leave the kidney and cross the whole urinary tract when they have a small enough size in order to allow an easy elimination from the body. In this phase, there is not necessary any treatment. On the other hand, larger “stones” can block the ureter. As a result, symptoms such as pain may occur. They can prevent leakage of urine from the kidney to the bladder through the ureter. Usually, the pain gets worse over a period of 15-60 minutes, getting to be constant and of a very high intensity. Pain decreases in intensity when the stone is mobilized and does not block the ureter. Pain disappears when the stone is removed in the bladder. In most cases, the large stones require special treatment. The smaller the stone, the more likely to be removed from the body without the need for treatment. About 90% of the stones smaller than 5 mm and about half of those over 5 mm are removed by themselves. Home treatment is necessary for 10-20% of them. On average, a stone crosses the urinary tract in 1-3 weeks, and two thirds of those who remove by themselves, cross the tract in 4 weeks after the onset of symptoms.
About half of those with at least one kidney stone will develop new calculi in the next five years if no treatment is followed. When kidney stones are formed several times within a few years, the time between their formation tends to be increasingly smaller. You can not know who will have a greater number of stones or who will not have at all.

Complications

The complications of nephrolithiasis may be:
-increased risk for urinary tract infection or exacerbation of a preexisting infection
-kidney lesions that can lead to acute renal failure if the stone prevents the elimination of the urine from the kidneys; for most people whose kidneys are healthy, the stones do not cause significant damage, only when they completely block the urinary tract for at least 4 weeks.
Kidney stone is a more serious problem for patients with one kidney, people with deficiencies of the immune system or had a kidney transplant.

Kidney stones in pregnant women

When kidney stones develop during pregnancy, the obstetrician and the urologist must decide if treatment is necessary and the moment when it should be initiated. The type of treatment depends on the trimester of pregnancy.

Kidney stones in children

Kidney stones in children is not common. When it still occurs, it occurs between the ages of 8 and 10 years. Children with kidney stones can associate a urinary tract infection. Most children with kidney stones have other diseases as well, such as urinary tract development abnormalities, metabolic or genetic disorders like cystic fibrosis.

Consulting a specialist

There are many factors that increase the risk of developing kidney stones. Some of them can be controlled and others can not.
Consulting a specialist is required when specific symptoms of nephrolithiasis appear. They may be:
-constant, severe pain in the flank, abdomen, pelvis or genitals
-hematuria (blood in the urine)
- signs of urinary tract infection.

Medical intervention is necessary also when there is a diagnosis of kidney stones and other problems occur, such as:
-severe nausea and vomiting
-fever and chills
-strong pain in the flanks, more pronounced in the kidneys.

The family doctor decides whether you need a specialized medical examination when:
- the diagnosis of kidney stones has been established, but the patient needs stronger medication against pain
-when he considers necessary to examine the composition of the stone; if a stone has been removed, even if the pain did not exist or it was of a very low intensity, the stone must be recovered and the family doctor should be asked whether it needs to be examined.

Watchful waiting

If the patient feels better after a renal colic, treatment is not necessary. If symptoms worsen, the doctor will decide together with the patient what to do.
You can remove a kidney stone without medical treatment if:
-pain can be controlled with medication
-there are no signs of infection such as fever and chills
- large amounts of liquid are consumed
-there is no sensation such as nausea or vomiting.

Recommended doctors

If you need immediate treatment because of pain which occurs in kidney stones,the patient may address to an emergency department. Health professionals who can diagnose and treat kidney stones outside emergency situations are:
-GP
-doctor of internal medicine
-urologist.

