Nephrolithiasis - urinary stones

Common disorder with an annual incidence of 0.1% to 0.5%.
The peak age at onset is 20 to 30 years
Men > Women ( until 50s )
Wide geographic variations exist, due to differences in diet and water composition, as well as ambient and sunlight exposure. 5-9% in Europe 20% in Saudi Arabia

1. Nephrolithiasis Urinary Stone Disease Musa Abu Sabha

2. Outlines General Characteristics Common types of kidney stones Clinical Presentation Diagnosis Treatment Prevention Prognosis

3. General Characteristics Epidemiology Common disorder with an annual incidence of 0.1% to 0.5%. The peak age at onset is 20 to 30 years Men > Women ( until 50s ) Wide geographic variations exist , due to differences in diet and water composition, as well as ambient and sunlight exposure . 5-9% in Europe 20% in Saudi Arabia

4. General Characteristics Sites of obstruction Ureterovesicular junction -most common site of impaction Calyx of the kidney Ureteropelvic junction Intersection of the ureter and the iliac vessels (near the pelvic brim)

5. General Characteristics : Risk Factors High amount of stone substance in blood: Hypercalcemia Hyperuricemia Low urine volume Increases concentration of urine substances Low fluid intake-most common and preventable risk factor Diuretics In general, hydration lowers risk of stones

6. General Characteristics : Risk Factors Conditions Increase risk of specific type of stone formation ( gout [hyperuricemia], Crohn disease [hyperoxaluria], hyperparathyroidism [ hypercalciuria ] Dietary factors —low calcium and high oxalate intake, both of which lead to hyperoxaluria (high calcium intake itself is rarely associated with increased stones) Positive family history has a risk 2.5 % .

7. General Characteristics Types of Stones 1.Calcium 2.Struvite 3.Urate 4.Cystine

8. Stone type Pt. Factors Radiographic appearance Crystal morphology Calcium (oxalate, phosphate) (> 75% of stones) Hyperparathyroidism High-sodium, high-oxalate diet; malabsorption (oxalate) Renal tubular acidosis (phosphate) Small Radiopaque Octahedron or envelope (oxalate) Wedge or rosette (phosphate Magnesium ammonium phosphate (struvite) (15°/o of stones Upper tract infection with urease-producing organisms ( eg , Proteus Large Radiopaque Rectangular/prism Uric acid (5°/o-8°/o of stones) • Gout • Diabetes/metabolic syndrome Myeloproliferative disorders Small Radiolucent • Yellow/brown • Rhomboidal Common types of kidney stones

9. Calcium stones (most common form) Account for 80% to 85% of urinary stones ; composed of calcium oxalate or calcium phosphate (less often) or both Bipyramid or biconcave ovals Radiodense (i.e., visible on an abdominal radiograph) Secondary to hypercalciuria and hyperoxaluria , which can be due to a variety of causes. Acidic urine pH promotes calcium oxalate stone formation while a basic pH induces calcium phosphate stones

10. These crystals have the typical octahedral morphology of calcium oxalate dihydrate crystals.

11. Magnesium ammonium phosphate 2 nd MC Type Radiodense ( visible on KUB ); rectangular prisms Occur in patients with recurrent UTIs due to urease-producing organisms ( Proteus, Klebsiella , Serratia , Enterobacter spp. ) They are facilitated by alkaline urine : urea-splitting bacteria convert urea to ammonia, thus producing the alkaline urine. The resultant ammonia combines with magnesium and phosphate to form struvite calculi , which may involve the entire renal collecting system .

12. Struvite Crystals :coffin lid-appearance

13. Staghorn Calculi

14. Uric acid stone Flat square plates Radiolucent (cannot be seen on KUB require CT, ultrasound, or IVP for detection. Associated with: hyperuricemia, secondary to gout or to chemotherapeutic treatment of leukemias and lymphomas with high cell destruction. The release of purines from dying cells leads to hyperuricemia. A persistently acidic urine pH (<5.5) promotes uric acid stone formation . More common in hot areas

15. A clump of three clear, diamond-shaped (rhomboid) crystals is visible

16. Cystine Stones Rare type of stone Seen in children with cystinuria Tubular defect  cannot absorb cysteine. Only clinical manifestation is kidney stones Radiolucent Not visible on X-ray Can see with CT scan Hexagon-shaped crystals are poorly visualized. Rotten Egg Odor of urine Child With recurrent stones and positive family history

17. Clinical Presentation Sudden onset of colicky Flank pain associated with : Hematuria ( 90% of cases ) Nausea and Vomiting Dysuria, frequency, and urgency More common in  distal  ureteral stones . These symptoms may mimic  UTI  or actually be signs of a concurrent  UTI . The presence of  FEVER  and chills (usually absent in an uncomplicated nephrolithiasis) may help to distinguish nephrolithiasis from an upper  UTI .

