Renal Calculi: Etiology, Types, and Treatment PDF

***RENAL CALCULI*** **\ Etiology\ **It is complex, summary of current opinion: *1.Dietetic\ *Deficiency of vitamin A causes desquamation of epithelium forming a nidus on which a stone is deposited. This mechanism is probably active in the formation of bladder calculi.\ *2.Altered urinary solutes a...

***RENAL CALCULI*** **\ Etiology\ **It is complex, summary of current opinion: *1.Dietetic\ *Deficiency of vitamin A causes desquamation of epithelium forming a nidus on which a stone is deposited. This mechanism is probably active in the formation of bladder calculi.\ *2.Altered urinary solutes and colloids\ ***Dehydration** concentrates urinary solutes until they precipitate Reduction of urinary colloids, which adsorb solutes, or mucoproteins, which chelate calcium, might tend to crystal and stone formation.\ *3.Decreased urinary citrate\ *The presence of citrate in urine, 300--900 mg per 24 hours, as citric acid, keeps relatively insoluble calcium phosphate and citrate in solution.\ *4.Renal infection\ *Infection favor's the formation of urinary calculi. Clinical and experimental stone formation are common when urine is infected with urea-splitting streptococci, staphylococci and especially *Proteus* spp.\ *5.Inadequate urinary drainage and urinary stasis\ *Stones are liable to form when urine is static.\ *6.Prolonged immobilization\ *Immobilization is liable to result in skeletal decalcification and an increase in urinary calcium favoring the formation of calcium phosphate calculi. *7.Hyperparathyroidism\ *Hyperparathyroidism leading to hypercalcemia and hypercalciuria is found in 5%. A parathyroid adenoma should be removed before definitive treatment for the urinary calculi. ***Types of renal calculus*** **\ ***1.Oxalate calculus (calcium oxalate):\ *Oxalate stones are irregular with sharp projections. A calcium oxalate monohydrate stone is ***hard and*** ***radiodense.***\ *2. Phosphate calculus:\ *A phosphate calculus (calcium phosphate often with ammonium magnesium phosphate (struvite) is smooth and dirty white. It grows in alkaline urine, especially when urea-splitting *Proteus* organisms are present. The calculus may enlarge to fill most of the collecting system, forming a stag-horn calculus.\ *3. Uric acid and urate calculi:\ *These are hard, smooth and often multiple and multifaceted. Pure uric acid stones are ***radiolucent***. CT important to diagnose it. Most uric acid stones contain some calcium, so they cast a faint radiological shadow.\ *4. Cystine calculus\ *An uncommon congenital error of metabolism leads to cystinuria. Cystine stones are often multiple and may grow to form a cast of the collecting system. Cystine stones are ***radio-opaque and very hard***. ***Clinical features*\ **Renal calculi are common. Approximately 50 per cent of patients present between the ages of 30 and 50 years. The male--female ratio is 4:3. ***Renal failure*** may be the first indication of bilateral silent calculi, although secondary ***infection*** usually produces symptoms first. *Pain\ *Pain occurs in 75 per cent of people with urinary stones. Fixed renal pain occurs in the renal angle, the hypochondrium, or in both. Ureteric colic is an agonizing pain passing from the loin to the groin. Pain resulting from renal stones rarely lasts more than 8 hours in the absence of infection. There is no pyrexia. Ureteric colic is often caused by a stone entering the ureter but it may also occur when a stone becomes lodged in the pelviureteric junction. The severity of the colic is not related to the size of the stone. **Ureteric colic\ ** Severe exacerbations on a background of continuing pain\ Radiates to the groin, penis, scrotum or labium as the stone\ progresses down the ureter\ Severity of pain is not related to stone size\ Haematuria is very common\ There may be few physical signs, tender bimanual exam. Kidney. **Abdominal examination\ **During an attack of ureteric colic, tenderness present, Percussion over the kidney produces a stab of pain and there may be tenderness on gentle bimanual palpation. Hydronephrosis or pyonephrosis leading to a palpable loin swelling is rare. *Haematuria\ *Haematuria, usually small in amount, is common and sometimes is the only symptom of stone disease. *Pyuria (renal infection)\ *Infection of kidney is common complication of obstruction, and a septicemia can quickly develop, ***Stones may cause pyuria by irritating the urothelium even in the absence of infection.*** **Investigation of suspected urinary stone disease:** **\ ***X-ray\ *The 'KUB' film shows the kidney, ureters and bladder. About 80-85%, of renal stone are radiopaque, visualized in KUB. **Opacities on a plain abdominal radiograph that may be confused with renal calculus:** Calcified mesenteric lymph node\ Gallstones or concretion in the appendix\ Tablets or foreign bodies in the alimentary canal.