Urinary Lithiasis 

Noon conference January 19, 2014
Marc S. Curvin, MD, MS BME


Calculi in the Calyxes of the Right Kidney

Some History

    Urinary stones have afflicted humans since the dawn of history and are among the oldest of known human maladies. 

4500-5000 B.C.

    The first known stones were discovered in Egyptian mummies. In 1901, the English Archeologist E. Smith found a bladder stone from a 4500-5000 year old mummy in El Amrah, Egypt. Treatments for stones were mentioned in ancient Egyptian medical writings as far back as 1500 B.C.

First Treatments: 1500 B.C.

8th Century B.C.

    Surgery to treat stones was first described in the 8th century B.C. by an ancient Indian surgeon named Sushruta. He provided detailed information on urinary stones, urinary anatomy, and surgery for stones in his writings, compiled as the Sushruta Samhita.

A statue dedicated to Sushruta at the Patanjali Yogpeeth institute in Haridwar.
The sign dubs Sushruta as the "founding father of surgery", and identifies the Sushrut Samhita as "the best and outstanding commentary on Medical Science of Surgery".

4th Century B.C.

Hippocrates specifically mentioned stones in the Hipprocratic Oath. The quote: 

“I will not use the knife, not even on sufferers from stone, but will withdraw in favor of such men as are engaged in this work.”

Most historians feel that this statement was a warning that physicians should refrain from participating in surgery, which was considered dangerous. At that time, and for many subsequent centuries, surgery was instead performed by barber/surgeons who were not considered physicians.

Urinary Stones in the Middle Ages

In the middle ages, surgeons called “lithotomists” traveled around Europe with their special tables called “lithotomy tables” on which they placed patients to cut out stones. We still use the term “lithotomy position” in the operating room today. The patients these lithotomists treated were typically men with bladder stones from enlarged prostates rather than actual kidney stones.

Lithotomy Table

The patient would lie face up with their buttocks positioned at the end of the operating table. The hips and knees were fully bent and the feet were locked in position using a crutch.

Lithotomy Crutch

This device was used to hold a patient in position during a horrific lithotomy operation. Sadly, this
 example was invented by Joseph Clover (1825-1885), a surgeon and anaesthetist who became an expert at lithotomy procedures.

Double Bladed Bistoury Cache (16th century)
In French, bistoury caché translates as ‘hidden knife.’ The device was used to cut internal organs or to open cavities, particularly during the surgical removal of a bladder or kidney stone.

Tableau of a Lithotomy

Some 250 years ago a French composer, Marin Marais, wrote - to the best of our knowledge - the only musical description of a surgical operation, he called it "Tableau of a Lithotomy".

Surgery in the middle ages occurred, of course, in the absence of anesthesia or antibiotics and many men chose instead to not undergo treatment for their stones. The number of patients who died from their lithotomy surgery was frighteningly high and lithotomists were known to leave town quickly if things went badly - which was usually the case. The surgeries were so fraught with danger and pain that Jan de Doot, a Dutch blacksmith, was said to have performed a surgery on himself to remove a bladder stone. A painting from 1655 by Carel de Savoyen depicts Doot, holding his knife and bladder stone. His approach was to make an incision below the scrotum directly into the bladder, find the stone, and extract it. He had his brother help him in the surgery by holding his scrotum aside. de Doot apparently had already experienced two of these surgeries by lithotomists before performing his third “diy” surgery. 

Jan de Doot

Modern Urinary Stone Surgery

Modern stone surgery was developed in the last half century. In 1976, the first percutaneous stone surgery was performed by Fernstrom and Johansson.

ESWL (shockwave lithotripsy) was developed out of early research on the effect of shockwaves on aircraft parts by the German company Dornier. This was further developed for the treatment of stones in the first human procedure occurring in 1980. The Dornier HM-3  (which stood for human model-3) required the use of a water bath and an elaborate overhead gurney to position patients. Nowadays, ESWL machines instead use fluid filled “balloons” and gel placed against the patient’s body to allow transmission of shockwaves for treatment. 

Modern ESWL

Ureteroscopy, or the placement of a lens into the ureter was first described in 1912 by Hugh Hampton Young but the first ureteroscopic stone surgery did not occur until 1981.