18. Clinical Presentation Patients are usually unable to sit still and move around frequently. Stone location could be expected based on radiation: UPJ : costovertebral angle. Mid ureter : RIF ( mimic Appendicitis & Ovarian torsion) Distal part : Female( labia majora ) Male ( testis) Small  Kidney  stones may also be asymptomatic and detected incidentally

19. Diagnosis Initial diagnostic workup includes: Imaging studies to locate the stone. laboratory Tests to determine   Kidney  function and assess for UTI.

20. Diagnosis : Labs Urinalysis : Hematuria plus pyuria indicates a stone with concomitant infection . Examine the urinary sediment for crystals. Determine the urinary pH Urine culture—obtain if infection is suspected Serum chemistry—BUN, Cr and electrolytes

21. Diagnosis : Imaging Best initial Test : noncontrast spiral CT scan All stones are visible THE GOLD STANDERED

22. There is a hyperdense concrement (red circle) in the left renal pelvis, which is a kidney stone. The renal pelvis is not dilated, indicating that the kidney stone is not currently causing an obstruction.

23. Diagnosis : Imaging Best initial in pregnancy : abdominal US Can detect hydronephrosis Can be used if the CT unavailable False-negative results are common in early obstruction.

24. Transhepatic longitudinal ultrasound of the right kidney: There is a round, hyperechoic lesion (green area) at the upper pole of the kidney in the renal parenchyma, which shows a dorsal acoustic shadow (white area) and is most likely a kidney stone. The central areas of the kidney show, as far as can be seen in this image, no dilation, which indicates no obstruction.

25. Diagnosis : Imaging Rarely used : KUB : Can not detect hydronephrosis Miss small and radiolucent stones IV Pyelogram Most useful test for defining degree and extent of urinary tract obstruction This is usually not necessary for the diagnosis of renal calculi.

26. Upper ureteral calculus with right-sided urinary obstruction

27. Treatment Determine if it is a complicated case, including: High-grade hydronephrosis or Infected hydronephrosis Urosepsis, AKI, intractable pain, or vomiting

28. Treatment Treatment depends on the size of the stone: < 5 mm: often pass spontaneously . < 10 mm :. likelihood of spontaneous passage increases with alpha-blocker or CCB therapy > 10 mm : often require shock wave lithotripsy or ureterorenoscopy > 20 mm : percutaneous nephrolithotomy

29. Treatment : Medical Therapy General measures (for all types of stones): Analgesia: IV morphine, parenteral NSAIDS (ketorolac) Vigorous fluid hydration-beneficial in all forms of nephrolithiasis Alpha-1 blockers ( tamsulosin ) may be used to facilitate stone passage Antibiotics-f UTI is present Most patients are treated as Outpatient . Indications for hospital admission include : • Pain not controlled with oral medications • Anuria (usually in patients with one kidney) • Renal colic plus UTI and/or fever • Large stone (> 1cm) that is unlikely to pass spontaneously

30. Treatment : Medical Therapy Specific measures (based on severity of pain): Mild to moderate pain : high fluid intake, oral analgesia while waiting for stone to pass spontaneously (give the patient a urine strainer) Severe pain (especially with vomiting) Prescribe IV fluids and pain control. Obtain a KUB and an IVP to find the site of obstruction. If a stone does not pass spontaneously after 3 days, consider urology consult.

