KIDNEY STONES

Kidney stones have plagued humans since the earliest records of civilization. Kidney stones were found in a 7000-year-old Egyptian Mummy. Unfortunately; kidney stones are one of the most common disorders of the urinary tract.

Kidney Stone Management Program at Bay Urology

Our doctors at Bay Urology are leaders in the diagnosis, treatment and prevention of kidney stones. We have state of the art equipment necessary for the diagnosis and treatment of all types of kidney stones. Our program offers a unique approach to the treatment of kidney stones and is designed for all patients who suffer from any type of kidney stone disease – from simple to complex. We offer both innovative surgical and medical treatments and also set a course of long term management for recovery and prevention. We at Bay Urology are committed to progressive treatments and prevention plans.

Basic Principles of Why and How Stones Are Formed

The kidneys continuously filter blood and make urine to remove waste products, minerals and excess water from the blood. Kidney stones are deposits of these minerals that grow slowly over months or years in the kidneys. Many of these deposits come out spontaneously in the urine without or with minimal discomfort. Some may stay in the kidney and continue to grown and few may pass from the kidneys and become lodged in the ureter and cause severe pain.

Stone formation requires super saturation which results in precipitation of salt usually in association with organic matrix. The role of super saturation is very clear; the greater the concentration of two ions, the more likely they are to precipitate. It is impossible for a stone to grow if the urine is not super saturated.

Imagine a glass of water and you add a small teaspoon of salt. It will dissolve, add another teaspoon and it will dissolve. If you keep on adding salt, soon it will NOT dissolve. That means the concentration of salt in the water is now high and it is called super saturation.

Besides super saturation, there are three other factors involved in the stone formation:

• Inhibitors and Promoters: Pyrophosphate, Citrate and magnesium are known as inhibitors of calcium phosphate and oxalate crystal growth.
• Crystal Retention: Crystals are formed in the papillary collecting ducts but they are flushed out with the urine. People who form kidney stones may have an abnormal tendency for small crystals to adhere to the epithelial lining of the upper urinary tract.
• Matrix: Kidney stones contain a variable amount of organic material called matrix. Presence of this matrix acts as a ground substance for stone formation.
  

The Players In The Game of Stone Formation

• Calcium: Calcium is a major ion present in urinary crystals. Almost 98% of the calcium filtered by the kidneys is reabsorbed and only 2% is excreted in the urine.
• Oxalate: Oxalate is a normal waste product of metabolism. Only about 10-15% of oxalate found in the urine comes from the diet. Oxalate is present in many foods (leaf tea, powdered coffee, spinach and rhubarb). Excess amount of oxalate is found in patients with inflammatory bowel disease.
• Phosphate: Phosphate is an important buffer. The amount of phosphate present in the urine is related to the amount of dietary phosphate (meat and dairy products).
• Uric Acid: Uric Acid is the by-product of purine metabolism. Approximately 10% of the filtered uric acid finds its way in the urine. Patients with excessive amount of uric acid in the urine not only form uric acid stones, but also calcium oxalate stones. Uric acid promotes calcium oxalate crystallization. Excessive red meat, poultry and fish causes high uric acid.
• Sodium: Sodium plays an important role in regulating the crystallization of calcium stone in urine.
• Citrate: Citrate is a key factor affecting the development of calcium urinary stones, deficiency is associated with stone formation.
• Magnesium: Lack of dietary magnesium is associated with increased calcium oxalate stone formation.
• Sulfate: Urinary sulfates may help prevent urinary stones.
  

What Are The Different Types of Kidney Stones?

• Calcium stones - Calcium containing stones represent approximately 75-80% of all stones.
  Calcium oxalate stones – 60%
  Calcium phosphate stones – 20%
  Mixed calcium oxalate and phosphate stones – 20%
• Struvite stones
• Uric acid stones
• Cystine stones
  

The basis for calcium stone formation is super saturation of urine with stone forming calcium salts.