So What is a Kidney Stone ?

A kidney stone, also known as a renal calculus (from the Latin rēnēs, "kidneys," and calculus, "pebble"), is a solid concretion or crystal aggregation formed in the kidneys from dietary minerals in the urine.

Urinary stones are typically classified by their location: 
- Kidney (nephrolithiasis)
- Ureter (ureterolithiasis)
- Bladder (cystolithiasis) 

Or by their chemical composition:
- calcium-containing
- struvite
- uric acid
- other compounds we will discuss 

A Calcium Oxalate Kidney Stone

Signs and symptoms

Hallmark of stones that obstruct the ureter or renal pelvis:
- excruciating, intermittent pain 
- *radiates from flank to groin or genital area / inner thigh 
- urgency
- restlessness
- hematuria
- sweating
- nausea and emesis

It typically comes in waves lasting 20 to 60 minutes caused by peristaltic contractions of the ureter as it attempts to expel the stone.

- "Renal colic" - among worst pain sensations known. 

- Complications of obstruction:
- postrenal azotemia 
- hydronephrosis 

* Pain in the LLQ can mimic diverticulitis 
- The sigmoid colon overlaps the ureter making it difficult to isolate the pain.

* The embryological link between the urinary tract, the genital system, and the gastrointestinal tract is the basis of the radiation of pain to the perineum and the nausea and vomiting that are also common in urolithiasis. 

Diagnosis of Kidney Stones

- H&P, UA
- Radiological studies
- Location, severity and timing of pain.

Bilateral kidney stones can be seen on this KUB radiograph. Phleboliths seen in the pelvis can be misinterpreted as bladder stones.

Axial CT scan of abdomen without contrast, showing a 3-mm stone (marked by an arrow) in the left proximal ureter.

A stone at the ureteral vesicular junction (UVJ).

Lab Studies

UA: RBC, bacteria, leukocytes, urinary casts, crystals.
UCx: Identify infecting organisms (struvite stones)
CBC: neutrophilia - suggestive of infection
BMP: Renal function, hypercalcemia
24 hour urine collection
- daily volume
- Mg
- Na
- Uric acid
- Calcium
- Citrate
- Oxalate
- Phosphate
- Collection of passing stones
- Analysis of stones for composition

Management of Kidney Stones

~ 98% of stones < 5 mm pass spontaneously 
~ 56% of stones 5 - 10 mm pass spontaneously
~ 53% of larger stones require other interventions

Stone location influences the likelihood of spontaneous passage. 

48% of stones located in the proximal ureter 
~ 79% at the vesicoureteric junction
-- these spontaneously pass regardless of size 
-- with mild sx meds to increase flow are sufficient

- Repeat offenders need more intense management:
-- proper fluid intake 
-- certain medications


- Intravenous administration of NSAIDs or opioids. 
- Oral meds for less severe discomfort.

Expulsion Therapy

- Meds to speed the spontaneous passage of calculi.
- alpha adrenergic blockers (ex tamsulosin) 
- CCBs (ex. nifedipine)
- tamsulosin + corticosteroid may be better than tamsulosin alone 
- These tx are also a useful adjunct to lithotripsy.


ESWL - Extracorporeal shock wave lithotripsy.

- External high-intensity US frag stone in 30–60 minutes. 

- Usu used when the stone is near the renal pelvis. 

- 80% of simple renal calculi can be tx with ESWL.

- Following its introduction in United States in February 1984, ESWL was rapidly and widely accepted as a treatment alternative for renal and ureteral stones.

- It is currently used in the treatment of uncomplicated stones located in the kidney and upper ureter, provided the aggregate stone burden (stone size and number) is less than 20 mm and the renal anatomy is NL.

- If stone is > 10 mm 2-3 treatments may be needed.

Factors Influencing ESWL Efficacy

- chemical composition of the stone
- anomalous renal anatomy 
- location within the kidney
- presence of hydronephrosis
- Distance of the stone from the surface of the skin.

