URINARY CALCULI POWERPOINT_EASY READABLE
- 1. URINARY CALCULI Presenter: Methusela Nsengiyumva – G/S Mmed-1 Moderator: Dr J Igenge (MD, Mmed Urologist)
- 2. Presentation outline •Introduction •Incidence •Risk factors •Pathophysiology •Causes of urinary calculi •Types of urinary stones •Diagnosis •Investigations •Differential diagnoses •Treatment of urinary calculi •Complications
- 3. Introduction • Urinary stones or calculi are concretions formed within the renal tract by the crystallization of one or more substances normally found within the urine. • The urinary tract stone disease has been a part of the human condition for millennia • Ureteral calculi almost always originate in the kidneys, although they may continue to grow once they lodge in the ureter.
- 4. THE INCIDENCE OF URINARY TRACT STONE DISEASE • The stone disease is rare in only a few areas, such as Greenland and the coastal areas of Japan. • Bladder calculi are more common than upper urinary tract calculi in the developing countries, but the opposite is true in developed countries. • The stone disease is a common disease in Middle-East and in Indian subcontinent and these differences of prevalence are believed to be environment and diet related.
- 5. Risk Factors • Family or personal history • Dehydration • Certain diets • Obesity
- 6. Risk Factors … • Digestive diseases and surgery: Gastric bypass surgery, inflammatory bowel disease or chronic diarrhea lead to effect on absorption of calcium and water • Other medical conditions e.g. renal tubular acidosis, cystinuria, hyperparathyroidism and repeated urinary tract infections also can increase risk of kidney stones • Certain supplements and medications E.g. vitamin C, dietary supplements, laxatives, calcium-based antacids and certain medications used to treat migraines or depression
- 7. PATHOPHYSIOLOGY OF UROLITHIASIS • The urinary tract stone disease is likely caused by two basic phenomena. First phenomenon is supersaturating of the urine by stone forming constituents, including calcium, oxalate and uric acid. The crystals or foreign bodies can act as nidus, upon which ions from the supersaturated urine form microscopic crystalline structures. Majority of renal calculi contain calcium.
- 8. Uric acid calculi and crystals of uric acid, with or without other contaminating ions, comprise the bulk of the remaining minority. Less frequent stone types include cystine, ammonium acid urate, xanthine, dihydroxyadenine and various rare stones related to precipitation of medications in the urinary tract. Calcium-based stones (especially calcium oxalate stones) likely have a more complex etiology.
- 9. PATHOPHYSIOLOGY OF UROLITHIASIS … The second phenomenon is most likely responsible for calcium oxalate stones, is deposition of stone material on a renal papillary calcium phosphate nidus, typically a Randall’s plaque (subepithelial deposits). • The calcium phosphate precipitates in the basement membrane of the thin loops of Henle, erodes into the interstitium and then accumulates in the subepithelial space of the renal papilla. • Randall’s plaques, eventually erode through the papillary urothelium.
- 10. • The stone matrix, calcium phosphate and calcium oxalate gradually deposit on the substrate to create a urinary calculus. • It was seen that the Randall’s plaques are always composed of calcium phosphate.
- 11. CAUSES OF UROLITHIASIS Currently, most of the research on the etiology and prevention of urinary tract stone disease has been directed towards the role of elevated urinary levels of • calcium, • oxalate • uric acid and • reduced urinary citrate levels, in stone formation.
- 12. Types of urinary stones 1. Oxalate Stone • Oxalate, a major component of most stones, is either produced endogenously by the enzymatic cleavage of glyoxylate to oxalic acid and glycine or by intestinal absorption. 2. Uric Acid Stone • Uric acid is a product of purine metabolism and is excreted in the urine • Low pH (an acid urine) and • High levels of urinary uric acid (hyperuricosuria).
- 13. Types of urinary stones 3. Cystine Stones Cystinuria is an inherited autosomal recessive defect in the renal tubular reabsorption of four amino acids; • Cystine • Ornithine • Arginine and • Lysine. Normal urinary cystine levels are less than 100 mg/24 hours
- 14. Types of urinary stones 4. Infection Stones (Struvite) • Magnesium ammonium phosphate (MgNH4PO4.6H2O) stones occur in the setting of persistently high urinary pH caused by urea splitting bacteria resulting in high ammonia production. • Alkaline pH greater than 7.2 markedly reduces the solubility of magnesium ammonium phosphate in urine, resulting in its precipitation. 5. Calcium Stones • Calcium oxalate, as either a monohydrate or dihydrate (less dense), is a major component of most urinary stones. • Calcium phosphate (appetite) is the second most common component of stones and is usually found in association with calcium oxalate. Both are highly insoluble salts in urine.
- 15. Diagnosis of Urinary Calculi • The magnesium, pyrophosphates and especially citrate are important inhibitors of stone formation in the urinary tract. • Low fluid intake, with a subsequent low volume of urine production, produces high concentrations of stone forming solutes in the urine An important environmental factor in kidney stone formation.