31. Treatment : Surgical intervention Indications Stones > 10 mm Complicated stones (e.g., concomitant high-grade obstruction, urosepsis , impending AKI, intractable pain, vomiting) After failed medical therapy, relapse, recurrent infection, or if preferred by the patient (i.e., patients who decline conservative treatment) Failure to pass stone spontaneously after 4–6 weeks

32. Extracorporeal shock wave lithotripsy Noninvasive method enabling stone fragmentation using an acoustic pulse. Treatment option for renal and proximal ureteral stones > 10 mm Lowest complication rate but often repeated SWL is necessary for patients with residual stones Stones should be clearly visible on x-ray and/or ultrasound Contraindicated in cases of untreated UTI , during pregnancy , and in patients with bleeding diathesis Not preferred in  morbidly obese  patients  

33. Extracorporeal shock wave lithotripsy

34. Extracorporeal shock wave lithotripsy

35. Ureterorenoscopy A transurethral endoscopic procedure used to visualize the urinary tract up to the renal pelvis for retrieval or destruction of urinary stones or sampling of biopsies . Treatment option for ureteral stones >10 mm ( especially mid or distal ureteral stones ) and very large renal stones ≥ 20 mm For stones in the proximal ureter, flexible URS is usually preferred , whereas for distal stones, rigid or semirigid URS is often superior Greatest stone-free rate

36. Ureterorenoscopy

37. Ureterorenoscopy

38. Percutaneous nephrolithotomy Treatment option for renal stones > 20 mm Involves : the puncture of the renal pelvis calyx under sonographic and radiological guidance introduction of the nephroscope and instruments fragmentation of stones and retrieval of the fragments

39. Percutaneous nephrolithotomy

40. Percutaneous nephrolithotomy

41. Ureteral Stenting or Percutaneous Nephrostomy Stenting can be performed following endoscopic stone removal and in the case of ureteral injury, evidence of ureteral stricture, or large residual stones. Nephrostomy can be used for decompression in the case of severely obstructed or infected pyelon (in these patients, definite stone treatment should be delayed until the infection has resolved).

42. Ureteral Stenting or Percutaneous Nephrostomy

43. Ureteral Stenting or Percutaneous Nephrostomy

44. Pyelolithotomy / ureterolithotomy Laparoscopic or open stone removal Only considered in rare cases where other interventional methods have previously failed or are likely to do so (e.g ., because of complex staghorn stones )

45. Pyelolithotomy / ureterolithotomy

46. Pyelolithotomy / ureterolithotomy

47. Prognosis 50% of patients may have a new episode of nephrolithiasis within 10 years.

48. Prevention Hydration: sufficient fluid intake (≥ 2.5 L/day) The dietary recommendations for patients with renal calculi are: 1. Increased fluid intake 2. Decreased sodium intake 3. Normal dietary calcium intake Pharmacologic measures • Thiazide diuretics reduce urinary calcium and have been found to lower recurrence rates, especially in patients with hypercalciuria . • Allopurinol is elective in preventing recurrence in patients with high uric acid levels in the urine

49. Quiz A 50-year-old man arrives to the emergency department with severe acute colicky flank pain and hematuria. The patient has a long- standing history of gout. Which of the following is true regarding the type of kidney stone the patient likely has ? ( A) Most are radiopaque . ( B) They are often seen in patients with hyperparathyroidism. ( C) Shock wave lithotripsy is not helpful . ( D) Sodium bicarbonate administration is beneficial . ( E) Suppressive antibiotics are helpful in prevention.

50. Quiz Answer D. The most likely diagnosis in a patient with a past medical history significant for gout presenting with acute colicky pain and hematuria is nephrolithiasis secondary to uric acid renal stones. Unlike other types of renal stones, this type is radiolucent and will not show up on X-ray (A). Patients with gout are at increased risk for developing uric acid stones. Sodium bicarbonate will alkalinize the urine to achieve a urinary pH of 6–6.5, as this would provide optimal conditions for dissolution of uric acid stones. Patients with hyperparathyroidism are more prone to developing calcium oxalate renal stones (B). Suppressive antibiotics should be considered in the case of struvite stones secondary to recurrent urinary tract infections (E). Shock wave lithotripsy may be added as an adjunct to urine alkalinization to further improve the stone-free rate (C).