Side Effects of ESWL

- Bruising at the site of shock administration
- Damage to renal blood vessels of the kidney
- Majority of pts have some degree of kidney injury
- Injury is dose-dependent 
- Worst: internal bleeding & subcapsular hematomas. 
- transfusions and ARF occur but rarely.
- somewhat technique and machine dependent
- scar formation may result in loss of renal volume

- AUA established the ESWL Task Force to address.
- 2009 concluded risk/benefit ratio favorable for many.

Advantages of ESWL

- Noninvasive nature
- Easy to treat most upper urinary tract calculi
- Generally well-tolerated, low-morbidity for most.


- Again, most stones under 5 mm pass spontaneously.

Surgery required generally required in pts with:

1. Only one working kidney
2. Bilateral obstructing stones
3. Presence of UTI (an infected kidney)
4. Intractable pain.

Mid-1980s: Surgery begun to be replaced by:

- Ureteroscopy 
- Percutaneous nephrolithotomy (large or complicated)


Flexible ureteroscopy - retrograde nephrostomy creation for percutaneous nephrolithotomy.

Ureteroscopic Surgery

 - Ureteroscopy has become increasingly popular
-  Driving force: smaller ureteroscopes  
-  Ex: Placement of a ureteral stent to provide immediate relief of an obstructed kidney. 

Advantages of Uteroscopy

1. Saving a K at risk for post renal ARF 2/2
- hydrostatic pressure
- swelling
- pyelonephritis 
- pyonephrosis all caused by obstruction.

2. Designed to allow urine to flow past an obstruction in the ureter and may be left in place for days or weeks.

3. Dilate the ureters facilitating instrumentation and also providing radiographic landmarks.


What are causes / risk factors for stone formation ?

    1. Low fluid volume
    2. Hypercalciuria
    3. Hyperoxaluria
    4. Hyperuricosuria
    5. Hypocitrauria
    6. Low Urine pH

How do we prevent Kidney Stones ?

1. Low fluid volume
   - increase fluid intake
   - water is the best fluid
   - goal - 2.5 liters of urine output / 24 hours
   - clear urine should be seen

2. Hyper-calci-uria

   - Thiazide diuretics (HCTZ or Chlorthalidone)
   - Keeps Ca out of urine & in your bones 
   - SE: K loss - K supplements may be needed
    - Lower Na intake 
      -- Will decrease amount of Ca2+ lost in urine
      -- lower Na also increases the eff. of thiazides
      -- goal range - 2300-3300 mg/day
      -- NL Ca2+ intake - 800-1200 mg/day 
      -- Decreasing Ca increases u. oxalate levels
      -- AND calcium oxalate stones are the MC
      -- Ca2+ & oxalate bind in the intestines for elim.
      -- If low Ca2+, oxalate is reabs & excr thru urine:(
      -- Increase water to output 2.5 liters / 24 hrs.

3. Hyper-oxal-uria

     -- Bad news - oxalate is found in healthy foods.
     -- Confusion many pts (CHF, BP, DM) already on diets
     -- "Eat a low fat diet yada yada w/ lots of veges".
     -- Cut portion size / freq & add 8oz of H2O b4 & after 
     -- Normal Ca2+ intake - binds oxalate bowel.
     -- A low Ca2+ will increase your urine oxalate level.
     -- Increase water to output 2.5 liters / 24 hrs.

4. Hyper-uricos-uria
     -- Avoid organ meats
     -- Reduce animal meats to 6-8 oz / day. 
     -- Allopurinol is prescribed if diet alone insufficient.
        - blocks conversions of purines to uric acid
        - high uric acid promotes Ca-oxalate stones 
        - Allopurinol treats gout so tx 2 problems with 1 med
     -- Lose weight - obesity increases uric acid
     -- Urine output goal is the same 2.5 L/24 yours.

5. Hypo-citra-uria
  -- Citrate - a molecule in blood & urine that binds Ca
  -- Citrate binds u. Ca2+ - decr Ca2+Ox or Ca2+Phos st.
  -- Urocit K, K-lyte, Klor-con, Polycitra K incr. citrate
  -- K citrate may - prescribed if a pt has low or normal K+
  -- K citrate is a "supplement" rather than a medication.
  -- Pts with high K+ may be rx an Na salt such as Bicitra.
  -- Restrict protein to 6-8 oz / day.
  -- Protein lowers urine citrate levels :(
  -- Increase Citrus juice intake w/ OJ or dilute lemon. 
  -- These increase urine citrate and decrease urine Ca+ 
  -- Water intake as above.