- 16. Diagnosis of Urinary Calculi… Nature of the tubular damage or dysfunction that leads to stone formation has not been characterized. The most common causes of stone disease may include • Hypercalciuria - Excess calcium in the urine • Hyperoxaluria – Excessive urinary excretion of oxalate • Hyperuricosuria - Excessive amounts of uric acid in the urine • Hypocitraturia - Urinary citrate excretion less than 320 mg (1.67 mmol) per day for adults, is a common metabolic abnormality in stone formers, occurring in 20% to 60%. • Low urinary volume. The other factors, such as high urinary sodium and low urinary magnesium concentrations, may also play a role.
- 17. Diagnosis of Urinary Calculi… Twenty-four hours urine profile, including appropriate serum tests of renal function, uric acid and calcium are needed to exclude the risk factors. Evidence of hypercalcemia should prompt follow-up with an intact parathyroid hormone (PTH) study to evaluate for primary and secondary hyperparathyroidism. The basic mechanism of stone formation is unclear in most cases, however, a number of factors have been identified • Metabolic abnormalities • Anatomical abnormalities • Infection • Idiopathic
- 18. Metabolic Abnormalities • Many people with stone have found to increase solute burden in their urine particularly when they become dehydrated. • Crystallization is encouraged by a mucoprotein complex, probably secreted by renal tubular cells. • Excess solutes are commonly found in the form of calcium oxalate, cysteine and urate, etc.
- 19. Anatomical Abnormalities • Microscopic anatomic abnormalities may be responsible for stone formation, intrarenal microconcretion may be found in some cases (Carr’s concretion). • Subepithelial papillary calcification may give rise to papillary calcification, which later slough and form stone. • All these changes are probably due to structural abnormality in nephron.
- 20. Anatomical Abnormalities… They include • Renal tubular ectasia or medullary sponge kidney • Obstruction of the ureteropelvic junction • Diverticula or cysts in the renal calyces • Ureteral stricture • Vesicoureteral reflux • Ureterocele and • Horseshoe kidney
- 21. Idiopathic Stone Formation • No abnormalities are found in this group of people, most of them form calcium oxalate calculi and many of them excrete alkaline urine. Infection • Staghorn calculi made of struvite (calcium, magnesium and ammonium phosphate) are formed by the urea splitting organism. Are branched stones that fill all or part of the renal pelvis and branch into several or all of the calyces.
- 22. Diagnosis of Urinary Calculi This is done through • History taking • Physical examination • Investigations
- 23. History • Patients with urinary calculi may report pain, infection or hematuria. • Small non-obstructing stones in the kidneys only occasionally cause symptoms. • If present, symptoms are usually moderate and easily controlled. • Urolithiasis in a patient who has got a single kidney may pass into acute renal failure if the ureter is blocked by a small stone in the ureter. • The passage of stones into the ureter with subsequent acute obstruction, proximal urinary tract dilation and spasm is associated with classic renal colic.
- 24. History … • Renal colic is characterized by undulating cramps and severe pain and is often associated with nausea and vomiting. • As the stone travels through the ureter, the pain moves from the flank to the lower abdomen, down to the groin and eventually to the scrotal or labial areas. • Associated irritative bladder symptoms are common when the stone is located in the distal or intramural ureter. • Patients with large renal stones known as staghorn calculi, are often relatively asymptomatic.
- 25. Physical Examination • The costovertebral angle tenderness is common (Murphy's punch sign, Pasternacki's sign, Giordano’s sign or Goldflam's sign); this pain can move to the upper or lower abdominal quadrant as a ureteral stone migrates distally. The specific location of tenderness does not always correlate with the exact location of the stone, although the calculus is often in the general area of maximum discomfort. • Others: Looks in pain and restless, fever, tachypnoea, tachycardic, hematuria.
- 26. Investigations Laboratory Studies Urinalysis • Urine is examined for oevidence of hematuria (RBC) and infection oPh • About 85% of patients with urinary calculi exhibit gross or microscopic hematuria • Absence of hematuria does not rule out urinary calculi
- 27. Investigations … Complete Blood Cell Count • An elevated white blood cell count • The serum electrolytes, creatinine, calcium, uric acid, PTH and phosphorus • High serum uric acid level may indicate gouty diathesis or hyperuricosuria • Hypercalcemia suggests either renal leak hypercalciuria (with secondary hyperparathyroidism) or primary hyperparathyroidism.
- 28. Investigations … Imaging Studies Non-contrast Computed Tomography • A helical computed tomography (CT) scan without contrast material • If positive: kidneys, ureters and bladder (KUB) radiography is recommended to assist in follow-up and planning. • Multislice CT without intravenous contrast material CT scanning is the most sensitive clinical imaging modality for calcifications • The calculi that are radiolucent on a plain radiograph are clear and distinct on a CT scan as opaque shadow.