51. Quiz A 78-year-old man arrives to the emergency department with colicky flank pain for the past 4 days that is now accompanied by nausea, vomiting, fever, and hematuria. Past medical history is significant for congestive heart failure and prior myocardial infarc - tion . On physical examination, the patient has a blood pressure of 100/60 mmHg, temperature of 38.0 °C, and a heart rate of 110/min. Urinalysis reveals 150 RBC/ hpf and 20 WBC/ hpf . Laboratory tests demonstrate a WBC of 15 × 103/ μL (normal 4.1–10.9 × 103/ μL ) with 10% bands. Imaging demonstrates a 10-millimeter stone lodged in the ureterovesical junction with dilation of the right renal calyx. Broad-spectrum antibiotics are administered intravenously. What is the best next step in management ? (A) Percutaneous nephrostomy tube ( B) Open nephrostomy ( C) Shock wave lithotripsy ( D) Placement of a ureteral stent ( E) Admit to ICU for close monitoring

52. Quiz Answer A Ureteral obstruction in association with sepsis requires emergent urinary decompression . This is most expeditiously achieved via a percutaneous nephrostomy tube. Shock wave lithotripsy is unlikely to relieve the obstruction caused by a stone of this size (C). Open nephrostomy is rarely indicated (B). Close monitoring in the ICU as the sole management plan would be inappropriate for a patient with sepsis secondary to a blocked ureter (E). Hydration, analgesics, and bed rest would be appropriate for an uncomplicated and small renal stone without accompanying hydronephrosis. A ureteral stent is an option; however, it is a more time-consuming procedure that will not be as expeditious in a septic patient compared to a percutaneous nephrostomy (D).

53. Quiz A 37-year-old obese woman arrives to the emergency department with left flank pain and hematuria. She has never experienced these symptoms before. Her past medical history includes Crohn’s which has been controlled with mesalamine. She is afebrile with a blood pressure of 130/84 mmHg and a pulse of 104/min. Physical examination reveals a laparotomy scar in her right lower quadrant. She is given analgesics for pain control. What is the most likely etiology of her acute symptoms? Gallstones Hypercalciuria Increased absorption of oxalate Urease-producing bacteria Mesalamine

54. Quiz Answer C Patients with Crohn’s that present with flank pain and hematuria should raise suspicion for nephrolithiasis secondary to hyperoxaluria. Her laparotomy scar suggests that she had an ileocolic resection, which would predispose her to fat malabsorption as the terminal ileum is the principal site for fat absorption. In healthy patients, intraluminal calcium binds to oxalate to prevent its reabsorption from the GI tract. In patients with increased amounts of fat in the GI lumen (e.g., Crohn’s status-post ileocolic resection ), the calcium preferentially binds to fat leaving the unbound oxalate available for reabsorption and, thus, increases the risk of developing calcium oxalate renal stones. Hypercalciuria would have been the most likely etiology had she not had Crohn’s (B). Urease-producing bacteria are associated with struvite stones and recurrent urinary tract infections (D). Gallstones do not cause flank pain or hematuria, and mesalamine is not a known risk factor for the development of renal stones (A, E).

55. Quiz A 52-year-old male is brought to the hospital by his wife with complaints of intense pain that started around his right flank and now radiates to his right groin. He said that his urine appears pink. He appears to be in severe pain and is unable to remain still during examination. His abdominal exam is unremarkable. Urinalysis reveals 100 RBC/ hpf . IV fluids and analgesics are administered. Which of the following is the most appropriate imaging? Helical CT scan of the abdomen and pelvis without contrast Helical CT scan of the abdomen and pelvis with contrast Upright abdominal X-ray Intravenous pyelogram (IVP) Renal ultrasound

56. Quiz Answer A The presentation is consistent with nephrolithiasis. Initial management should focus on IV fluid hydration and analgesia. Recommended imaging includes a KUB (a supine X-ray of the abdomen) and a non-contrast CT of the abdomen and pelvis. The use of contrast may interfere with visualization of the stone (B). An upright abdominal X-ray is used to look for air-fluid levels in association with a small bowel obstruction or free air under the diaphragm (C). Such a film cuts off the pelvis and as such will miss many ureteral stones. IVP has largely been replaced by CT (D). Renal ultrasound may be used in pregnant patients but may miss stones; it is also used to look for hydronephrosis as an adjunct to KUB (if a CT scan is not obtained) (E).

57. Too many things to keep in mind

58. Thank You! Prepared by : Musa Abu Sabha