Kidney Stones in Adults
On this page:
A) Anatomy of the urinary tract
B) What is a kidney stone?
C) Who gets kidney stones?
D) What are the causes?
E) What are the symptoms?
F) How are are they diagnosed?
G) Stone prevention
H) Treatment options for urinary stone disease?
Kidney stones, one of the most painful of the urologic disorders, have beset humans for centuries. Scientists have found evidence of kidney stones in a 7,000-year-old Egyptian mummy. Unfortunately, kidney stones are one of the most common disorders of the urinary tract.
Most kidney stones pass out of the body without any intervention by a physician. Stones that cause lasting symptoms or other complications may be treated by various techniques, most of which do not involve major surgery. Also, research advances have led to a better understanding of the many factors that promote stone formation and thus better treatments for preventing stones.
Introduction to the Urinary Tract
The urinary tract, or system, consists of the kidneys, ureters, bladder, and urethra. The kidneys are two bean-shaped organs located below the ribs toward the middle of the back, one on each side of the spine. The kidneys remove extra water and wastes from the blood, producing urine. They also keep a stable balance of salts and other substances in the blood. The kidneys produce hormones that help build strong bones and form red blood cells(erythropoietin).
The urinary tract.
Narrow tubes called ureters carry urine from the kidneys to the bladder, an oval-shaped chamber in the lower abdomen. The bladder stores the urine and evacuates it when the patient wants to pass the urine.
What is a kidney stone?
A kidney stone is a aggregated crystalline mass developed from crystals from the urine within the urinary tract. Normally, urine contains chemicals that prevent or inhibit the crystals from forming. These inhibitors do not seem to work for everyone, however, so some people form stones. If the crystals remain tiny enough, they will travel through the urinary tract and pass out of the body in the urine without being noticed.
Kidney stones may contain various combinations of chemicals. The most common type of stone contains calcium in combination with either oxalate or phosphate. These chemicals are part of a person’s normal diet and make up important parts of the body, such as bones and muscles.
A less common type of stone is caused by infection in the urinary tract. This type of stone is called a struvite or infection stone. Another type of stone, uric acid stones, are a bit less common, and cystine stones are rare.
Gallstones and kidney stones are not related. They form in different areas of the body
Who gets kidney stones?
Stones occur more frequently in men. The prevalence of kidney stones rises dramatically as men enter their 40s and continues to rise into their 70s.
What causes kidney stones?
Doctors do not always know what causes a stone to form. While certain foods may promote stone formation in people who are susceptible, scientists do not believe that eating any specific food causes stones to form in people who are not susceptible.
A person with a family history of kidney stones may be more likely to develop stones. Urinary tract infections, kidney disorders such as cystic kidney diseases, and certain metabolic disorders such as hyperparathyroidism are also linked to stone formation.
Stones also get formed whenever there is blockage in the pathway of urination- prostatic enlargement, pelvi-ureteric junction obstruction etc..( secondary calculi)
In addition, more than 70 percent of people with a rare hereditary disease called renal tubular acidosis develop kidney stones.
Cystinuria and hyperoxaluria are two other rare, inherited metabolic disorders that often cause kidney stones. In cystinuria, too much of the amino acid cystine, which does not dissolve in urine, is voided, leading to the formation of stones made of cystine. In patients with hyperoxaluria, the body produces too much oxalate, a salt. When the urine contains more oxalate than can be dissolved, the crystals settle out and form stones.
Hypercalciuria is inherited, and it may be the cause of stones in more than half of patients. Calcium is absorbed from food in excess and is lost into the urine. This high level of calcium in the urine causes crystals of calcium oxalate or calcium phosphate to form in the kidneys or elsewhere in the urinary tract.
Other causes of kidney stones are hyperuricosuria, which is a disorder of uric acid metabolism; gout; excess intake of vitamin D.
The calcium-based antacids may increase the risk of forming kidney stones by increasing the amount of calcium in the urine.
Calcium oxalate stones may also form in people who have chronic inflammation of the bowel or who have had an intestinal bypass operation.
The struvite stones can form in people who have had a urinary tract infection.
What are the symptoms of kidney stones?
Kidney stones often do not cause any symptoms. Usually, the first symptom of a kidney stone is extreme pain, which begins suddenly when a stone moves in the urinary tract and blocks the flow of urine. Typically, a person feels a sharp, cramping pain in the back and side in the area of the kidney or in the lower abdomen. Sometimes nausea and vomiting occur. Later, pain may spread to the groin.
If stone is impacted in lower ureter the patient will have the hematuria, pain in passing urine or frequency of the urination.
If the stone gets impacted in the urethra it can cause retention of the urine.
If fever and chills accompany any of these symptoms, an infection may be present. In this case, a person should contact a doctor immediately. The infection in immunocompromised patients- like old age group or diabetics can flare up and pose serious problem to the patient.
How are kidney stones diagnosed?