Investigations

Often kidney stones is first diagnosed when the patient goes to the doctor because of the pain of high intensity. Your doctor, either the emergency doctor or the family doctor, may ask you some questions and do a brief physical examination before suggesting treatment. After removing a kidney stone, it may be needed another examination in order for your doctor to determine if the risk of recurrence of nephrolithiasis does exist.
Diagnostic tests for kidney stones
The doctor may ask a series of tests to help him in diagnosing nephrolithiasis or to determine location of the stone and to bring information about the fact that these can cause urinary tract lesions.
Such tests are:
-Computed tomography (CT) without contrast, in spiral, is the examination of choice for kidney stones; it is a CT scan of the urethra and the kidneys in which the scanner describes a circular motion while the patient goes through the used device; this test takes half the time of a standard CT scan, offers clearer pictures of the kidneys and other organs and they can be viewed from different angles of incidence
-Intravenous Pyelogram (IVP) is an x-ray examination that can show the size, shape and position of the urinary tract, including kidneys and ureters; during IVP, a dye called contrast substance is injected intravenously in the arm, then a series of radiographies are made at regular intervals; before the appearance of the CT scan without contrast, in spiral, this was an examination of choice
-If you can not establish a diagnosis by IVP, a retrograde pyelogram; this time the contrast substance is not injected into the arm, but it reaches the urinary tract through the tubules that remove urine outside (urethra)
-Urine culture and urinalysis: the urine culture determines if there is a urinary tract infection, and the urinalysis measures several different parameters, including acidity (pH) and if your urine contains crystals
-Abdominal radiography illustrate the kidneys, ureters and bladder; kidney stones or other sources of pain can be identified, this test can be made also several weeks after the removal of a stone to see if all the stone was removed or if there were lesions of the urinary tract
- Renal ultrasound uses ultrasounds that are reflected in order to give an image of the kidney; it is preferable to examine pregnant women.

Examinations that determine the composition of calculi
Determining the type of calculi is useful in treatment decisions, as well as in establishing measures that must be taken in order to prevent the recurrence of nephrolithiasis. The tests that make this possible are:
- the medical history and physical examination, oriented towards the discovery of risk factors for kidney stones: include questions about diet and lifestyle
- the analysis of calculi: the patient is asked to keep the stone after removal, filtering the urine by using a small sieve or gauze
-the biochemical analyses which measure the renal function, the serum levels of calcium, uric acid, phosphorus, electrolytes and other substances that may contribute to the occurrence of kidney stones; they can suggest the likelihood of the recurrence of kidney stones
-a 24-hour urine collection to measure volume, pH, calcium, oxalates, uric acid and other substances that may contribute to stone formation.
These tests are not obligatory, but some doctors do them routinely, while others require these examinations only if they believe the risk of recurrence exists. Your doctor may recommend these examinations if the patient has removed more than one stone and if he has a family history of kidney stones. Women in the procreation age, can make a pregnancy test in order to eliminate a pregnancy as the cause of symptoms and to know if the radiological examinations are safe.

Treatment – Overview

Nephrolithiasis is often first diagnosed when the patient goes to the doctor because the appearance of a pain of high intensity. The doctor may recommend to the patient to first eliminate the stone and follow an analgesic treatment or may recommend a procedure for the removal of the calculus. The doctor may prescribe a treatment before knowing the size of the calculus. Most small stones (less than 5 mm) are removed without the need for further treatment, except for the ingestion of fluids and drugs that relieve pain. The smaller the stone, the more likely to be removed from the body without the need for treatment. About 90% of the stones smaller than 5 mm and about half of those over 5 mm are removed by themselves. Home treatment is necessary for 10-20% of them. On average, a stone crosses the urinary tract in 1-3 weeks, and two thirds of those who remove by themselves, cross the tract in 4 weeks after the onset of symptoms. Not all kidney stones are diagnosed as a result of the occurrence of symptoms. The calculus may not cause pain and the doctor can detect it only during a routine checkup or an examination for an associated pathology. Treatment in this case is identical to that for symptomatic lithiasis, as it is shown below.

Initial treatment

If the doctor considers that the stone can be removed by itself and the pain caused by this is bearable for the patient, he may recommend home treatment, which includes:
- using analgesic medication: nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce pain; if necessary, your doctor may prescribe stronger medications
- Drinking plenty of fluids: it is recommended the consumption of liquids above the normal, 8-10 glasses per day, that is 2 glasses of water every 2 hours; consult a doctor about drinking plenty of fluids if the patient has kidney, heart or liver diseases, which have as an interdiction the consumption of fluids
- It is best to avoid drinking sodas or fruit juices such as grapefruit juice; foods high in oxalate (green vegetables, nuts and chocolate) sould be avoided.

