Ans. a. Cysteamine (Ref: Harrison 19/e p1868, 1871, 18/e p3221; Smith 17/e p249-254; Campbell 10th/1296-1302: Bailey 25/e p1295-1300)Patient with cystinuria with multiple renal stones should be treated with increase urine volume (high fluid intake), alkalinization of urine Penicillamine and tiopronin.Cystinuria (AR)Inheritance: Autosomal recessiveQMolecular defect: Shared dibasic cystine transporter SLC3A1, SLC7A9QTissue manifesting transport defect: Proximal renal tubule, jejunal mucosaQIndividual substrate: COLA (Cystine, Ornithine, Lysine, Arginine)QClinical features: Cystine nephrolithiasisQTreatment:Increase urine volumeQ (high fluid intake)Alkalinization of urineQPenicillamineQ and tiopronin undergoes sulfhydryl-disulphide exchange with cystine to form mixed disulphides, since these disulphides are much soluble than cystine, pharmacologic therapy can prevent and promote dissolution of calculi.In the given image, which shows enveloped or bipyramidal crystals are seen in calcium oxalate (dihydrate) stones.Calcium oxalateCalcium oxalate monohydrateBrushiteEnveloped or bipyramidalQDumbbell or hourglassQNeedle shapedQ StruviteUric acidCystineCoffin lidQMultifaceted, irregular plates or rosettesHexagonal or benzene ringQTypes of Renal CalculiCalcium oxalate:MC type of kidney stone (85%)QRisk factors are hypercalciuria, hypercalcemia, hyperoxaluriaHave hard, small & jagged surfaceUric acid stones:5-10 % of all kidney stones, MC radiolucent urinary calculiQ, formed in acidic urinePatients with uric acid stones may have gout, myeloproliferative disorders or Lesch-Nehan syndrome (hyperuricemia)Uric Acid Stones ManagementCornerstone of treatment: Low purine diet hydration & alkalization of urineQAllopurinolQ (Inhibits conversion of hypoxanthine & xanthine to uric add)AcetazolamideQ (may be added if urine pH is <6.5)Struvite stones (Infection stones):Composed of calcium, ammonium, magnesium phosphate (Triple phosphate stones)QTend to grow in alkaline urineQ, especially with Proteus infection and fill whole of the PCS. forming staghorn calculiyQFormed in high urinary concentration of ammoniaMore common in womenQ (increased susceptibility for UTI)Most of the stag horn calculi are silentQ & cause progressive destruction of renal parenchymaQ.Increased tendency to form struvite calculi is seen in: Foreign body in the urinary' tract (Foley's catheter) & Neurogenic bladderQ /Bladder dysfunction/Bladder outlet obstructionStruvite stones ManagementComplete stone removal +Treatment of a metabolic abnormality' + Correction of any anatomic abnormalities contributing to stasisPCNL+ESWL (best treatment option)QAntibiotics to prevent stone recurrences or growth after operative procedureAcetohydroxamic acid (irreversible inhibitor of urease)Q decreases likelihood of precipitationLow calcium, low phosphorus diet.Upto 50% of patient have stone recurrences or UTI over 10 years follow upCystine:Extremely hard stone, formed in acidic urineRelatively resistant to fragmentation by ESWLOccur in cystinuria with typical "ground glass" appearance with a round smooth outlineQTypical benzene or hexagonal cystine crystalsQ in urine.Cystine Stones ManagementStone removalTo lower cystine concentration in urine (Low methionine diet & alkalization)QCystine complexing agents: D- PenicillamineQ & Alpha-mercaptopropionylglycine (MPG)QXanthine:Seen in xanthinuria, radioluscentQStones are smooth, brick red colored, round & show lamination on cross sectionQ.Management: High fluid intake (most effective therapy) & AllopurinolQIndinavir:A protease inhibitor used in AIDS patients, resulting in radioluscent calculiQ in 6% patients.Silicate: Associated with long term use of antacids containing silicaQTriamterene: Antihypertensive medication, leading to radioluscentQ stones