Sometimes “silent” stones—those that do not cause symptoms—are found on x rays taken during a general health exam. If the stones are small, they will often pass out of the body unnoticed. Often, kidney stones are found on an x ray or ultrasound taken of someone who complains of blood in the urine or sudden pain. These diagnostic images give the doctor valuable information about the stone’s size and location. Blood and urine tests help detect any abnormal substance that might promote stone formation (Blood calcium, uric acid and phosphate tests).
The doctor may decide to scan the urinary system using a special test called a computerized tomography (CT) scan or an intravenous pyelogram (IVP).
Urologists usually advise IVP for anatomical and functional delieneation.This helps him to prepare the road map for surgery.Sometimes on its basis when the kidney is non excreting he may even decide to remove the kidney.
Preventing Kidney Stones
A person who has had more than one kidney stone may be likely to form another; so, if possible, prevention is important. To help determine their cause, the doctor will order laboratory tests, including urine and blood tests. The doctor will also ask about the patient’s medical history, occupation, and eating habits. If a stone has been removed, or if the patient has passed a stone and saved it, a stone analysis by the laboratory may help the doctor in planning treatment.
The doctor may ask the patient to collect urine for 24 hours after a stone has passed or been removed. For a 24-hour urine collection, the patient is given a large container, which is to be refrigerated between trips to the bathroom. The collection is used to measure urine volume and levels of electrolytes, calcium, sodium, uric acid, oxalate, inorganic phosphate citrate, and creatinine. The doctor will use this information to determine the cause of the stone. A second 24-hour urine collection may be needed to determine whether the prescribed treatment is working.
How are kidney stones treated?
Small stones which are not causing infection/damage or infection can be spontaneously passed if patient takes plenty of water combined with medications (this may include alpha blockers, steroids along with pain killers. Some doctors also add diuretics thinking that it will increase the hydrostatic pressure of urine?)
Lifestyle Changes
Drinking advice:
• Balanced fluids
• 2.5-3.0 liters per day
• Diuresis 2.0-2.5 liters per day
• Specific gravity of urine < 1.010
• Neutral beverages
• Circadian drinking
Nutritional advice:
• Rich in vegetable fiber
• Rich in alkaline potassium
• Normal calcium (1000-1200mg/day)
• Limited salt (4-5 gm/day)
• Limited animal protein (0.8-1 gm/Kg/day)
60 Kg- 60 gm/day or 250g 2/7
• Limited sugars and fat
• Limited oxalate intake
Life style advice:
• BMI 18-25 Kg/m2
• Stress limitation
• Adequate physical activity
• Balancing of excessive fluids
Should dietary calcium be restricted:
• No
Foods to be avoided:
Cabbage, cauliflower, chicken, meat, fish, salty food, pickle, beer, berries, amla, chickoo, mushroom, brinjal, bhindi, tomatoes, eggs, cucumber, cashewnuts, milk(more than 2 glasses per day), lot of dairy products.
Foods to be taken:
Pineapple juice, carrots, coconut water, karela, barley( preferrable made up of jowar), lime juice( donot take more than 1 ½ glasses per day), Horse gram(you can find out from Maharashtrian cuisine how to make items out of it), almonds, banana.
Medical Therapy
A doctor may prescribe certain medications to help prevent calcium and uric acid stones. These medicines control the amount of acid or alkali in the urine, key factors in crystal formation. The medicine allopurinol may also be useful in some cases of hyperuricosuria.
Doctors usually try to control hypercalciuria, and thus prevent calcium stones, by prescribing certain diuretics, such as hydrochlorothiazide. These medicines decrease the amount of calcium released by the kidneys into the urine by favoring calcium retention in bone. They work best when sodium intake is low.
Rarely, patients with hypercalciuria are given the medicine sodium cellulose phosphate, which binds calcium in the intestines and prevents it from leaking into the urine.
If cystine stones cannot be controlled by drinking more fluids, a doctor may prescribe penicillamine which help reduce the amount of cystine in the urine.
For struvite stones that have been totally removed, the first line of prevention is to keep the urine free of bacteria that can cause infection. A patient’s urine will be tested regularly to ensure no bacteria are present.
People with hyperparathyroidism sometimes develop calcium stones. Treatment in these cases is usually surgery to remove the parathyroid glands, which are located in the neck. In most cases, only one of the glands is enlarged. Removing the glands cures the patient’s problem with hyperparathyroidism and kidney stones.
Surgical Treatment
Surgery may be needed to remove a kidney stone if it
• does not pass after a reasonable period of time ( no timeframe is possible so regular screening for ultrasound is essential)
• is too large to pass on its own or is caught in a difficult place(usually stone more than 6 mm in the ureter is less likey to pass on its own)
• Causes Kidney or urinary blockage
• Stones causing recurrent urinary tract infection
• Causing kidney damage/hydronephrosis
Until 20 years ago, open surgery was necessary to remove a stone. The surgery required a recovery time of 4 to 6 weeks. Today, treatment for these stones is greatly improved, and many options do not require major open surgery and can be performed in an outpatient setting.