• Hypercalciuria (too much calcium in the urine)
• Hypocitraturia (too little citrate in the urine)
• Hyperoxaluria (too much oxalate in the urine)
• Hyperuriosuria (too much uric acid in the urine)
• Hypercalcemia (too much calcium in the blood)
  

Hypercalciuria

Hypercalciuria is the most important risk factor in calcium stone formation. There are three different types of clinical situations which may cause hypercalciuria.

• Absorptive Hypercalciuria – Problem: Increased intestinal absorption of calcium.
• Renal Hypercalciuria – Problem: Leak of calcium in the urine from the kidneys.
• Rasorptive Hypercalciuria – Problem: bone demineralization.

Hypercalcemia and Kidney Stones

Primary hyperparathyroidism is the most common cause of hypercalcemia. The diagnosis is based on the presence of hypercalcemia along with elevated parathyroid hormone.

Non-Calcium Calculi

• Struvite Stones: These are composed of magnesium, ammonia and phosphate struvide stones are more common in female, mostly present in the kidney and are due to chronic infections.
• Uric acid Stones:
  Usually in men
  History of gout
  Acid Urine
  

Cystine Stones

• These are rare
• Due to inborn error of metabolism resulting in abnormal absorption of cystine or nitrine, Lysine and arginine
  

Epidemiology

• Causes significant morbidity in our society
• 12% of the population will have a kidney stone at some point in their lives
• More common in men than in women
• There is a 50% risk of developing recurrent stone within 5-10 years. Some patients have as high as 80%.
• Upper tract stones ( kidney and ureter) are more common in developed countries.
• Bladder stones are common in less developed countries.
• Climate, diet and geography are important factors.
• Kidney stone incidence is on rise – world wide. Causes:
  Increased affluence
  Increased dietary protein intake
  Increased use of refined sugar
  Decreased dietary fiber
  High consumption of animal protein
  High salt intake
  Excessive sweating
  Consumption of carbonated beverages
  Consumption of Ice Tea
  

Clinical Presentation

Even though many patients may have kidney stones, they experience no symptoms, no pain and the diagnosis of stone is made incidently on routine examination such as x-rays, ultrasounds for evaluation of other symptoms. Many of these stones are small and are in the kidneys producing no obstruction to the flow of urine.
However, when the same stone moves and causes obstruction to the flow of urine either in the kidne, at the junction of ureter with renal pelvis or the ureter, it causes severe pain called renal colic. There are several locations where stones can get stuck:

• Renal calyx
• Renal pelvis
• Uretero-pelvic junction
• Upper ureter
• Ureter near the pelvic brim
• Uretero-vesical junction

Renal Colic: The vast majority of patients with kidney stones present with acute onset of pain due to acute obstruction and distention of the ureter and renal pelvis. The severity and location of the pain can vary from patient to patient due to stone size, stone location, degree of obstruction and onset of obstruction. The pain frequently is abrupt in onset and severe associated with nausea and vomiting. Usually the pain begins in the area of the flank, courses laterally around the abdomen, and generally radiates to the area of the groin and testicle in the male or to the labia in the female. Other associated symptoms:

• Nausea and vomiting
• Ileus
• Urinary frequency, urgency
• Blood in the urine
• Fever
  

Physical Examination

• Patients are very uncomfortable
• High pulse rate
• High blood pressure
• Deep tenderness

Urinalysis

• Gross or microscopic hematuria
• In some cases – crystals on microscopic examination

Radiological Evaluation

• Plain abdominal film: More than 90% of stones within the urinary tract are radioopaque and can easily be seen in a plain film.
• Spiral CT:
  Currently the preferred diagnostic tool
  In this study, cross sections pictures of the body are taken without any injections
  Very sensitive to detect even a small stone
• Intravenous Pyelogram (IVP): In this study, contrast dye is given through the veins and x-rays pictures are taken as the dye is filtered by the kidneys and excreted in the urine
• Renal Ultrasound: This study is particularly helpful in pregnant women with kidney stones
• Nuclear Scan: This study is helpful in determining the function of the kidney
  

Treatment of Kidney Stones

Most stones pass spontaneously and require only supportive treatment. In about 80% of cases, kidney stones are small enough to pass during urination. The best treatment for these stones is to drink plenty of water and stay physically active and wait. Pain medications may be prescribed to help with the pain associated with passing a stone. The chance of passing a stone is largely related to stone size, location and type. After the diagnosis is made, our doctors will discuss the treatment options with you. Surgical intervention is usually indicated for persistent pain, presence of infection or sepsis, large stone size where spontaneous stone passage is unlikely.