6. Low urine pH
    -- Maybe 2/2 low K+ levels
    -- Can exist in the setting of of NL K+
    -- Urocit K, K-lyte, Kloc-con, Polycitra K
    -- These increase K+ and thus pH
    -- Like antacid in stomach raising the urine pH level.
    -- If pt has high K+ may be rx'd Bictra as above
    -- Lower protein intake to raise pH
    -- Fluids as above

This is kind of complicated...or at least tedious.

Having addressed the physiology of stone formation is there a more efficient method to manage stones than attempting to run all these tests and treat stone formers ? IE: "Methods to address populations" ?

Thankfully the answer is "YES".

Several labs that will process the data and provide concise tx options.


Questions ?

Thanks !


- Ancient History of Stones: http://www.kidneystoners.org/information/history-of-stones/
- http://en.wikipedia.org/wiki/Kidney_stone
- http://thechirurgeonsapprentice.com/2011/10/04/cutting-for-the-stone-the-case-of-stephen-pollard/
- http://thechirurgeonsapprentice.com/category/casebooks/page/4/
- http://www.litholink.com/en/Home

        1. Low fluid volume
            - increase fluid intake
            - water is the best fluid
            - goal - 2.5 liters of urine output / 24 hours
            - appearance of your urine should be the same as water

        2. Hyper-calci-uria
            - Thiazide diuretics (HCTZ or Chlorthalidone)
            - Thiazide keep calcium out of the urine and in your bones (where it belongs)
            - Mechanism:            
            - SE: Potassium loss - pt may need to take potassium supplements
            - Lower Na intake 
                - this will decrease the amount of Ca2+ lost in your urine
                - lower Na also increases the efficacy of thiazide diuretics
                - goal range - 2300-3300 mg/day
            - Normal Ca2+ intake - 800-1200 mg/day from foods and calcium fortified juices
                - decreasing Ca2+ increases urine oxalate levels - calcium oxalate stones are the MC
                - Ca2+ and oxalate bind in the intestines and are eliminated normally
                - If there is insufficient Ca2+ in your body oxalate is reabsorbed and excreted thru urine :(
             - Increase water to output 2.5 liters / 24 hrs.

        3. Hyper-oxal-uria
            - The bad news is that oxalate is found in lots of healthy plant foods.
            - The confusion for many pts is that they my already be on dietary restrictions (CHF, BP, DM)
            - The pt may have been advised "eat a low fat diet yada yada but with lots of vegetables".
            - Just cut back on portion size and frequency and add 8oz of H2O b4 and after.
            - Normal Ca2+ intake - again Ca2+ and oxalate bind in the intestine.
                - A low Ca2+ will increase your urine oxalate level.
            - No matter what the dx - you should produce 2.5 liters of clear urine daily.
        4. Hyper-uricos-uria
            - Avoid organ meats
            - Reduce animal meats to 6-8 oz / day. 
            - Allopurinol is prescribed if diet alone insufficient.
                - blocks conversions of purines to uric acid
                - high uric acid content promotes calcium oxalate stone formation
                - Allopurinol works for gout so you may address 2 problems with 1 medication
            - Lose weight if you heavy - obesity contributes to uric acid buildup.
            - Urine output goal is the same 2.5 L/24 yours.

        5. Hypo-citra-uria
            - Citrate is a molecule in blood and urine that binds to calcium.
            - Citrate binds urine calcium shielding Ca2+ from binding oxalate or phosphate. 
            - Urocit K, K-lyte, Klor-con and Polycitra K increase citrate and strengthening the shield.
            - Potassium citrate may be prescribed if a pt has low or normal K+
                - Potassium citrate is considered a supplement rather than a medication.
            - Pts with high K+ may be prescribed a sodium salt such as Bicitra.
            - Restrict protein to 6-8 oz / day.
                - Protein lowers urine citrate levels promoting Ca+ oxalate / phosphate stone formation.
            - Increase Citrus juice intake with OJ or diluted lemon juice.
                - Studies indicate these increase urine citrate and decrease urine calcium.
            - Water intake as above.