\ Phleboliths -- calcification in the walls of veins, especially in the pelvis\ Ossified tip of the 12th rib\ Calcified tuberculous lesion in the kidney\ Calcified adrenal gland *CT scan:\ *CT, preferably spiral, has become the mainstay of investigation of acute ureteric colic. but non-contrast CT- scan is the main stay for diagnosis of urolithiasis. *Excretion urography\ *IVU will establish the anatomy of urinary passages and presence and position of a calculus and give a hint about function of the other kidney. *Ultrasound scanning\ *Ultrasound scanning is of value in locating stones for treatment by extracorporeal shock wave lithotripsy (ESWL). ***treatment of urinary calculi*:** *A. Conservative management***\ ***\ *Calculi smaller than 0.5 cm pass spontaneously unless they are impacted. Surgical intervention should be avoided. Small renal calculi may cause symptoms by obstructing a calyx or acting as a focus for secondary infection that need urgent intervention. Most can be safely observed until they pass. *\ \ * *B. Modern methods of stone removal* Kidney stones: Most stones should be treated by minimal access and minimally invasive when the stone larger than 0.5 mm techniques. preoperative treatment with Antibiotic treatment starts before surgery and continues afterwards. 1.Extracorporeal shock wave lithotripsy:\ stones disintegrate under the impact of shock waves produced by the ESWL machine. The shocks may be aimed by ultrasound or x-ray imaging. by using special frequency and power, can be given without general anesthesia with minimal pain and may use analgesia or sedative treatment. Ureteric colic is common after ESWL, and the patient needs analgesia, usually in the form of a non-steroidal anti-inflammatory drug. Bulky stone fragments may impact in the ureter, causing obstruction. To avoid this, a JJ stent should be placed in the ureter to drain the kidney while stone fragments pass. Occasionally, impacted fragments have to be removed ureteroscopically.\ The principal complication of ESWL is infection. So, prophylactic antibiotics before ESWL. If obstructed system should be decompressed by a ureteric stent or percutaneous nephrostomy before treatment.\ The clearance of stone from the kidney will depend upon the consistency of the stone and its site. The clearance of stone fregments, after ESWL depending on the type of stone , site, and size. 2.Percutaneous nephrolithotomy (PNL): **\ Endoscopic instruments** are passed into the kidney by a percutaneous technique. Small stones may be grasped under vision and extracted whole. Larger stones are fragmented by an ***ultrasound, laser or electrohydraulic*** ***probe*** and removed in pieces. The aim is to remove all fragments. A nephrostomy drain is left in the system when the procedure is complete. This\ decompresses the kidney and allows repeated access if necessary.\ *Percutaneous nephrolithotomy is sometimes combined with ESWL in the treatment of complex (stag-horn) calculi.* Complications of percutaneous nephrolithotomy include: \(1) haemorrhage from the punctured renal parenchyma; \(2) perforation of the collecting system with extravasation of saline irrigant; (3) perforation of the colon or pleural cavity during placement of the percutaneous track. 3\. retrograde intrarenal surgery (RIRS): Special new technique using flexible uretro-renoscopy, passing through urethra reaching the renal pelvis guided sometime by fluoroscopy, using laser fiber for destruction renal stones. It is indicated when small stone less tha15 mm diameter, or small stones not responding to ESWL or small stone in lower calyx. Open surgery for renal calculi\ Operations for kidney stone are usually performed via a loin or lumbar approach. It is indicated, when it large stone as staghorn stone, or failure of previous procedures m or if associated with special congenital anatomy of the kidney or body deformity as kyphosis, or scoliosis. Pyelolithotomy\ indicated if the stones in the renal pelvis, by extraction of the stone from it. Extended pyelolithotomy: by doing wide incision to renal pelvis for stone extraction. or Nephrolithotomy: (incisions into the renal parenchyma) to clear the kidney. Sometime Partial nephrectomy is sometimes preferable for a stone in the lowermost calyx with infective damage to the adjacent parenchyma.\ A functionless kidney destroyed by stone disease may do nephrectomy. Treatment of bilateral renal stones\ Usually the kidney with better function is treated first, unless the other kidney is more painful or there is pyonephrosis which needs urgent decompression. ***Prevention of recurrence***\ Ideally, stone formers should be investigated to exclude metabolic factors, with, and the urine should be screened for infection. The following investigations are appropriate in bilateral and recurrent stone formers:\ serum: for calcium, parathyroid hormone for hyperparathyroidism;\ serum uric acid;\ 24-hour collection :for urinary urate, calcium and phosphate , cystine , oxalate ,also for citrate and magnesium.