Until 25 years ago, open surgery was the only way to remove a kidney stone, upper or mid ureteral stone. For small lower ureteral stones, cystoscopy with stone basketing was the procedure of choice. All these procedures were associated with significant morbidities. Today, treatment for kidney stones has greatly improved using less invasive techniques.

Extracorporeal Shockwave Lithotropsy (ESWL)

• The introduction of ESWL in the early 1980s revolutionized the management of patients with kidney stones.
• ESWL is the only truly non-invasive treatment for kidney stones.
• Successful ESWL require; shock wave generation, focusing, coupling and stone localization

Contraindications for ESWL

• Pregnancy
• Uncontrolled coagulopathy
• Patients on blood thinners
• Patients with cystine stone
  

ESWL involved the administration of a series of shock waves to the stone. The shock waves are generated by a machine, are then focused onto the stone. The shock waves travel through the body, raching the stone where they break it into small fragments like sand particles. For several weeks after the treatment, these small fragments come out in the urine.

If your stone is larger or you have multiple stones, you may require repeat treatment. Sometimes, if you have a stone impacted in the upper or mid ureter, we may do a procedure to unblock the ureter and place a double J stent prior to ESWL.

Before your procedure:

• Procedure will be done as an outpatient; either in the hospital or at the Surgery Center
• If yYou will need Pre-operative Testing (EKG, chest x-ray and blood work). Hospital will call you to arrange this
• Please do not take any blood thinning medications for 7 days prior to your scheduled surgery date. These medications include Aspirin, Coumadin, Plavix, Percentine. Lovenox, Vitamin E, Motrin, Ibuprofen, Advil.Please contact our office if you are unsure about which medications to stop prior to surgery. Do not stop any medication, without contacting the prescribing doctor to get their approval.
• Please take some mild laxative for few days prior to surgery date and night before take a Fleet’s enema.
  

Preoperative Instructions:

• The night before surgery, eat a light supper. Nothing to eat or drink after midnight
• The anesthesiologist will see you on the day of surgery to discuss your anesthesia
• Please arrive 2 hours before surgery
• Bring your driver’s license and your insurance cards with you
• Wear loose-fitting clothes and comfortable shoes.
• Leave all valuables and Jewelry at home
• Be sure you have made arrangements with a responsible person – family member for your ride home
  

The Procedure:

• Procedure will be done under mild to general anesthesia
• There are no incisions
• X-rays are used to see the stone and monitor the breakage of stone
• We may insert a double J stent or remove the stent if it was inserted in the past

What to expect after the procedure:

• You will be transferred to recovery room and once your vital signs are stable, you will be sent home with your family members.
• Please drink plenty of fluids, this will help pass stone fragments
• Most patients will experience some degree of discomfort for a day or two after ESWL. The pain is described as a dull ache over the kidney.
• It is normal to see some blood in the kidney for several weeks.
• You may notice some bruising in the flank.
• Please call our office to make an appointment to see us in 2-3 weeks. We will perform an x-ray to determine if stone broke up into small pieces and if these small pieces have passed out of the kidney. If the stone fragments are still present, we will repeat x-rays. You may need either repeat ESWL or other treatment modalities.
• If all fragments have passed, we will arrange for you to have your double J stent removed.
• Don’t forget, after 3 months you should be seen in our office for diagnostic evaluation to know why you form kidney stones.
  

When to call us?