When the pain is too intense in order to be supported, usually the calculus blocks the urinary tract or there is a concomitant infection, which will determine the doctor to recommend one of the following treatments:
- Extracorporeal shock wave lithotripsy (ESWL): This method ultrasounds that easily cross the body but which are strong enough to break up kidney stones; it is the most used treatment of nephrolithiasis
-Nefro-lithotripsy or percutaneous nefro-lithotomy: the surgeon places a telescopic tube into the kidney through a small incision in the renal lodge and via this he extracts the calculus (lithotomy) or breaks it and then extract the fragments (or lithotripsy lithotripsy), this procedure can be used if ESWL fails or the calculus has large dimensions
-Ureteroscopy: the surgeon inserts along the urinary tract a thin telescopic tube (ureteroscopic) to the calculus, which he will extract or break and then extract it with special tools; sometimes a small hollow tube is needed (ureteral stent) which is placed in the ureter to hold it open and facilitate the flow of urine along with any fragments of calculus; this method is mostly used for kidney stones that have slipped from the kidneys into the ureter.
The size of the calculus, its location in the urinary tract and the overall health, as well as other factors are taken into account when you have to choose a method to break or to extract the kidney stones.
- Classical surgery during which the surgeon makes a lateral incision in the stomach to reach the kidneys and extract the calculus; the method is rarely used now.

Treatment of relapses

If kidney stones are present, it is very likely for them to recur after the initial episode was resolved. Almost half of those diagnosed with nephrolthiasis will develop more stones in 5 years after the initial diagnosis unless preventive measures are taken, such as increased fluid intake and diet adjustments. If there are associated risk factors such as family history of kidney stones, the doctor may prescribe medication that prevents stone formation.
A recent study found that the use of some drugs, such as Nifedipine or Prednisone during calculus removal, increases the possibility of eliminating multiple calculi and decreases the number of necessary days for relaxation, hospitalization and surgery, as compared with fluid intake and analgesic medication. The doctor may ask you to collect the urine for 24 hours after a calculus has been ewmoved so that it should be tested in order to determine the type of calculus and the cause of its formation. Knowing the precise type of calculus helps the patient avoid situations that can cause the appearance of other stones.
In rare cases, calculi occur because of the parathyroid glands, which produce large amounts of hormones, this leading to increased calcium levels and the occurrence of kidney stones with high calcium content. In order to prevent this situation, your doctor may recommend the surgical removal of one of the glands (parathyroidectomy). Additional treatment for kidney stones is necessary if the symptoms continue and there are also:
- recurrent urinary-tract infections
- decreased renal function
- unique kidney
- diseases of the immune system
- renal transplantation.

Prophylaxis

If the first time more stones are removed and there is a family history of kidney stones associated, relapses are very likely. In order to prevent recurrence it is recommended:
-consumption of fluids (between 8-10 glasses of water a day)
-increased consumption of fiber; fiber includes oat and wheat bran, beans, wheat bread, wheat cereals, cabbage and carrots
-lower consumption of beef, pork and poultry
-consumption of moderate amounts of foods high in calcium such as dairy products; calcium intake in the recommended amount, but in combination with hyposodic and hyperproteic diet increase the risk; there are studies that have shown that in elderly and young women, the consumption of large amounts of calcium decreases the risk of kidney stones
-Avoid foods high in oxalates, such as green vegetables, nuts and chocolate
-Hyposodic food (not salted).

Fluid intake should be increased gradually, one glass per day, until it reaches the number of 8-10 glasses daily. This rhythm allows the body to slowly adapt to the increased amount of liquid. When fluid intake is sufficient , urine is pale yellow or almost colourless and on the contrary dark yellow, when liquids are in low quantity. Consult a doctor about drinking plenty of fluids if you have kidney, heart or liver diseases, which have fluid restriction as an indication. The doctor may require further investigation before deciding whether dietary changes reduce the risk of nephrolithiasis recurrence.
If kidney stones recur despite the increased fluid consumption and diet changes, your doctor may prescribe medications to help dissolve calculi and prevent forming new ones. The drugs are prescribed also in the case of associated pathology, which increases the risk of new stone formation. The type of medication is strongly related to composition of the calculus.