        6. Low urine pH
            - Thought to be 2/2 low K+ levels but can exist in the setting of normal K+
            - Urocit K, K-lyte, Kloc-con, Polycitra K - increase K+ and thus pH as above
            - Acts like antacid in stomach raising the urine pH level
            - If you have high K+ may be rx'd Bictra as above
            - Lower protein intake to raise pH
            - Fluids as above

2. Manage elevated PSA
    - Q1 who gets bx vs who does not ?
    - DDX could be U retention vs prostatitis
    - PSA rises with age
    - a level of 4 or less is ok.
    - a level of 5 = 25% chance of prostate CA
    - PSA is organ specific and not disease specific.
    - PSA is elevated 2/2 cancer, inflammation and BPH.
    - 2.6 ng/ml - cut off for transrectal ultrasound-guided biopsy.
    - PSA increases at .04 ng/ml w/o BPH, .07 ng/ml (per year).
    - Prostate CA observation - PSA Q6 months
    - There are 2 patterns of prostate CA
        - 1. Slow and indolent
        - 2. Rapid - ex PSA 5, 7, 12, 20.

3. Manage Hematuria - h in adults = malig until proven OTW and demands immed uro examination.
    - microscopic vs gross
    - 3276 RBCs > 3 per HPF is significant - in adults it is urologic malignancy until proven OTW.
    - Q1 - gross vs microscopic ?
    - Q2 - at what time during urination does h occur ? (beginning, entire, end).
    - Q3 - is the h associated with pain ?
    - Q4 - is the pt passing clots ?
    - Q5 - if clots then are they a specific shape ?
    - The sig of gross v micro h is the chances of identifying sig pathology increase w/ degree of h.
    - The most common cause of gross h in a pt > age 50 is bladder cancer.    
    - Older women and men who present with hematuria and irritative voiding symptoms may have               cystitis secondary to infection arising in a necrotic bladder tumor or, more commonly , flat                        carcinoma in situ of the bladder.
    - Pts with micro h may have a negative workup.
    - Timing
        - initial h usu arises from the urethra (least common, usu 2/2 inflammation).
    Workup ~
    - gross 
       - cystoscopy asap b/c src can often be readily identified
       - c will determine place of origin (urethra, bladder or upper urinary tract)

    Who should not be worked up for h ~
        - young women w/ acute bacterial hemorrhagic cystitis

    Hematuria stats ~ contradict ea other:
    - 3928 Of 2000 pts in Mayo C study with asymp h 0.5% had u malignancy. 1.8% dev sig ds w/in 3 y.
    -- At U of Wisconsin 26% w / asymp h were found to have malignancy.
    - if a dipstick is used always confirm with a microscopic exam b4 ordering studies

    - Algorithms -  CC hematuria algorithm
    - Procedures - Cystoscopy
    - Patient Info - PreOp.com cystoscopy
    - Check out preOp.com in general - v nice

    - DDX for hematuria - first 5 are in order of most common.
    - calculi
    - infection
    - CA (bladder, kidney, prostate, urothelial)
    - obstruction
    - bleeding diathesis
    - anticoagulation
    - abx (rifampin [Rifadin])
    - DM
    - HTN
    - Sickle cell anemia
    - chronic renal ds
    - congenital
    - vascular malformation & aneurysms
    - artifactual
    - food (beets, berries, rhubarb)
    - food coloring
    - medications
    - menstrual blood

4. Manage Incontinence vs OAB

5. Managing males males with trouble urinating - e.g. TURP vs HOLEP

6. Manage adrenal tumors (way down the line - remember Brian manages them in off and is the expert)
    - can learn the 30s approach or the "weeks" approach

To do list:

Chapters in Campbell 9th Edition to Know: 4, 13-27, 38-40, 85-88, 96-99.
- Chs 14-19 cover infection and inflammation.

Look at pt list daily - look up all diagnoses / questions raised / treatments. Start the log.

Marc Curvin,
Jan 7, 2014, 7:52 AM