Dr. Sanjeev Mehta MDDr. Sanjeev Mehta MD

Ahmedabad, INDIAAhmedabad, INDIAwww.urolab.net

Metabolic Evaluation&Stone Analysis

Practical implications

Role of laboratory

• What lab can not tell you, you will not know.• What it tells you in error, you will not

correct by using your instincts, your medical experience or your art.

• Misdirected treatment : unreasonable expenses.

• The Kidney Stone Handbook; Gail Savitz & co auth.

Stone : Supersaturation of Urine

Stone Promoting and Inhibiting Factors

PROMOTORS INHIBITORS

Calcium Inorganic : Magnesium

Sodium Phosphorus

Oxalate Citrate

Urate Organic : Nephrocalcin

Cystine Tomm-Horsfall Protein

Low Urine Ph Urinary Prothrombin fragment.

Tomm-Horsfall Protein

Bacterial products

Evaluation of Stone Disease

ROUTINE BLOOD AND URINE TESTSSTONE ANALYSIS.24 HRS URINE METABOLIC PROFILE

New advances in Stone analysis, Blood and Urinary Chemical analysis can find out 90-95% cause.

Clinical usefulness

1.Identify treatable metabolic abnormality2.Identify underlying medical disease that

predisposes to stone formation.3.Outline a treatment plan.

A. Routine Tests

BLOOD low K, and HCO3- RTA High Uric acid - Uric acid

diathesisHigh Calcium- pri

hyperparathyroidism Low phosphorus- renal

phosphorus leak. Parathyroid ; sos

URINEpH > 7.5 – infection

lithiasis pH < 5.5 – Uric acid lithiasisSediments for crystalluriaUrine cultureQualitative cystine

Renal Stone Analysis

• Essential step in the examination and initial treatment of Urolithiasis.

• Yields fundamental information about ;- Metabolic abnormality.- Presence of infection.- Possible artifacts.- Drug metabolism.

Technique

Integrated analysis with Infra-red spectrometryXenthene and Ca.oxalate Dihydrite

INTEGRETED ANALYSIS ;Mixed Stone

11

Actually up to 65 different chemical compounds are found in urinary calculi.

Clinical significance of Stone analysis• Three categories :1.Composition and hardness of Renal

Stones.2.Composition and its predictive value.3.Composition and related metabolic

abnormalities. Kourambas J, Aslan P, Teh CL, Mathias BJ, Preminger GM.J Endourol. 2001

Mar;15(2):181-6

Clinical Significance: Hardness pattern in Stone.• Useful in describing consistency in individual.• Formulation of treatment strategies. - Number of re-treatments. - Number of Shock waves. • Energy index (KV x number of shock waves).

Ringdén I, Tiselius HG, Scand J Urol Nephrol. 2007;41(4):316-23

Hardness Factor of Stone

Calcium Oxalate Dihydrate 1.0Calcium Oxalate Monohydrate 1.3Hydroxy-peptite 1.1Brushite 2.2Uric Acid/ Urate 1.0Cystine 2.4Carbonate Apatite 1.3Struvite 1.0Mixed Stone 1.0* Ringden I, Scand J Urol Nephrol.2007;41(4):316-23

Clinical value : Calcium

• Present in approximately 80% stones.• Combines with phosphate or oxalate or both.• Risk factors : hypercalciuria, Hyperoxaluria. hyperuricosuria. predominantly acid or alk urine. hypocitraturia. low urine volume.

Calcium Stones …..

Pure calcium Stones

• More Acid urine• Low Urine volume• High Oxalate

excretion

Mixed Stone formers

• pH is higher• High Calcium • High Calcium

excretion• High recurrence rate

* Schroeppel j Smith et all ; J Am Soc Nephrol 1997;8:568A

Calcium Stone…..

Ca-oxalate Monohydrate

• Hypo- megnesuria• Acidic Urine• Low Urine volume• Hardness +

• Ca-ox Dihydrate

• Hyper-calciuria• Alkaline Urine• Hypo-citraturia• Hardness ; less

Renal tubular acidosis

Carbonate apattite

• Consider RTA• Increases with amount • (5-39%)

Brushite Stones

• Consider RTA

Struvite Stone Magnesium Ammonium Phosphate

• Mixed Stone : Infection. ‘Proteus’ • Strains of staphylococci, pseudomonas and

kelbsiella. • Rarely; E.coli.• Urine Ph. Is < 7.5

Ammonium Urate

• Calcium oxalate – containing calculi, may start hyperuricosuria.

• Elders : associated with infection.• Children : May as result of hyperuricosuria,

but No UTI

Brushite : Amm. Calcium Phosphate

• Sizable stone burden. Increasing trend • High recurrence rate , 3 yrs• Familial tendency• Hypercalciurea and underlying metabolic

abnormality. • Extreme Alkaline Urine.

J Urol. Oct 2010; 184(4): 1367–1371.

Dahilite ( Carbonate apatite)

• Phosphate stone• Infection in body.• May not accompanying sign of disease.• RTA• Disorder of phosphate metabolism. • Rare in pure form ( 2-3%).

Uric Acid

URIC ACID• Hyperuricemia, hyperuricosuria.• Low Urine Ph. < 6.2• Causes: - Gout. - Myeloproliferative dis. - Chemotherapy and Radiotherapy.

Cystine

CYSTINE• Cysteinuria.• Autosomal recessive

disorder.• Occurs predominantly

in pure form.

• XENTHENE Most frequent causes:- Xanthinuria. - Absence of Xanthene

oxidase.• Genetic autosomal

hereditary recessive enzyme disorder.

• Trigger : Allopurinol Treating Gout.

Urine: Metabolic Evaluation24 hrs Urine collections: multiple parameters Stone risk factors : Quantitation Volume and pH Calcium Oxalate Citrate Uric acid. Creatinine

Metabolic Evaluation: 24 hrs Urine

• Dietary risk factors: Sodium, Potassium Magnesium Urinary analysts : phosphorus, sulphate, Urea Children : state sample Repeat 24 hrs Urine collection 4-6 weeks post

interventi

GOLD STANDARDSupersaturation value.

•High risk parameter can be monitored.

Graphic presentation

Super-saturation : Gold standard….

Conclusion

• Advancement in laboratory can now diagnose cause of stone formation uo tp 90% cases.

• By appropriate Stone analysis and metabolic

evaluation can effectively treat impact of Nephrolithiasis and prevent recurrence .

Conclusion: Significance

• Advancement in laboratory can diagnise cause of Stone disease up to 90%

• Impact mitigated by appropriate metabolic evaluation.

• Identify risk factor.• Focused medical treatment • Significantly reduces recurrence• Social and financial burden. • Batter quality of life

Thank you !

For further details contact:

sanjeev@urolab.net

Phone: +91 79 40380380