Although ESWL is a safe non-invasive treatment, adverse events, although rare, can happen. You should contact us if :

• Persistent pain
• Persistent blood or clots in the urine
• Fever
  

Kidney Stones During Pregnancy

• Incidence 1:1500
• More common in multiparous
• Pregnancy by itself does not predispose to calculi
• The diagnosis and treatment – very difficult
• Ultrasound examination is the investigation of choice and x-rays should be avoided
• First trimester is the most significant period as the risk of fetal malformation and spontaneous abortion is significant following radiation exposure
• The goal of the therapy to do the least (observation or simple double-j stent placement)
• ESWL is contraindicated
• In exceptional circumstances, one may consider ureteroscopy with laser lithotripsy or percutaneous nephrostomy
  

Ureteroscopy and Laser Lithotripsy

Up until 25 years ago, open surgery was the sole form of treatment for renal and ureteral stones. Non-invasive surgery at that time meant cystoscopy with retrieva of stone with the help of a basket. The development of ESWL provided a truly non-invasive therapy for all urinary calculi. ESWL displayed good success rate in treating both renal and ureteral stones with minimum morbidity.

While ESWL became the first line of treatment option for all ureteral calculi. Semirigid and flexible ureteroscope miniaturized using fiberoptic image and light were introduced in the late 1980s. During the same period the pulsed dye laser for fragmentation of ureteral stone were introduced. Significant advances in laser fiber power generation system and ureteroscopy have propelled Laser Lithotripsy as the treatment of choice for fragmentation of most ureteral stones.

Before your procedure:

• Procedure will be done as an outpatient; either in the hospital or at a Surgery Center
• You may need Pre-operative Testing (EKG, chest x-ray and blood work), the Hospital will call you to arrange this
• Please do not take any blood thinning medications for 7 days prior to your scheduled surgery date. These medications include Aspirin, Coumadin, Plavix, Percentine. Lovenox, Vitamin E, Motrin, Ibuprofen, Advil.Please contact our office if you are unsure about which medications to stop prior to surgery. Do not stop any medication, without contacting the prescribing doctor to get their approval.
• Please take some mild laxative for few days prior to surgery date and night before take a Fleet’s enema.
  

The Procedure:

• Procedure will be done general anesthesia
• There are no incisions and it is minimally invasive
• X-rays are used to see the stone and monitor the breakage of stone
• The instrument, ureteroscopy is passed through the urethra, into the bladder and then up into the ureter until we see the stone in the ureter. Laser fiber is then introduced through the ureteroscopy and the stone is fragmented. On a rare occasion we might use a basket to retrive a large stone fragment
• The passage of ureteroscope may result in swelling of the ureter. Therefore, it may be necessary to leave a small tube called a double J stent, inside the ureterr. This stent also helps promote passage of stone fragments.
• Procedure usually lasts less than 20 minutes
• You will be given a prescription for pain killer and antibiotic
  

What to expect after your procedure:

• You can expect to have some pain that may require pain killers for few days
• Expect some blood in the urine
• You may have discomfort from the stent
• You may resume all normal activities after 1-2 days
• Drink plenty of fluids
• Please call our office to make a follow-up appointment
• We will do x-rays to make sure all stone fragments have passed. Then we will arrange for you to have stent removed in the office
  

When to call us?

Although ureteroscopy and laser lithotripsy is a minimally invasive procedure, adverse events, although rare can happen. You should contact us if:

• Persistent pain
• Persistent blood or clots in the urine
• Fever
  

PERCUTANEOUS NEPHROLITHOTOMY

• Invasive procedure
• Indicated for large stones within the kidney
  

Before your procedure:

• Procedure will be done as an outpatient; either in the hospital of your choice or at the Surgery Center
• You will need Pre-operative Testing (EKG, chest x-ray and blood work). Hospital will call you to arrange this
• Please do not take any blood thinning medications for 7 days prior to your scheduled surgery date. These medications include Aspirin, Coumadin, Plavix, Percentine. Lovenox, Vitamin E, Motrin, Ibuprofen, Advil.Please contact our office if you are unsure about which medications to stop prior to surgery. Do not stop any medication, without contacting the prescribing doctor to get their approval.
• Please take some mild laxative for few days prior to surgery date and night before take a Fleet’s enema.
  