- 29. Investigations … • Currently, most institutions have replaced intravenous urography (IVU) with CT for the assessment of urinary tract stone disease, especially for acute renal colic. • Plain radiography to non-contrast CT scanning increases the value of the study, by allowing visualization of the size, shape and relative position of the stone. • The lucent stone that is not visible on the KUB radiograph but is clearly visible on the CT scan may indicate a uric acid calculus. • It may suggest a different diagnosis and therapy (allopurinol and/or urinary alkalinization) than for a calcium stone. • For these reasons, many institutions routinely perform KUB radiography whenever renal colic non-contrast CT scanning is performed.
- 30. Investigations … Plain Abdominal Radiography The plain KUB or plain abdominal is useful for assessing • total stone burden • the size • shape and • location of urinary calculi in most patients Helpful in determining the progress of the stone without the need for more expensive tests with greater radiation exposures.
- 31. Investigations … Renal Ultrasonography • The renal ultrasonography by itself is frequently adequate to determine the presence of a renal stone. • The stones are easily identified with renal ultrasonography but not visible on the plain radiograph may be a uric acid or cystine stone, which is potentially dissolvable with urinary alkalinization therapy. • The ureteral calculi, especially in the distal ureter and stones smaller than 5 mm are not easily observed with ultrasonography.
- 32. Investigations … Intravenous Urography (IVU) • Intravenous urography was the standard imaging tool for determining the size and location of urinary calculi up until recently. • Intravenous urography is no longer the standard for use.
- 35. TREATMENT … Medical Treatment Acute colic should be treated urgently Stone causing complications need to be taken out and further stone formation should be prevented The stone prevention should be considered most strongly in patients who have risk factors for increased stone activity, including: • Stone formation before the age of 30 years, • Family history of stones • Multiple stones at presentation • Renal failure and • Residual stones after surgical treatment
- 36. Medical Treatment … General Guidelines for Emergency Management • The ureteral colic, determines the presence or absence of obstruction • The obstruction in the absence of infection can be initially managed with analgesics and with other medical measures to facilitate passage of the stone • If the obstruction is minimum and no feature of infection, tamsulosin and the calcium channel blocker may help the stone to be passed out if the diameter of the stone is smaller than 5mm • When obstruction and infection are present, emergent decompression of the upper urinary collecting system is required by a percutaneous nephrostomy
- 37. Surgical Treatment Primary indications for surgical treatment (3) Contraindications for definitive stone manipulation (2) 1. An obstructed and infected collecting system secondary to stone disease, is treated best by percutaneous nephrostomy (PCN) under local anesthesia
- 38. Approaches 2. Extracorporeal Shockwave Lithotripsy (ESWL) Today most urinary tract calculi that require treatment are currently managed with this ESWL, which is the least invasive of the surgical methods of stone removal Some models of new lithotripters that have two shock heads, which deliver a synchronous or asynchronous pair of shocks to increase the efficiency of shock wave delivery Contraindications and biological effects of extracorporeal shockwave lithotripsy are • Urinary sepsis • Obstruction • Stone larger than 2.5 cm • Stone in ureter (relative contraindication)
- 39. ESWL video
- 40. Approaches … 3. Ureteroscopy • The ureteroscopic manipulation of a stone
- 41. Approaches … Percutaneous Nephrolithotomy • Percutaneous nephrolithotomy (PCNL) allows fragmentation and removal of large calculi from the kidney and ureter and is often used for the many ESWL failures • Correct puncture of the pelvicaliceal system with a PCN needle allows a guidewire in to the PCS tract and in to the ureter • The tract is dilated gradually over the guide wire by appropriate dilators until an Amplatz sheath is inserted • Through the sheath the nephroscope allows the visualization, fragmentation and removal of the stone fragments
- 42. Approaches … Other surgery Open surgery Laparoscopic or Robotic surgery may be used only if all other less invasive procedures fail.
- 43. Urinary tract calculi - prophylaxis … - prognosis … - follow up …
- 44. COMPLICATIONS OF STONE DISEASE Complications of urinary tract stone disease may include: •The abscess formation • Progressive deterioration of renal function • Genitourinary fistula formation • Ureteral stricture • Urosepsis.
- 45. References • Principles and Practice of Urology, MA Salam 2nd edition, Volume 1 & 2 • Internet search
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Editor's Notes
- #21: Urea splitting organisms i/c proteus, klebsiella, pseudomonas and coagulase neg. staphy.
- #25: In US, Murphy (surgeion) sign 1884; In Post-Soviet states and Eastern Europe, Pasternacki’s sign (internist) 1888; in Italy, Giordano’s sign (physician); in Poland, Goldflam’s sign (neurologist) 1900
- #27: Note: When the serum calcium level is elevated: Serum PTH levels should be obtained. Twenty-four hours urine collection for levels of pH, calcium, oxalate, uric acid, sodium, phosphorus, citrate, magnesium, creatinine and Total volume should be estimated.
- #36: Tamsulosin – Selective alfa blocker: Relaxation ofureteric smooth muscle Nifedipine – CCB: Relieves the colic pain