Medicines to prevent the formation of calculi rich in calcium
Approximately 80% of the people with kidney stones have stones rich in calcium. The drugs for preventing the formation of calculi rich in calcium include:
-Thiazides (Hidroclortiazid and Chlorthalidone) and potassium citrate: are typically used for preventing the formation of calculi rich in calcium
-Orthophosphate and cellulose phosphate are sometimes used; they have more adverse effects than the previous category
-Calcium carbonate or calcium citrate and cholestyramine: they can be used if there are high levels of oxalate in the urine.

Medicines to prevent the formation of calculi rich in uric acid
Approximately 5% to 10% of calculi are composed of uric acid, a remnant substance which is normally eliminated from the body through urine. The drugs for preventing the formation of calculi rich in uric acid are:
-Potassium citrate and sodium bicarbonate (baking soda) prevent the acidification of urine, which prevents the formation of calculi rich in uric acid
-Allopurinol prevents uric acid production of the body.

Medicines to prevent the formation of calculi rich in cystine
Less than 1% of calculi are formed from a chemical called cystine. These stones occur more often in families where there is a metabolic disturbance that causes the cystine levels in the urine to be increased (cystinuria). The drugs for preventing the formation of calculi rich in cystine are:
-Penicillamine, tiopronin and captopril: help dissolve the cystine in the urine and therefore the formation of calculi decreases
-Potassium citrate prevents the increased urine acidification, which decreases the risk of calculi formation.

Medicines to prevent formation of calculi rich in struvite
They represent about 10% -15% of the kidney stones. They are also called infection calculi if formed over kidney or urinary infections. The drugs for preventing the formation of calculi rich in struvite are:
-Urease inhibitors: they are rarely used because of the side effects and only when stone removal procedures can not be used or do not work.

To be retained!
If the calculi are formed of uric acid or cysteine, the drugs against the formation of these stones must be taken for all life. The calculi of large struvite, appear after repeated kidney infections. Usually, antibiotics and surgery are necesary in order to cure and prevent the occurrence of new calculi.

Home Treatment

Home treatment is often the only treatment necessary to eliminate the calculus. This includes drinking plenty of fluids, analgesic medication and sometimes filtering and collecting the urine to determine the type of calculus.
Drinking plenty of fluids
It is recommended the consumption of liquids above the normal rate, 8-10 glasses per day, namely:
-2 glasses of water every 2 hours; consult a doctor about drinking plenty of fluids if you have kidney, heart or liver diseases which have fluid restriction as an indication
-it is best to avoid drinking sodas or fruit juices such as grapefruit juice
-is best to avoid foods high in oxalate (green vegetables, nuts and chocolate).

Analgesic medication

Analgesic medications such as nonsteroidal anti-inflammatory drugs, can decrease pain intensity. These include aspirin, ibuprofen and ketoprofen. Your doctor may prescribe stronger medications if necessary.
Collecting calculi and urine
The doctor may ask the patient to keep the removed stone in order to examine it and find the cause of its formation.
It is recommended urinating through a sieve and keep all stones, including those that look like sand or gravel; the maneuver is made within 3 days after the renal colic passed.
Another method is to urinate into a container and empty it through a sieve in order to retain the calculus.
The stones should be let to dry and then stored in plastic or glass container until they are taken to the doctor for examination. The doctor may ask the patient to collect urine for 24 hours after a calculus was removed in order to be tested to determine the type of calculus and the cause of its formation. Knowing the precise type of ccalculus helps patients avoid situations that can cause the appearance of other stones.

Surgical treatment

Patients rarely need traditional surgery to treat kidney stones. In most cases, other less invasive treatments are successful. Resort to traditional surgery is made when the calculus causes severe bleeding that can not be controlled. The surgeon makes an incision in the lateral side of the stomach in order to reach the kidneys and extract the calculus.
Another type of surgery is sometimes used, namely, nefro-lithotripsy or percutaneous nefro-lithotomy.

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  1. emily jacob says:

    the causes of kidney stones can be determined through various tests and a thorough study of medical and family history of the patient. The diagnosis of kidney stones is imporatante for our doctors to present all available options to help relieve symptoms and ensure that the calculations do not return to form. Urology Specialists Our doctors will assess your symptoms to determine if there are kidney stones or if you have another urological condition. Will conduct diagnostic testing to provide the most suitable and effective treatment his condition requires – what causes kidney stones.

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