The procedure:

• Outpatient procedure, but some times patients are admitted for a day or two
• Cystoscopy is performed to place an ureteral catheter in the kidney, to inject contrast to visualize the interior of kidney containing the stone and also to prevent stone fragments to go down into the ureter.
• Patients lay face down on a special table.
• X-rays are used to monitor the procedure.
• A small needle is passed into the kidney
• A series of guide wire and dilators are then used to dilate the tract created by the needle.
• A plastic tube is placed to maintain the tract.
• Through this tract, an instrument similar to cystoscope is placed to see the stone.
• Stone is then broken up with an instrument call ultrasonic or pneumatic (aircharged) or Laser Lithotripsy.
• Stone fragments are then irrigated out.
• At the end of the procedure, a soft tube is left in the kidney through the tract.
• We place a double J stent through the bladder into the kidney.

What to expect after the procedure:

• Once you are stable, you will be discharged under care of your family
• You may have some pain. Please take pain pills as prescribed.
• Please take all your medications as prescribed.
• Please drink plenty of fluids.
• Take it easy 2-3 weeks
• No driving or going to work for 2-3 weeks.
• Call our office to make a follow-up appointment for removal of nephrostomy tube and double-j stent.
• Please pay attention to nephrostomy tube. Check on a daily basis to make sure the tube is draining urine into the bag and tube is not kinked.
• Tube is securely anchored to the skin with tape.
• Keep the urinary bag secured by straps to your thigh
• Clean the skin around the tube, place some antibiotics and apply dressing and tape.
  

When to call us?

• Persistent pain or increasing pain
• Large amount of blood in the urine
• Excessive bleeding near the tube
• Fever and chills
• No urine in the urinary bag
• Urine leaking around the tube
  

PREVENTION OF KIDNEY STONES

If you had one kidney stone, you have 50% chance of forming another stone. However, if you have had more than one kidney stone you have more than 80% chance of forming recurrent stones. There prevention is very important. There are 3 steps to prevention:

• Metabolic evaluation
• Medications
• Lifestyle changes
  

Metabolic evaluation:

• Stone analysis
• Blood test for calcium, phosphorous, uric acid, creatinine, total protein
• Urinalysis, culture, fasting pH
• 24 hours urine collection for stone risk profile which includes
• Calcium
• Phosphorous
• Uric acid
• Oxalate
• Citrate
• Sodium
• Magnesium
  

Medical Management

• Thiazide
  Indications – Hypercalciuria
  Dose – 50 mg twice a day
  Side effects – mild
• Allopurinol
  Indications – Uric acid stones and calcium oxalate stones
  Dose – 100 mg three times a day or 300 mg once a day
  Side effects – mild
• Citrate
  Indications – Calcium oxalate stone and hypocitriuria
  Dose – Pottasium citrate 60 mEg/day
  Side effects – mild
• Cellulose phosphate
  Indications – Calcium oxalate stone. Binds calcium in the intestines and inhibits calcium absorption
  Dose – 5 gm three times a day with meal
  Side effects – mild
• Acetohydroxanic acid
  Indications – Infected kidney stones
  Dose – 250 mg three times a day
  Side effects – mild
• Penicillamine
  Indications – Cystine stones
  Dose – 250 mg three times a day
  Side effects – mild
• Theola
  Indications – Cystine stones
  Dose – 200 mg three times a day
  Side effects – mild
• Orthophostate
  Indications – Calcium oxalate stone
  Dose – 2 gm daily
  Side effects – mild
• Magenesium oxide
  Indications – Calcium oxalate stones
  Dose – 1 gm daily
  Side effects – mild
  

Lifestyle Changes

• Water – A simple and most important lifestyle change to prevent kidney stone is to drink plenty of water. 8-12 oz every hour while you are awake.
• Diet
• Limit daily meat intake
• Limit dairy products
• Avoid antacids with calcium base
• Limit salt intake (avoid table salt, processed and canned food)
• Avoid access Vitamin C & D
• Eat plenty of bran, fiber rich food (low fat, high fiber diet)
• Avoid fried and processed food
• Limit or avoid beets, chocolate, coffee, cola, nuts, rhubarb, spinach, strawberries, ice tea, scallops and mussels
• Enjoy lemonade and orange juice

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