Extracorporeal Shock Wave Lithotripsy
ESWL or extracorporeal shock wave lithotripsy has revolutionized the treatment of renal stones. Kidney stones less than or equal to 1.5 cm in size in the kidney or upper ureter are best treated with ESWL.
Usually, this is an outpatient type of procedure using IV sedation or full anesthesia. Treatment time runs from 1 to 2 hours. The stone is usually visualized with fluoroscopy and once centered for treatment, a shock wave is generated that penetrates the body and impacts upon the stone. After usually 3000 shocks are given, the stone gradually pulverizes, and the fragments are passed spontaneously over the next several days to weeks (It may sometimes take upto 3 months to pass all the fragments). Complications of this procedure bleeding which is self resolving, infection so peri-procedure cover of antibiotics is essential. The third potential complication is sometimes the stone breaks and the gravels line up along the lower ureter making it necessary for the patient to undergo secondary/auxialiary procedure- Ureteroscopic clearance.
As with any procedure; pre-operative urine culture should be sterile and the patient should be off from the anti-platelet agents atleast for the 7 days for the safety otherwise large hematomas not only in kidneys but also in liver and adjacent organs are reported.
Extracorporeal shock wave lithotripsy.
Percutaneous Nephrolithotomy
The percutaneous stone extraction gained acceptance as the procedure of choice for management of most patients with upper tract calculi in the late 1970’s and early 1980’s. In 1987, Leroy et al at the Mayo clinic reported a contemporary experience with percutaneous stone management in the era of ESWL. The authors concluded that despite the increased complexity of patients undergoing percutaneous management, excellent result could still be achieved with acceptably low morbidity.
Indications for PCNL
• Renal calculi greater than 2 cms in diameter.
• Stone with composition inappropriate for ESWL(lower calyceal stone more than 1.5 cm in size).
• Renal malformations like infundibular stenosis, pelvi - ureteric Junction obstruction.
• Failure of ESWL.
• ESWL not suitable because of problems in focussing For ex.Kyphoscoliosis
The patient needs to undergo pre operative workup as required in open operation and Urine culture should be treated with antibiotics, the PCNL procedure is done with help of imaging "C" Arm under spinal anaesthesia. Intra-venous Pyelography is a must as most of the urologists decide pre-operatively the puncture and access. Often even with the development of CT urography the IVP has been a favorite with all urologists.
Technique of Percutaneous Nephrostomy
Initial step of PCNL is cystoscopy and placement of an open ended or ureteric catheter on the side of the stone and injecting dye which will give the configuration of the pelvi-calyceal system. Under the general anesthesia in lithotomy position, retrograde ureteric catheterization was done in all the patients. Later the position was changed to prone and desired calyceal puncture was made under fluoroscopic guidance with the help of retrograde instillation of dye in the pelvi-calyceal system. The initial puncture was decided on table based on the location of the stone bulk and the abnormal anatomy, to access the maximal stone bulk, after a retrograde pyelography. After the initial puncture the gradual dilatation was carried out with the fascial dilators with intermittent fluoroscopic guidance till 16 Fr Amplatz sheath fits in. A Karl Storz 15Fr miniature nephroscope (Karl-Storz) was used in majority cases.In staghorn calculi,conentional PCNL with 26 fr Amplatz was done. The stone fragmentation was done with pneumatic lithotripter. When multiple tracts were needed (the need was assessed prior to puncture), multiple punctures were made initially in the desired calyces and guide wires were left in situ for dilatation as need arises.
Standard Puncture
The puncture is made with needle and help of "C" Arm. Once the needle is in pelvicalyceal system, a J tipped, Teflon coated movable core guidewire is negotiated into the renal pelvis and across the Pelviureteric Junction into the ureter.The position of the guide wire is confirmed both in 0 and 90 degrees rotation of the C-arm so that misguided dilatation and resultant extravasation o bleeding will not occur.
Tract Dilatation
Dilatation need to be done under fluoroscopy to see that it is along the guide wire and it should not be bent during the process of dilatation.
We use miniature nephroscope so that the dilataton is done till 16 Fr over guide rod followed by Karl Storz mini-nephroscope is inserted.
Stone fragmentation:
Renal pelvis is flushed with irrigant through thesheath or from below by open ended catheter. Once the stone is visible, with the Holmium LASER fragmentation is carried out. The LASER often makes up for shortcomings of the miniature nephrosocpy. The pulverisation is fast.
Ureteroscopic Stone Removal
Although some stones in the ureters can be treated with ESWL, ureteroscopy may be needed for mid- and lower-ureter stones. No incision is made in this procedure. Instead, the surgeon passes a small fiberoptic instrument called a ureteroscope through the urethra and bladder into the ureter. The surgeon then locates the stone and either removes it with a cage-like device or shatters it with a special instrument that produces a form of shock wave. A small tube or stent may be left in the ureter for a few days to help urine flow. Before fiber optics made ureteroscopy possible, physicians used a similar “blind basket” extraction method. But this technique is rarely used now because of the higher risks of damage to the ureters.
Ureteroscopic stone removal.