Urinary Stones: Key Points

Transcription

1 Urinary Stones: Key Points Don Griffith, MD Professor, Baylor; Dept of Urology Micheal E DeBakey VAMC, Houston USNR Flight Surgeon CVA-66 USS America Vietnam Era Both Stones are CaOx 1H20 Why Difference? Reason for Grow Patterns Unknown

2 Solubility of Substances Concentration of substance [solute], i.e. grmg/100ml or mg/liter [1000ml] ph--i.e. Degree of acidiity or alkalinity Temperature Saturation = Max quantity of substance soluble in 100ml of water [urine]; Kidney can excrete super-saturated urine

3 Principal Composition & Causes 1] Calcium Phosphate: [supersaturation, alkalinity induced]=1st crystal * of many calcium oxalate stones] ---CaHPO4=brushite=>initial crystal ---Ca10[PO4]6[OH]2=hydroxy-apatite=>stable crystal ---Ca10[PO4]CO3=carbonate-apatite=>infection induced 2] Magnesium Ammonium Phosphate MgNH4PO4=>infection induced [urease + microbes, i.e. Proteus, Pseudomonas, Klebsiella] 3] Calcium Oxalate: 1H20 or 2H2O: 1H20=hard, stable; epitaxy=growth on CaHPO4 crystal. 4] Uric Acid: Excessive Protein + Acidity of Urine 5] Cystine: Genetic=> [Excesss Cystine (amino acid) in urine

4 Preventive Steps To Slow Recurrence 1] Calcium Phosphate: Calcium Conc & ph 2] MgNH4PO4 : Eliminate Stone; Eliminate Infection 3] CaOx: Ur-Ca & Ur-Ox & Urine vol.+ Citrate 4] Uric Acid: Uric Acid in Urine by Protein diet + ph of urine w/ K-Citrate & of allopurinol-a drug 5] Cystine: Complex cystine w/ to increase solubility

5 Stone Risk --Serum: Calcium, Parathyroid Hormone. Lytes Hyper-parathyroid Elevation Renal Tubular Acidosis; i.e. systemic acidosis --24 hour Stone Risk Profile CPRS=OP orders/ Stone Risk /calculous CPR=OP orders/ Stone Risk /Urine Volume, Calcium [<300mg/day], Uric Acid [<700mg/day], ph, Citrate

6 Calcium Oxalate Monohydrate Calcium Oxalate presents in many forms and colors.

7 Crystallogrphic Analysis in Action

8 Crystallographic Stone Analysis--Most Accurate ID --Polarized light passes in straight line. --Stone crystals bend light; the degree of bending identifies the crystal. Multiple crytals create different colors; rainbows are created by water droplets. --isotropic=only one crystal present --bi-refringent [colored image]=multiple crystals

9 Calcium Oxalate Monohydrate Crystallographic Analysis

10 CaOx 1H20

11 Ammonium Acid Urate [Uncommon Variant] of Uric Acid Metabolism Urate stones may present in certain disease & diet conditions

12 Xanthine Rare Variant of Uric Acid Metabolism Xanthine stones in man is a hereditary condition that may eventually lead to kidney failure

13 Calcium Oxalate Nidus w/ External Struvite Infection-induced Shell Urinary colonization by Proteus, Pseudomonas, or Klebsiella grow stone on existine foreign body--i.e. CaOx stone. Ca Ox Nidus MgNH4PO4 Shell

14 Calcium Oxalate Monohydrate Calcium Oxalate and Ammonium Acid Urate may occasionally occur as a 'Jack' Stone

15 Calcium Oxalate Dihydrate Calcium Oxalate Dihydrate is also a common stone composition and often appears 'flowerlike'

16 Artifact nidus (Bullet or Hair) Any foreign body [bullet, suture, hair, etc in urine triggers stone formation Bullet Nidus of bladder Stone Pubic Hair Nidus of bladder Stone; Patient intermittently Self-catheterized

17 Surveillance Candidates No Immediate Rx Needed Nephro-calcinosis--i.e. Punctate Ca++ throughout kidney Lower Pole [only] stones: SWL will pulverize stone but sand held by gravity in lower pole. Stones invisible on KUB radiograph-> commonly <5mm dia. Ureteral stones <5mm dia. These pass spontaneously in 80+% of cases; Females w/ phx of pregnancy pass 4+mm stones as pregnancy dilates ureters; L>R

18 Preventive Rx CaHPO4 & CaOx: Hydroclorthiazide + K-Citrate + modest Calcium intake MgNH4PO4: Eliminate Bacteria + Stones Uric Acid: Allopurinol 300mg qd, + Urine alkaline urine [potassium citrate?]=> Succesful Dissolution Cystine: / D-penicillamine, or Alpha-MPG or Captopril

19 Flexsible Ureteroscopic Laser Lithotripsy --Uretero-scopic laser framentation --Stones <1.5cm dia. -->1.5 cm stone-> stented 1st. --Shockwave lithotripsy [SWL]-> After stent placment in some patients.