\ analysis of stone. ***\*Dietary advice is not usually helpful in avoiding stone recurrence in people who have a balanced diet***. \*Patients with hyperuricemia should avoid red meats, offal and fish, which are rich in purines, and should be treated with allopurinol. \*should drink plenty water to keep their urine dilute. \*Drug treatment is largely ineffective except in those few patients who are shown to have idiopathic hypercalciuria. \* a calcium-restricted diet reduces urinary calcium. \* ***Stones are more common in those who have had a previous stone. Unless there is a specific biochemical abnormality,*** ***high fluid intake is the best prophylactic measure*** **URETERIC CALCULUS** **\ A stone in the ureter usually comes from the kidney. Most pass spontaneously.** **Clinical features\ **A stone passing down the ureter often causes intermittent attacks of ureteric colic.\ *Ureteric colic\ *The waves of ***agonizing loin pain*** are typically referred to the groin, external genitalia and the anterior surface of the thigh. As the stone enters the bladder, the pain can be referred to the tip of the penis. *stone Impaction:\ *There are five sites of narrowing where the stone may be arrested. **1.** Ureteropelvic junction**\ 2.** Crossing the iliac artery\ **3.** Juxtaposition of vas deferens or broad ligament**\ ** **4.** Entering the bladder wall**\ 5.** Ureteric orifice.**\ ** An impacted stone causes a more consistent dull pain, often in the iliac fossa. Distension of the renal pelvis due to obstruction may cause loin pain. The stone may become embedded as the adjacent ureteric wall becomes eroded and edematous as a result of pressure ischemia. Perforation of the ureter and extravasation of urine is a rare complication.\ Severe renal pain subsiding after a day or so suggests complete ureteric obstruction. If obstruction persists after 1--2 weeks, the calculus should be removed to avoid pressure atrophy of the renal parenchyma. *Haematuria\ *Almost all ureteric colic is associated with transient microscopic haematuria. Serious bleeding is uncommon and should suggest clot colic. *Abdominal examination\ *There is tenderness on the course of the ureter. ***The presence of haematuria does not rule out appendicitis because an inflamed appendix can give rise to a local ureteritis leaking some red cells into the urine.*** ***The patient with acute ureteric colic is usually in greater pain and less ill\ than one with appendicitis or acute cholecystitis.*** **Imaging for diagnosis:** **\ **KUB: Most urinary calculi are radio-opaque. Stones are difficult to see if small or obscured by bowel contents or nearby bones. IVU while the patient has pain can confirm the diagnosis, there will probably be little or no, excretion on the affected side In ureteric colic. spiral CT is preferable.\ \ Cystoscopy is not indicated for diagnosis. Sometime ureteroscopy my indicated as diagnostic and therapeutic. **Treatment\ ***Pain\ *Non-steroidal anti-inflammatory drugs, such as diclofenac and indomethacin, have replaced opiates as the first line of treatment for renal colic. The value of smooth muscle relaxants, such as propantheline (Pro-Banthine), is debatable.\ *Removal of the stone\ *Expectant treatment is appropriate for small stones likely to pass naturally. If the patient is not disabled by recurrent attacks of colic, progress can be followed by x-rays every 6--8 weeks. **Indications for surgical removal of a ureteric\ calculus\ **\* Repeated attacks of pain and the stone is not moving\ \*Stone is enlarging\ \*Complete obstruction of the kidney\ \*Urine is infected\ \*Stone is too large to pass\ \*Stone is obstructing solitary kidney or there is bilateral\ obstruction \*or arrested stone in ureter with partial obstruction 6 weeks. Endoscopic stone removal\ 1.Dormia basket\ by use wire baskets under image intensifier control has been.\ There is a danger of ureteric injury even with small stones. now use it with ureteroscopy guide. 2.Ureteric meatotomy\ Endoscopic incision with a diathermy knife will enlarge the opening and free a stone lodged in the intramural ureter. 3.Ureteroscopic stone removal\ A ureteroscope is introduced transurethrally across the bladder into the ureter to remove stones impacted in the ureter, under direct vision are fragmented using an electrohydraulic ,pneumatic or laser lithotripter. 4.Push bang\ A stone in the middle or upper part of the ureter can often be flushed back into the kidney using a ureteric catheter. A J-stent secures the calculus in the kidney for subsequent treatment with ESWL. A flexible fiberoptic ureteroscope can be used for laser destruction of calculi in the renal collecting system or ureter and to retrieve small stones from the kidney. 5.Lithotripsy *in situ\ *A stone in a part of the ureter that can be identified by the imaging system of the lithotripter can be fragmented *in situ*. Using ESWL, This form of treatment is not appropriate if there is complete obstruction or if the stone has been impacted for a long time. *6.Open surgery\ *Ureterolithotomy\ rarely used now days unless failure of previous option of treatment or if associated with anatomical abnormality. Dr. Mohammed R. Judi Jalo Professor of urology 2024-2025