20 Ureteroscopic Video

21 Extracorporeal Shockwave Lithotripsy [ESWL] Water & Human cells have same density; Pressure waves generated in water pass through human cells without damage. Same wave accelerates in stones --causing fragmentation/pulverization. ESWL=>Very Effective for Renal Stones <2cm dia. Large stones create much debris and leave large fragments.

22 Percutanous Nephrostolithotomy --Stones >2.0cm dia. --Multiple large stones --Multiple punctures? --Electrohydralic, Laser & electromechanical fragmentation --Ureteral Stent + Neprostomy in situ postop --Multiple procedures? --General anesthesia Cysto + Retrograde catheter w/ patient prone. Needle + guide-wire puncture in flank near 12 rib. Track dilated with balloons + sheath.

23 PCNL Video

24 Questions? Thank you for your Attention

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29 The Properties of Refracted Light Light moving through a vacuum moves at a constant speed and in a straight path. If we allow light to pass through any object, it may go in a different path or paths and at a different velocity. We can measure the refracted light paths of a crystal and identify it by these unique optical properties.

30 Definitions: Index of Refraction: The definition of how far a light path is refracted from its original path when passing through a crystal. A straight line has an index of 1.0. Indices of refraction will be a number above 1.0, such as 1.53, which is the most commonly used oil of refraction used in the identification of crystalline material using a petrographic microscope. Isotropic: This is a crystal that has only one index of refraction. All light passing through isotropic material is sent off in only one direction and will not show 'color' under the microscope. Birefrigent: This is a crystal with two indices of refraction. Light is sent off in two different directions when passed through this material. Extinction: If a birefringent crystal is rotated on the stage of a petrographic microscope, it will 'black out' when its optical axis aligns with the microscope polarizers. This will happen every 90 degrees of the microscope stage rotation. Complete rotation of the microscope stage will show extinction twice for each axis.

31 Becky's Line: The 'halo' of light that appears around a crystal and moves in and out of the crystals edge as you focus up and down on the microscope. Relief: A crystal that may be barely visible on the microscope, almost like a 'ghost' is a material with LOW relief. Some crystals are very visible with dark lines and vivid features have HIGH relief. Relief is a function of the difference between the indices of the specimen and the refractive oil it is viewed in. Size or thickness of the crystals do not change the relief. Relative Birefringence: All birerefringent minerals refract light in two directions. The numerical difference between the two indices of refraction will be their Relative Birefringence. If material # 1 has indices of 1.02 and 1.04, their birefringence is very low. If material #2 has indices of 1.02 and 1.99, their birefringence is very high. Size and thickness of the crystal will change the look of Relative Birefringence comparatively in the microscope.

32 Order of Color: Most birefringent crystals will show colors when viewed through crossed polarizers. The relative birefringence will determine if these are very pale pastel colors (first order/low birefringence) or very brilliant prisms of 'electric' colors. (fourth order/high birefringence)

33 Example of Becky s Line (Halo of Light)

34 Images of the same photographs using a petrographic microscope First picture uses a quartz plate Second picture uses dark field Third picture is in plain light All are necessary for proper identification of crystalline material Note the difference in 'relief' under plain light

35 Calcium Oxalate Monohydrate

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38 Brushite

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41 Struvite

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44 Cystine

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47 Calcium Oxalate Dihydrate

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50 Ammonium Acid Urate

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53 Uric Acid

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56 Triamterene

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59 Brushite K+MgPyrophosphatePentahydrate Identical except for Becky's Line The indices are opposite

60 Transition of Brushite to Ca Apatite over time due to ph change. (6% Calcium Oxalate Monohydrate is also seen)

61 Analysis in Action (Nell Anderson)

62 Refractive oil index value used for identification is 1.53 Calcium Oxalate Monohydrate Calcium Oxalate Dihydrate Struvite Calcium Apatite (Isotropic) Brushite Uric Acid Cystine Sodium Urate Hydrate Ammonium Acid Urate Indice values are uncertain due to the minute crystal size